Comparison between a complete preconditioning programme and conventional conduct on behaviour, health and performance of young bulls from small cow-calf herds

Bovine respiratory diseases (BRDs) have major socioeconomic impacts in the beef sector. Antimicrobials have been traditionally used to prevent the development of BRDs upon arrival in fattening units. Currently, from a "One Health and One Welfare" perspective, alternative solutions are being investigated. Preconditioning programmes that aim at reducing stress and reinforcing immune functions have been proposed to decrease BRDs incidence. In this study, we assessed the effect of a preconditioning protocol set up in nine commercial beef herds on young bulls' behaviour, health, and performance. Preconditioned bulls (PREC) were weaned indoors 50 days before departure, and progressively fed a concentrate diet supplemented with vitamins and trace elements. They also received an anthelmintic treatment, and two doses of a trivalent vaccine against respiratory pathogens at 4-week intervals. In contrast, controls (CTRL) were kept on pasture with their dams with no vaccination or particular diets. All calves were transported together to a single sorting facility to be sorted by experimental groups, origins, and BW, forming new groups before dispatch to four fattening units. At arrival, CTRL were treated with anthelmintic drugs and received one injection of the same BRDs vaccine. No intervention was performed on PREC bulls. BRD-scores were 0.73 in PREC versus 0.07 in CTRL (P = 0.01) during the preconditioning period and 0.96 in PREC versus 0.54 in CTRL (P = 0.41) after 15 days in the fattening units. Morbidity estimates were 18% in PREC versus 1% in CTRL (P < 0.001) during the preconditioning period and 32% in PREC versus 19% (P = 0.07) in CTRL after 15 days in the fattening units. Poor housing conditions during preconditioning and a different aetiology could partly explain these results. At arrival to fattening, the average daily gain (ADG) was 1 605 g for PREC versus 1 140 g (P = 0.012) for CTRL. After fattening for 180 days, differences in BW, ADG, carcass weight and conformation were inconclusive. In Europe, preconditioning programmes including vaccination must be set up coherently with good husbandry practices and with a global adaptation of batch management of the beef sector otherwise, they may be less effective than expected.

[Hepatopulmonary syndrome]

The hepatopulmonary syndrome (HPS) is one of the lung diseases associated with cirrhosis and portal hypertension. It should be discussed for any dyspnea in cirrhotic patients. HPS is a pulmonary vascular disease characterized by intrapulmonary vascular dilatations (IPVD). The pathogenesis is complex and seems to rely on communications between the portal and pulmonary circulations. The diagnosis is based on a triad of liver disease and portal hypertension, evidence of IPVDs, and impaired gas exchange (alveolar-arterial oxygen difference [A-aO2]≥15mmHg). HPS impairs prognosis (23% survival at 5years) and patients' quality of life. Liver transplantation (LT) allows regression of IPDVD in almost 100% of cases, normalization of gas exchange and improves survival with a 5-year post-LT survival between 76 and 87%. It is the only curative treatment, indicated in patients with severe HPS, defined by an arterial partial pressure of oxygen (PaO2) below 60mmHg. When LT is not indicated or feasible, long-term oxygen therapy may be proposed as a palliative treatment. A better understanding of the pathophysiological mechanisms is needed to improve the therapeutic possibilities in a near future.

[Dysfunction of endothelial BMP-9 signaling in pulmonary vascular disease]

The signaling pathway of the bone morphogenetic protein (BMP)-9 binding to the endothelial receptor BMP receptor type II (BMPR-II), activin receptor-like kinase-1 (ALK1) and the coreceptor endoglin is essential to maintain the pulmonary vascular integrity. Dysregulation of this pathway is implicated in numerous vascular diseases, such as pulmonary arterial hypertension (PAH), hereditary hemorrhagic telangiectasia (HHT) and hepatopulmonary syndrome (HPS). This article aims to provide a comprehensive review of the implication of the BMP-9/BMPR-II/ALK1/endoglin pathway in the pathophysiology of these diseases.

First-In-Human, First-In-Class, Phase I Trial of the Fucosylation Inhibitor SGN-2FF in Patients with Advanced Solid Tumors

LESSONS LEARNED

Inhibition of glycoprotein fucosylation, as monotherapy and in combination with immune checkpoint blockade, is a promising therapeutic strategy for treating a broad range of cancers. In this first-in-human, first-in-class, phase I study in advanced solid tumors, SGN-2FF demonstrated dose-proportional pharmacokinetics, evidence of pharmacodynamic target inhibition of glycoprotein fucosylation, and preliminary antitumor activity. SGN-2FF was associated with thromboembolic events that led to study termination.

BACKGROUND

We conducted a first-in-human, first-in-class, phase I study of SGN-2FF, a potent small molecule inhibitor of glycoprotein fucosylation, in patients with advanced solid tumors.

METHODS

The study consisted of four parts: SGN-2FF monotherapy dose-escalation (Part A) and expansion (Part B), and SGN-2FF + pembrolizumab dose-escalation (Part C) and expansion (Part D). The objectives were to evaluate safety and tolerability, maximum tolerated dose (MTD), pharmacokinetics (PK), pharmacodynamics (PD), and antitumor activity of SGN-2FF monotherapy and SGN-2FF + pembrolizumab.

RESULTS

Forty-six patients were enrolled (Part A, n=33; Part B, n=6; Part C, n=7; Part D did not enroll any patients). During Part A (n=32) exploring 1-15 g QD and 2-5 g BID, grade 3 dose-limiting toxicities were diarrhea (2 g and 15 g QD) and increased lipase (2 g QD). The MTD was 10 g daily. In Part A, common toxicities were grades 1-2 diarrhea, fatigue, and nausea (each 47%); thromboembolic events (grades 2-5) occurred in 5/32 patients (16%). Safety measures implemented included concurrent prophylactic anticoagulation with low-molecular weight heparin (LMWH). In Part C, despite the safety measures implemented, a thromboembolic event occurred in 1/7 patients (14%) during the SGN-2FF lead-in period. Of 28 evaluable patients in Part A, 1 patient with advanced head and neck squamous cell carcinoma achieved RECIST v1.1 complete response (CR) and 10 (36%) had RECIST v1.1 stable disease, including 1 patient with advanced triple negative breast cancer with 51% tumor burden reduction. SGN-2FF administration led to dose-proportional increases in exposure and PD reduction in protein fucosylation.

CONCLUSION

SGN-2FF demonstrated proof-of-mechanism and preliminary antitumor activity but was associated with thromboembolic events leading to study termination.

Preliminary safety, pharmacokinetics (PK), pharmacodynamics (PD) and clinical efficacy of uliledlimab (TJ004309), a differentiated CD73 antibody, in combination with atezolizumab in patients with advanced cancer

2511

Background: CD73 is implicated in tumor resistance to checkpoint immunotherapy (CPI) and plays a critical role in adenosine-mediated immune suppression. Uliledlimab, a differentiated CD73 antibody, inhibits the adenosine pathway in a non-competitive and unique intra-dimer binding mode. Uliledlimab suppresses tumor growth when combined with a PD-(L)1 inhibitor in multiple pre-clinical models. Methods: This 3+3 dose-escalation phase 1 study (NCT03835949) evaluated safety, tolerability, PK, PD and preliminary efficacy in cancer patients. Uliledlimab was administered intravenously at doses of 5, 10 or 15 mg/kg weekly (QW) or 15 or 20 mg/kg every 3 weeks (Q3W) alone in the first cycle and in combination with atezolizumab (1,200 mg Q3W) starting on week 4. Soluble CD73 in serum and CD73 receptor occupancy (RO) in circulating CD19+ B cells were measured. Expression of PD-L1, CD73 and A2A receptor was analyzed in baseline tumor specimens (n = 14). Tumor responses were assessed by RECIST/iRECIST. Results: As of 17 January 2021, 20 patients with advanced solid tumors were enrolled (M:F 8:12; mean age = 64; median prior regimens = 3 (range 1-9)). Uliledlimab was well-tolerated with no dose limiting toxicity. The most common treatment-related adverse events were first dose infusion related reactions (65%, n = 13) most commonly comprising chills/rigors, nausea, and vomiting (Grade 1 or 2) that resolved in subsequent infusions. PK appears linear at doses ≥ 10 mg/kg and modelling indicated a mean derived effective half-life of ̃19 days. Soluble CD73 was undetectable and complete RO was achieved in all patients after the first dose at ≥ 10 mg/kg. Anti-drug antibody was detected in 3/20 patients (15%). Among 13 efficacy-evaluable patients dosed at ≥ 10 mg/kg, complete response (CR = 1) and partial response (PR = 2) were observed in 3 patients (ORR = 23%) together with 3 stable disease (SD) patients (DCR = 46%). One PD-(L)1 inhibitor naïve patient with clear cell ovarian cancer achieved CR at 10 mg/kg QW and remains on study after 12 months. Two patients with NSCLC dosed at 15 mg/kg QW and 20 mg/kg Q3W, respectively, achieved PR. One patient failed nivolumab and the other received no prior PD-(L)1 inhibitor treatment. CD73 was expressed on 78% (mean) of malignant cells from archival tumor specimens in responders compared to 23% in non-responders. Conclusions: Uliledlimab is safe and well tolerated up to 20 mg/kg Q3W and 15 mg/kg QW. Full saturation of circulating and cell-bound CD73 was achieved at doses ≥ 10 mg/kg. Uliledlimab exhibited evidence of clinical activity in both PD-(L)1 treatment naïve and refractory cancer patients with high archival tumor expression of CD73. The results of this phase 1 study encourage further clinical investigation to evaluate the efficacy of uliledlimab in the treatment of solid tumors. Clinical trial information: NCT03835949.

SGN228-001: A phase I open-label dose-escalation, and expansion study of SGN-CD228A in select advanced solid tumors

TPS3652

Background: SGN-CD228A is an investigational antibody-drug conjugate (ADC) that targets CD228, a cell-surface oncofetal protein with prevalent expression in several types of cancer and limited expression on normal tissues. SGN-CD228A consists of a humanized IgG1 anti-CD228 monoclonal antibody conjugated to an average of 8 molecules of monomethyl auristatin E (MMAE) via a PEGylated β-glucuronidase cleavable linker. MMAE is a well-studied and highly active chemotype with an established safety profile. The proposed mechanism of action involves binding CD228 on cell surfaces, ADC internalization, and trafficking to lysosomes. MMAE is then released through β-glucuronidase cleavage of the glucuronide MMAE linker. MMAE then binds tubulin, which disrupts microtubule networks and causes cell cycle arrest and apoptosis. Methods: SGN228-001 (NCT04042480) is a phase 1, open label, multicenter, dose escalation, and expansion study enrolling up to 240 subjects to evaluate the safety, tolerability, PK, and antitumor activity of SGN-CD228A in select advanced solid tumors. Eligible subjects are ≥18 years of age and have metastatic cutaneous melanoma, malignant pleural mesothelioma, human epidermal growth factor receptor 2-negative metastatic breast cancer, advanced non-small cell lung cancer, metastatic colorectal cancer, or advanced pancreatic ductal adenocarcinoma. Subjects must have relapsed, refractory, or progressive disease, and should have no appropriate standard therapy available. Measurable disease per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST v1.1), Eastern Cooperative Oncology Group (ECOG) performance status score of ≤1, and adequate renal, hepatic, and hematologic function are required. The study includes dose escalation and dose expansion, with multiple disease-specific dose expansion cohorts and a biology cohort. Dose escalation will be conducted using the modified toxicity probability interval method (Ji 2010) to evaluate the safety and identify the maximum tolerated dose of SGN-CD228A. Following dose escalation, disease-specific expansion cohorts and a biology cohort (to evaluate exploratory biomarkers) are planned. Response assessments will be conducted every 6 weeks per RECIST v1.1 and all subjects will be followed for safety. Pharmacokinetics and markers of pharmacodynamics will be assessed regularly. Key efficacy endpoints include objective response rate, progression-free survival, and duration of objective response. Enrollment is ongoing in the US and planned in Europe. Clinical trial information: NCT04042480 .

Lung Cancer in Nonelderly Patients: Facility and Patient Characteristics Associated With Not Receiving Treatment

Background: In elderly patients with lung cancer, race/ethnicity is associated with not receiving treatment; however, little attention has been given to nonelderly patients (aged ≤65 years) with a range of disease stages and histologies. Nonelderly patients with lung cancer have superior survival at NCI-designated Comprehensive Cancer Centers (CCCs), although the reasons remain unknown. Patients and Methods: A retrospective cohort study was conducted in 9,877 patients newly diagnosed with small cell or non–small cell lung cancer (all stages) between ages 22 and 65 years and reported to the Los Angeles County Cancer Surveillance Program registry between 1998 and 2008. Multivariable logistic regression examined factors associated with nontreatment. Results: In multivariable analysis, race/ethnicity was associated with not receiving cancer treatment (black: odds ratio [OR], 1.22; P=.004; Hispanic: OR, 1.17; P=.04), adjusting for patient age, sex, disease stage, histology, diagnosis year, distance to treatment facility, type of facility (CCC vs non-CCC), and insurance status. With inclusion of socioeconomic status (SES) in the model, the effect of race/ethnicity was no longer significant (black: OR, 1.02; P=.80; Hispanic: OR, 1.00; P=1.00). Factors independently associated with nontreatment included low SES (OR range, 1.37–2.15; P<.001), lack of private insurance (public: OR, 1.71; P<.001; uninsured: OR, 1.30; P<.001), and treatment facility (non-CCC: OR, 3.22; P<.001). Conclusions: In nonelderly patients with lung cancer, SES was associated with nontreatment, mitigating the effect of race/ethnicity. Patients were also at higher odds of nontreatment if they did not have private insurance or received cancer care at a non-CCC facility. These findings highlight the importance of understanding how both patient-level factors (eg, SES, insurance status) and facility-level factors (eg, treatment facility) serve as barriers to treatment of nonelderly patients with lung cancer.

Dietary supplementation of Scutellaria baicalensis extract during early lactation decreases milk somatic cells and increases whole lactation milk yield in dairy cattle

Systemic inflammation is common in early lactation dairy cows and is associated with decreased milk production. The Scutellaria baicalensis plant contains flavonoids with anti-inflammatory and anti-oxidative properties, which may counteract the inflammatory state in early lactation dairy cows. The objective of this experiment was to determine whether Scutellaria baicalensis extract (SBE), a source of bioactive flavonoids, would alter the adaptation to lactation. Multiparous Holstein cows (n = 122) were used in a randomized block design to determine the effect of short-term and long-term postpartum administration of SBE on 305-d milk yield, 120-d milk component yield, and early lactation milk markers of inflammation and metabolic function. Treatments were 1) control, 2) short term (5-d) administration of the SBE (SBE5), and 3) long term (60-d) administration of the SBE (SBE60). Treatments were included in a treatment pellet that was identical to a control pellet in ingredient source and composition except for the extract (10 g/d SBE providing 3.3 g/d of the flavonoid baicalin), both provided via an automated milking system beginning on d 1 of lactation. Milk samples were collected on d 1, 3, and once during d 5–12 of lactation, followed by weekly sampling until 120 days in milk (DIM). Milk samples collected in the first 2 wk were used for biomarker analysis (haptoglobin, β-hydroxybutyrate [BHB], and glucose-6-phosphate [G6P]), and all samples were used for composition analysis. Cows were body condition scored every 2 wk prepartum and postpartum. Milk production, programmed pellet allocation, and actual provision of both pelleted feeds were recorded daily. Treatment effects were evaluated by contrasts between control and SBE5 and control and SBE60 for both the treatment (TP; wk 1–9) and carryover periods (CP; wk 10–37). Total pellet offered was greater for SBE60 in both the TP (P < 0.01) and CP (P = 0.02) but was not different for SBE5 during either period (P ≥ 0.13). No treatment effects were observed for body condition score (BCS), milk haptoglobin, BHB, or G6P. SBE5 did not alter milk yield or milk components. SBE60 increased whole-lactation milk yield by 1,419 kg (13%; P = 0.03). SBE60 increased milk lactose and fat yields (P ≤ 0.04) and tended to increase milk protein yield (P = 0.09) during TP, and each increased during CP (P ≤ 0.04). Somatic cell count decreased by 10% in SBE60 during TP (P = 0.02) but not CP (P = 0.13). Mastitis incidence tended to differ by treatment, being lesser for both SBE5 and SBE60 vs. control (14 and 15% vs. 33%). SBE supplementation did not impact time to pregnancy or hazard of leaving the herd. In conclusion, despite no detected treatment effects on BCS or milk biomarkers of inflammation and metabolic status, supplementation of postpartum dairy cows with Scutellaria baicalensis extract for 60 d was effective at increasing whole lactation milk yield.

Abstract 5551: SGN-2FF: A small-molecule inhibitor of fucosylation modulates immune cell activity in preclinical models and demonstrates pharmacodynamic activity in early phase 1 analysis

SGN-2FF, an orally bioavailable small molecule inhibitor of glycoprotein fucosylation, demonstrates encouraging preclinical antitumor activity in mouse models with suggested multiple mechanisms of action, including direct and indirect effects on immune cells, tumor cells, and the tumor microenvironment. The effects of SGN-2FF were evaluated on tumors implanted in multiple strains of mice to determine how differences in the immune repertoire affect the antitumor activity. SGN-2FF treatment of nude mice, which maintain functional B cells and antibody production, resulted in a delay in LS174T tumor growth compared with untreated mice, while LS174T tumors in SCID mice, which lack B cells, were unaffected by SGN-2FF. These data suggest that activity of SGN-2FF in nude mice may be dependent on residual B cells and circulating antibodies. The antitumor effect of SGN-2FF in syngeneic mouse models with intact immune systems also appears to be dependent on T cell activity. Transfer of T cells isolated from SGN-2FF-treated tumor-bearing mice to naïve tumor-bearing mice was sufficient to delay tumor growth. T cells isolated from untreated tumor-bearing mice did not have the same effect. These results demonstrate that afucosylated immune cells play a key role in the preclinical activity of SGN-2FF.

Various preclinical assays were used to detect SGN-2FF-mediated changes in cellular and IgG fucosylation important for biological activity. These assays are being applied in evaluating patient samples in the ongoing phase 1, multicenter, dose-escalation study investigating the safety, tolerability, PK, and biomarkers of antitumor activity of SGN-2FF administered orally to adult patients with advanced solid tumors (NCT# 02952989). Changes in peripheral IgG fucosylation, absolute neutrophil count, and immune cell surface fucosylation were identified as initial biomarkers for proof of pharmacodynamic activity. Preliminary data following daily doses of SGN-2FF demonstrate that cell surface fucosylation on granulocytes was significantly reduced and neutrophil count was significantly increased in 6 of 7 treated subjects; additionally, IgG fucosylation was significantly decreased in 7 of 7 subjects. PK have been characterized, and preliminary results are within the expected range as predicted from preclinical studies. Following daily administration of SGN-2FF, accumulation of the active metabolite, GDP-2FF, was observed intracellularly, while no accumulation of SGN-2FF was observed in plasma. Collectively, these data demonstrate robust biological effects of SGN-2FF. The pharmacodynamic biomarkers and PK analysis are informing next steps in identifying an optimal dose and dosing schedule for SGN-2FF.

Citation Format: Nicole M. Okeley, Ryan A. Heiser, Weiping Zeng, Shawna Mae Hengel, Jason Wall, Peter C. Haughney, Timothy Anthony Yap, Francisco Robert, Rachel E. Sanborn, Howard Burris, Laura Q. Chow, Khanh T. Do, Martin Gutierrez, Karen Reckamp, Amy Weise, D Ross Camidge, John Strickler, Conor Steuer, Zejing Wang, Megan M. O'Meara, Stephen C. Alley, Shyra J. Gardai. SGN-2FF: A small-molecule inhibitor of fucosylation modulates immune cell activity in preclinical models and demonstrates pharmacodynamic activity in early phase 1 analysis [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 5551.

TC-PTP regulates the IL-7 transcriptional response during murine early T cell development

Cytokines play a critical role in directing the discrete and gradual transcriptional changes that define T cell development. The interleukin-7 receptor (IL-7R), via its activation of the JAK-STAT pathway, promotes gene programs that change dynamically as cells progress through T cell differentiation. The molecular mechanism(s) directing differential gene expression downstream of the IL-7R are not fully elucidated. Here, we have identified T cell protein tyrosine phosphatase (TC-PTP), also known as PTPN2, as a negative regulator of IL-7R-STAT signaling in T cell progenitors, contributing to both the quantitative and qualitative nature of STAT-gene targeting. Novel genetic strategies used to modulate TC-PTP expression demonstrate that depletion of TC-PTP expression heightens the phosphorylation of STAT family members, causing aberrant expression of an interferon-response gene profile. Such molecular re-programming results in deregulation of early development checkpoints culminating in inefficient differentiation of CD4⁺CD8⁺ double positive cells. TC-PTP is therefore shown to be required to safeguard the dynamic transcriptome necessary for efficient T cell differentiation.

A pilot study of zoledronic acid in the treatment of patients with advanced malignant pleural mesothelioma

Purpose

Malignant pleural mesothelioma (MPM) is a rare malignancy with a dismal median survival of <12 months with current therapy. Single and combination chemotherapy regimens have shown only modest clinical benefit. In preclinical studies, nitrogen-containing bisphosphonates (zoledronic acid) inhibit growth of mesothelioma cells by different mechanisms: inhibition of mevalonate pathway, inhibition of angiogenesis, activation of apoptosis through caspase activation, and alteration in activity of matrix metalloproteinases, thereby affecting invasiveness of cancer cells.

Patients and methods

We investigated the role of zoledronic acid in a pilot, single-arm trial of MPM patients with Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0–2 who had progressed on prior treatments or had not received systemic therapy due to poor PS. Primary end point was composite response rate by modified response evaluation criteria in solid tumors and/or metabolic response by 2-deoxy-2-[fluorine-18]fluoro-d-glucose (¹⁸F-FDG) positron emission tomography criteria. Secondary end points were progression-free survival (PFS) and overall survival (OS). Exploratory end points include the effect of zoledronic acid therapy on vascular endothelial growth factor (VEGF), basic fibroblast growth factor, interleukin 8, transforming growth factor beta, mesothelin, and osteopontin levels.

Results

Eight male patients (median age of 62 years) with the following clinical characteristics were treated; ECOG PS was 0–2, 75% with epithelioid type, and 62% had prior chemotherapy Overall composite response rate was 12.5% and the clinical benefit rate (response + stable disease) was 37.5%. Median PFS was 2 months (0.5–21 months) and median OS was 7 months (0.8–28 months). No treatment-related toxicities were observed. Lower VEGF levels were predictive of favorable response and mesothelin levels correlated with disease course.

Conclusion

Zoledronic acid shows modest clinical activity without significant toxicity in patients with advanced MPM.

A phase 1b, open label, single institution trial of nintedanib in combination with bevacizumab in patients with advanced solid tumors

TPS2614

Background: Vascular endothelial growth factor (VEGF) is a potent factor in inducing angiogenesis. VEGF inhibitors have produced demonstrable but limited and transient clinical benefit for various cancers. One mechanism of resistance includes revascularization secondary to up-regulation of alternative pro-angiogenic signals such as platelet derived growth factor receptor (PDGF) and fibroblast growth factor receptor (FGFR) pathway. Nintedanib is an oral triple kinase inhibitor that blocks the VEGFR, PDGFR and FGFR pathways. Our study is using combination of Nintedanib (Nin) and Bevacizumab (Bev) which will block VEGF as well as salvage pathway of angiogenesis (PDGFR and FGFR). Phase I dose selection studies revealed that Nin is generally well tolerated (Clin Can Res 16:47, 2010). LUME-Lung 1 phase 3, international, double blind, placebo controlled trial using Nin and docetaxel in non-small cell lung cancer (NSCLC) showed significant improvement in progression free survival (PFS) regardless of histology and improvement in overall survival (OS) in lung adenocarcinoma (Lancet oncology 15:2, 2014). Methods: This is a phase 1b, open label, single institution trial with standard 3+3 design. Primary objective is to evaluate the safety and tolerability of combination of Nin and Bev. The secondary objective is to determine clinical efficacy (objective response), PFS, and evaluation of plasma levels of angiogenic and anti-angiogenic biomarkers like VEGF, PDGF, VEGF-R and FGF. Patients (pts) in cohort I will be treated with Bev 15 mg/kg day 1 intravenously every 3 weeks and Nin 150 mg orally (PO) twice daily (BID) from day 2-21. In the absence of dose limiting toxicities, Nintedanib dose will be increased to 200 mg PO BID in cohort II. Major inclusion criteria includes advanced solid tumors for which Bev has an indication (non-squamous, NSCLC, colon, ovarian, cervical and renal cancer), progression after at least 1 line of systemic treatment, and measurable disease. Pts with prior treatment with Bev can be enrolled. We will enroll 18 patients. Cohorts I has been completed without DLT (n = 3). Cohort II has enrolled 10 patients. Clinical trial information: NCT02835833.

Pilot phase II study of metronomic chemotherapy in combination with bevacizumab in patients with advanced non-squamous non-small cell lung cancer

INTRODUCTION

The goal of this study was to explore the efficacy and tolerability of metronomic chemotherapy, a novel anti-angiogenic treatment strategy, in combination with bevacizumab in patients with advanced non-small cell lung cancer (NSCLC).

METHODS

Subjects with newly diagnosed stage IV NSCLC were treated with 4-week cycles of paclitaxel 80mg/m² and gemcitabine 300mg/m² weekly for three weeks, plus bevacizumab 10mg/kg every two weeks. Radiologic assessments were performed every 8 weeks. The primary endpoint was progression free survival (PFS). An exploratory objective was to correlate plasma levels of angiogenic biomarkers with treatment response.

RESULTS

Thirty-nine subjects were included in the intent to treat (ITT) analysis. The objective response rate (ORR) was 56%, the median PFS was 8.5 months, and median overall survival (OS) was 25.5 months. The PFS rate at 6, 12, and 24 months was 61%, 21%, and 11% respectively. The OS rate at 12 and 24 months was 74% and 53% respectively. Treatment was well tolerated, without significant myelosuppressive, gastrointestinal, or neurologic events. Subjects with less than median baseline values of angiopoietin-2 and IL-8 experienced significantly longer PFS. Longer OS was associated with subjects with less than the median baseline values for PLGF and angiopoietin-2. There were statistically significant differences in median values of several biomarkers between cycles 1 and 3 in subjects with objective responses.

CONCLUSIONS

The combination of paclitaxel and gemcitabine, delivered in a metronomic schedule, in combination with bevacizumab, appears to be an effective and tolerable treatment strategy in patients with advanced NSCLC.

Rovalpituzumab tesirine, a DLL3-targeted antibody-drug conjugate, in recurrent small-cell lung cancer: a first-in-human, first-in-class, open-label, phase 1 study

BACKGROUND

Rovalpituzumab tesirine is a first-in-class antibody-drug conjugate directed against delta-like protein 3 (DLL3), a novel target identified in tumour-initiating cells and expressed in more than 80% of patients with small-cell lung cancer. We aimed to assess the safety and activity of rovalpituzumab tesirine in patients who progressed after one or more previous regimen.

METHODS

We conducted a phase 1 open-label study at ten cancer centres in the USA. Eligible patients were aged 18 years or older and had histologically or cytologically confirmed small-cell lung cancer or large-cell neuroendocrine tumours with progressive measurable disease (according to Response Evaluation Criteria in Solid Tumors [RECIST], version 1.1) previously treated with one or two chemotherapeutic regimens, including a platinum-based regimen. We assigned patients to dose-escalation or expansion cohorts, ranging from 0·05 mg/kg to 0·8 mg/kg rovalpituzumab tesirine intravenously every 3 weeks or every 6 weeks, followed by investigation of the dose schedules 0·3 mg/kg and 0·4 mg/kg every 6 weeks and 0·2 mg/kg every 3 weeks. Primary objectives were to assess the safety of rovalpituzumab tesirine, including the maximum tolerated dose and dose-limiting toxic effects. The primary activity endpoint was objective response by intention-to-treat analysis. This study is registered with ClinicalTrials.gov, number NCT01901653. The study is closed to enrolment; this report focuses on the cohort with small-cell lung cancer.

FINDINGS

Between July 22, 2013, and Aug 10, 2015, 82 patients were enrolled, including 74 patients with small-cell lung cancer and eight with large-cell neuroendocrine carcinoma, all of whom received at least one dose of rovalpituzumab tesirine. Dose-limiting toxic effects of rovalpituzumab tesirine occurred at a dose of 0·8 mg/kg every 3 weeks, including grade 4 thrombocytopenia (in two of two patients at that dose level) and grade 4 liver function test abnormalities (in one patient). The most frequent grade 3 or worse treatment-related adverse events in 74 patients with small-cell lung cancer were thrombocytopenia (eight [11%]), pleural effusion (six [8%]), and increased lipase (five [7%]). Drug-related serious adverse events occurred in 28 (38%) of 74 patients. The maximum tolerated dose of rovalpituzumab tesirine was 0·4 mg/kg every 3 weeks; the recommended phase 2 dose and schedule is 0·3 mg/kg every 6 weeks. At active doses of rovalpituzumab tesirine (0·2 mg/kg or 0·4 mg/kg every 3 weeks or 0·3 mg/kg or 0·4 mg/kg every 6 weeks), 11 (18%) of 60 assessable patients had a confirmed objective response. 11 (18%) of 60 assessable patients had a confirmed objective response, including ten (38%) of 26 patients confirmed to have high DLL3 expression (expression in 50% or more of tumour cells).

INTERPRETATION

Rovalpituzumab tesirine shows encouraging single-agent antitumour activity with a manageable safety profile. Further development of rovalpituzumab tesirine in DLL3-expressing malignant diseases is warranted.

FUNDING

Stemcentrx Inc.

Phase I Results from a Study of Crizotinib in Combination with Erlotinib in Patients with Advanced Nonsquamous Non-Small Cell Lung Cancer

INTRODUCTION

This phase I trial was conducted to determine the safety, maximum tolerated dose (MTD)/recommended phase II dose, and efficacy of crizotinib plus erlotinib in patients with advanced NSCLC.

METHODS

Patients with NSCLC and an Eastern Cooperative Oncology Group performance status of 0 to 2 after failure of one or two prior chemotherapy regimens were eligible. Erlotinib, 100 mg, was given continuously once daily starting between day -14 and -7; crizotinib, 200 mg twice daily (dose level 1) or 150 mg twice daily (dose level -1), was added continuously beginning on day 1 of treatment cycle 1. Potential pharmacokinetic interactions between crizotinib and erlotinib were evaluated.

RESULTS

Twenty-seven patients received treatment; 26 received crizotinib plus erlotinib. Frequent adverse events were diarrhea, rash, decreased appetite, and fatigue. Dose-limiting toxicities were dehydration, diarrhea, dry eye, dysphagia, dyspepsia, esophagitis and vomiting. The MTD was crizotinib, 150 mg twice daily, with erlotinib, 100 mg once daily. Crizotinib increased the erlotinib area under the concentration-time curve 1.5-fold (dose level -1) and 1.8-fold (dose level 1). The plasma level of crizotinib appeared to be unaffected by coadministration of erlotinib. Two patients whose tumors harbored activating EGFR mutations achieved confirmed partial responses, one at each crizotinib dose level.

CONCLUSIONS

The MTD of the combination of crizotinib and erlotinib in patients with advanced NSCLC was crizotinib, 150 mg twice daily, with erlotinib, 100 mg once daily, which is less than the approved dose of either agent. The phase II portion of the study was not initiated.

Safety and efficacy of single-agent rovalpituzumab tesirine (SC16LD6.5), a delta-like protein 3 (DLL3)-targeted antibody-drug conjugate (ADC) in recurrent or refractory small cell lung cancer (SCLC)

LBA8505

Background: SCLC remains among the most deadly of malignancies. Rovalpituzumab tesirine is a first-in-class ADC comprised of a humanized monoclonal antibody against DLL3, a dipeptide linker, and a pyrrolobenzodiazepine (PBD) dimer toxin. DLL3 is highly expressed in neuroendocrine tumors, including approximately 80% of SCLC. The emerging results of the SCLC patients (pts) in a first-in-human study (NCT01901653) are reported here. Methods: Pts with progressive SCLC after at least 1 previous systemic therapy were eligible. Efficacy was assessed by the investigator via RECIST v1.1, and toxicity graded per CTCAE v4.03. When available, archived tumor tissue was assessed retrospectively for DLL3 expression by immunohistochemistry. Results: Seventy-four (74) pts were enrolled at dose levels ranging from 0.05 to 0.8 mg/kg at either q3w or q6w. Among evaluable pts treated at doses of 0.2-0.4 mg/kg, 15/61 (25%; 95% CI 15-37%) achieved a best response of PR or CR, and 44/61 (72%; 95% CI 59-83%) achieved clinical benefit (best response of at least SD). Among pts with available archive tissue specimens and ≥ 50% of cells expressing DLL3 (DLL3hi, an intended companion diagnostic cutoff), 12/22 (55%; 95% CI 32-76%) achieved a best response of PR or CR, and 20/22 (91%; 95% CI 71-99%) achieved clinical benefit, with a median overall survival of 8 (range 1-18+) months. In 3rd line DLL3hi pts (n = 10), where no approved therapy currently exists, the ORR and CBR were 70% and 90%, respectively, with at least 4 evaluable pts achieving OS of > 6 (8, 15, 18 and 18) months. Among responders treated at the phase 2 dose of 0.3 mg/kg, the median duration of response was 6 (range 1-8+) months. Among all SCLC pts, the most common grade 3+ toxicities considered study drug-related have included serosal effusions (14%), thrombocytopenia (12%) and skin reactions (8%). Conclusions: With manageable toxicity, rovalpituzumab tesirine demonstrates encouraging single-agent anti-tumor activity and durability in recurrent or refractory SCLC. A single-arm pivotal study in 3rd line DLL3-expressing SCLC has been initiated. Clinical trial information: NCT01901653.

Repression of p53-target gene Bbc3/PUMA by MYSM1 is essential for the survival of hematopoietic multipotent progenitors and contributes to stem cell maintenance

p53 is a central mediator of cellular stress responses, and its precise regulation is essential for the normal progression of hematopoiesis. MYSM1 is an epigenetic regulator essential for the maintenance of hematopoietic stem cell (HSC) function, hematopoietic progenitor survival, and lymphocyte development. We recently demonstrated that all developmental and hematopoietic phenotypes of Mysm1 deficiency are p53-mediated and rescued in the Mysm1(-/-)p53(-/-) mouse model. However, the mechanisms triggering p53 activation in Mysm1(-/-) HSPCs, and the pathways downstream of p53 driving different aspects of the Mysm1(-/-) phenotype remain unknown. Here we show the transcriptional activation of p53 stress responses in Mysm1(-/-) HSPCs. Mechanistically, we find that the MYSM1 protein associates with p53 and colocalizes to promoters of classical p53-target genes Bbc3/PUMA (p53 upregulated modulator of apoptosis) and Cdkn1a/p21. Furthermore, it antagonizes their p53-driven expression by modulating local histone modifications (H3K27ac and H3K4me3) and p53 recruitment. Using double-knockout mouse models, we establish that PUMA, but not p21, is an important mediator of p53-driven Mysm1(-/-) hematopoietic dysfunction. Specifically, Mysm1(-/-)Puma(-/-) mice show full rescue of multipotent progenitor (MPP) viability, partial rescue of HSC quiescence and function, but persistent lymphopenia. Through transcriptome analysis of Mysm1(-/-)Puma(-/-) MPPs, we demonstrate strong upregulation of other p53-induced mediators of apoptosis and cell-cycle arrest. The full viability of Mysm1(-/-)Puma(-/-) MPPs, despite strong upregulation of many other pro-apoptotic mediators, establishes PUMA as the essential non-redundant effector of p53-induced MPP apoptosis. Furthermore, we identify potential mediators of p53-dependent but PUMA-independent Mysm1(-/-)hematopoietic deficiency phenotypes. Overall, our study provides novel insight into the cell-type-specific roles of p53 and its downstream effectors in hematopoiesis using unique models of p53 hyperactivity induced by endogenous stress. We conclude that MYSM1 is a critical negative regulator of p53 transcriptional programs in hematopoiesis, and that its repression of Bbc3/PUMA expression is essential for MPP survival, and partly contributes to maintaining HSC function.

Abstract CT222: Differences in pharmacokinetics of TRC105 (anti-endoglin antibody) when administered as a single agent versus in combination with bevacizumab (Bev)

Background: TRC105 is an anti-endoglin chimeric monoclonal antibody that inhibits angiogenesis and tumor growth and is being studied in randomized Phase 2 trials with Bev. TRC105 is cleared through binding to endoglin expressed on proliferating endothelium when given as a single agent to cancer patients (Spencer et al, ASCO 2012). Preclinical data indicate that endoglin expression is increased in response to VEGF targeted treatment, and increased endoglin expression in response to Bev may increase the clearance of TRC105 when administered in combination to cancer patients.

Methods: Patients (pts) with solid tumors (ST) or ovarian cancer (OC) received 10 mg/kg/wk TRC105 as a single agent, and additional patients with ST (primarily ovarian and colorectal) received 10 mg/kg/wk TRC105 with Bev. Peak and trough levels were assessed by ELISA in 39 patients who received TRC105 alone and compared to that of 35 patients (largely Bev refractory) who received TRC105 and Bev. Pts administered TRC105 and Bev were considered a population sub-group and treated as a covariate. A population pharmacokinetic model of TRC105 disposition was built using rich sampling from the ST trial, with sparse data from OC and TRC105+Bev included in the base model. A two-compartment model with nonlinear elimination best fit the data, utilizing Michaelis-Menten parameters for saturable clearance.

Results: TRC105 peak and trough concentrations exceeded target serum concentrations of TRC105 known to saturate endoglin receptors in all pts dosed with 10 mg/kg/wk of TRC105 with and without Bev. The PK of TRC105 given with Bev had mean predicted (following 10,000 simulations) parameters of volume of distribution in the central compartment (VC), VMAX, and KM that were increased compared to population estimated parameters of TRC105 given as a single agent [VC= 44.5±2 (SE) (mL/kg) Pop mean estimate vs. 68.8±4 (mL/kg) Bev predicted; VMAX = 92.6±16 (μg/hr) vs. 297.5±40 (μg/hr) predicted, and KM= 5.91±2 (μg/mL) vs. 61.6±8.8 (μg/mL)]. All differences were significant (p&lt;0.001). Observable data from patients administered the combination yielded PK parameters that were consistent with increased target-mediated clearance of TRC105 when given with Bev.

Conclusions: Peak and trough TRC105 serum levels exceed target serum concentrations when given at 10 mg/kg/wk as a single agent or with Bev. Central compartment distribution of TRC105 increased when given with Bev, which is consistent with increased endoglin expression on proliferating endothelium following Bev treatment. The maximum rate of elimination (Vmax) also increased, consistent with increased turnover; however the intrinsic clearance ratio of Vmax/Km remained the same, suggesting no change in endoglin turnover efficiency. Future studies will assess whether PK parameters correlate with responses to the combination of TRC105 and Bev in Bev refractory patients.

Citation Format: Shawn D. Spencer, Lee S. Rosen, Michael S. Gordon, Francisco Robert, Daniela Matei, Cody J. Peer, Bonne Adams, Delia Alvarez, Ben K. Seon, Charles P. Theuer, W. Douglas Figg. Differences in pharmacokinetics of TRC105 (anti-endoglin antibody) when administered as a single agent versus in combination with bevacizumab (Bev). [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr CT222. doi:10.1158/1538-7445.AM2014-CT222

An open-label phase Ib dose-escalation study of TRC105 (anti-endoglin antibody) with bevacizumab in patients with advanced cancer

PURPOSE

Endoglin, an endothelial cell membrane receptor expressed on angiogenic tumor vessels, is essential for angiogenesis and upregulated in the setting of VEGF inhibition. TRC105 is an anti-endoglin IgG1 monoclonal antibody that potentiates VEGF inhibitors in preclinical models. This study assessed safety, pharmacokinetics, and antitumor activity of TRC105 in combination with bevacizumab.

EXPERIMENTAL DESIGN

Patients (n = 38) with advanced solid tumors, Eastern Cooperative Group performance status 0-1, and normal organ function were treated with escalating doses of TRC105 plus bevacizumab until disease progression or unacceptable toxicity using a standard 3 + 3 phase I design.

RESULTS

TRC105 and bevacizumab were well tolerated at their recommended single-agent doses (10 mg/kg) when the initial dose of TRC105 was delayed by one week and divided over 2 days to limit the frequency of headache. The concurrent administration of bevacizumab and TRC105 did not otherwise potentiate known toxicities of TRC105 or bevacizumab. Hypertension and proteinuria were observed, though not at rates expected for single-agent bevacizumab. Several patients who had previously progressed on bevacizumab or VEGF receptor tyrosine kinase inhibitor (VEGFR TKI) treatment experienced reductions in tumor volume, including two partial responses by RECIST, and 6 remained without progression for longer periods than during their prior VEGF inhibitor therapy.

CONCLUSIONS

TRC105 was well tolerated with bevacizumab and clinical activity was observed in a VEGF inhibitor-refractory population. Ongoing clinical trials are testing TRC105 in combination with bevacizumab in glioblastoma and with VEGFR TKIs in renal cell carcinoma, hepatocellular carcinoma, and soft tissue sarcoma.

Endoglin for targeted cancer treatment

Endoglin is a homodimeric cell membrane glycoprotein receptor for transforming growth factor β and bone morphogenetic proteins. Endoglin is essential for angiogenesis, being densely expressed on proliferating endothelial cells and upregulated during hypoxia. Its expression is implicated in development of resistance to vascular endothelial growth factor (VEGF) inhibition. TRC105 is an antibody that binds endoglin and prevents endothelial cell activation. Targeting endoglin and the VEGF pathway concurrently improves treatment in vitro and appears to reverse resistance to bevacizumab in some refractory cancer patients. Randomized trials are under way to assess the clinical benefit of adding TRC105 therapy to bevacizumab therapy. Further trials are under way to assess the activity of TRC105 with small-molecule inhibitors of the VEGF pathway in renal cell carcinoma, hepatocellular carcinoma, and soft tissue sarcoma. Stratification of soft tissue sarcomas based on endoglin expression levels is proposed to identify patients most likely to benefit from TRC105 treatment. The development of a TRC105 antibody-drug conjugate is also described.

EGFR expression and survival in patients given cetuximab and chemoradiation for stage III non-small cell lung cancer: a secondary analysis of RTOG 0324

PURPOSE

We investigated whether expression of epidermal growth factor receptor (EGFR) was associated with survival and disease control in this secondary analysis of a phase II trial of cetuximab+chemoradiation for stage III non-small cell lung cancer.

METHODS

Patients received cetuximab weekly before and during radiation (63 Gy/35 fractions/7 weeks) with weekly carboplatin + paclitaxel. We analyzed EGFR expression by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) in pretreatment biopsy specimens and compared findings with overall and progression-free survival (OS, PFS) and time to progression (TTP).

RESULTS

Specimens for IHC and FISH were collected from 51 and 45 of 87 evaluable patients. Pretreatment characteristics did not differ for patients with (n = 51) or without (n= 36) EGFR IHC data, or with (n = 45) or without (n = 42) FISH data. However, patients without IHC data had worse OS (HR = 1.63, P = 0.05), worse PFS (HR = 1.88, P = 0.008), and worse TTP [HR = 1.99, P = 0.01] than those with IHC data. EGFR protein expression was not related to pretreatment characteristics or OS; FISH-positive disease was associated with better performance status but not with OS, PFS, or TTP.

CONCLUSIONS

Surprisingly, outcomes differed not by EGFR expression but by the availability of samples for analysis, underscoring the importance of obtaining biopsy samples in such trials.

Abstract A2: Exploratory textural CT evaluation of the combination of TRC105 (anti-endoglin monoclonal antibody; MAb) and bevacizumab (BEV) indicates partial response by Choi criteria in BEV refractory advanced cancer patients (pts) and identifies candidate markers of response

Background: Endoglin (CD105) is an endothelial cell membrane receptor, highly expressed on angiogenic tumor vessels, that is essential for angiogenesis and upregulated by hypoxia and VEGF inhibition. TRC105 is an anti-endoglin MAb that potentiates VEGF inhibitors in preclinical models. TRC105 10 mg/kg weekly was well tolerated with BEV 10 mg/kg q2wk and the combination demonstrated activity in BEV and VEGF TKI refractory pts. This study assessed radiographic responses to TRC105 + BEV using Choi criteria and tumor morphology by applying novel quantitative textural analysis (QTA: TexRad -University of Sussex, UK) in pts with durable stable disease by RECIST, to determine predictive markers of response.

Methods: Contrast enhanced CT scans from 5 pts with advanced solid tumors who demonstrated stable disease by RECIST in a trial of escalating doses of TRC105 (3, 6, 8 or 10 mg/kg/wk) plus BEV were reviewed. Seventeen target lesions were selected from baseline scans and assessed for target lesion diameter, whole lesion density, and tumor volume at baseline and follow-up. QTA analysis was assessed on the same target lesions using six different filter levels at baseline and on follow-up scans. The results were correlated to anatomic tumor response using non-parametric evaluation and regression analysis. Statistical significance was defined as a two-tailed p &lt; 0.05.

Results: Scans from 5 patients (median age 56; M:F 2:3; median 4 prior regimens; 3 metastatic colorectal and 2 ovarian cancer) 4 of whom progressed following VEGF inhibitor treatment were selected and demonstrated stable disease by RECIST for at least 4 months (range: 4-14 months) of treatment with TRC105 + BEV. Four of five patients (80%) had partial responses by Choi criteria. Predictive markers of tumor response on baseline scans included 1) elevated mean pixel density (median values of responder (R) vs non responder (NR): 27.2 vs -4.3) that correlated with subsequent tumor size reduction, 2) elevated entropy (a measure of tumor heterogeneity; median R vs NR: 5.1 vs 4.7) that correlated with subsequent decrease in mean tumor volume, and 3) low kurtosis (a measure of tumor heterogeneity; median R vs NR: 0.2 vs 1.1) that correlated with subsequent reduction in lesion density (p&lt;0.01). Mean positive pixel values (an indicator of hypoxia) on follow-up scans correlated with decreased tumor density.

Conclusions: Assessment of radiographic response using Choi criteria identified VEGF inhibitor refractory patients who demonstrated partial response to the combination of TRC105 + BEV. Using novel QTA measures, markers of tumor heterogeneity and hypoxia correlated with individual lesion responses and are worthy of prospective evaluation as predictive imaging biomarkers.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A2.

Citation Format: Ron L. Korn, Michael S. Gordon, Lee S. Rosen, Francisco Robert, Daniela Matei, Jonathan W. Goldman, David S. Mendelson, E. Gabriela Chiorean, Robert Matthew Strother, Ben K. Seon, Delia Alvarez, Bonne J. Adams, Charles P. Theuer. Exploratory textural CT evaluation of the combination of TRC105 (anti-endoglin monoclonal antibody; MAb) and bevacizumab (BEV) indicates partial response by Choi criteria in BEV refractory advanced cancer patients (pts) and identifies candidate markers of response. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A2.

Modifying chemotherapy response by targeted inhibition of eukaryotic initiation factor 4A

Translation is regulated predominantly at the initiation phase by several signal transduction pathways that are often usurped in human cancers, including the PI3K/Akt/mTOR axis. mTOR exerts unique administration over translation by regulating assembly of eukaryotic initiation factor (eIF) 4F, a heterotrimeric complex responsible for recruiting 40S ribosomes (and associated factors) to mRNA 5′ cap structures. Hence, there is much interest in targeted therapies that block eIF4F activity to assess the consequences on tumor cell growth and chemotherapy response. We report here that hippuristanol (Hipp), a translation initiation inhibitor that selectively inhibits the eIF4F RNA helicase subunit, eIF4A, resensitizes Eμ-Myc lymphomas to DNA damaging agents, including those that overexpress eIF4E—a modifier of rapamycin responsiveness. As Mcl-1 levels are significantly affected by Hipp, combining its use with the Bcl-2 family inhibitor, ABT-737, leads to a potent synergistic response in triggering cell death in mouse and human lymphoma and leukemia cells. Suppression of eIF4AI using RNA interference also synergized with ABT-737 in murine lymphomas, highlighting eIF4AI as a therapeutic target for modulating tumor cell response to chemotherapy.

Phase II study of metronomic chemotherapy (MC) with bevacizumab (B) in patients (Pts) with advanced (Adv) nonsquamous non-small cell lung cancer (NS-NSCLC)

8057

Background: Targeting vascular endothelial growth factor (VEGF) has shown modest improvement in pts with adv NS-NSCLC. The incorporation into MC regimens of antiangiogenic agents has been shown to further enhance efficacy in preclinical models. The goal of this pilot study was to achieve a 30% improvement in the 6.4 months (M) progression-free survival (PFS) observed in ECOG 4599. Methods: Untreated pts with stage 4 NS-NSCLC, PS 0-1 and measurable disease were treated with a 4-week (W) cycle of paclitaxel (80mg/m2 D1, 8, 15), gemcitabine (G) (200-300mg/m2 D1, 8, 15) and B (10mg/m2 D1, 15) for 6 cycles. Pts without progressive disease or significant toxicity (Tx) received maintenance B every 2 w. Primary endpoint:PFS. Secondary endpoints: ORR, OS, Tx and biomarker (BM) correlation. Blood samples for angiogenic (VEGF, sVEGFR2, BFGF, PLGF, PDGFα, Ang-2, IL-8, E-Selectin, ICAM-1, TGFβ-1, SDF-1α, endocan) and antiangiogenic (Thrombospondin-1, Ang-1) bm were collected at different intervals in 21 pts. Response assessment (RECIST) was performed every 8 w. Results: 33 evaluable pts were enrolled. Pt characteristics: median age 59 yrs (37-76), 60% female, 70% > 5% weight loss, 24% never/light smokers, 48% genetic testing (mut EGFR-4; ALK(+)-1), and 9% brain mets. Efficacy parameters are shown in the table. 24 pts had an OR (CR-1, PR-23) and 6 pts had stable disease. No significant differences were observed in the efficacy parameters between former smokers vs. never/light smokers. Worst hematologic and non-hematologic Tx: gr 3 neutropenia (N=1); gr 3/4 nausea/vomiting (N=1); gr 3/4 fatigue (N=2); ischemic colitis (N=1); cerebral ischemia (N=1); gr 3/4 pneumonitis [related to G] (N=2); gr 3/4 proteinuria (N=3), and no gr 3/4 hypertension. Conclusions: While conclusions are limited by the size of the trial, the results are consistent with the hypothesis that the addition of B to MC may result in enhanced anti-angiogenic effect and clinical benefits in adv NS-NSCLC. Analysis of prognostic or predictive bm of angiogenesis will be presented. Clinical trial information: NCT00655850. [Table: see text]

A phase Ib dose-escalation study of TRC105 (anti-endoglin antibody) in combination with bevacizumab (BEV) for advanced solid tumors

3059

Background: CD105 (endoglin) is an endothelial cell membrane receptor highly expressed on angiogenic tumor vessels that is essential for angiogenesis and upregulated by hypoxia and VEGF inhibition. TRC105 is an anti-CD105 monoclonal antibody that potentiates VEGF inhibitors in preclinical models. This study assessed safety, PK and preliminary efficacy of TRC105 in combination with BEV. Methods: Pts with advanced solid tumors, ECOG PS 0-1, and normal organ function were treated with escalating doses of IV TRC105 (3, 6, 8 or 10 mg/kg/wk) plus bevacizumab (BEV) at 15 mg/kg q3wk or 10 mg/kg q2wk. Results: Thirty one pts (median age = 62; M:F 14:17; median 4 prior regimens; primarily metastatic colorectal or ovarian cancer) were treated with TRC105 wkly + BEV. TRC105 3 mg/kg wkly + 15 mg/kg q3wk BEV was well tolerated. Concurrent administration of TRC105 6 mg/kg wkly + 15 mg/kg BEV q3wk resulted in headaches in 4 of 5 pts on cycle 1 day 1 (two grade 3). Dose escalation to the recommended single-agent phase II dose of 10 mg/kg TRC105 weekly + BEV (10 mg/kg q2wk) was tolerated when the initial TRC105 dose was introduced one week after BEV dosing and administered over 2 days. Headache was the only serious adverse drug reaction observed. Adverse events characteristic of each individual drug were not increased in frequency or severity. Target TRC105 serum concentrations were achieved at 6 mg/kg. Mucocutaneous telangiectasia, a marker of TRC105 target modulation, was observed beginning at 6 mg/kg and was dose proportional. Five of 19 heavily pretreated, BEV or VEGF receptor tyrosine kinase inhibitor (TKI) refractory pts with colorectal and ovarian cancer, each with marked tumor burden, experienced radiographic reductions in tumor volume (10-17%). Three of these patients remained on study longer than the prior VEGF inhibitor treatment and two are ongoing. Seven ongoing patients have been treated for 2-8 months. Conclusions: TRC105 10 mg/kg wkly was well tolerated with BEV 10 mg/kg q2wk. The combination demonstrated activity in BEV and VEGF TKI refractory pts. Randomized phase II trials of BEV +/- TRC105 have commenced in renal cell cancer and glioblastoma. Clinical trial information: NCT01332721.