Association between Liver Metastases and Treatment Response in Patients with Metastatic, Microsatellite Stable Colorectal Cancer Treated with Radiation Therapy and Dual Immune Checkpoint Blockade

PURPOSE/OBJECTIVE(S)

Most patients with metastatic colorectal cancer (CRC) have microsatellite stable (MSS) disease with a limited response to immune checkpoint inhibitors (ICIs). In our phase 2 trial (NCT03104439), 27 patients with metastatic MSS CRC received ipilimumab, nivolumab, and RT (24 Gy/3 fractions) on C2D1 with a disease control rate (DCR) of 37% (10/27) and overall response rate (ORR) of 15% (4/27). Our follow up phase 2 study with ipilimumab, nivolumab, and RT moved to C1D1 (NCT04361162) showed a DCR of 33% (10/30) and an ORR of 13% (4/30). Clinical and preclinical data suggest liver metastases are less responsive to systemic ICIs and complementary liver-directed RT can potentially overcome this effect. To address this, we investigated the association between liver metastases and response rates among patients treated with and without liver-directed RT in a pooled analysis of our phase 2 studies of nivolumab and ipilimumab with RT.

MATERIALS/METHODS

In this pooled secondary analysis of two open-label, single-arm, phase 2 studies, eligible patients had metastatic MSS CRC, ECOG PS 0-1, and progressed on at least one line of chemotherapy. Treatment consisted of ipilimumab 1 mg/kg q6weeks for 4 cycles, nivolumab 240 mg q2weeks on a 6-week cycle, and RT (24 Gy/3 fractions) on C1D1 or C2D1 to one site. Responses were defined outside of the RT field by RECIST 1.1 with centrally reviewed imaging q3months. ORR/DCR and PFS/OS were compared between patients with and without liver metastases with the Fisher's exact and log-rank tests, respectively. P-values are two-sided.

RESULTS

We treated 57 patients (median age 57 years [range, 26-85], 61% male, 88% white, 65% with liver metastases) from 07/2017 to 05/2022. Patients received a median of 3 (range, 1-10) prior lines of systemic therapy. The combined ORR was 14% (8/57; 95% CI, 6-26%) and DCR was 35% (20/57; 95% CI, 23-49%). The ORR was 30% (6/20; 95% CI, 12-54%) in patients without liver metastases and 5% (2/37; 95% CI, 1-18%) in patients with liver metastases (p = 0.017). The DCR was 55% (11/20; 95% CI, 32-77%) in patients without liver metastases and 24% (9/37; 94% CI, 12-41%) in patients with liver metastases (p = 0.040). 76% (28/37) of patients with liver metastases received liver-directed RT including 2/2 (100%) patients with a PR. The ORR was 0% in patients with liver metastases without liver-directed RT. The median PFS was 1.8 months (95% CI, 1.2-2.4 months) and OS was 9.8 months (95% CI, 6.8-12.8). OS was longer in patients without liver metastases (median 13.6 v 6.8 months, p = 0.010) and in patients treated with liver-directed RT among those with liver metastases (median 7.5 months v 4.5 months, p = 0.025).

CONCLUSION

Among patients with metastatic MSS CRC treated with ICIs and RT in two phase 2 studies, ORR, DCR, and OS are significantly higher in patients without liver metastases. Liver-directed RT may improve ICI efficacy and OS in patients with liver metastases. Further analysis of PFS and prospective study of ICIs with comprehensive liver-directed RT are warranted.

A crown-group cnidarian from the Ediacaran of Charnwood Forest, UK

Cnidarians are a disparate and ancient phylum, encompassing corals and jellyfish, and occupy both the pelagic and benthic realms. They have a rich fossil record from the Phanerozoic eon lending insight into the early history of the group but, although cnidarians diverged from other animals in the Precambrian period, their record from the Ediacaran period (635–542 million years ago) is controversial. Here, we describe a new fossil cnidarian—Auroralumina attenboroughii gen. et sp. nov.—from the Ediacaran of Charnwood Forest (557–562 million years ago) that shows two bifurcating polyps enclosed in a rigid, polyhedral, organic skeleton with evidence of simple, densely packed tentacles. Auroralumina displays a suite of characters allying it to early medusozoans but shows others more typical of Anthozoa. Phylogenetic analyses recover Auroralumina as a stem-group medusozoan and, therefore, the oldest crown-group cnidarian. Auroralumina demonstrates both the establishment of the crown group of an animal phylum and the fixation of its body plan tens of millions of years before the Cambrian diversification of animal life.

A new fossil cnidarian, Auroralumina attenboroughi, from the Ediacaran of Charnwood Forest, UK, described as showing mosaic anthozoan and medusozoan characters, is the oldest yet-known crown-group cnidarian.

Changes in Functional Assessment of Cancer Therapy: General (FACT-G) to predict treatment response and survival outcomes in patients with metastatic gastrointestinal (GI) cancer

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Background: The FACT-G contains 27 questions within 4 subscale domains [Physical Well-Being, Social/Family Well-Being, Emotional Well-Being, Functional Well-Being] related to health-related quality of life (QOL) in the past 7 days, with higher scoring indicating better QOL. In this prospective cohort study, we assessed longitudinal FACT-G data with treatment response and survival outcomes among patients with metastatic GI cancer. Methods: From 5/2019-11/2021, we enrolled patients at Massachusetts General Hospital with metastatic GI cancer to study before their treatment start. We collected the FACT-G survey at baseline (start of treatment) and 1-month later. We then used regression models to assess associations of 1-month changes in FACT-G with treatment response and survival outcomes (progression-free survival [PFS] and overall survival [OS]). For treatment response, clinical benefit was defined as decreased or stable tumor burden versus progressive disease at the time of first scan. All models were adjusted for baseline values of each respective variable. Results: We enrolled 203 of 262 patients approached (77.5% enrollment); 160 had 1-month follow-up data (median age = 63.0 years [range: 28.0-84.0 years], 66.3% male, 45.6% pancreaticobiliary cancer). For treatment response, 66.3% experienced a clinical benefit and 33.8% had progressive disease at the time of first scan (mean time to first scan = 2.7 months). Increases in FACT-G Total were predictors for treatment response (OR = 1.05, p = 0.0028), and improved PFS (HR = 0.98, p = 0.026) and OS (HR = 0.98, p = 0.038). Increases in FACT-G Emotional were associated with clinical benefit at the time of first scan (OR = 1.18, p = 0.0024), improved PFS (HR = 0.94, p = 0.023), and improved OS (HR = 0.93, p = 0.012). Improvement in FACT-G Physical were predictors for clinical benefit at time of first scan (OR = 1.08, p = 0.038) and better PFS (HR = 0.96, p = 0.038), while increases in FACT-G Functional were associated with improved PFS (HR = 0.96, p = 0.034) and OS (HR = 0.96, p = 0.019). Finally, changes in FACT-G Social were only associated with treatment response (OR = 1.16, p = 0.011). Conclusions: We found that 1-month increases in FACT-G can predict for treatment response and improved survival outcomes in patients with metastatic GI cancers. Notably, the FACT-G Total and FACT-G Emotional subscore predicted for all three outcomes of interest, while the FACT-G Social only predicted for clinical benefit at first scan. These data support previous findings indicating the possible use of early changes in patient-reported outcomes as a biomarker for early treatment response while emphasizing the growing need to integrate more patient-centric interventions into clinical care for cancer patients. Clinical trial information: NCT04776837.

A phase II study of niraparib and dostarlimab with radiation in patients with metastatic pancreatic cancer

564

Background: PARP inhibitors have activity as monotherapy in BRCA1/2 mutated metastatic pancreatic cancer; however, several other genes and associated proteins exist in the homologous recombination repair (HRR) pathway promoting resistance to chemotherapy and radiation-induced damage. Tumors with HRR deficiency have an impaired ability to repair themselves and are susceptible to PARP inhibition, but ionizing radiation can also induce DNA breaks. Ongoing research suggests that PARP inhibitors may cause radio-sensitization and may also enhance sensitivity to immunotherapy. We conducted a phase 2 study of niraparib and dostarlimab with radiation in a biomarker unselected PDAC population given PARP inhibitors' immunomodulatory and radiosensitizing effects. Methods: In this open-label, single-arm, phase-2 study, eligible patients had histologically confirmed MSS PDAC, ECOG PS 0-1, and progressed on at least one line of jm. Treatment consisted of niraparib 200 mg daily on a 21-day cycle, dostarlimab 500 mg every 3 weeks every 4 weeks for the first four doses, then 1000 mg every 6 weeks, and 3 fractions of 8 Gy at Cycle 2. Treatment continued until progressive disease, discontinuation, or withdrawal. The primary endpoint was DCR by RECIST 1.1 with radiological evaluations every 3 months. Secondary endpoints included DCR by irRECIST, PFS, OS, and safety. Responses were defined as disease control outside the radiation field. We obtained serial tumor biopsies, including pre-treatment. A two-stage design was used, requiring disease control in at least one of the first 15 patients before proceeding to the full accrual of 25 patients. Intention to treat analysis included all patients receiving at least one dose of any study agent. Results: We enrolled and treated 15 pts (median age 60 years [range 37-77], 53% male) from 08/2020 to 05/2021. Overall, DCR was 0/15 (95% CI: 0-22%), median PFS was 1.6 months (95% CI: 1.1-2.7), and median OS 3.1 months (95% CI: 1.5-7.7). Among 27 treatment-related serious adverse events, 15 (56%) were grade 3, including decreased CD4 lymphocytes, thrombocytopenia, anemia, and fatigue being the most common. Conclusions: The combination of niraparib and dostarlimab with radiation did not meet the pre-specified criteria for expansion to full accrual. Further analyses of dose intensity in this heavily pretreated and evaluation of in-field responses are underway. Further investigation of the combination with biomarker selection is warranted. Clinical trial information: NCT04409002.

Changes in patient-reported outcomes (PROs) and tumor markers (TMs) to predict treatment response and survival in patients with metastatic gastrointestinal (GI) cancer

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Background: PROs assessing quality of life (QOL) and symptoms at a single timepoint frequently correlate with clinical outcomes in patients with cancer, yet efforts to understand how longitudinal changes in PROs can predict for treatment outcomes are lacking. In practice, oncologists often use changes in serum TMs (CEA and CA19-9) to monitor patients with GI cancer, and thus we sought to examine associations of 1-month changes in PROs and TMs with treatment response and survival outcomes among patients with advanced GI cancer. Methods: We prospectively enrolled patients with metastatic GI cancer prior to initiating chemotherapy at Massachusetts General Hospital from 5/2019-12/2020. At baseline (start of treatment) and 1-month later, we collected PROs (QOL [Functional Assessment of Cancer Therapy General {FACT-G}], physical symptoms [Edmonton Symptom Assessment System {ESAS}], and psychological symptoms [Patient Health Questionnaire-4 {PHQ-4}]) and TMs. We used regression models to examine associations of 1-month changes in PROs and TMs with treatment response (clinical benefit [defined as decreased or stable tumor burden] or progressive disease at the time of first scan) and survival outcomes (progression-free survival [PFS] and overall survival [OS]), adjusted for baseline values of each respective variable. Results: We enrolled 159 of 191 patients approached (83.2% enrollment); 134 had 1-month follow-up data (median age = 64 years [range: 28 to 84 years], 64.2% male, 46.3% pancreaticobiliary cancer). For treatment response, 63.4% had clinical benefit and 36.6% had progressive disease at the time of first scan (mean time to first scan = 2.01 months). Changes in PROs (ESAS-Total: OR = 0.97, p = 0.022; ESAS-Physical: OR = 0.96, p = 0.027; PHQ-4 depression: OR = 0.67, p = 0.014; FACT-G: OR = 1.07, p = 0.001), but not TMs (CEA: OR = 1.00, p = 0.836 and CA19-9: OR = 1.00, p = 0.796), were associated with clinical benefit at the time of first scan. Changes in ESAS-Total (HR = 1.03, p = 0.004), ESAS-Physical (HR = 1.03, p = 0.021), PHQ-4 depression (HR = 1.22, p = 0.042), FACT-G (HR = 0.97, p = 0.003), and CEA (HR = 1.00, p = 0.001) were predictors of PFS. Changes in ESAS-Total (HR = 1.03, p = 0.006) and ESAS-Physical (HR = 1.04, p = 0.015) were predictors of OS, but 1-month changes in TMs (CEA: HR = 1.00, p = 0.377 and CA19-9: HR = 1.00, p = 0.367) did not significantly predict for OS. Conclusions: We found that 1-month changes in PROs can predict for treatment response and survival outcomes in patients with advanced GI cancers. Notably, 1-month changes in CEA only correlated with PFS, while changes in CA19-9 did not significantly predict treatment response or survival outcomes. These findings highlight the potential for early changes in PROs to predict treatment outcomes while underscoring the need to monitor and address PROs in patients with advanced cancer. Clinical trial information: NCT04776837.

Changes in patient-reported outcomes (PROs) and tumor markers (TMs) to predict treatment response and survival outcomes in patients with metastatic gastrointestinal (GI) cancer

6560

Background: PROs assessing quality of life (QOL) and symptoms at a single timepoint frequently correlate with clinical outcomes in patients with cancer, yet efforts to understand how longitudinal changes in PROs can predict for treatment outcomes are lacking. In practice, oncologists often use changes in serum TMs (CEA and CA19-9) to monitor patients with GI cancer, and thus we sought to examine associations of 1-month changes in PROs and TMs with treatment response and survival outcomes among patients with advanced GI cancer. Methods: We prospectively enrolled patients with metastatic GI cancer prior to initiating chemotherapy at Massachusetts General Hospital from 5/2019-12/2020. At baseline (start of treatment) and 1-month later, we collected PROs (QOL [Functional Assessment of Cancer Therapy General {FACT-G}], physical symptoms [Edmonton Symptom Assessment System {ESAS}], and psychological symptoms [Patient Health Questionnaire-4 {PHQ-4}]) and TMs. We used regression models to examine associations of 1-month changes in PROs and TMs with treatment response (clinical benefit [defined as decreased or stable tumor burden] or progressive disease at the time of first scan) and survival outcomes (progression-free survival [PFS] and overall survival [OS]), adjusted for baseline values of each respective variable. Results: We enrolled 159 of 191 patients approached (83.2% enrollment); 134 had 1-month follow-up data (median age = 64 years [range: 28 to 84 years], 64.2% male, 46.3% pancreaticobiliary cancer). For treatment response, 63.4% had clinical benefit and 36.6% had progressive disease at the time of first scan (mean time to first scan = 2.01 months). Changes in PROs (ESAS-Total: OR = 0.97, p = 0.022; ESAS-Physical: OR = 0.96, p = 0.027; PHQ-4 depression: OR = 0.67, p = 0.014; FACT-G: OR = 1.07, p = 0.001), but not TMs (CEA: OR = 1.00, p = 0.836 and CA19-9: OR = 1.00, p = 0.796), were associated with clinical benefit at the time of first scan. Changes in ESAS-Total (HR = 1.03, p = 0.004), ESAS-Physical (HR = 1.03, p = 0.021), PHQ-4 depression (HR = 1.22, p = 0.042), FACT-G (HR = 0.97, p = 0.003), and CEA (HR = 1.00, p = 0.001) were predictors of PFS. Changes in ESAS-Total (HR = 1.03, p = 0.006) and ESAS-Physical (HR = 1.04, p = 0.015) were predictors of OS, but 1-month changes in TMs (CEA: HR = 1.00, p = 0.377 and CA19-9: HR = 1.00, p = 0.367) did not significantly predict for OS. Conclusions: We found that 1-month changes in PROs can predict for treatment response and survival outcomes in patients with advanced GI cancers. Notably, 1-month changes in CEA only correlated with PFS, while changes in CA19-9 did not significantly predict treatment response or survival outcomes. These findings highlight the potential for early changes in PROs to predict treatment outcomes while underscoring the need to monitor and address PROs in patients with advanced cancer.

Clinical and mutational profile of ARID1A-mutated gastrointestinal cancers: Duration of response to platinum-based chemotherapy

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Background: ARID1A is mutated in several cancer types, with studies reporting mutations in up to 10% of colorectal cancers (CRC) and as high as 35% of gastric and pancreatic cancers. The ARID1A gene encodes a member of the SWI/SNF (SWItch/Sucrose Non-Fermentable) chromatin remodeling complex and functions as a tumor suppressor. ARID1A has also been implicated in double-stranded DNA repair via both homologous recombination and non-homologous end-joining, potentially conferring platinum sensitivity. We sought to characterize this subset of gastrointestinal (GI) malignancies. Methods: We identified patients with locally advanced or metastatic ARID1A-mutated GI malignancies treated at Massachusetts General Hospital (MGH) by next-generation sequencing. Patients were selected who gave consent to molecular testing and who were enrolled on to a study. We evaluated clinical characteristics and outcomes for patients undergoing treatment at MGH between 2009 and May 2020. The Kaplan-Meier method was used to calculate progression free survival (PFS) to first-line platinum-based chemotherapy. Results: We captured 38 patients with ARID1A-mutated tumors. Median age at diagnosis was 66 (range 31-87) and 63.2% of patients were male (n = 24). Tumor types varied, including CRC (n = 13, 34.2%), esophagogastric (n = 13, 34.2%), pancreatic (n = 6, 15.7%), cholangiocarcinoma (n = 2, 5.3%), small bowel (n = 1, 2.6%), anal (n = 1, 2.6%), and unknown GI primary (n = 2, 5.3%). Most were metastatic at diagnosis (n = 23, 60.5%). The identified ARID1A mutations were each distinct, occurring along the length of the gene and were comprised of missense (n = 10, 26.3%), nonsense (n = 12, 31.6%), frameshift (n = 13, 34.2%), and splice-site (n = 3, 7.9%) mutations. We observed on average 4-5 co-mutations per tumor, with TP53 (n = 25, 65.8%), KRAS (n = 14, 36.8%), APC (n = 11, 28.9%), BRCA2 (n = 7, 18.4%) and BRAF (n = 7, 18.4%) occurring most frequently. Tumors were both microsatellite stable (n = 23, 60%) and microsatellite unstable (n = 7, 18.4%). Most patients (n = 37, 97.4%) received a platinum-based chemotherapy as first-line therapy including FOLFOX (n = 23, 60.5%), FOLFIRINOX (n = 10, 26.3%), gemcitabine/cisplatin (n = 2, 5.3%), carboplatin/5-FU (n = 1, 2.6%), and carboplatin/etoposide (n = 1, 2.6%). Median PFS for first-line platinum based chemotherapy was 14.0 months (CI 8.2-34.7) overall. For patients with CRC, PFS to platinum-based therapy was 14.0 months (CI 4.8-not reached) compared with 9.6 months for non-CRC (CI 7.4-not reached). Conclusions: To our knowledge, this is the first assessment of clinical characteristics and outcomes for ARID1A-mutated GI malignancies. Mutations in ARID1A are highly diverse, without a clear association with tumor type. Future studies assessing response to platinum-based chemotherapy are warranted.

Local and systemic recurrence following total neoadjuvant therapy (TNT) and resection for borderline resectable and locally advanced pancreatic adenocarcinoma: Long-term follow up from two phase II studies

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Background: With the advent of FOLFIRINOX, the management of pancreatic cancer has undergone a profound change. There has been a shift to TNT with FOLFIRINOX followed by radiation and an attempt at surgical resection. Recent trials of TNT have demonstrated an ability to resect locally advanced (LA) and borderline resectable disease. There is a lack of prospective data demonstrating local and systemic recurrence rates after TNT. Methods: Two previously reported prospective clinical trials (Murphy JE, et al, JAMA Oncol 2018, 2019) of total neoadjuvant therapy were conducted between 2012 and 2018 for borderline and LA disease (NCT01591733, NCT01821729). Patients received FOLFIRINOX for 8 cycles. Upon restaging, patients with resolution of vascular involvement received short-course chemoradiotherapy (5 Gy x 5 with protons or 3 Gy x 10 w photons) with capecitabine (N=34). Patients with persistent vascular involvement received long-course chemoradiotherapy with capecitabine (N=56). All patients were considered for resection after TNT except for those patients with metastatic or unresectable disease. Results: 97 eligible patients were enrolled and started treatment on the borderline resectable (n = 48) and locally advanced (n= 49) study. 90 patients completed therapy. 80 patients were taken to the operating room. 61 patients had R0 resection and 5 patients had R1 resection. The table shows the distribution of local recurrences, local recurrences and metastatic disease, and metastatic disease alone. With a median follow-up of 5.2 years (range: 2.4-6.0), of the 61 R0 patients, 22 patients remained alive and free of disease, 7 patients had a local recurrence, 4 patients had locoregional and metastatic recurrence, and 24 patients had a metastatic recurrence. 3 patients who underwent R0 resection died of unrelated causes. Median survival for patients undergoing R0 resection is 43.8 months. Conclusions: Total neoadjuvant therapy for locally advanced and borderline resectable pancreatic cancer is potentially curable and may change the pattern of spread.[Table: see text]

Pancreatic acinar cell carcinoma: A multi-center series on clinical characteristics and treatment outcomes

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Background: Acinar cell carcinoma (ACC) is a very rare tumor of the exocrine pancreas, representing less than 1% of all pancreatic malignancies. The majority of data regarding ACC are limited to small case series. Methods: This is a retrospective study conducted at a large healthcare system from 1996-2019. Patients with pathologically confirmed ACC were included, and demographic data, tumor characteristics, and treatment outcomes were abstracted by chart review. Survival curves were obtained by using the Kaplan-Meier method and compared using the log-rank test. Results: Sixty-six patients with ACC were identified. The median patient age at diagnosis was 64, and 42% presented with metastatic disease. The majority presented with abdominal pain or pancreatitis (69%), and laboratory parameters did not correlate with tumor size, metastatic disease, or survival. Several somatic abnormalities were noted in tumors (BRCA2, TP53, and mismatch-repair genes). In patients with localized disease that underwent resection, the median time to develop metastatic lesions was 13 months. The median overall survival (OS) was 24.7 months from diagnosis, with a survival difference based on metastatic disease at diagnosis (median 15 vs 38 mos). Surgery conferred OS benefit in non-metastatic cases (p = 0.006) but not metastatic cases (p = 0.22), and chemotherapy provided OS benefit in metastatic disease (p < 0.01). Patients with metastatic ACC treated after 2010 utilized more platinum-based agents, and there was a OS benefit to FOLFOX or FOLFIRINOX chemotherapy compared to gemcitabine or capecitabine-based regimens (p = 0.006). Conclusions: Pancreatic ACC patients often present with advanced disease. Surgery confers survival benefit among patients presenting with localized disease. The use of FOLFOX or FOLFIRINOX chemotherapy regimens was associated with improved OS in metastatic patients. These data add to our knowledge in this rare malignancy, and improves understanding about the genomic underpinnings, prognosis and treatment for acinar cancers.

The use of elevated circulating hepatocyte growth factor (HGF) level as a potential prognostic biomarker in locally advanced pancreatic cancer

429

Background: The hepatocyte growth factor (HGF)/c-MET pathway has pleiotropic functions in tumor progression including invasion and cancer cell survival. The potential use of circulating plasma HGF as a prognostic biomarker is not known. Methods: This was an analysis of plasma HGF in patients enrolled in a single arm phase II study (NCT01821729) of patients with previously untreated locally advanced pancreatic ductal adenocarcinoma (PDAC) treated with FOLFIRINOX and losartan followed by chemoradiotherapy before resection was attempted (Murphy JE et al., 2019). Eligible patients from the trial included those who had undergone baseline research labs including HGF. Circulating HGF was measured in the plasma on day 1 of treatment using ELISA, and the median value was used to define high vs low levels for the purpose of analysis. The association of elevated HGF with overall survival (OS) was analyzed by univariable and multivariable Cox regression, adjusting for tumor size (≤ versus > 40 mm) and serum CA19-9 (≤ versus > 37 U/mL). Results: There were 46 eligible patients with a median follow up of 31 months. The median age was 63 (range 42-78) and 52% were female (24/46). Median tumor size was 41.4 mm (range 18–68 mm). There were 41/46 patients (89.1%) with elevated baseline CA19-9. Median baseline HGF was 1,250.55 pg/mL (range 650.9–6,459.1). Median OS was 38.4 months for patients with baseline HGF at or below the median, and 19.3 months for those with elevated HGF. On univariate analysis, elevated HGF was associated with poorer OS (HR 2.28, 95% CI 1.06–4.87, p = 0.03). On multivariate analysis, after controlling for tumor size and baseline CA19-9, elevated plasma HGF remained significantly associated with poorer OS (HR 2.58, 95% CI 1.16–5.70, p = 0.02). Conclusions: In conclusion, elevated baseline circulating plasma HGF is an independent biomarker of poorer OS in patients with locally advanced PDAC treated with neoadjuvant therapy. Further randomized studies are needed to define the negative predictive biomarker value for high plasma HGF and identify the optimal HGF range as well as determine applicability to other stages of disease. These results support the continued investigation of plasma HGF in ongoing clinical trials with PDAC patients.

Prognostic impact of chemoradiation-related lymphopenia in patients with gastric and gastroesophageal cancer

249

Background: Limited data exists on how chemoradiation (CRT)-induced lymphopenia affects survival outcomes in patients with gastric and gastroesophageal junction (GEJ) cancer. We evaluated the association between severe lymphopenia and its association with survival in gastric and GEJ cancer patients treated with CRT. We hypothesized that severe lymphopenia would be a poor prognostic factor. Methods: We performed a retrospective analysis of 154 patients with stage 1-3 gastric or GEJ cancer who underwent CRT at our institution. Patients underwent photon-based radiation therapy (RT) with a median dose of 50.4 Gy (IQR 45.0-50.4 Gy) over 28 fractions and concurrent chemotherapy (CTX) with carboplatin/paclitaxel, 5-fluorouracil based regimen, or capecitabine. 49% received CTX prior to RT. 84% underwent surgical resection, 57% pre-CRT and 26% post-CRT. Absolute lymphocyte count (ALC) at baseline and at 2 months since initiating RT were analyzed. Severe lymphopenia, defined as Grade 3 or worse lymphopenia (ALC < 0.5 k/μl), was analyzed for any association with overall survival (OS). Results: Median time of follow up was 48 months. Median age was 65. 77% were male and 86% were Caucasian. ECOG PS was 0 or 1 in 90% and 2 in 10%. Tumor location was stomach in 38% and GEJ in 62%. Timing of CRT was preoperative among 68% and postoperative among 32%. The median ALC at baseline for the entire cohort was 1.6 k/ul (range 0.3-7.0 k/ul). At 2 months post-CRT, 49 (32%) patients had severe lymphopenia. Patients with severe lymphopenia post-CRT had a slightly lower baseline TLC compared to patients without severe lymphopenia (median TLC 1.4 k/ul vs. 1.6 k/ul; p = 0.005). There were no differences in disease and treatment characteristics between the two groups. On the multivariable Cox model, severe lymphopenia post-CRT was significantly associated with increased risk of death (HR = 3.99 [95% CI 1.55-10.28], p = 0.004). ECOG PS 2 (HR = 34.97 [95% CI 2.08-587.73], p = 0.014) and postoperative CRT (HR = 5.55 [95% CI 1.29-23.86], p = 0.021) also predicted worse OS. The 4-year OS among patients with severe lymphopenia was 41% vs. 61% among patients with vs. without severe lymphopenia (log-rank test p = 0.041). Conclusions: Severe lymphopenia significantly correlated with poorer OS in patients with gastric or GEJ cancer treated with CRT. CRT-induced lymphopenia may be an important prognostic factor for survival in this patient population. Closer observation in high-risk patients and treatment modifications may be potential approaches to mitigating CRT-induced lymphopenia.

Use of patient-reported outcomes (PROs) to predict treatment outcomes in patients with advanced cancer

186

Background: PROs assessing quality of life (QOL) and physical symptoms often correlate with clinical outcomes in patients (pts) with cancer. Yet, data are lacking about the use of PROs to predict treatment response. We evaluated associations of baseline PROs with treatment response, healthcare use, and survival among pts with advanced gastrointestinal cancer. Methods: We prospectively enrolled pts with metastatic gastrointestinal cancer prior to initiating chemotherapy at Massachusetts General Hospital. At baseline (start of treatment), pts reported their QOL (Functional Assessment of Cancer Therapy General [FACT-G], subscales assess QOL across 4 domains: functional, physical, emotional, social well-being) and symptom burden (Edmonton Symptom Assessment System [ESAS]). Higher scores on FACT-G indicate better QOL, while higher scores on ESAS represent a greater symptom burden. We used regression models to examine associations of baseline PRO scores with treatment response (clinical benefit [CB] or progressive disease [PD] at the time of first scan based on clinical documentation), healthcare use (unplanned hospital admissions), and survival. Results: From 5/2019-3/2020, we enrolled 112 of 131 (85.5% enrollment) consecutive pts (median age = 62.8, 61.6% male, 45.5% pancreatobiliary cancer). For treatment response, 64.3% had CB and 35.7% had PD. Higher ESAS-physical (B = 1.04, p = .027) and lower FACT-G functional (B = 0.92, p = .038) scores at baseline were significant predictors of PD. On the specific ESAS items, pts who experienced PD were more likely to report moderate/severe poor well-being (57.9% vs 29.7%; p = .001), pain (44.7% vs 25.0%; p < .050), drowsiness (42.1% vs 20.3%; p = .024), and diarrhea (23.7% vs 4.7%; p = .008) at baseline. Lower FACT-G total (HR = 0.96, p = .003), FACT-G physical (HR = 0.89, p < .001), FACT-G functional (HR = 0.87, p < .001), and higher ESAS-physical (HR = 1.03, p = .028) scores at baseline were significantly associated with greater risk of hospital admission. Lower FACT-G total (HR = 0.96, p = .009), FACT-G emotional (HR = 0.87, p = .014), as well as higher ESAS-total (HR = 1.03, p = .018) and ESAS-physical (HR = 1.03, p = .040) scores at baseline were significantly associated with greater risk of death. Conclusions: We found that baseline PROs predict treatment response in pts with advanced cancer, namely physical symptoms and functional QOL, in addition to healthcare use and survival outcomes. These findings further support the use of PROs to predict important clinical outcomes, including the novel finding of treatment response.

Phase I, first-in-human study of AbGn-107, a novel antibody-drug conjugate (ADC), in patients with gastric, colorectal, pancreatic or biliary cancers

e16771

Background: AbGn-107 is an ADC directed against AG-7 antigen, a Lewis A-like glycol-epitope expressed in 24-61% of gastric (G), colorectal (CRC), pancreatic (PDA), and biliary (BIL) cancers. Based on promising antitumor activity of AbGn-107 in both in vitro and in vivo preclinical studies, we performed a Phase Ia trial in patients with the aforementioned GI malignancies. Methods: Standard 3+3 dose escalation was used. Key eligibility included locally advanced or metastatic G, CRC, PDA, or BIL cancer, previously treated, ECOG PS 0-1; positive AG-7 expression was not required. Two dosing intervals were tested: AbGn-107 administered i.v. Q4 weeks (at doses ranging from 0.1-1.2 mg/kg) and Q2 weeks (at doses from 0.8-1.0 mg/kg). Dose limiting toxicities (DLT) were based on grade 3/4 hematologic and non-heme AEs occurring during the initial 4-week rx window. Patients were treated until disease progression or unacceptable toxicity, with tumor assessments Q8 weeks. 1o objectives: safety and MTD; 2o objectives: PK, immunogenicity, and efficacy defined by ORR (RECIST 1.1). Results: 35 patients were enrolled across 6 dose levels (median age 61.5 yo (range 40 – 81); G (0)/CRC (12)/PDA (20)/BIL (3); median # lines of prior rx = 3 (range 1-7). Safety: 5 patients experienced Grade 3 or 4 neutropenia, all at higher dose levels, inc. 1 episode of febrile neutropenia. Other frequent drug-related AEs, mostly grade 1/2, inc. fatigue (29%), nausea (20%), and diarrhea (14%). DLTs included grade 4 CK elevation (n = 1) at 0.8 mg/kg Q4W and grade 3 arthralgias (n = 1) at 1.2 mg/kg Q4W. Based on safety profile and PK data, 1.0 mg/kg Q2W was selected as the dose schedule for cohort expansion phase. Efficacy: Median duration of treatment = 56 days (range, 8 – 225 days). Six pts have demonstrated a minor response by RECIST (range, -1.3 to -21.1%); 4 pts (all PDA) have had durable dz control > 180 days. Conclusions: Overall, AbGn-107 appears well-tolerated with encouraging prelim signs of efficacy in unselected pts with heavily pre-treated advanced GI cancers. Updated safety and efficacy data will be provided at the time of the meeting for the cohort expansion phase of this study (currently open across multiple sites in U.S. and Taiwan), in which subjects with G, CRC, PDA, and BIL cancers are pre-screened for high levels of AG-7 tumor expression. Clinical trial information: NCT02908451 .

Comparing clinicopathologic feature and treatment outcome of patients who underwent surgical resection or liver transplant for nonalcoholic fatty liver disease (NAFLD)-related and non-NAFLD related hepatocellular carcinoma (HCC)

e16675

Background: NAFLD associated HCC is rapidly increasing in frequency worldwide. In this study, we evaluated potential differences in clinical characteristics and outcomes of patients who underwent surgery or liver transplant for NAFLD-associated HCC compared to HCC from other etiologies. Methods: Demographic, clinicopathological features and outcomes of patients with HCC who underwent liver resection or liver transplant at Massachusetts General Hospital and Brigham and Women’s Hospital were collected (January 2004 - April 2018). Of 713 patients screened, 481were eligible: 260 underwent resection [NAFLD (n = 61), viral (n = 150), cryptogenic (CC) (n = 49)]. 221 underwent transplant [(NAFLD (n = 14), viral (n = 201), CC (n = 6)]. Results: In the Resected cohort, NAFLD patients presented with median age of (71.5 years) compared with Viral (63.4) and Cryptogenic (68.4). NAFLD patients had significantly higher Body Mass Index (BMI) > 28.8 39(66%) p = < 0.001, while patients with cryptogenic HCC presented with large tumor size (>5cm) 37(75%) p = 0.001. In multivariate analysis, tumor size 5cm (HR1.78,p = 0.002), R1 or R2 resection (HR 2.48, p = < 0.001and 2.8,p = 0.007), low platelet count (HR 2.8,p = 0.002) and diabetes (HR 1.5,p = 0.025) were poor prognostic factors in resection cohort. Median overall survival (OS) was not significantly different between NAFLD, Cryptogenic and Viral (47.2, 69.7 and 69.0 months, p = 0.18) etiologies, respectively. In the Transplant cohort, NAFLD patients had a median age of 65.5 and cryptogenic, viral (61.3 and 58.5 years) respectively. NAFLD and Cryptogenic HCC patients compared with viral HCC patients had low AFP median 3.7, 3.9 and 7.5 ng/mL(p = 0.012) respectively. In multivariate analysis patients with perineural invasion (HR 20.7,p = 0.009), disease recurrence (HR 2.5,p = 0.001) and high AFP (HR 2.1,p = 0.001) were at higher risk of death among transplant patients. No significant difference in median OS was seen between NAFLD, cryptogenic and viral (69.1,92.3 and 88.0 months, p = 0.38). Conclusions: NAFLD patients had higher BMI and had a lower AFP than viral and CC. NAFLD had similar median OS following resection and transplant when compared to those with Viral and CC.

A pilot study of durvalumab/tremelimumab (durva/treme) and radiation (XRT) for metastatic biliary tract cancer (mBTC): Preliminary safety and efficacy

547

Background: Metastatic biliary tract cancer (mBTC) is a lethal malignancy with median 5 year OS of less than 10%. Immunotherapy, particularly single agent anti-PD-1/PD-L1, has limited efficacy in mBTC with ORR~9-15%. Recently presented data shows responses in metastatic MSS pancreatic or colon cancer with combination anti-PD-1/CTLA-4 and radiation (XRT) to produce systemic response (abscopal effect) (Parikh A, GI ASCO 2019, ASCO 2019.). We evaluate safety and efficacy of dual PD-1/CTLA-4 inhibition with XRT in MSS mBTC. Methods: 15 of a planned 15 mBTC patients were enrolled. Eligible pts had histologically-confirmed mBTC, ECOG-PS 0/1, and must have progressed on at least one line of previous therapy or refused standard therapy. Safety cohort of 6 pts of durva 1500 mg/treme 75 mg q4w was enrolled. If > 2 DLTs, patients were enrolled subsequently to dose level -1 (durva 1125 mg/ treme 75 mg q4w). 3 fractions of 8 Gy of radiation at C2D1 every other day to a single metastatic site. Durva/treme continued for 4 cycles, followed by 4 cycles of maintenance durva until progressive disease, discontinuation or withdrawal. Endpoints include disease control rate (DCR (SD+PR+CR)), PFS and OS and safety. Radiological evaluations were done q2 mo. Results: 15 mBTC pts enrolled and evaluable from May 2018 to March 2019. Median age 63 years (range 48-75), 47% male. DLTs occurred in 3 patients during the safety run-in. One patient experienced DLT at dose level -1 and subsequent expansion. 3 patients did NOT reach radiation therapy. DCR was 27% with a 13% PR and 7% CR. Of those who reached radiation, DCR was 33% with a 17% PR and 8% CR. At time of analysis, median PFS was 54 days for ITT mBTC. Duration of response for 4 patients with DCR was 26, 52, 122, 254+ days. Treatment-related adverse events were reported in 12/15 patients (80%). Grade ≥3 toxicities were seen in 9/15 pts (60%) with lymphopenia (5 grade 3) and elevated LFTs (2 grade 4 and 4 grade 2) being the main adverse events. All patients with disease control were not MSI. Conclusions: Combination of durva/treme XRT is feasible and shows preliminary activity in metastatic BTC. An expansion cohort is being planned to confirm activity. Clinical trial information: NCT03482102.

Noninvasive comprehensive genomic profiling from plasma ctDNA in pancreatic cancer patients

753

Background: The use of comprehensive genomic profiling (CGP) is increasing in pancreatic ductal adenocarcinoma (PDAC) as knowledge improves regarding molecular drivers of tumorigenesis and effective targeted therapies emerge. However, adequate tissue sampling is often limited. Plasma-based CGP offers a non-invasive approach to assess biomarkers that may impact treatment decisions. Methods: We retrospectively evaluated genomic and clinical data from 97 PDAC patients with circulating tumor DNA (ctDNA) testing from 9/2016-8/2019 (Guardant Health, Inc.). ctDNA analysis included single nucleotide variants (SNV), fusions, indels and copy number variations (CNV) of up to 74 genes. ctDNA results were assessed across clinical variables. We evaluated for actionable alterations. Results: A total of 114 samples were obtained from 97 patients for ctDNA testing. ctDNA alterations were detected in 82% (93/114) of all samples, including 90% (18/20) at diagnosis, 88% (59/67) at progression, and 56% (10/18) while on stable therapy. ctDNA alterations were found at each stage of PDAC: in 25% (1/4) of samples with resectable disease, 75% (3/4) with borderline resectable disease, 82% (9/11) with locally advanced disease, and 85% (81/95) with metastatic disease. One or more KRAS alterations were detected in 55% (51/93) of patients with alterations present. The median maximum mutant allele frequency was similar between the cohort of patients with KRAS detected (0.55%) versus not detected (0.70%). 8% (8/97) of patients had potentially actionable alterations (2 activating BRAF SNVs, 1 ERBB2 CNV, 1 ERBB2 activating SNV, 1 KRAS G12C, and 3 indels in Homologous Recombination Deficiency genes). Median turnaround time was 8 days. 51% (49/97) of patients had both plasma-based CGP and tissue-based CGP. Of these patients, tissue-based CGP showed ≥ 1 alterations detected in 82% (40/49), test failure in 14% (7/49), and no alterations detected in 4% (2/49). Conclusions: Plasma-based CGP detected ctDNA alterations in 90% of samples tested at diagnosis and 82% of all samples. Potentially actionable mutations were found in 8% of patients, with prompt processing time allowing for rapid decision making.

Clinical and genomic factors associated with outcome following ablative radiotherapy for oligometastatic and oligoprogressive liver tumors

515

Background: There is increasing use of ablative radiotherapy (RT) for oligometastatic and/or oligoprogressive cancer, but the population who may benefit from this more aggressive treatment remains poorly defined. We aimed to identify factors associated with improved outcomes following ablative RT for oligometastatic/oligoprogressive liver tumors. Methods: We retrospectively analyzed 106 patients who had tumor genomic profiling and received a 5, 6, or 15-fraction course of ablative RT for liver metastases from 2008-2019. The interval off systemic therapy post-RT was calculated for patients who did not continue treatment through RT. Overall survival (OS) was estimated using the Kaplan-Meier method. The association between clinical and genomic variables and OS were assessed using uni- and multivariable Cox regression. Results: Median follow-up was 12.6 months. Median age was 61.3 years and 57% were male. The most common primary site was colorectum (42%), followed by pancreas (25%) and non-small cell lung cancer (10%). 42% had colorectal adenocarcinoma, 46% had other adenocarcinoma, and 12% had other histology. A BRAF/RAS family mutation (KRAS, NRAS, and/or BRAF) was present in 41%, 69% had > 1 metastasis, and 38% had extra-hepatic disease. Median biological effective dose (α/β = 10) (BED) was 92 Gy. The RT field encompassed all liver metastases in 91%, and 11% received radiosensitizing chemotherapy. Median time off systemic agents was 5 months. Patients with 1 vs > 1 metastasis had a longer interval off systemic therapy (9 vs 4 months, p = 0.026). Median OS was 12.6 months. The table shows the multivariable Cox model for OS. Conclusions: Presence of a BRAF/RAS family mutation, extra-hepatic metastases, exclusion of liver metastases from RT fields, lower BED, and concurrent radiosensitizing chemotherapy were associated with worse OS. This may inform patient selection and RT delivery for aggressive local therapy for liver metastases.

[Table: see text]

Chemoradiation-related lymphopenia and its association with survival in patients with anal cancer

3

Background: While treatment-related lymphopenia (TRL) is common and associated with poorer survival in multiple solid malignancies, little data exists for anal cancer. We evaluated TRL and its association with survival in anal cancer patients treated with chemoradiation (CRT). Methods: A retrospective analysis of 140 patients with non-metastatic anal squamous cell carcinoma (SCC) treated with definitive CRT was performed. Total lymphocyte counts (TLC) at baseline and monthly intervals up to 12 months after initiating CRT were analyzed. Multivariable Cox regression analysis was performed to evaluate the association between overall survival (OS) and TRL, dichotomized by G4 TRL ( < 0.2k/μl) two months after initiating CRT. Kaplan-Meier and log-rank tests were used to compare OS between patients with versus without G4 TRL. Results: Median time of follow-up was 55 months. Prior to CRT, 95% of patients had a normal TLC ( > 1k/μl). Two months after initiating CRT, there was a median of 71% reduction in TLC from baseline and 84% of patients had TRL: 11% G1, 31% G2, 34% G3, and 8% G4. On multivariable Cox model, G4 TRL at two months was associated with a 3.7-fold increased risk of death (p = 0.013). On log-rank test, the 5-year OS rate was shorter in the cohort with versus without G4 TRL at two months (32% vs. 86%, p < 0.001). Conclusions: TRL is common and may be another prognostic marker of OS in anal cancer patients treated with CRT. The association between TRL and OS supports the hypothesis that host immunity plays an important role in survival among patients with anal cancer. These results support ongoing efforts of randomized trials underway to evaluate the potential role of immunotherapy in localized anal cancer.

Phase II study of lamivudine in p53 mutant metastatic colorectal cancer (mCRC)

149

Background: Non-coding repeat RNAs in cancers are pervasive and “mimic” viruses with activation of pattern recognition receptors and the innate immune response. Many repeat RNAs replicate in cancer genomes through a reverse transcriptional intermediate analogous to retroviruses. Nucleoside reverse transcriptase inhibitors (NRTIs) block this retroviral life cycle to increases repeat RNAs in p53 mutant colon cancer cell cancer lines. We initiated a Phase 2 study of lamivudine (3TC) in TP53 mutant mCRC. Methods: Two-stage design with target accrual of 20 patients (pts) in stage 1 and total of 32. Eligibility: pts with p53 mutant refractory mCRC with progression on or intolerance to 5FU, oxaliplatin and irinotecan and anti-EGFR if RAS WT. RNA sequencing was performed on pre-treatment (tx) and on tx biopsy to evaluate for repeat RNA expression and expression of other genes linked to 3TC response/resistance. Radiation was allowed. 9 pts were treated with 3TC 150 mg po bid for 28-day cycles, the maximum FDA approved dose of 3TC in HIV. Subsequent pts were treated at 600 mg po bid, previously tested in P1 trials. Tumor assessments were performed every 8 weeks until documented disease progression by RECIST 1.1 criteria or drug intolerance. Results: 29/32 pts have been treated. Median age: 60 yrs. (27-82) 18 males, 11 females. 2/ 9 (22%) pts on standard 3TC dosing had stable disease (SD) on single agent 3TC with a duration of tx of 169 and 167 days, respectively. Both pts had an initial drop in CEA upon initiation of 3TC. Of the next 20 pts on high dose 3TC, 19 were evaluable. 4 had SD, for 110, 159, 130 and 228+ days. 14 pts had tx-related adverse events (TRAE). 1 pt with a definite Grade 1 TRAE (fatigue). No pts with Grade ≥3 TRAEs. We obtained pre-tx fresh frozen biopsies on 24/29 pts. Of those with SD, 4 had biopsies and differential expression identified significantly higher HSATII repeat RNA in pts with SD compared to PD. There was an association of decreased epigenetic gene expression in HSATII repeat RNA high tumors. Conclusions: This proof-of-concept study demonstrates the safety and activity of single-agent 3TC. Repeat RNA levels appear to correlate with clinical benefit and can be measured in biopsies. Further combination studies and correlatives are planned. Clinical trial information: NCT03144804.

The role of circulating tumor DNA (ctDNA), tumor markers (TMs), and patient-reported outcomes (PROs) in predicting treatment response in patients with metastatic gastrointestinal (GI) cancer

833

Background: Changes in ctDNA and serum TMs (CEA and CA19-9) can serve as predictors of response to systemic therapy in GI cancer patients (pts). Similarly, PROs correlate with survival and treatment response. We present a preliminary analysis of ctDNA, TMs, and PROs in predicting treatment response. Methods: We are enrolling 200 pts in a prospective study with metastatic pancreatic (PDAC), colorectal (CRC), gastroesophageal (GE), and biliary cancers. We are collecting ctDNA, TMs (CEA for all tumor types; CA19-9 for PDAC, GE, biliary), and PROs (FACT-G for QOL [higher scores indicate better QOL]; ESAS-r and PRO-CTCAE for symptoms; and PHQ-4 [consists of GAD-2 and PHQ-2 for anxiety and depression]; higher ESAS-r, PRO-CTCAE, and PHQ-4 scores reflect greater symptom burden) at baseline and 4 weeks. ctDNA is benchmarked against somatic tissue alterations, and serially assessed by digital droplet PCR. We correlated median percent change from baseline to 4 weeks for ctDNA, TMs, and PROs with treatment response (clinical benefit [CB], progressive disease [PD]). Results: From April to August 2019, we have enrolled 38/45 (84.4%) eligible pts (median age = 64 years; 36.8% female). Among these 38 pts, tumor types are PDAC (36.8%), CRC (31.6%), GE (28.9%), and biliary (2.6%). 18/38 pts were evaluable for ctDNA. Change in ctDNA was -94.5% in pts with CB (n = 10) and -19.5% in pts with PD (n = 8; p = 0.025). No correlation was observed between CEA and treatment response (p = 0.367). Change in CA19-9 was -1.5% for pts with CB and +47% for pts with PD (p = 0.019). Changes in PRO-CTCAE (p = 0.345), GAD-2 (p = 0.697), and ESAS scores (p = 0.743) did not differ between pts with CB and PD. However, changes in PHQ-2 (CB 0% v. PD +22.5%; p < 0.001), PHQ-4 (CB -8.5% v. PD +5%; p = 0.015), and FACT-G (CB +30% v. PD +5%; p = 0.049) were significant. Conclusions: Preliminary analysis suggests that ctDNA and PROs demonstrate promising utility for early prediction of treatment response, with favorable performance relative to standard TMs. Further analyses of larger pt numbers in this ongoing study may clarify the use and integration of these measures to better predict pt outcomes.

Phase Ia, first-in-human study of AbGn-107, a novel antibody-drug conjugate (ADC), in patients with gastric, colorectal, pancreatic, or biliary cancers

713

Background: AbGn-107 is an ADC directed against AG-7 antigen, a Lewis A-like glycol-epitope expressed in 24-61% of gastric (G), colorectal (CRC), pancreatic (PDA), and biliary (BIL) cancers. Based on promising antitumor activity of AbGn-107 in both in vitro and in vivo preclinical studies, we performed a Phase Ia trial in pts with the aforementioned GI malignancies. Methods: Standard 3+3 dose escalation was used. Key eligibility criteria: locally adv or metastatic G, CRC, PDA, or BIL cancer, previously treated, ECOG PS 0-1; positive AG-7 expression was not required. Two dosing intervals were tested: AbGn-107 administered i.v. Q4 weeks (at doses ranging from 0.1-1.2 mg/kg) and Q2 weeks (at doses from 0.8-1.0 mg/kg). DLTs were based on grade 3/4 hematologic and non-heme AEs occurring during the initial 4-week rx window. Pts were treated until dz progression or unacceptable toxicity, with tumor assessments Q8 weeks. 1o objectives: safety and MTD; 2o objectives: PK, immunogenicity, and efficacy defined by ORR (RECIST 1.1). Results: 35 patients were enrolled across 6 dose levels (median age 61.5 yo (range 40 – 81); G (0)/CRC (12)/PDA (20)/BIL (3); median # lines of prior rx = 3 (range 1-7). Safety: 5 pts experienced Grade 3 or 4 neutropenia, all at higher dose levels, with 1 episode of febrile neutropenia. Other frequent drug-related AEs, mostly grade 1/2, inc. fatigue (29%), nausea (20%), and diarrhea (14%). DLTs include grade 4 CK elevation (n = 1) at 0.8 mg/kg Q4W and grade 3 arthralgias (n = 1) at 1.2 mg/kg Q4W. MTD was not reached at either 1.2 mg/kg Q4W or 0.8 mg/kg Q2W; the 1.0 mg/kg Q2W cohort will complete enrollment in Oct 2019. Efficacy: Median duration of treatment = 56 days (range, 8 – 225 days); best response observed to date is stable dz lasting > 6 months at 0.8 mg/kg Q4W and Q2W cohorts (n = 1 each). Conclusions: Overall, AbGn-107 appears well-tolerated with encouraging prelim signs of efficacy (prolonged dz control) in non-biomarker selected pts with advanced GI cancers. Pre-screening for high AG-7 expression is underway for subjects with G, CRC, PDA, and BIL cancers for the cohort expansion phase of this study, which will be open across multiple sites in U.S. and Taiwan. Clinical trial information: NCT02908451.

NuTide: 302—A phase Ib study of the ProTide NUC-3373 in combination with standard therapies in advanced colorectal cancer

TPS274

Background: Although 5-FU-based regimens such as FOLFOX and FOLFIRI remain the cornerstone of treatment for patients (pts) with colorectal cancer (CRC), their clinical utility is limited by resistance mechanisms and toxicity. Anti-cancer activity of 5-FU is dependent on conversion to an active metabolite, fluorodeoxyuridine-monophosphate (FUDR-MP), which binds to and inhibits thymidylate synthase (TS), a critical enzyme in de novo nucleotide synthesis and cell survival. However, due to multiple limitations including: reliance on enzymatic activation; catabolism by dihydropyrimidine dehydrogenase (DPD) and a short plasma half-life, 5-FU is not efficiently converted to FUDR-MP. NUC-3373, a phosphoramidate transformation of FUDR-MP, was designed to bypass the key resistance mechanisms that limit the clinical utility of 5-FU. NUC-3373 demonstrated a favorable PK/PD profile and promising efficacy signals in the first-in-human study (NuTide:301) in pts with advanced solid tumors. NUC-3373 has a longer plasma t1/2 (9.7 hours) than 5-FU (8-14 minutes) and generates high intracellular levels of FUDR-MP (Ghazaly et al ESMO, 2017). TS is efficiently inhibited and sequestered into TS-ternary complexes, depleting the pool of deoxythymidine monophosphate (dTMP) within 2-4 hours. Methods: NuTide:302 is a three-part, Phase Ib study in pts with advanced CRC who have relapsed after ≥2 prior lines of 5-FU-containing therapies. Primary objective is to identify a RP2D of NUC-3373 when administered weekly and q2w in combination with standard agents used in CRC treatment. Secondary objectives include safety, PK/PD and anti‐tumor activity. In Part 1, patients are receiving NUC-3373 with leucovorin (LV) to determine if LV augments TS inhibition. In Part 2, NUC-3373 (±LV) will be administered in dose escalating cohorts, in a modified 3+3 design, with either oxaliplatin (NUFOX) or irinotecan (NUFIRI). In Part 3, the NUFOX and NUFIRI regimens selected in Part 2 will be combined with biologics targeting VEGF or EGFR pathways. To date, 22 pts have received study treatment. Recruitment is ongoing in the US and Europe. Clinical trial information: NCT03428958.

Crizotinib in ROS1-rearranged advanced non-small-cell lung cancer (NSCLC): updated results, including overall survival, from PROFILE 1001

BACKGROUND

In the ongoing phase I PROFILE 1001 study, crizotinib showed antitumor activity in patients with ROS1-rearranged advanced non-small-cell lung cancer (NSCLC). Here, we present updated antitumor activity, overall survival (OS) and safety data (additional 46.2 months follow-up) for patients with ROS1-rearranged advanced NSCLC from PROFILE 1001.

PATIENTS AND METHODS

ROS1 status was determined by FISH or reverse transcriptase-polymerase chain reaction. All patients received crizotinib at a starting dose of 250 mg twice daily.

RESULTS

Fifty-three patients received crizotinib, with a median duration of treatment of 22.4 months. At data cut-off, treatment was ongoing in 12 patients (23%). The objective response rate (ORR) was 72% [95% confidence interval (CI), 58% to 83%], including six confirmed complete responses and 32 confirmed partial responses; 10 patients had stable disease. Responses were durable (median duration of response 24.7 months; 95% CI, 15.2-45.3). ORRs were consistent across different patient subgroups. Median progression-free survival was 19.3 months (95% CI, 15.2-39.1). A total of 26 deaths (49%) occurred (median follow-up period of 62.6 months), and of the remaining 27 patients (51%), 14 (26%) were in follow-up at data cut-off. Median OS was 51.4 months (95% CI, 29.3 to not reached) and survival probabilities at 12, 24, 36, and 48 months were 79%, 67%, 53%, and 51%, respectively. No correlation was observed between OS and specific ROS1 fusion partner. Treatment-related adverse events (TRAEs) were mainly grade 1 or 2, per CTCAE v3.0. There were no grade ≥4 TRAEs and no TRAEs associated with permanent discontinuation. No new safety signals were reported with long-term crizotinib treatment.

CONCLUSIONS

These findings serve as a new benchmark for OS in ROS1-rearranged advanced NSCLC, and continue to show the clinically meaningful benefit and safety of crizotinib in this molecular subgroup.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov identifier NCT00585195.

A pilot study of neoadjuvant FOLFIRINOX followed by chemoradiation for gastric and gastroesophageal cancer: Preliminary results

4057

Background: We performed a single-arm pilot study of total neoadjuvant approach including FOLFIRINOX and chemoradiation (CRT) with concurrent carboplatin/taxol (C/T) followed by surgery in patients with locally advanced gastric or gastroesophageal junction (GEJ) cancer. Methods: Patients were enrolled on a NCI sponsored, prospective, single arm study (NCT03279237). Key eligibility criteria included: histologically confirmed T3/4 or lymph node (LN) positive gastric or GEJ cancer, ECOG PS ≤1, age 18+, life expectancy > 3 months. Exclusion criteria included: visceral metastases, prior chemotherapy or RT, or prior targeted therapy. Extensive LN disease beyond the surgical field (supraclavicular or para-aortic) was permitted if deemed feasible to be encompassed within a RT field. Laparoscopy was not required. Pts were treated with neoadjuvant FOLFIRINOX x 8, restaging, CRT (45 Gy for gastric, 50.4 Gy for GEJ) with concurrent C/T, restaging, followed by surgical resection. Dose reductions were at discretion of the treating physician. The primary objective was to determine the rate of completion of FOLFIRINOX x 8 followed by CRT delivered in the preoperative setting. Secondary endpoints included: 1) acute toxicity and 2) pathologic complete response (pCR). Results: From Oct 2017 to June 2018, 25 pts were enrolled. Median age was 60 (range:30-76), 17 pts were male (68%). All pts started FOLFIRINOX; 23 (92%) pts completed all 8 planned cycles. Two pts did not complete the planned 8 cycles due to metastatic progression. Rates of grade 3+ overall, gastrointestinal, and hematologic toxicities were 28%, 12%, and 28% respectively. Of the entire cohort, 23 (92%) pts started chemoRT and 22 (88%) pts completed chemoRT (1 pt died during CRT due to pulseless electrical activity arrest). All 22 pts (88%) who completed CRT went for surgical exploration, of whom 2 pts were found with intraoperative metastases. Therefore, 20 (80%) pts underwent surgical resection. At time of abstract, 1 pt’s pathology is in process; 7 pts had a pCR (37% in resected cohort, 28% in ITT cohort), all with R0 resection. Conclusions: Total neoadjuvant FOLFIRINOX followed by CRT is feasible with acceptable rates of treatment completion and grade 3+ toxicity. In our small series, the rate of pCR is promising and a follow-up study is currently planned. Clinical trial information: NCT03279237.

A phase II study of ipilimumab and nivolumab with radiation in microsatellite stable (MSS) metastatic colorectal adenocarcinoma (mCRC)

3514

Background: mCRC remains a lethal cancer and immunotherapy in MSS mCRC has yet to show significant activity. In preclinical models, radiation induced cellular damage may increase responsiveness to immunotherapy via the abscopal effect, with evidence for synergy between radiation therapy (RT) and dual checkpoint blockade. In this study, we assessed dual blockade of CTLA-4 and PD-1 combined with RT as a strategy to stimulate an immune response for patients with MSS mCRC. Methods: In this open-label, single arm phase-2 study, we enrolled 40 MSS mCRC patients (pts). Eligible pts had histologically-confirmed MSS mCRC, ECOG PS 0-1, and progression on at least two lines of therapy. Treatment (Tx) consisted of ipilimumab (1mg/kg q6 weeks), nivolumab (240 mg q2 weeks) and 3 fractions of 8 Gy of RT at cycle 2 every other day. Tx continued until progression, discontinuation or withdrawal. The primary endpoint was Disease Control Rate (DCR), with radiological evaluations every 3 months. Exploratory endpoints included ORR, PFS, OS and safety. Response was defined as disease control outside the radiation field. We obtained serial tumor biopsies pre-tx, during checkpoint blockade alone (cycle 1) and 2 weeks after initiation of radiation. Intention-to-treat analysis (ITT) includes all pts receiving at least one dose of study agent. Results: 40 pts (median age 59 years (26-83), 58% male) enrolled and started treatment from 7/2017 to 12/2018. DCR was 17.5% (7/40) with a 7.5% (3/40) ORR by ITT. Median duration of disease control was 77 days in the ITT; 252 days for those with disease control (n=7) based on the first re-staging scans at 3 months or censored (n=3) and 70.5 days for pts with PD (n=17) or who did not receive RT due to clinical progression (n=13). In the modified ITT (all pts receiving RT and restaged), N=24 pts, excluding 1 pt pending 1st scans post-RT, DCR was 29.2% (7/24) and ORR 12.5% (3/24). Median duration of disease control in mITT was 77.5 days: 252 days for those with disease control and 77 days for those with PD. TRAEs were reported in 22/40 (55%). 20/40 (50%) with grade ≥3 toxicities, with fatigue, nausea, vomiting, diarrhea, infusion-related reaction and dyspnea being the most common. 1(2%) pt died of respiratory failure possibly related to tx. Conclusions: Dual blockade of CTLA-4 and PD-1 with RT is feasible and demonstrates durable activity in pts with MSS mCRC. There are 3 pts who have not completed RT or had their post-RT re-staging. We will report updated efficacy data and outcomes from correlative serial tumor biopsies upon trial completion. Clinical trial information: NCT03104439.

Aggressiveness of care and overall survival in young metastatic colorectal cancer patients

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Background: Colorectal cancer (CRC) incidence in patients younger than 50 years of age is steadily rising by 2% annually. Early-onset CRC usually presents with more aggressive features; however, data on prognosis are widely conflicting. Clinicians may hold an age-related bias in treating younger patients, but this proclivity and its effects have not been quantified. Methods: Patients with a history of metastatic CRC who consented to a departmental chart review protocol were collected between 2014 and 2018 at Massachusetts General Hospital. The cohort was divided into two groups based on age at initial diagnosis: < 50 and ≥50. Data were gathered on treatments and clinicopathological features. A log-rank test compared survival from the diagnosis of metastatic disease between age groups. The distributions of clinicopathological features were compared using Wilcoxon rank sum tests. Results: 464 metastatic CRC patients were identified. 155 patients (33%) were < 50 (median age 43, 49% female) and 309 patients (67%) were ≥50 (median age 61, 45% female). Sex did not significantly differ between the two groups (p = 0.45). Patients < 50 received more lines of therapy after metastatic diagnosis than patients ≥50 (mean 2.7 v. 2.2; p = 0.002). Younger patients also received more resections of distant metastases (mean 0.62 v. 0.48; p = 0.01). A higher rate of enrollment in clinical trials for patients < 50 approached significance (p = 0.06). Even so, patients < 50 did not see a significant survival benefit over older patients (2/5-year survival from metastatic diagnosis 77%/47% v. 73%/38%, p = 0.23). Patients < 50 had a lower proportion of right-sided tumors (p = 0.0002) and BRAF mutations (p = 0.0009). There was no difference in MSI status (p = 0.28), RAS mutational status (p = 0.40), mucinous features (p = 0.53), or signet ring features (p = 0.26). Conclusions: Overall survival in patients < 50 is similar to patients ≥50, despite patients < 50 receiving more aggressive therapy. Further study is warranted to better understand these differences. Potential areas of interest include performance status, age-related treatment bias, and biological factors.

Gemcitabine (G) + nab-paclitaxel (nab-P) versus G in patients (pts) with advanced pancreatic cancer (PDAC) after FOLFIRINOX: A single center, retrospective review

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Background: The MPACT study showed that G + nab-P improved OS and PFS over G as first line therapy for metastatic PDAC. However, there is limited data studying this combination after FOLFIRINOX. Here, we compared G + nab-P to G in pts with advanced PDAC previously treated with FOLFIRINOX. Methods: From 3/2010 to 5/2014, we identified all pts treated with FOLFIRINOX for PDAC who later received G +/- nab-P at the MGH. PFS and OS were calculated from the start of G +/- nab-P and analyzed using Kaplan-Meier and Cox-regression analyses. Results: 40 pts received G + nab-P and 36 pts received G. 29 of 36 pts in the G arm started G prior to the FDA approval of nab-P. Baseline characteristics were similar except 7 pts in the G + nab-P arm had locally advanced PDAC at start of G + nab-P while all other pts in both arms had metastatic PDAC. The median OS was 4.8 months (m) for G + nab-P vs 4.2m with G (HR 0.69, 95% CI 0.42 – 1.13). The median PFS was 2.4m for G + nab-P vs 1.8m for G (HR 0.70, 95% CI 0.44-1.12). The median OS did not change when the analysis was restricted to pts with metastatic PDAC – 4.8m vs 4.2m (HR 0.68, 95% CI 0.41-1.14). The median PFS for pts with metastatic PDAC was also similar – 2.7m for G + nab-P vs 1.8m with G (HR 0.69, 95% CI 0.42-1.12). Pts treated with G + nab-P received a median of 4m of treatment vs 2m for pts with G alone. The median relative dose of G was 50% of the maximum anticipated dose over the first 8 weeks for G + nab-P vs 66% with G. The median relative dose for nab-P was 50% of the maximum anticipated dose over the first 8 weeks. The most common reasons for discontinuing therapy were progression (62.5% vs 69%), patient decision (5% vs 11%), and infection (12.5% vs 0%). Conclusions: Although retrospective and limited by a small sample size, our data suggests that G + nab-P could be considered over G for advanced PDAC after FOLFIRINOX. However, G + nab-P affords marginal improvement in median OS and PFS, thus calling for the need to explore other agents in the second-line setting. Moreover, our experience suggests that the addition of nab-P led to a reduction in the achievable dose of G – raising the question of tolerability in combining further agents to G + nab-P in this setting.

Clinical benefit of continuing ALK inhibition with crizotinib beyond initial disease progression in patients with advanced ALK-positive NSCLC

BACKGROUND

Crizotinib is approved to treat advanced ALK-positive non-small-cell lung cancer (NSCLC), but most patients ultimately develop progressive disease (PD). We investigated whether continuing ALK inhibition with crizotinib beyond PD (CBPD) is clinically beneficial and attempted to identify clinicopathologic characteristics associated with patients who experience clinical benefit.

PATIENTS AND METHODS

Patients with advanced ALK-positive NSCLC enrolled in two ongoing multicenter, single-arm trials who developed RECIST-defined PD were allowed to continue crizotinib if they were deriving ongoing clinical benefit. In the present retrospective analysis, continuation of CBPD was defined as >3 weeks of crizotinib treatment after PD documentation. Patients who had PD as best response to initial crizotinib treatment were excluded. Baseline and post-progression characteristics, sites of PD, and overall survival (OS) were compared in patients who continued CBPD versus those who did not. The impact of continuing CBPD on OS after adjusting for potential confounding factors was assessed.

RESULTS

Among 194 crizotinib-treated patients with RECIST-defined PD, 120 (62%) continued CBPD. A significantly higher proportion of patients who continued CBPD than patients who did not had an ECOG performance status (PS) of 0/1 at PD (96% versus 82%; P=0.02). CBPD patients had significantly longer OS from the time of PD [median 16.4 versus 3.9 months; hazards ratio (HR) 0.27, 95% confidence interval (CI): 0.17-0.42; P<0.0001] and from the time of initial crizotinib treatment (median 29.6 versus 10.8 months; HR 0.30, 95% CI: 0.19-0.46; P<0.0001). The multiple-covariate Cox regression analysis revealed that CBPD remained significantly associated with improved OS after adjusting for relevant factors.

CONCLUSIONS

Patients who continued CBPD were more likely to have good ECOG PS (0/1) at the time of PD. Continuing ALK inhibition with crizotinib after PD may provide survival benefit to patients with advanced ALK-positive NSCLC.

Phase I/II study of neoadjuvant bevacizumab, erlotinib and 5-fluorouracil with concurrent external beam radiation therapy in locally advanced rectal cancer

BACKGROUND

To determine the maximal tolerated dose of erlotinib when added to 5-fluorouracil (5-FU) chemoradiation and bevacizumab and safety and efficacy of this combination in patients with locally advanced rectal cancer.

PATIENTS AND METHODS

Patients with Magnetic resonance imaging (MRI) or ultrasound defined T3 or T4 adenocarcinoma of the rectum and without evidence of metastatic disease were enrolled. Patients received infusional 5-FU 225 mg/M2/day continuously, along with bevacizumab 5 mg/kg days 14, 1, 15 and 29. Standard radiotherapy was administered to 50.4 Gy in 28 fractions. Erlotinib started at a dose of 50 mg orally daily and advanced by 50 mg increments in the subsequent cohort. Open total mesorectal excision was carried out 6-9 weeks following the completion of chemoradiation.

RESULTS

Thirty-two patients received one of three dose levels of erlotinib. Erlotinib dose level of 100 mg was determined to be the maximally tolerated dose. Thirty-one patients underwent resection of the primary tumor, one refused resection. Twenty-seven patients completed study therapy, all of whom underwent resection. At least one grade 3-4 toxicity occurred in 46.9% of patients. Grade 3-4 diarrhea occurred in 18.8%. The pathologic complete response (pCR) for all patients completing study therapy was 33%. With a median follow-up of 2.9 years, there are no documented local recurrences. Disease-free survival at 3 years is 75.5% (confidence interval: 55.1-87.6%).

CONCLUSIONS

Erlotinib added to infusional 5-FU, bevacizumab and radiation in patients with locally advanced rectal cancer is relatively well tolerated and associated with an encouraging pCR.

Phase II study of gemcitabine, oxaliplatin in combination with panitumumab in KRAS wild-type unresectable or metastatic biliary tract and gallbladder cancer

BACKGROUND

Current data suggest that platinum-based combination therapy is the standard first-line treatment for biliary tract cancer. EGFR inhibition has proven beneficial across a number of gastrointestinal malignancies; and has shown specific advantages among KRAS wild-type genetic subtypes of colon cancer. We report the combination of panitumumab with gemcitabine (GEM) and oxaliplatin (OX) as first-line therapy for KRAS wild-type biliary tract cancer.

METHODS

Patients with histologically confirmed, previously untreated, unresectable or metastatic KRAS wild-type biliary tract or gallbladder adenocarcinoma with ECOG performance status 0-2 were treated with panitumumab 6 mg kg(-1), GEM 1000 mg m(-2) (10 mg m(-2) min(-1)) and OX 85 mg m(-2) on days 1 and 15 of each 28-day cycle. The primary objective was to determine the objective response rate by RECIST criteria v.1.1. Secondary objectives were to evaluate toxicity, progression-free survival (PFS), and overall survival.

RESULTS

Thirty-one patients received at least one cycle of treatment across three institutions, 28 had measurable disease. Response rate was 45% and disease control rate was 90%. Median PFS was 10.6 months (95% CI 5-24 months) and median overall survival 20.3 months (95% CI 9-25 months). The most common grade 3/4 adverse events were anaemia 26%, leukopenia 23%, fatigue 23%, neuropathy 16% and rash 10%.

CONCLUSIONS

The combination of gemcitabine, oxaliplatin and panitumumab in KRAS wild type metastatic biliary tract cancer showed encouraging efficacy, additional efforts of genetic stratification and targeted therapy is warranted in biliary tract cancer.

Merging of Landau levels in a strongly interacting two-dimensional electron system in silicon

We show that the merging of the spin- and valley-split Landau levels at the chemical potential is an intrinsic property of a strongly interacting two-dimensional electron system in silicon. Evidence for the level merging is given by available experimental data.

First report of the visceral leishmaniasis vector Phlebotomus martini (Diptera: Psychodidae) in Tanzania

Phlebotomus martini is a known vector of visceral leishmaniasis caused by Leishmania donovani in sub-Saharan Africa. The disease is known to be endemic in areas of north and south Sudan, Kenya, Ethiopia, Uganda, and Somalia but has not been reported from Tanzania. In this report we present the first documented collection of P. martini and P. vansomerenae in Tanzania. Sand flies were collected using standard dry-ice baited CDC light traps (John W. Hock Company, Gainesville, FL) from five sampling sites in the Arusha and Kilimanjaro regions from 14 to 20 July 2010. Phlebotomus martini was collected from all sites and represented 6.6% of the total identified sand flies. Phlebotomus martini ranged from 4.5 to 9.4% of the total identified catch from the four sites in the Kilimanjaro region and 17.9% of the total identified catch at the one collection site in the Arusha region. In addition, one male specimen of the sibling species, Phlebotomus vansomerenae, was found at Chemka Springs in the Kilimanjaro region. These data indicate the presence of an established population(s) of P. martini in northern Tanzania that could support L. donovani transmission in an area with no prior case history of visceral leishmaniasis.

A mechanical model of the human heart relating septal function to myocardial work and energy

A thorough understanding of ventricular interaction and the effects of septal function on right and left ventricular performance in the human heart requires measurement of interventricular pressure gradients using high fidelity pressure transducers. The advent of newer echocardiographic techniques provides an opportunity to combine high resolution images with bi-ventricular catheterization data in the cardiac catheterization laboratory, and obtain the detailed hemodynamic and echocardiographic information necessary to more fully understand the clinical manifestations of normal and abnormal septal and free wall mechanical function. We have anticipated these developments and modified the description of heart mechanics in our integrated multi-scale model of the human cardio-respiratory system (H-CRS) to closely analyze how the mechanical properties of the inter-ventricular septum affect the work, energy utilization, and oxygen consumption of the atria, ventricles, septum, and each ventricular free wall. Combined with the H-CRS model, these modifications allow one to observe how tissue properties of the septum affect the entire heart and circulation. For example, the normal septum transfers energy from the left to the right ventricle, and assists the pre-load of both, acting as a third pump. Diseases that increase septal elastance cause abnormalities resembling left ventricular diastolic dysfunction (LVDD), including a decrease in cardiac output and an increase in pulmonary pressures despite a normal left ventricular ejection fraction. Similar applications of the H-CRS model to other regional disorders such as hypertrophic obstructive cardiomyopathy and myocardial infarction might likewise allow one to study their clinical implications in greater detail.

Weekly docetaxel, cisplatin, and irinotecan (TPC): results of a multicenter phase II trial in patients with metastatic esophagogastric cancer

BACKGROUND

Recent studies have examined the addition of docetaxel to fluorouracil and cisplatin in advanced esophagogastric cancer.

PATIENTS AND METHODS

We carried out a phase I dose-escalation study of weekly docetaxel, cisplatin, and irinotecan (TPC), given on days 1 and 8 every 3 weeks, in patients with chemonaive solid tumors. Subsequently, we completed a multiinstitutional phase II study of TPC in patients with previously untreated, metastatic esophagogastric cancer.

RESULTS

Thirty-nine patients were enrolled in the phase I trial; a weekly schedule of TPC was well tolerated. On that basis, docetaxel 30 mg/m(2), cisplatin 25 mg/m(2), and irinotecan 65 mg/m(2) were selected for the phase II trial, where in the first 18 patients irinotecan 65 mg/m(2) caused too much diarrhea and was reduced to 50 mg/m(2). Among 56 eligible patients with previously untreated, metastatic esophagogastric cancer enrolled in the phase II trial, three complete and 27 partial responses were observed (overall response rate=54%), and 15 patients (30%) had stable disease. Median progression-free survival was 7.1 months, and median survival was 11.9 months. At the final irinotecan dose of 50 mg/m(2), grade 3 or higher toxicity included diarrhea (26%), neutropenia (21%), nausea (18%), fatigue (16%), anorexia (13%), and thrombosis/embolism (13%).

CONCLUSIONS

Weekly TPC is an active and well-tolerated regimen for patients with esophagogastric cancer.

Improved quantum hard-sphere ground-state equations of state

The London ground-state energy formula as a function of number density for a system of identical boson hard spheres, corrected for the reduced mass of a pair of particles in a "sphere-of-influence" picture, and generalized to fermion hard-sphere systems with two and four intrinsic degrees of freedom, has a double-pole at the ultimate regular (or periodic, e.g., face-centered-cubic) close-packing density usually associated with a crystalline branch. Improved fluid branches are constructed based upon exact, field-theoretic perturbation-theory low-density expansions for many-boson and many-fermion systems, extrapolated to intermediate densities via Padé and other approximants, but whose ultimate density is irregular or random closest close-packing as suggested in studies of a classical system of hard spheres. Results show substantially improved agreement with the best available Green-function Monte Carlo and diffusion Monte Carlo simulations for bosons, as well as with ladder, variational Fermi hypernetted chain, and so-called L -expansion data for two-component fermions.

Merging of single-particle levels and non-Fermi-liquid behavior of finite Fermi systems

We examine the problem of finite Fermi systems having a degenerate single-particle spectrum and show that the Landau approach, applied to such a system, admits the possibility of merging single-particle levels. It is demonstrated that the opportunity for this behavior is widespread in quantum many-body systems. The salient feature of the phenomenon is the occurrence of nonintegral quasiparticle occupation numbers, leading to a radical alteration of the standard quasiparticle picture. Implications of this alteration are considered for nuclear, atomic, and solid-state systems.

Using a Human Cardiopulmonary Model to Study and Predict Normal and Diseased Ventricular Mechanics, Septal Interaction, and Atrio-Ventricular Blood Flow Patterns

We upgraded our human cardiopulmonary (CP) model with additional data that enables it to more accurately simulate normal physiology. We then tested its ability to explain human disease by changing two parameter values that decrease ventricular compliance, and found that it could predict many of the hemodynamic, gas exchange, and autonomic abnormalities found in patients with left ventricular diastolic dysfunction (LVDD). The newly incorporated information includes high-fidelity pressure tracings simultaneously recorded from the RV and LV of a normal human in a cardiac catheterization laboratory, Doppler echocardiographic inlet flow velocity patterns, measures of right and left ventricular impedance, and atrial volumes. The revised cardiovascular section details the hemodynamics of a normal subject to the extent that it can now explain the effects of septal compliance on ventricular interaction, the differences in left and right ventricular pressure development, and venous blood gas mixing in the right atrium. The model can isolate the highly interrelated features of normal and abnormal physiology, and simultaneously demonstrate their interaction in a manner that would be very difficult or impossible using an intact organism. It may therefore help physicians and scientists understand, diagnose, and improve their treatment of complicated cardiovascular and pulmonary diseases. It could also simulate the hemodynamic and respiratory effects of ventricular and pulmonary assist devices, and thus help with their development.

Pooled safety analysis of BAY 43-9006 (sorafenib) monotherapy in patients with advanced solid tumours: Is rash associated with treatment outcome?

In this analysis of the safety and efficacy of BAY 43-9006 (sorafenib) -- a novel, oral multi-kinase inhibitor with effects on tumour and its vasculature -- pooled data were obtained from four phase I dose-escalation trials. Time to progression (TTP) was compared in patients with/without grade 2 skin toxicity/diarrhoea. Grade 3 hand-foot skin reactions (HFS; 8%) and diarrhoea (6%) were common. At the recommended 400mg bid dose for phase II/III trials (RDP), 15% of patients experienced grade 2/3 HFS, and 24% experienced grade 2/3 diarrhoea. Sorafenib induced stable disease for 6 months in 12% of patients (6% stabilized for 1 year). Patients receiving sorafenib doses at or close to the RDP, who experienced skin toxicity/diarrhoea, had a significantly increased TTP compared with patients without such toxicity (P < 0.05). Sorafenib was well tolerated at the RDP, and induced sustained disease stabilization, particularly in patients with skin toxicity/diarrhoea.

A macrophage cell model for pH and volume regulation

A whole-cell model of a macrophage (mphi) is developed to simulate pH and volume regulation during a NH4Cl prepulse challenge. The cell is assumed spherical, with a plasma membrane that separates the cytosolic and extracellular bathing media. The membrane contains background currents for Na+, K+ and Cl-, a Na(+)-K+ pump, a V-type H(+)-extruder (V-ATPase), and a leak pathway for NH4+. Cell volume is controlled by instantaneous osmotic balance between cytosolic and extracellular osmolytes. Simulations reveal that the mphi model can mimic alterations in measured pH(i) and cell volume (Vol(i)) data during and after delivery of an ammonia prepulse, which induces an acid load within the cell. Our analysis indicates that there are substantial problems in quantifying transporter-mediated H+ efflux solely from experimental observations of pH(i) recovery, as is commonly done in practice. Problems stemming from the separation of effects arise, since there is residual NH4+ dissociation to H+ inside the mphi during pH(i) recovery, as well as, proton extrusion via the V-ATPase. The core assumption of conventional measurement techniques used to estimate the H+ extrusion current (I(H)) is that the recovery phase is solely dependent on transporter-mediated H+ extrusion. However, our model predictions suggest that there are major problems in using this approach, due to the complex interactions between I(H), NH3/NH4+ buffering and NH3/NH4+ efflux during the active acid extrusion phase. That is, the conventional buffer capacity-based I(H) estimation must also take into account the perturbation that a prepulse challenge brings to the cytoplasmic acid buffer itself. The importance of this whole-cell model of mphipH(i) and volume regulation lies in its potential for extension to the characterization of several other types of non-excitable cells, such as the microglia (brain macrophage) and the T-lymphocyte.

A phase I clinical trial of continual alternating etoposide and topotecan in refractory solid tumours

The goal of this phase I study was to develop a novel schedule using oral etoposide and infusional topotecan as a continually alternating schedule with potentially optimal reciprocal induction of the nontarget topoisomerase. The initial etoposide dose was 15 mg m(-2) b.i.d. days (D)1-5 weeks 1,3,5,7,9 and 11, escalated 5 mg per dose per dose level (DL). Topotecan in weeks 2,4,6,8,10 and 12 was administered by 96 h infusion at an initial dose of 0.2 mg m(-2) day(-1) with a dose escalation of 0.1, then at 0.05 mg m(-2) day(-1). Eligibility criteria required no organ dysfunction. Two dose reductions or delays were allowed. A total of 36 patients with a median age of 57 (22-78) years, received a median 8 (2-19) weeks of chemotherapy. At DL 6, dose-limiting toxicities consisted of grade 3 nausea, vomiting and intolerable fatigue. Three patients developed a line-related thrombosis or infection and one subsequently developed AML. There was no febrile neutropenia. There were six radiologically confirmed responses (18%) and 56% of patients demonstrated a response or stable disease, typically with only modest toxicity. Oral etoposide 35 mg m(-2) b.i.d. D1-5 and 1.8 mg m(-2) 96 h (total dose) infusional topotecan D8-11 can be administered on an alternating continual weekly schedule for at least 12 weeks, with promising clinical activity.

Proteasome Inhibition With Bortezomib (PS-341): A Phase I Study With Pharmacodynamic End Points Using a Day 1 and Day 4 Schedule in a 14-Day Cycle

Purpose

We performed a phase I study of a day (D) 1 and D4 bortezomib administration once every 2 weeks to determine the recommended phase II dose and toxicity profile, and the extent of 20S proteasome inhibition obtained.

Patients and Methods

Patients with solid tumors or lymphomas were treated with bortezomib at 0.25 to 1.9 mg/m2on D1 and D4, every 2 weeks. 20S proteasome levels in blood were assayed at baseline and at 1, 4, and 24 hours postdose in cycle 1.

Results

On this D1 and D4 every 2 weeks' schedule, dose-limiting toxicity (DLT) was evident at the 1.75 and 1.9 mg/m2dose levels, most commonly in patients receiving individual total doses ≥ 3.0 mg. The main DLT was peripheral neuropathy evident at the higher doses and in patients previously exposed to neurotoxic agents. Other DLTs included diarrhea and fatigue; grade 3 thrombocytopenia was also noted. Reversible inhibition of 20S proteasome activity was dose dependent and best fit a total dose (mg) per fraction rather than mg/m2; 70% of baseline activity was inhibited by a dose of 3.0 to 3.5 mg given on D1 and on D4 every other week. Antitumor effects short of confirmed partial responses were observed in patients with melanoma, non–small-cell lung cancer, and renal cell carcinoma.

Conclusion

Bortezomib (PS-341) is a novel antineoplastic agent that is well tolerated at doses not exceeding 3.0 mg (equivalent to 1.75 mg/m2), repeated on D1 and D4 every other week. This dose correlates with 70% inhibition of 20S proteasome activity. DLTs include neuropathy, fatigue, and diarrhea.

Phase transitions in nucleonic matter and neutron-star cooling

A new scenario for neutron-star cooling is suggested by the correspondence between pion condensation, induced by critical spin-isospin fluctuations, and the metal-insulator phase transition in a 2D electron gas. Above the threshold density for pion condensation, the neutron single-particle spectrum acquires an insulating gap that quenches neutron contributions to neutrino production. In the liquid phase just below the transition, the fluctuations play dual roles by (i) creating a multisheeted neutron Fermi surface that extends to low momenta and activates the normally forbidden direct Urca cooling mechanism, and (ii) amplifying the nodeless P-wave neutron superfluid gap while suppressing S-wave pairing. Lighter stars without a pion-condensed core undergo slow cooling, whereas enhanced cooling occurs in heavier stars via direct Urca emission from a thin shell of the interior.

Motion-contrast computation without directionally selective motion sensors

The detection of relative motion, i.e., motion contrast, has been reported for motion-sensitive neurons in several vertebrate systems, yet the mechanism underlying motion-contrast sensitivity remains unknown. An algorithm for computing motion contrast directly from the moving intensity distribution is proposed. In this algorithm, the time-dependent intensity distribution of the visual space is convolved with a periodic function. For coherent motion, the resulting convolution integral reduces to a traveling wave of fixed amplitude, while incoherent motion causes the amplitude to oscillate. The frequency of the amplitude oscillation provides a measure of motion contrast. The algorithm is successful in reproducing tuning curves derived from measurements of motion-contrast sensitivity in avian tectum and primate middle temporal area.

Cerebral autoregulation and gas exchange studied using a human cardiopulmonary model

The goal of this work is to study the cerebral autoregulation, brain gas exchange, and their interaction by means of a mathematical model. We have previously developed a model of the human cardiopulmonary (CP) system, which included the whole body circulatory system, lung and peripheral tissue gas exchange, and the central nervous system control of arterial pressure and ventilation. In this study, we added a more detailed description of cerebral circulation, cerebrospinal fluid (CSF) dynamics, brain gas exchange, and cerebral blood flow (CBF) autoregulation. Two CBF regulatory mechanisms are included: autoregulation and CO(2) reactivity. Central chemoreceptor control of ventilation is also included. We first established nominal operating conditions for the cerebral model in an open-loop configuration using data generated by the CP model as inputs. The cerebral model was then integrated into the larger CP model to form a new integrated CP model, which was subsequently used to study cerebral hemodynamic and gas exchange responses to test protocols commonly used in the assessment of CBF autoregulation (e.g., carotid artery compression and the thigh-cuff deflation test). The model can closely mimic the experimental findings and provide biophysically based insights into the dynamics of cerebral autoregulation and brain tissue gas exchange as well as the mechanisms of their interaction during test protocols, which are aimed at assessing the degree of autoregulation. With further refinement, our CP model may be used on measured data associated with the clinical evaluation of the cerebral autoregulation and brain oxygenation in patients.

Generating neural circuits that implement probabilistic reasoning

We extend the hypothesis that neuronal populations represent and process analog variables in terms of probability density functions (PDFs). Aided by an intermediate representation of the probability density based on orthogonal functions spanning an underlying low-dimensional function space, it is shown how neural circuits may be generated from Bayesian belief networks. The ideas and the formalism of this PDF approach are illustrated and tested with several elementary examples, and in particular through a problem in which model-driven top-down information flow influences the processing of bottom-up sensory input.