Clinical and biomarker results from a phase II trial of combined cabozantinib and durvalumab in patients with chemotherapy-refractory colorectal cancer (CRC): CAMILLA CRC cohort

CAMILLA is a basket trial (NCT03539822) evaluating cabozantinib plus the ICI durvalumab in chemorefractory gastrointestinal cancer. Herein, are the phase II colorectal cohort results. 29 patients were evaluable. 100% had confirmed pMMR/MSS tumors. Primary endpoint was met with ORR of 27.6% (95% CI 12.7-47.2%). Secondary endpoints of 4-month PFS rate was 44.83% (95% CI 26.5-64.3%); and median OS was 9.1 months (95% CI 5.8-20.2). Grade≥3 TRAE occurred in 39%. In post-hoc analysis of patients with RAS wild type tumors, ORR was 50% and median PFS and OS were 6.3 and 21.5 months respectively. Exploratory spatial transcriptomic profiling of pretreatment tumors showed upregulation of VEGF and MET signaling, increased extracellular matrix activity and preexisting anti-tumor immune responses coexisting with immune suppressive features like T cell migration barriers in responders versus non-responders. Cabozantinib plus durvalumab demonstrated anti-tumor activity, manageable toxicity, and have led to the activation of the phase III STELLAR-303 trial.

Circulating Tumor Cell Subpopulations Predict Treatment Outcome in Pancreatic Ductal Adenocarcinoma (PDAC) Patients

There is a high clinical unmet need to improve outcomes for pancreatic ductal adenocarcinoma (PDAC) patients, either with the discovery of new therapies or biomarkers that can track response to treatment more efficiently than imaging. We report an innovative approach that will generate renewed interest in using circulating tumor cells (CTCs) to monitor treatment efficacy, which, in this case, used PDAC patients receiving an exploratory new therapy, poly ADP-ribose polymerase inhibitor (PARPi)-niraparib-as a case study. CTCs were enumerated from whole blood using a microfluidic approach that affinity captures epithelial and mesenchymal CTCs using anti-EpCAM and anti-FAPα monoclonal antibodies, respectively. These antibodies were poised on the surface of two separate microfluidic devices to discretely capture each subpopulation for interrogation. The isolated CTCs were enumerated using immunophenotyping to produce a numerical ratio consisting of the number of mesenchymal to epithelial CTCs (denoted "Φ"), which was used as an indicator of response to therapy, as determined using computed tomography (CT). A decreasing value of Φ during treatment was indicative of tumor response to the PARPi and was observed in 88% of the enrolled patients (n = 31). Changes in Φ during longitudinal testing were a better predictor of treatment response than the current standard CA19-9. We were able to differentiate between responders and non-responders using ΔΦ (p = 0.0093) with higher confidence than CA19-9 (p = 0.033). For CA19-9 non-producers, ΔΦ correctly predicted the outcome in 72% of the PDAC patients. Sequencing of the gDNA extracted from affinity-selected CTC subpopulations provided information that could be used for patient enrollment into the clinical trial based on their tumor mutational status in DNA repair genes.

A phase II study of perioperative pembrolizumab plus mFOLFOX in patients with potentially resectable esophagus, gastroesophageal junction (GEJ), and stomach adenocarcinoma

BACKGROUND

Perioperative chemotherapy/chemoradiation is standard in esophageal/gastric/gastroesophageal junction (GEJ) adenocarcinoma, immune checkpoint inhibitors (ICI) effect in setting of metastatic and postoperatively. This study is to assess ICI + chemotherapy perioperatively.

METHODS

Patients with locally advanced (T1N1-3M0 or T2-3NanyM0) potentially resectable esophageal/gastric/GEJ adenocarcinoma by PET/EUS/CT and staging-laparoscopy, were treated preoperative 4 cycles mFOLFOX6 (Oxaliplatin 85 mg/m2 /Leucovorin 400 mg/m2 /5-FU bolus 400 mg/m2 then infusion 2400 mg/m2 for 46 h q2weeks) and 3 cycles pembrolizumab (200 mg q3week). Those without distal disease post-neoadjuvant and eligible for resection underwent surgery. Postoperative treatment was initiated at 4-8 weeks with 4 cycles mFOLFOX and 12 cycles pembrolizumab. The primary objective is pathological response (ypRR with tumor regression score, TRS ≤2). The expression of ICI-related markers PD-L1 (CPS), CD8, and CD20 were analyzed before and after preoperative therapy.

RESULTS

Thirty-seven patients completed the preoperative treatment. Twenty-nine patients had curative R0 resection. 6/29 (21%; 95% CI: 0.08-0.40) achieved ypCR with TRS 0 in resected patients. 26/29 (90%; 95% CI: 0.73-0.98) had ypRR with TRS ≤2. Twenty-six patients finished adjuvant therapy with a median 36.3-month follow-up. Three patients had recurrence/metastatic disease (at 9-, 10-, 22 months enrollment) with one dead at 23 months, and two are still alive at 28 and 36.5 months. The remaining (23/26) are free of disease with 3 years DFS of 88.5% and 3 years OS of 92.3%. There were no unexpected toxicities. Preoperative ICI + chemotherapy enhanced immune responses significantly with increasing expression of PD-L1 (CPS ≥10, p = 0.0078) and CD8 (>5%, p = 0.0059).

CONCLUSIONS

The perioperative pembrolizumab and mFOLFOX combination in resectable esophageal/gastric/GEJ adenocarcinoma is very effective with 90% ypRR, 21% ypCR, and impressive long-time survival benefits.

A Multicenter, Open-Label, Phase I/II Study of FN-1501 in Patients with Advanced Solid Tumors

BACKGROUND

FN-1501, a potent inhibitor of receptor FMS-like tyrosine kinase 3 (FLT3) and CDK4/6, KIT, PDGFR, VEGFR2, ALK, and RET tyrosine kinase proteins, has demonstrated significant in vivo activity in various solid tumor and leukemia human xenograft models. Anomalies in FLT3 have an established role as a therapeutic target where the gene has been shown to play a critical role in the growth, differentiation, and survival of various cell types in hematopoietic cancer and have shown promise in various solid tumors. An open-label, Phase I/II study (NCT03690154) was designed to evaluate the safety and PK profile of FN-1501 as monotherapy in patients (pts) with advanced solid tumors and relapsed, refractory (R/R) AML.

METHODS

Pts received FN-1501 IV three times a week for 2 weeks, followed by 1 week off treatment in continuous 21-day cycles. Dose escalation followed a standard 3 + 3 design. Primary objectives include the determination of the maximum tolerated dose (MTD), safety, and recommended Phase 2 dose (RP2D). Secondary objectives include pharmacokinetics (PK) and preliminary anti-tumor activity. Exploratory objectives include the relationship between pharmacogenetic mutations (e.g., FLT3, TP53, KRAS, NRAS, etc.), safety, and efficacy; as well as an evaluation of the pharmacodynamic effects of treatment with FN-1501. Dose expansion at RP2D further explored the safety and efficacy of FN-1501 in this treatment setting.

RESULTS

A total of 48 adult pts with advanced solid tumors (N = 47) and AML (N = 1) were enrolled at doses ranging from 2.5 to 226 mg IV three times a week for two weeks in 21-day cycles (2 weeks on and 1 week off treatment). The median age was 65 years (range 30-92); 57% were female and 43% were male. The median number of prior lines of treatment was 5 (range 1-12). Forty patients evaluable for dose-limiting toxicity (DLT) assessment had a median exposure of 9.5 cycles (range 1-18 cycles). Treatment-related adverse events (TRAEs) were reported for 64% of the pts. The most common treatment-emergent adverse events (TEAEs), defined as those occurring in ≥20% of pts, primarily consisted of reversible Grade 1-2 fatigue (34%), nausea (32%), and diarrhea (26%). The most common Grade ≥3 events occurring in ≥5% of pts consisted of diarrhea and hyponatremia. Dose escalation was discontinued due to DLTs of Grade 3 thrombocytopenia (N = 1) and Grade 3 infusion-related reaction (N = 1) occurring in 2 pts. The maximum tolerated dose (MTD) was determined to be 170 mg.

CONCLUSIONS

FN-1501 demonstrated reasonable safety, tolerability, and preliminary activity against solid tumors in doses up to 170 mg. Dose escalation was terminated based on 2 DLTs occurring at the 226 mg dose level.

Phase 1 study to determine the safety and dosing of autologous PBMCs modified to present HPV16 antigens (SQZ-PBMC-HPV) in HLA-A*02+ patients with HPV16+ solid tumors

We conducted a dose escalation Phase 1 study of autologous PBMCs loaded by microfluidic squeezing (Cell Squeeze® technology) with HPV16 E6 and E7 antigens (SQZ-PBMC-HPV), in HLA-A*02+ patients with advanced/metastatic HPV16+ cancers. Preclinical studies in murine models had shown such cells resulted in stimulation and proliferation of antigen specific CD8+ cells, and demonstrated antitumor activity. Administration of SQZ-PBMC-HPV was every 3 weeks. Enrollment followed a modified 3+3 design with primary objectives to define safety, tolerability, and the recommended Phase 2 dose. Secondary and exploratory objectives were antitumor activity, manufacturing feasibility, and pharmacodynamic evaluation of immune responses. Eighteen patients were enrolled at doses ranging from 0.5 × 106 to 5.0 × 106 live cells/kg. Manufacture proved feasible and required < 24 h within the overall vein-to-vein time of 1 - 2 weeks; at the highest dose, a median of 4 doses were administered. No DLTs were observed. Most related TEAEs were Grade 1 - 2, and one Grade 2 cytokine release syndrome SAE was reported. Tumor biopsies in three patients showed 2 to 8-fold increases in CD8+ tissue infiltrating lymphocytes, including a case that exhibited increased MHC-I+ and PD-L1+ cell densities and reduced numbers of HPV+ cells. Clinical benefit was documented for the latter case. SQZ-PBMC-HPV was well tolerated; 5.0 × 106 live cells/kg with double priming was chosen as the recommended Phase 2 dose. Multiple participants exhibited pharmacodynamic changes consistent with immune responses supporting the proposed mechanism of action for SQZ-PBMC-HPV, including patients previously refractory to checkpoint inhibitors.

Cabozantinib plus durvalumab in advanced gastroesophageal cancer and other gastrointestinal malignancies: Phase Ib CAMILLA trial results

This is the phase Ib part of the phase I/II CAMILLA trial evaluating cabozantinib plus durvalumab in advanced chemo-refractory proficient mismatch repair or microsatellite stable (pMMR/MSS) gastrointestinal malignancies including gastric/gastroesophageal junction/esophageal (G/GEJ/E) adenocarcinoma, colorectal cancer (CRC), and hepatocellular carcinoma (HCC). Thirty-five patients are enrolled. There are no observed dose-limiting toxicities during dose escalation. The overall grade 3/4 treatment-related adverse event rate is 34%. Among evaluable patients (n = 30), the objective response rate (ORR) is 30%, disease control rate (DCR) 83.3%, 6-month progression-free survival (PFS) 36.7%, median PFS 4.5 months, and median overall survival (OS) 8.7 months. Responses are seen in 4 of 17, 3 of 10, and 2 of 3 patients with CRC, G/GEJ/E adenocarcinoma, and HCC, respectively. Participants with a PD-L1 combined positive score (CPS) ≥5 have numerically higher ORR, PFS, and OS. Cabozantinib plus durvalumab demonstrates a tolerable safety profile and potential efficacy in previously treated advanced pMMR/MSS gastrointestinal malignancies.

Abstract CT134: Phase 1, first-in-human, dose-escalation, safety, pharmacokinetic (PK), and pharmacodynamic study of oral TP-0184, an activin receptor-like kinase-2 (ALK2) inhibitor, in patients (pts) with advanced solid tumors (ASTs)

Background: ALK2 is mutated in several cancers, including melanoma and endometrial, colorectal, bladder, and breast cancers. TP-0184 is an orally delivered ALK2 inhibitor, part of the transforming growth factor beta receptor superfamily of serine/threonine kinases, expected to reduce tumor growth in ALK2-dependent cancers. Safety, PK, and preliminary anti-tumor activity from a phase 1 study of TP-0184 in pts with ASTs (NCT03429218) are presented.

Methods: Pts with metastatic/progressive ASTs refractory to/intolerant of established therapy received oral TP-0184. Escalating doses were evaluated via a 3+3 design, starting with 30 mg/day (d) for 21/28 d. However, preliminary time-to-steady-state PK data (data cutoff: March 31, 2021) suggested a half-life of ~3-5 d. Given the estimated longer half-life (compared to available preclinical data), the protocol was amended to a dose of 60 mg once a wk (QW) for 4 wks. All pts continued on the same regimen until disease progression or unacceptable toxicity. Primary objectives: maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs). Secondary objectives: PK, antitumor activity, and recommended phase 2 dose.

Results: At data cutoff (May 27, 2021), 24 pts were treated. Mean age was 63.1 (range 34.1-83.4) y, 83.3% were female, and 75.0% had an ECOG PS of 1. Most common tumor types (≥2 pts) were colorectal (n=5); pancreatic (n=3); and lung, ovarian, and peritoneal (n=2 each). Dose escalation reached 125 mg QW (not expanded due to lack of meaningful antitumor response at 125 mg QW and study closure). No pt experienced a DLT; MTD was not reached. All pts experienced a treatment-emergent adverse event (TEAE), most commonly nausea (50%); 14 (58.3%) pts experienced a Grade 3-4 TEAE, most commonly anemia (n=3); abdominal pain, pulmonary embolism, nausea, and vomiting (n=2 each). Eight (33.3%) pts experienced a serious adverse event and 1 pt in the 60-mg QD group died during study due to disease progression, considered unrelated to treatment. Best response was stable disease in 7 (30.4%) and progressive disease in 15 (65.2%) pts; not done (n=1, 4.3%). No partial responses were observed. Preliminary PK data (data cutoff: March 31, 2021) from the weekly dosing cohorts indicated dose-related increases in exposure (maximum concentration [Cmax]) from 60 mg (Day [D] 1=20.9 [standard deviation (SD) 12.9] ng/mL; D21=32.3 [SD 26.9] ng/mL) to 125 mg (D1=45.3 [SD 27.8] ng/mL; D21=144.0 ng/mL [SD not available]), except for a decrease in mean Cmax on D1 from 90 mg to 125 mg (data not shown). Drug accumulation was observed with QW dosing but to a lesser extent than daily dosing.

Conclusions: Preliminary data suggest that TP-0184 is tolerated as monotherapy at doses up to 125 mg QW; MTD was not reached. A study in pts with myelodysplastic syndromes is ongoing.

Citation Format: Joaquina Baranda, Michael S. Gordon, Aparna R. Parikh, Huyuan Yang, Gregory K. Pennock, Philip Komarnitsky, Muhammad S. Beg. Phase 1, first-in-human, dose-escalation, safety, pharmacokinetic (PK), and pharmacodynamic study of oral TP-0184, an activin receptor-like kinase-2 (ALK2) inhibitor, in patients (pts) with advanced solid tumors (ASTs) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT134.

Pre-operative Carboplatin/Paclitaxel Versus 5-Fluorouracil (5-FU)-based Chemoradiotherapy for Older Adults With Esophageal Cancer

BACKGROUND/AIM

This study aimed to compare the efficacy and tolerability of pre-operative platinum/5-fluorouracil (P5F) and carboplatin/paclitaxel (CP), in combination with radiation therapy in older adults with locally advanced, stage I-III esophageal cancer.

PATIENTS AND METHODS

We retrospectively reviewed 51 patients aged ≥70 years who underwent chemoradiotherapy followed by esophagectomy for stage I-III esophageal cancer between 2008 and 2018. Pathological complete response (pCR) and survival rates were compared across the two chemotherapy regimen arms.

RESULTS

Treatment completion (p=0.28), pCR (p=0.89), and partial response rates were similar across both chemotherapy groups. Overall survival (OS) and disease-free survival (DFS) were similar across both groups with HR=0.80 (p=0.62) and HR=0.72 (p=0.72) respectively.

CONCLUSION

The lesser toxic CP regimen may be used in older patients with locally advanced esophageal cancer, with tumor response and survival rates similar to P5F chemotherapy.

345 Phase I/II trial of cabozantinib plus durvalumab in advanced gastroesophageal cancer and other gastrointestinal malignancies (CAMILLA): phase Ib safety and efficacy results

Background

Cabozantinib is a multi-tyrosine kinase inhibitor primarily targeting VEGFR, MET, and AXL. These targets promote a tumor immune permissive microenvironment. Cabozantinib has demonstrated immunomodulatory properties & clinical synergy when paired with PD-L1 inhibitors such as durvalumab. Here, we present final results of phase Ib of the Camilla trial assessing cabozantinib plus durvalumab in advanced GE adenocarcinoma (GEA), colorectal cancer (CRC), and hepatocellular carcinoma (HCC). This is an investigator-initiated trial funded by Exelixis & Astrazeneca.

Methods

Patients were administered cabozantinib + durvalumab in a dose escalation (3+3) then expansion to find the Dose Limiting Toxicities (DLTs), Recommended Phase 2 Dose (RP2D), ORR, PFS, and OS. Subgroup analysis was conducted to assess efficacy in patients with PD-L1 Combined Positive Score (CPS) ≥ 5. Dosing of cabozantinib was 20mg QD, 40mg QD, and 60mg QD PO in the 1st, 2nd, and 3rd cohorts. Dosing of durvalumab was 1500mg IV Q4W in all cohorts. DLT window was 28 days. Treatment beyond progression was allowed following modified RECIST v1.1 criteria.

Results

35 patients (14F, 21M), median age 53 years (range 27–79) were enrolled. 10 patients had GEA, 20 had CRC, and 5 had HCC; none had MMR deficiency. Median number of prior systemic therapies was 3 (range 0–3). No DLTs were observed during dose escalation. Per mature tolerability data, 11/14 patients receiving cabozantinib 60mg required dose-reduction post cycle 2 to 40mg. RP2D was determined to be cabozantinib 40mg QD plus durvalumab 1500mg Q4W. Of the 247 observed Treatment-Related Adverse Events (TRAEs), 10% (24) were grade≥3. Most common TRAEs were grade 1–2 fatigue (57%), nausea (43%), anorexia (40%), diarrhea (37%), transaminitis (34%), hand-foot syndrome (23%), & weight loss (23%). 2 patients each developed grade≥3 fatigue, weight loss, & abdominal pain. Overall, 30 pts were evaluable for efficacy. ORR 26.7%; DCR 83.3%; median PFS 4.5 months; 6-month PFS 36.7%; and median OS 9.1 months. 12 patients had PD-L1 CPS ≥5. In this subgroup, ORR 33.33%; DCR 91.67%; median PFS 6.13 months; 6-month PFS 50%; and median OS was not reached.

Conclusions

Cabozantinib plus durvalumab demonstrated promising efficacy and was fairly tolerated without new safety signals. High PD-L1 expression defined as CPS ≥ 5 was associated with improved efficacy & survival. The phase II multi-cohort part of the trial is currently ongoing.

Trial Registration

NCT03539822

Ethics Approval

The study was approved by the participating site’s local IRB.

Consent

All study participants granted a written informed consent prior to treatment initiation.

523 Preliminary clinical experience with XmAb20717, a PD-1 x CTLA-4 bispecific antibody, in patients with advanced solid tumors

Background

XmAb20717 is a humanized bispecific monoclonal antibody that simultaneously targets PD-1 and CTLA-4. We report updated data on patients treated at the recommended expansion dose from an ongoing, multicenter, Phase 1, dose-escalation and -expansion study of intravenous XmAb20717 in patients with selected advanced solid tumors that progressed after treatment with all standard therapies or with no standard therapeutic options.

Methods

A maximum tolerated dose was not reached in dose escalation. XmAb20717 10 mg/kg every 2 weeks (Q2W) was selected as the expansion dose, based on consistent T-cell proliferation in peripheral blood indicative of dual PD-1/CTLA-4 checkpoint blockade, and response to treatment (RECIST[1.1]).1 Parallel expansion cohorts included ~20 patients each with melanoma, renal cell carcinoma (RCC), non-small cell lung cancer (NSCLC), castration-resistant prostate cancer (CRPC), and a basket of tumor types without an FDA-approved checkpoint inhibitor (CI). Patients treated with 10 mg/kg in dose escalation were pooled with expansion cohorts for analysis of clinical activity and safety.

Results

As of 9 June 2021, 110 patients, ranging in age from 39 to 89 years and 66.4% male, were treated, and 5 were continuing treatment. Patients had received a median of 4 prior systemic treatment regimens, including CI therapy for 64.5%. The objective response rate was 13.0% (10/77 patients evaluable for efficacy), including 1 complete response (melanoma [confirmed]) and 9 partial responses (confirmed: 1 melanoma, 2 RCC, 2 CRPC, 1 ovarian cancer; unconfirmed: 1 melanoma, 2 NSCLC). The CRPC responders (2/7 with RECIST-measurable disease) had confirmed PSA decreases ≥ 50% from baseline (to 0.02 and 0.3 ng/mL); neither had progression on bone scans. All responders had prior CI exposure, except those with CRPC. Robust CD4 and CD8 T-cell activation was seen. Low baseline tumoral expression of myeloid recruitment genes, including IL-8, was associated with clinical benefit. Grade ≥ 3 immunotherapy-related adverse events in ≥ 3 patients included rash (16.4%), transaminase elevations (9.1%), hyperglycemia (4.5%), acute kidney injury (3.6%), amylase and lipase increased (2.7%), and lipase increased (2.7%).

Conclusions

Preliminary data indicate 10 mg/kg XmAb20717 Q2W was associated with complete and partial responses in multiple tumor types and was generally well-tolerated in these heavily pretreated patients with advanced cancer. Changes in T-cell populations in the periphery and tumor are consistent with robust dual checkpoint blockade. These findings support further development of XmAb20717 in advanced solid tumors, including metastatic prostate cancer.

Trial Registration

NCT03517488

References

Shum E, Daud A, Reilley M, et al. Preliminary safety, pharmacokinetics/pharmacodynamics, and antitumor activity of XmAb20717, a PD-1 x CTLA-4 bispecific antibody, in patients with advanced solid tumors. JITC 2020;8(3):A247-8.

Ethics Approval

The study was approved by each institution’s IRB.

531 A Phase 1b multi-tumor cohort study of cabozantinib plus atezolizumab in advanced solid tumors: results of the triple-negative breast cancer, ovarian cancer, and endometrial cancer cohorts

Background

Cabozantinib, a multiple receptor tyrosine kinase inhibitor, promotes an immune-permissive environment which might enhance the activity of immune checkpoint inhibitors. COSMIC-021 (NCT03170960), a multicenter phase 1b study, is evaluating the combination of cabozantinib with atezolizumab in advanced solid tumors; here we present efficacy and safety results in patients with triple negative breast cancer (TNBC), ovarian cancer (OC), and endometrial cancer (EC).

Methods

Eligible patients had locally advanced or metastatic TNBC, OC, or EC and had radiographically progressed on prior systemic anticancer therapy. One or two lines of prior therapy were permitted. Patients with OC were platinum resistant or refractory. Prior treatment with anti-PD-1 or anti-PD-L1 agents was allowed for patients with TNBC. Patients received cabozantinib, 40 mg PO QD, plus atezolizumab, 1200 mg IV Q3W. The primary endpoint was objective response rate (ORR) per RECIST 1.1 as assessed by investigator. Other endpoints included safety, duration of response (DOR), progression free survival (PFS), and overall survival (OS). CT/MRI scans were performed Q6W for the first year and Q12W thereafter.

Results

As of February 19, 2021, 30–32 patients were enrolled in each of the cohorts. 47% of patients with TNBC, 47% with OC, and 40% with EC had received 2 lines of prior therapy. Median follow-up was 18.7 months, 20.8 months, and 19.0 months for the TNBC, OC, and EC cohorts, respectively. Grade 3/4 treatment-related adverse events occurred in 33% of patients with TNBC, 56% with OC, and 37% with EC. One Grade 5 treatment-related adverse event of pulmonary hemorrhage occurred in the TNBC cohort and one of encephalitis occurred in the OC cohort. Cabozantinib plus atezolizumab demonstrated clinical activity in all three tumor cohorts (table 1).

Abstract 531 Table 1

Conclusions

Cabozantinib in combination with atezolizumab demonstrated encouraging clinical activity in patients with previously treated advanced cancers.

Acknowledgements

Medical writing support provided by Suvajit Sen, PhD (Exelixis, Inc.)

Trial Registration

NCT03170960

Ethics Approval

Yes

Consent

Yes

Abstract P13: Prospective voluntary SARS-CoV-2 virus and anti-COVID-19 antibody tests in asymptomatic medical and research staff who work in direct contact with cancer patients: A single center study

Background The SARS–CoV-2 pandemic has assaulted all aspects of daily life. Medical professionals in oncology face additional challenges with balancing prompt cancer diagnosis and urgent treatment against potential COVID-19 exposure risk in these high-risk patients. We designed this prospective freewill study to offer testing for SAR2-CoV-2 viral RNA and/or anti-COVID-19, respectively in asymptomatic medical and research staff who work in direct contact with cancer patients. The overall goal was to evaluate the prevalence of infection in this group of asymptomatic healthcare providers to reduce exposure of cancer patients to asymptomatic staff. Methods Asymptomatic medical and research staff who work in direct contact with cancer patients were asked to voluntarily be tested for either SARS–CoV-2 viral RNA or antibodies or both. Either NP swabs and/or blood samples (EDTA tube) were collected. Tests are performed at Sinochips Kansas LLC, Sinochips Diagnostics (CLIA number:17D2176068, CAP number: 8709463). The PCR test is performed with FDA authorized 2019-Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel EUA. The Elecsys® Anti-SARS-CoV-2 (Roche Diagnostics) immunoassay was used to qualitative detection of antibodies to SARS-CoV-2 in human plasma. Results From 06/18/2020 to 12/18/2020, 861 participated in the study. 1095 tests were completed for SAR2-CoV-2 virus infection, and 918 were completed for antibody. Amount participants, 530 had both virus and antibody tested. 235 were tested more than once for viral infection and 166 were tested more than once for the antibody. Median age of participants was 39 years (IQR 32-51 years). Among these 84.7% were females, 84.4% white, 6.7% African American, 4.8% Asian and 84.7% non-Hispanic. The cumulative incidence of a positive test for the virus was 2.2% (16/712), and for the antibody test was 3.8% (26/679). 5 had both viral and antibody tests positive, with an average time of 4.1 weeks from viral testing positivity to detectable antibody among 3 cases and 2 cases with both viral infection and antibody detected at same time. There were 3 cases virus was detected more than once after turning positive. 2 remained positive at 16 and 22 days after initial test and one turned negative at 36 days as of last follow up. There were 7 cases where the antibody was tested more than once after turning positive and all 7 remained positive as of last follow up (range 7-103 days). Conclusion Prospective voluntary testing in asymptomatic medical and research staff who work in direct contact with cancer patients was feasible and resulted in identification of asymptomatic carriers who then placed in quarantine, thereby limiting exposure to cancer patients. Medical and research staff who work with cancer patients are general very cautious and the frequency of infections were significantly lower than general society. In addition, it seems that 1) virus and antibody may co-exist in the same person after exposure, and 2) the antibody may last for a relatively long time.

Citation Format: Weijing Sun, Andrew K. Godwin, Kathan Mehta, Natalie Streeter, Elizabeth Wulff-Burchfield, Anup Kasi, Tara L. Lin, Joaquina Baranda, Joseph McGuirk, Ziyan Pessetto, Adam Pessetto, B.J. Broome, Terry Tsue, Roy Jensen. Prospective voluntary SARS-CoV-2 virus and anti-COVID-19 antibody tests in asymptomatic medical and research staff who work in direct contact with cancer patients: A single center study [abstract]. In: Proceedings of the AACR Virtual Meeting: COVID-19 and Cancer; 2021 Feb 3-5. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(6_Suppl):Abstract nr P13.

Update on the Role of Poly (ADP-Ribose) Polymerase Inhibitors in the DNA Repair-Deficient Pancreatic Cancers: A Narrative Review

Purpose: Pancreatic ductal adenocarcinoma (PDAC) is the most common cancer found in the pancreas. It has a dismal prognosis and current therapeutic options, including surgical resection, provide only a temporary or limited response due to the development of treatment resistance. Methods: A narrative review of studies investigating poly (ADP-ribose) polymerase (PARP) pathway inhibitors in metastatic PDAC to highlight recent advances. Results: Mutations in BRCA genes confer a higher risk of PDAC, while germ line mutations are found in 4-7% of individuals harboring pancreatic cancer. Although solid tumors with defective DNA damage repair defect (DDR) genes such as BRCA show heightened sensitivity to platinum agents, tumors can exploit the PARP pathway as salvage pathways. Therefore, blocking this pathway will trigger cell death in vulnerable tumor cells with BRCA/DNA repair deficiency. Several drugs with inhibitory activity on the PARP pathway have been approved for breast and ovarian tumors harboring germ line or somatic BRCA mutations. Based on these results, the phase III POLO study showed a significant improvement in progression-free survival compared with placebo in BRCA mutant pancreatic tumors and highlighted the importance of germ line testing in everyone diagnosed with pancreatic cancer. In addition, expansion of the PARP inhibitor indication beyond BRCA mutations to other genes involved in DDR such as ATM and PALB2 merits attention. Conclusion: PARP inhibitors represent a safe and efficacious treatment for a subset of PDAC patients with BRCA mutations. Ongoing trials are evaluating PARP inhibitors in PDAC patients with non-BRCA DDR gene deficiencies as well as PARP inhibitors in combination with other agents, notably immune checkpoint inhibitors to expand the group of patients that derive benefit from this treatment.

Total Neoadjuvant Therapy vs Standard Therapy in Locally Advanced Rectal Cancer: A Systematic Review and Meta-analysis

Importance

Standard therapy for locally advanced rectal cancer includes concurrent chemoradiotherapy followed by surgery and adjuvant chemotherapy (CRT plus A). An alternative strategy known as total neoadjuvant therapy (TNT) involves administration of CRT plus neoadjuvant chemotherapy before surgery with the goal of delivering uninterrupted systemic therapy to eradicate micrometastases. A comparison of these 2 approaches has not been systematically reviewed previously.

Objective

To determine the differences in rates of pathologic complete response (PCR), disease-free and overall survival, sphincter-preserving surgery, and ileostomy between patients receiving TNT vs standard CRT plus A.

Data Sources

MEDLINE (via PubMed) and Embase (via OVID) were searched from inception through July 1, 2020, for the following terms: anal/anorectal neoplasms OR anal/anorectal cancer AND total neoadjuvant treatment OR total neoadjuvant therapy. Only studies in English were included.

Study Selection

Randomized clinical trials or prospective/retrospective cohort studies comparing outcomes in patients with locally advanced rectal cancer who received TNT vs CRT plus A.

Data Extraction and Synthesis

Data regarding the first author, publication year, location, sample size, and rates of PCR, sphincter-preserving surgery, ileostomy, and disease-free and overall survival were extracted using Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines and pooled using a random-effects model.

Main Outcomes and Measures

Rates of PCR, sphincter-preserving surgery, ileostomy, and disease-free and overall survival.

Results

After reviewing 2165 reports, 7 unique studies including a total of 2416 unique patients, of whom 1206 received TNT, were selected. The median age for the patients receiving TNT ranged from 57 to 69 years, with 58% to 73% being male. The pooled prevalence of PCR was 29.9% (range, 17.2%-38.5%) in the TNT group and 14.9% (range, 4.2%-21.3%) in the CRT plus A group. Total neoadjuvant therapy was associated with a higher chance of achieving a PCR (odds ratio [OR], 2.44; 95% CI, 1.99-2.98). No statistically significant difference in the proportion of sphincter-preserving surgery (OR, 1.06; 95% CI, 0.73-1.54) or ileostomy (OR, 1.05; 95% CI, 0.76-1.46) between recipients of TNT and CRT plus A was observed. Only 3 studies presented data on disease-free survival, and pooled analysis showed significantly higher odds of improved disease-free survival in patients who received TNT (OR, 2.07; 95% CI, 1.20-3.56; I2 = 49%). Data on overall survival were not consistently reported.

Conclusions and Relevance

The findings of this systematic review and meta-analysis suggest that TNT is a promising strategy in locally advanced rectal cancer, with superior rates of PCR compared with standard therapy. However, the long-term effect on disease recurrence and overall survival needs to be explored in future studies.

407 Preliminary safety, pharmacokinetics/pharmacodynamics, and antitumor activity of XmAb20717, a PD-1 x CTLA-4 bispecific antibody, in patients with advanced solid tumors

Background

XmAb20717 is a humanized bispecific monoclonal antibody that simultaneously targets PD-1 and CTLA-4. We report preliminary data from an ongoing, multicenter, Phase 1 study investigating the safety/tolerability, pharmacokinetics/pharmacodynamics, and clinical activity (RECIST 1.1) of XmAb20717 in patients with selected advanced solid tumors.

Methods

A 3+3 dose-escalation design was used to establish a maximum tolerated (MTD)/recommended dose for evaluation in parallel expansion cohorts, including melanoma, renal cell carcinoma, non-small cell lung cancer (NSCLC), prostate cancer, and a basket of tumor types without an FDA-approved checkpoint inhibitor (CI; n≤20 each). XmAb20717 was administered as an infusion on Days 1 and 15 of each 28-day cycle.

Results

As of 08Jul2020, 109 patients had been treated (table 1), and 30 were continuing treatment. In escalation, 6 dose levels (0.15–10.0 mg/kg) were evaluated (n=34); an MTD was not established. Expansion cohorts were initiated at 10 mg/kg (n=72), and a 15 mg/kg escalation cohort was added (n=3). T-cell proliferation was noted in peripheral blood at doses as low as 3 mg/kg and was highest at 10 mg/kg. At this dose, consistent proliferation of CD8+ and CD4+ T cells was observed, indicative of dual PD-1 and CTLA-4 checkpoint blockade (figure 1). Paired pre- and post-dosing biopsies showed increased intratumoral T-cell infiltration and IFN-response signatures following treatment. Grade 3/4 treatment-related adverse events (TRAEs) reported for ≥3 patients included rash (13%), transaminase elevations (7%), lipase increased (4% [2% with amylase increased]), and acute kidney injury (3%), all considered immune-related. There were 2 Grade 5 TRAEs: immune-mediated pancreatitis (in the presence of pancreatic metastases) and immune-mediated myocarditis (Grade 4) that contributed to respiratory failure. A complete response was reported as the best overall response for 1 patient (melanoma); partial responses were reported for 5 patients (2 melanoma, 2 NSCLC, 1 ovarian). The objective response rate was 13% overall and 21% at 10 mg/kg (6/46 and 6/29 evaluable patients, respectively). All responders had prior CI exposure. Responses were observed only at 10 mg/kg and, within the 10 mg/kg group, appeared to correlate with higher peak serum concentration and area under the curve.

Abstract 407 Table 1

Demographics and baseline characteristics

Abstract 407 Figure 1

Mean change from baseline in percentage of Ki67+ T–cell expression in peripheral blood during first two cycles of XmAb20717

Conclusions

XmAb20717 induced T-cell proliferation in peripheral blood consistent with dual-checkpoint blockade. Preliminary data indicate XmAb20717 was generally well-tolerated and associated with evidence of antitumor activity in CI-pretreated patients with various types of advanced solid tumors.

Trial Registration

NCT03517488

Ethics Approval

The study was approved by each institution’s IRB.

Association of Neutrophil, Platelet, and Lymphocyte Ratios with the Prognosis in Unresectable and Metastatic Pancreatic Cancer

We examined the relationship between the daily rate of change of cancer antigen 19-9 (CA19-9) over the first 90 days of treatment (DRC90) and the pretreatment levels of neutrophils, lymphocytes, and platelets with the overall survival (OS) and progression-free survival (PFS) in patients with stage IV pancreatic ductal adenocarcinoma (PDA) who received chemotherapy. We retrospectively evaluated 102 locally advanced and metastatic PDA patients treated at the University of Kansas Cancer Center (KUCC) between January 2011 and September 2019. We compared the ratio of the pretreatment absolute neutrophil count to the pretreatment absolute lymphocyte count (NLR) and the ratio between the pretreatment platelet count to the pretreatment absolute lymphocyte count (PLR) with the OS and PFS. We compared the DRC90 to the OS and PFS. The ratios were analyzed using the log-rank trend test using the mean of the NLR, PLR, and DRC90 as the threshold for two groups within each variable. Patients with ≥mean NLR (4.6 K/µL) had a significantly lower OS (p = 0.0444) and PFS (p = 0.0483) compared with patients below the mean. Patients with PLR ≥ mean (3.9 K/µL) did not have a significantly different OS (p = 0.507) or PFS (p = 0.643) compared with patients below the mean. Patients with DRC90 ≥ mean (-1%) did not have a significantly different OS (p = 0.342) or PFS (p = 0.313) compared with patients below the mean. Patients with NLR ≥ mean (4.6 K/µL) had a significantly lower OS and PFS compared with patients with NLR below the mean. This implies the possibility of NLR as a prognostic marker in PDA that could guide treatment approaches but still requires validation in a larger cohort.

Immune Checkpoint Inhibitors versus VEGF Targeted Therapy as Second Line Regimen in Advanced Hepatocellular Carcinoma (HCC): A Retrospective Study

Several targeted agents including multi-tyrosine kinase inhibitors (mTKIs) and immunotherapy (IO) agents have been approved for use beyond the frontline setting in patients with advanced hepatocellular carcinoma (HCC). Due to lack of prospective head-to-head comparative trials, there is no standardized way for alternating those agents beyond frontline. Therefore, we performed a retrospective review of the Kansas University (KU) cancer registry to determine whether IO may be superior to non-IO therapy. Patients with advanced HCC were divided into two groups based on the second-line systemic regimen received (IO vs. non-IO). Progression-free survival (PFS) and overall survival (OS) were calculated under the Kaplan-Meier and Cox proportional hazards models. No statistically significant differences in PFS and OS were found, although a non-significant delayed separation in the survival curve favoring IO was identified (median PFS 3.9 months vs. 3 months; median OS 10 months vs. 10 months respectively for IO vs. non-IO). This retrospective analysis is one of the earliest and largest studies comparing second-line IO and non-IO therapies thus far reported. Future studies should aim to define specific biomarkers for response prediction and treatment optimization based on individual patient and tumor characteristics. Furthermore, combinatorial therapeutic strategies is an evolving approach showing early promising signal.

Similar response rates and survival with PARP inhibitors for patients with solid tumors harboring somatic versus Germline BRCA mutations: a Meta-analysis and systematic review

BACKGROUND

PARP inhibitors (PARPi) have recently been approved for various malignancies based on the results of several clinical trials. However, these trials have mostly recruited patients with germline BRCA mutations, and it is unclear whether PARPi have similar efficacy in patients with somatic BRCA mutations. Our study aimed to determine the efficacy of PARPi in patients with somatic BRCA mutations.

METHODS

We performed a meta-analysis comparing overall response rate to PARPi in patients harboring somatic versus germline BRCA mutations. We looked at studies including somatic and germline mutations in BRCA patients that received PARPi.

RESULTS

After screening and removing duplicates, 18 studies met our criteria for including both somatic and germline BRCA mutations. Only 8 studies reported response rates for both somatic and germline BRCA mutations. In those studies, 24 out of 43 patients with somatic BRCA mutations (55.8%), and 69 out of 157 (43.9%) patients with germline BRCA patients had a response to therapy to PARPi. This difference was not statistically significant (p = 0.399). In all five studies that reported progression-free survival, there was no obvious difference in outcomes between somatic versus germline BRCA patients, however a precise statistical analysis could not be performed.

CONCLUSION

Our meta-analysis and systematic review of the literature indicates similar response rates of PARPi therapy in patients with somatic and germline BRCA mutations. Investigation of use of PARPi therapy in a broader patient population, and the inclusion of somatic BRCA mutations in further clinical trials is paramount in improving therapeutic options for our patients.

Cabozantinib in combination with atezolizumab in non-small cell lung cancer (NSCLC) patients previously treated with an immune checkpoint inhibitor: Results from cohort 7 of the COSMIC-021 study

9610

Background: First-line immunotherapy with/without chemotherapy is standard of care for patients (pts) with advanced NSCLC; however, there is a need for effective treatment options after progression on a prior immune checkpoint inhibitor (ICI). Cabozantinib (C) may augment response to ICI by inhibiting kinases implicated in suppressing immune cell responses and has shown encouraging clinical activity in combination with ICI in other tumor types including RCC and HCC. COSMIC-021, a multicenter phase 1b study, is evaluating the combination of C with atezolizumab (A) in various solid tumors (NCT03170960). We report results from cohort 7 in NSCLC pts after prior ICI therapy. Methods: Eligible pts had ECOG performance status (PS) 0-1 and radiographic progression after one prior anti-PD-1/PD-L1 ICI given alone or in combination with chemotherapy for metastatic non-squamous NSCLC. Up to 2 lines of prior systemic anticancer therapies were permitted. Pts received C 40 mg PO QD and A 1200 mg IV Q3W. CT/MRI scans were performed Q6W for the first year and Q12W thereafter. Primary endpoint is ORR per RECIST 1.1 by investigator. Other endpoints include safety, duration of response (DOR), progression-free survival, and overall survival. Results: Thirty pts with advanced NSCLC were enrolled. Median age was 67 yrs (range 41, 81), 43% were male, 57% had ECOG PS 1, and 23% had liver metastases. Median duration of prior ICI therapy was 4.8 months (mo; range 0.8, 29), and 15 (50%) pts were refractory to prior ICI (progressive disease as best response). As of December 20, 2019, the median follow-up was 8.9 mo (range 5, 20) with 9 (30%) pts continuing study treatment. The most common treatment related adverse events (TRAEs) of any grade were diarrhea (53%), fatigue (37%), nausea (23%), decreased appetite (20%), palmar-plantar erythrodysesthesia (20%) and vomiting (20%). Grade 3/4 TRAEs occurred in 14 (47%) pts, and 1 (3.3%) had grade 5 TRAEs of myocarditis and pneumonitis. Confirmed ORR per RECIST 1.1 was 23% (7 of 30 pts; all partial responses including 3 pts refractory to prior ICI). Time to response was 1.4 mo (range 1, 3), and median DOR was 5.6 mo (range 2.6, 6.9). DCR (CR+PR+SD) was 83%. Conclusions: The combination of C and A had an acceptable safety profile and showed encouraging clinical activity in pts with advanced NSCLC who had progressed after prior ICI therapy. The response rate was greater than previously observed with C monotherapy. Due to the promising data, enrollment in this cohort has been expanded and is ongoing. Clinical trial information: NCT03170960 .

EV-202: A phase II study of enfortumab vedotin in patients with select previously treated locally advanced or metastatic solid tumors

TPS3647

Background: Nectin-4, a transmembrane cell adhesion protein, is highly expressed in urothelial carcinoma (UC), breast cancer (BC), non-small cell lung cancer (NSCLC), and gastroesophageal cancers (GEC); targeting Nectin-4 on these tumors may provide a novel treatment approach. Enfortumab vedotin (EV), an investigational human monoclonal antibody-drug conjugate, binds to Nectin-4 and upon internalization releases MMAE resulting in cell cycle arrest and cell death. Recently, EV received accelerated approval by the FDA for the treatment of adults with locally advanced/metastatic UC who previously received a PD-1 or PD-L1 inhibitor, and a platinum-containing chemotherapy in the neoadjuvant/adjuvant, locally advanced or metastatic setting. Use of EV in this study is investigational. Methods: This open-label phase 2 study (NCT04225117) will assess the efficacy and safety/tolerability of EV in patients (pts) with previously treated locally advanced/metastatic malignant solid tumors. Adult pts (~240) with histologically or cytologically confirmed disease and an ECOG ≤1 will be enrolled into 1 of 6 tumor-specific cohorts (Table), with ~40 pts each. While Nectin-4 expression is not required for enrollment, it is being tested retrospectively. Patients with active CNS metastases, grade ≥2 preexisting sensory or motor neuropathy, grade ≥3 immunotherapy-related hypothyroidism or panhypopituitarism, ongoing grade >3 immunotherapy-related AEs requiring high-dose steroids, or a history of uncontrolled diabetes mellitus within 3 months of the study will be excluded. All pts will receive EV 1.25 mg/kg IV on Days 1, 8, and 15 of each 28-day cycle until treatment discontinuation criteria are met; dose reductions/interruptions will be permitted. For all cohorts, the primary endpoint is investigator-assessed confirmed objective response rate (RECIST v1.1); secondary endpoints include duration of response, disease control rate, progression-free and overall survival, and safety/tolerability of EV. This study is recruiting as of February 2020. Clinical trial information: NCT04225117 . [Table: see text]

Diphenylbutylpiperidine Antipsychotic Drugs Inhibit Prolactin Receptor Signaling to Reduce Growth of Pancreatic Ductal Adenocarcinoma in Mice

BACKGROUND & AIMS

Prolactin (PRL) signaling is up-regulated in hormone-responsive cancers. The PRL receptor (PRLR) is a class I cytokine receptor that signals via the Janus kinase (JAK)-signal transducer and activator of transcription and mitogen-activated protein kinase pathways to regulate cell proliferation, migration, stem cell features, and apoptosis. Patients with pancreatic ductal adenocarcinoma (PDAC) have high plasma levels of PRL. We investigated whether PRLR signaling contributes to the growth of pancreatic tumors in mice.

METHODS

We used immunohistochemical analyses to compare levels of PRL and PRLR in multitumor tissue microarrays. We used structure-based virtual screening and fragment-based drug discovery to identify compounds likely to bind PRLR and interfere with its signaling. Human pancreatic cell lines (AsPC-1, BxPC-3, Panc-1, and MiaPaCa-2), with or without knockdown of PRLR (clustered regularly interspaced short palindromic repeats or small hairpin RNA), were incubated with PRL or penfluridol and analyzed in proliferation and spheroid formation. C57BL/6 mice were given injections of UNKC-6141 cells, with or without knockdown of PRLR, into pancreas, and tumor development was monitored for 4 weeks, with some mice receiving penfluridol treatment for 21 days. Human pancreatic tumor tissues were implanted into interscapular fat pads of NSG mice, and mice were given injections of penfluridol daily for 28 days. Nude mice were given injections of Panc-1 cells, xenograft tumors were grown for 2 weeks, and mice were then given intraperitoneal penfluridol for 35 days. Tumors were collected from mice and analyzed by histology, immunohistochemistry, and immunoblots.

RESULTS

Levels of PRLR were increased in PDAC compared with nontumor pancreatic tissues. Incubation of pancreatic cell lines with PRL activated signaling via JAK2-signal transducer and activator of transcription 3 and extracellular signal-regulated kinase, as well as formation of pancospheres and cell migration; these activities were not observed in cells with PRLR knockdown. Pancreatic cancer cells with PRLR knockdown formed significantly smaller tumors in mice. We identified several diphenylbutylpiperidine-class antipsychotic drugs as agents that decreased PRL-induced JAK2 signaling; incubation of pancreatic cancer cells with these compounds reduced their proliferation and formation of panco spheres. Injections of 1 of these compounds, penfluridol, slowed the growth of xenograft tumors in the different mouse models, reducing proliferation and inducing autophagy of the tumor cells.

CONCLUSIONS

Levels of PRLR are increased in PDAC, and exposure to PRL increases proliferation and migration of pancreatic cancer cells. Antipsychotic drugs, such as penfluridol, block PRL signaling in pancreatic cancer cells to reduce their proliferation, induce autophagy, and slow the growth of xenograft tumors in mice. These drugs might be tested in patients with PDAC.

EV-101: A Phase I Study of Single-Agent Enfortumab Vedotin in Patients With Nectin-4-Positive Solid Tumors, Including Metastatic Urothelial Carcinoma

PURPOSE

To assess the safety/tolerability and antitumor activity of enfortumab vedotin (EV), a novel investigational antibody-drug conjugate that delivers the microtubule-disrupting agent, monomethyl auristatin E, to cells that express Nectin-4.

METHODS

EV-101 is a phase I dose escalation/expansion study that enrolled patients with Nectin-4-expressing solid tumors (eg, metastatic urothelial carcinoma [mUC]) who progressed on ≥ 1 prior chemotherapy regimen and/or programmed death-1 receptor/programmed death ligand-1 [PD-(L)1] inhibitor, including a cohort of patients with mUC who received prior anti-PD-(L)1 therapy. Patients received escalating doses of EV up to 1.25 mg/kg on days 1, 8, and 15 of every 28-day cycle. Primary objectives were evaluation of safety/tolerability and pharmacokinetics; antitumor activity was a secondary objective.

RESULTS

Enrolled patients with mUC (n = 155) were heavily pretreated, with 96% having prior platinum-based chemotherapy and 29% receiving ≥ 3 lines of prior treatment. Maximum tolerated dose of EV was not established; however, the recommended phase II dose was identified as 1.25 mg/kg. Rash, peripheral neuropathy, fatigue, alopecia, and nausea were the most common treatment-related adverse events (TRAEs); the most common TRAEs were grade 1-2 in severity. Among the 112 patients with mUC treated with single-agent EV 1.25 mg/kg, the investigator-assessed confirmed objective response rate (ORR) was 43%, and duration of response was 7.4 months. Median overall survival (OS) was 12.3 months, and the OS rate at 1 year was 51.8%. Similar ORR and estimated median OS were observed in patients ≥ 75 years of age with and without prior anti-PD-(L)1 treatment, liver metastases, or upper-tract disease.

CONCLUSION

Single-agent EV was generally well tolerated and provided clinically meaningful and durable responses in patients with mUC; survival data are encouraging. A pivotal phase II and a confirmatory phase III study are ongoing.

Abstract 599: Secondary malignancies in temozolomide-treated metastatic pancreatic neuroendocrine tumors

Purpose: To determine the incidence of secondary malignancies in patients treated with temozolomide (TMZ) for metastatic pancreatic neuroendocrine tumors (PNET).

Background: TMZ is an oral alkylating agent used to treat glioblastoma multiforme (GBM), refractory anaplastic astrocytoma (AA), and metastatic PNET. This imidazotetrazine analog of dacarbazine lacks the ability to directly crosslink DNA and is thought to be less leukemogenic than other alkylators. Given either alone, or in combination with other therapies, TMZ is associated with improved clinical outcomes. However, serious hematologic adverse events (HAEs) like agranulocytosis, lymphopenia and aplastic anemia are not uncommon. Until recently, metastatic PNET was primarily managed with somatostatin-analogs, but with more reports demonstrating therapeutic activity of TMZ-based regimens, it is anticipated that more patients with metastatic PNET will be exposed to TMZ.

Methods: To determine the incidence of secondary malignancy in TMZ-treated PNET, a systematic review of all known clinical trials, case reports, and other relevant literature regarding PNET and TMZ published before September 2017 was conducted using PubMed, Embase, Cochrane Library, and the FDA database.

Results: Twenty-one publications, including clinical trials, meta-analyses, case reports, and cohort studies were analyzed. HAEs ranged from agranulocytosis to myelodysplastic syndrome. No publications reported any secondary malignancies. Incidentally, at the University of Kansas Medical Center, 3 patients with TMZ-treated PNET developed hematologic malignancies. A 29-year-old female with metastatic PNET was treated with TMZ and subsequently developed acute myeloid leukemia (AML) with cytogenetics consistent with therapy-related leukemia. The second patient with TMZ-treated metastatic PNET developed diffuse large B-cell lymphoma. These two patients both had aggressive disease that was not responsive to multiple rounds of treatment. They succumbed to their hematologic malignancy, and not from metastatic PNET. The third patient is a 29-year-old who was recently diagnosed with high-grade T-cell lymphoblastic lymphoma and is currently undergoing treatment for his lymphoma.

Conclusion: This review did not find any cases of secondary malignancy in TMZ-treated metastatic PNET. Yet, at our own institution we have identified 3 cases of secondary hematologic malignancies in patients treated with TMZ for PNET. We believe that the leukemogenic potential of TMZ is underreported and anticipate increased reports of secondary malignancy as the use of TMZ increases. It is important for treatment guidelines to address this risk in the decision to pursue TMZ treatment. Appropriate dosing, proper follow-up and surveillance, especially in patients who are able to live long enough to develop these hematologic cancers, is crucial.

Citation Format: Nicole Balmaceda, Sunil Abhyankar, Tyler Mouw, Joaquina Baranda. Secondary malignancies in temozolomide-treated metastatic pancreatic neuroendocrine tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 599.

Randomized phase II study of PEGPH20 plus nab-paclitaxel/gemcitabine (PAG) vs AG in patients (Pts) with untreated, metastatic pancreatic ductal adenocarcinoma (mPDA)

4008

Background: Hyaluronan (HA) accumulation in the tumor microenvironment produces elevated tumor pressure, vascular compression, and reduced drug delivery. PEGPH20 degrades HA, increasing the access and therapeutic index of anticancer agents. Methods: In Stage 1 of this phase II study, pts with untreated mPDA were randomized 1:1 to PAG (P; 3 µg/kg IV 2x/wk x 3 wks in C1, then 1x/wk x 3 wks in C2+, plus AG) vs AG every 28 days. An imbalance in thromboembolic (TE) events in the PAG arm led to a clinical hold (~40% of pts discontinued PEGPH20), exclusion of pts at high risk for TE events and enoxaparin prophylaxis in both study arms. In Stage 2, randomization was 2:1 to PAG vs AG. Tumor HA was tested using a novel assay (VENTANA HA RxDx). Primary endpoints were PFS (evaluable pts) and TE event rate (Stage 2). Secondary endpoints were PFS by HA level and ORR. Results: 279 pts were randomized; 231 are evaluable for efficacy. Of 246 pts with HA data, 84 (34%) were HA-High. As of December 16, 2016, the primary PFS endpoint was statistically significant for PAG vs AG (HR 0.73, 95% CI 0.53-1.00; p = 0.048) (Table). PFS in HA-High pts was also statistically significant in the PAG vs AG arm (HR 0.51; 95% CI 0.26-1.00; p = 0.048). ORR in HA-High pts was 46% (PAG) vs 34% (AG). Overall survival in HA-High pts (exploratory) was 11.5 months (mo) (PAG) and 8.5 mo (AG) (HR 0.96, 95% CI 0.57-1.61). TE events were similar (PAG 14% vs AG 10%) following enoxaparin initiation. All grade treatment-related AE included peripheral edema (PAG 63% vs AG 26%), muscle spasms (56% vs 3%), neutropenia (34% vs 19%), and myalgia (26% vs 7%). Conclusions: Randomized Phase II study met both primary endpoints (PFS and TE event rate), with the largest improvement in the secondary endpoint of PFS in HA-High pts. These data support HA as a potential predictive biomarker for patient selection of PEGPH20, currently investigated in the ongoing global Phase III HALO 301 study with PFS and OS as co-primary endpoints. Clinical trial information: NCT01839487. [Table: see text]

Predictors of guideline treatment nonadherence and the impact on survival in patients with colorectal cancer

BACKGROUND

This study investigated the effect of comorbidity, age, health insurance payer status, and race on the risk of patient nonadherence to NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Colon and Rectal Cancers. In addition, the prognostic impact of NCCN treatment nonadherence on overall survival was assessed.

PATIENTS AND METHODS

Patients with CRC who received primary treatment at Memorial University Medical Center from 2003 to 2010 were eligible for this study. Modified Poisson regression was used to obtain risk ratios for the outcome of nonadherence with NCCN Guidelines. Hazard ratios (HRs) for the relative risk of death from all causes were obtained through Cox regression.

RESULTS

Guideline-adherent treatment was received by 82.7% of patients. Moderate/severe comorbidity, being uninsured, having rectal cancer, older age, and increasing tumor stage were associated with increased risks of receiving nonadherent treatment. Treatment nonadherence was associated with 3.6 times the risk of death (HR, 3.55; 95% CI, 2.16-5.85) in the first year after diagnosis and an 80% increased risk of death (HR, 1.80; 95% CI, 1.14-2.83) in years 2 to 5. The detrimental effect of nonadherence declined with increasing comorbidity and varied according to age.

CONCLUSIONS

Although medically justifiable reasons exist for deviating from NCCN Guidelines when treating patients with colorectal cancer (CRC), those who received nonadherent treatment had much higher risks of death, especially in the first year after diagnosis. This study's results highlight the importance of cancer health services research to drive quality improvement efforts in cancer care for patients with CRC.

Capecitabine versus 5-fluorouracil in colorectal cancer: where are we now?

Fluorouracil (5-FU) remains the most widely used agent for colorectal cancer. Capecitabine is a rationally designed 5-FU pro-drug developed to mimic the continuous infusion of 5-FU while avoiding complications and inconvenience of intravenous administration. Capecitabine is absorbed intact from the gastrointestinal tract, converted enzymatically to active 5-FU, and released directly into the tumor. Capecitabine’s efficacy and safety are shown in multiple phase III trials across different disease stages and therapy lines. Three randomized phase III trials demonstrated the equivalence of capecitabine plus oxaliplatin (XELOX) versus 5-FU/leucovorin (LV)/oxaliplatin (FOLFOX). The safety of capecitabine compared with 5-FU depends on the regimen of 5-FU used. The adverse event rate with oxaliplatin in combination with infusional 5-FU is similar to that of capecitabine plus oxaliplatin but is associated with more neutropenia and venous thrombotic events; capecitabine plus oxaliplatinbased regimens tend to be associated with more grade 3 diarrhea and hand-foot skin reaction. Combination therapy with capecitabine and irinotecan (CapeIRI) versus 5-FU/ LV and irinotecan (FOLFIRI) had more variable results; some former schedules resulted in excessive treatmentrelated toxicity. More recent data show that lower capecitabine and irinotecan doses, different schedules, and combination with targeted agents (e.g, bevacizumab) have resulted in more favorable outcomes.

Capecitabine versus 5-fluorouracil in colorectal cancer: where are we now?

Fluorouracil (5-FU) remains the most widely used agent for colorectal cancer. Capecitabine is a rationally designed 5-FU pro-drug developed to mimic the continuous infusion of 5-FU while avoiding complications and inconvenience of intravenous administration. Capecitabine is absorbed intact from the gastrointestinal tract, converted enzymatically to active 5-FU, and released directly into the tumor. Capecitabine’s efficacy and safety are shown in multiple phase III trials across different disease stages and therapy lines. Three randomized phase III trials demonstrated the equivalence of capecitabine plus oxaliplatin (XELOX) versus 5-FU/leucovorin (LV)/oxaliplatin (FOLFOX). The safety of capecitabine compared with 5-FU depends on the regimen of 5-FU used. The adverse event rate with oxaliplatin in combination with infusional 5-FU is similar to that of capecitabine plus oxaliplatin but is associated with more neutropenia and venous thrombotic events; capecitabine plus oxaliplatinbased regimens tend to be associated with more grade 3 diarrhea and hand-foot skin reaction. Combination therapy with capecitabine and irinotecan (CapeIRI) versus 5-FU/ LV and irinotecan (FOLFIRI) had more variable results; some former schedules resulted in excessive treatmentrelated toxicity. More recent data show that lower capecitabine and irinotecan doses, different schedules, and combination with targeted agents (e.g, bevacizumab) have resulted in more favorable outcomes.

Panitumumab activity in metastatic colorectal cancer (mCRC) patients (pts) with low or negative tumor epidermal growth factor receptor (EGFr) levels: An updated analysis

4082

Background: Panitumumab, a fully human monoclonal antibody against EGFr, is approved for EGFr-expressing mCRC pts with disease progression (PD) on or after fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy. However, the predictive value of EGFr tumor-membrane staining as measured by immunohistochemistry (IHC) is undetermined. Methods: This multicenter, single arm, phase 2 study enrolled pts with documented PD during or after fluoropyrimidine and adequate doses of irinotecan and oxaliplatin, and within 6 months after the most recent chemotherapy regimen (determined by an independent eligibility review committee [IERC]), 2–3 prior regimens, and low (1%-9%) or negative (<1%) EGFr tumor membrane staining (by IHC). Pts received panitumumab 6mg/kg Q2W until PD or intolerability. Tumor assessments (modified WHO, blinded central review) were performed every 8 weeks until PD or discontinuation. Endpoints were objective response rate (ORR) through wk 16 (+ =4 wk confirmation; primary), overall ORR, response duration, progression-free survival (PFS), and safety (secondary). Results: In this interim analysis, 91 pts had =20 wks of potential follow-up and comprised the IERC efficacy set; 118 pts comprised the evaluable safety set (=20 wks potential follow-up). In the IERC efficacy set, 57% were male, 86% were white, and median age (range) was 61 (26–85) years. ORR through week 16 is shown; overall ORR was the same ( Table ). The most common adverse events (all, grade 3/4) were dermatitis acneiform (72%, 6%), erythema (69%, 6%), pruritus (65%, 4%), and hypomagnesaemia by lab values (53%, 10%). Four pts (3%) had an infusion reaction per investigator (1 was grade 3). Conclusions: This analysis confirms earlier findings that panitumumab has anti-tumor activity in pts with low or undetectable EGFr tumor membrane levels as measured by IHC. This study has completed enrollment, and updated data will be presented.

[Table: see text]

No significant financial relationships to disclose.

The new paradigm in the treatment of colorectal cancer: are we hitting the right target?

The treatment of advanced colorectal cancer has definitely advanced in the last 10 years as newer and more active cytotoxic chemotherapy agents have become available. Better understanding of different fundamental molecular changes in carcinogenesis has resulted in the emergence of important therapeutic targets in colon cancer treatment. The era of nihilism has been replaced by a time of optimism with the development of targeted therapy, with the promise of agents with improved activity and a better toxicity profile in the management of colon cancer. This review focuses on novel agents, particularly targeted therapy in both earlier and more advanced phases of clinical investigations.

Panitumumab antitumor activity in patients (pts) with metastatic colorectal cancer (mCRC) expressing low (1–9%) or negative (<1%) levels of epidermal growth factor receptor (EGFr)

3547

Background: Panitumumab is a fully human monoclonal antibody directed against EGFr. We investigated the antitumor activity of panitumumab in pts with mCRC who failed prior therapy and had low or negative EGFr tumor expression. Methods: In this multicenter, phase 2 study of 150 planned pts, pts had documentation of disease progression (PD) during or after adequate doses of fluoropyrimidine, irinotecan, and oxaliplatin (centrally confirmed refractory disease [CCRD]), 2–3 prior regimens, ECOG score 0–2, and low or negative EGFr staining (by IHC) in evaluable tumor cells. Pts received panitumumab at 6 mg/kg Q2W until PD or drug intolerability. Tumor assessments (modified WHO, blinded central review) were taken periodically from wk 8 until PD. Endpoints were objective response (OR) through wk 16 (+ ≥ 4 wk confirmation; primary) and OR throughout study, response duration, progression-free survival (PFS) time, survival time, and safety (secondary). Results: In this interim analysis (6/05), 88 pts were enrolled and had ≥ 1 dose of panitumumab (safety set); 23 pts had ≥ 20 wks before the cutoff and CCRD (efficacy set). The efficacy set consisted of 16M/7W, median age of 65 (range: 46, 85) yrs, 83% white, 100% with ECOG ≤ 1, 74% colon cancer and 26% rectal cancer; all received ≥ 2 prior regimens (equivalent characteristics for safety set). 2/11 (18%) pts with EGFr-negative tumors and 1/12 (8%) with low EGFr staining had a partial response. Duration was up to 16 wks. 7/23 (30%) of all pts had SD. Median (95% CI) PFS was 7.9 (7.0, 23.0) wks. In the safety set, all pts had a treatment-related adverse event; 19% grade (gr) 3; 2% gr 4. Integument and eye toxicities were: 92% skin, 17% eye, 28% nail, 8% hair, and 2% chelitis. 20 (23%) had diarrhea (1 gr 3); 7 (8%) had hypomagnesemia (2 gr 3/4). Three pts had an infusion reaction-1 gr 3 (led to panitumumab discontinuation) and 2 gr 1/2. In 65 pts with both a baseline and post-baseline sample, no human anti-human antibodies to panitumumab were detected. Updated data will be presented. Conclusions: Responses to panitumumab were seen in pts with mCRC with both low and negative EGFr levels. Efficacy appears similar to that in other studies with panitumumab in pts with higher EGFr tumor levels.

[Table: see text]

Angiogenic switch in Barrett's adenocarcinoma: the role of vascular endothelial growth factor

The development of cancerous cells from the normal cells is the consequence of multiple genetic and epigenetic abuses. Activation of "Angiogenic switch" or formation of new blood vessels is one of the upshots of these abuses. Multiple factors are associated with the activation of angiogenic switch. Vascular endothelial growth factor (VEGF) and its down stream signaling molecules is important troupe of this event. In this article, we reviewed the role this troupe in the development of Barrett's adenocarcinoma and also discussed the possible remedies, which have the impact on blocking the function of this troupe.

Phase II clinical trial of 5-fluorouracil, trimetrexate, and leucovorin (NFL) in patients with advanced pancreatic cancer

BACKGROUND

Advanced pancreatic cancer has limited treatment options. 5-fluorouracil (5-FU) is frequently used in the treatment of pancreatic cancer. Preclinical studies suggest synergism between trimetrexate (TMTX),5-FU, and leucovorin (NFL).

AIM

We conducted a phase II trial to evaluate the activity and safety of NFL in pancreatic cancer.

METHOD

Eligible patients (n = 21) with untreated advanced pancreatic cancer were treated with 110 mg/m2 intravenous (IV) THTX on day 1 and 200 mg/m2 IV leucovorin prior to 500 mg/m2 IV 5-FU on day 2. Oral leucovorin (15 mg every 6 h for seven doses) started intravenous 24 h later.

RESULTS

Treatment was administered for 6 wk followed by a 2-wk rest period. Response was evaluated every 8 wk. All patients were evaluable for response and toxicity. Most patients (80%) had distant metastases. Forty-five cycles of chemotherapy were administered. The most common serious toxicities were Grade 3 diarrhea (23.8%) and nausea and vomiting (14.2%). The response rate was 4.1% (95% CI, 0-23%), median survival was 6.8 mo, and 1-yr survival was 19%.

CONCLUSION

Treatment with NFL is well-tolerated in patients with advanced pancreatic cancer. The median survival and 1-yr survival in these patients with poor prognosis compares favorably with other treatment options.

Docetaxel and ketoconazole in advanced hormone-refractory prostate carcinoma

BACKGROUND

Docetaxel has significant single-agent activity in patients with prostate carcinoma, and ketoconazole has activity as a second-line hormonal agent. In vitro, ketoconazole exhibits synergy with several chemotherapeutic agents. A potential drug interaction exists, however, because both docetaxel and ketoconazole are metabolized hepatically by the cytochrome p450 system (CYP3A4). The authors performed a Phase I study and a pharmacokinetic study evaluating the both tolerability of a docetaxel/ketoconazole combination as well as this potential drug interaction.

METHODS

For all initial patients, docetaxel was administered intravenously at a dose of 55 mg/m(2) over 1 hour every 21 days. Starting on Day 8 after their first docetaxel dose, cohorts of at least 3-5 new patients were enrolled to receive escalating doses of ketoconazole. When the maximally tolerated dose (MTD) of ketoconazole was reached, the subsequent cohort of patients received an escalating dose of docetaxel. Pharmacokinetic studies were performed after docetaxel infusions on Day 1 (prior to ketoconazole) and Day 22 (after starting ketoconazole).

RESULTS

Twenty-six patients were enrolled and completed at least 2 cycles of treatment. The MTD was ketoconazole 400 mg twice daily and docetaxel 55 mg/m(2). Dose-limiting toxicities included neutropenia and fatigue. Ketoconazole did not cause a consistent effect on docetaxel pharmacokinetics, although there was significant intrapatient and interpatient variability in serum levels.

CONCLUSIONS

The recommended Phase II dose for this combination is ketoconazole 400 mg twice daily and docetaxel 55 mg/m(2) every 21 days.