Strosberg, Jonathan

Abstract Purpose: The purpose of this study was to evaluate the safety and efficacy of ontuxizumab (MORAb-004), a monoclonal antibody that interferes with endosialin (tumor endothelial marker-1) function, in patients with chemorefractory metastatic colorectal cancer and to identify a responsive patient population based on biomarkers. Experimental Design: This was a randomized, double-blind, placebo-controlled, phase II study. Patients were randomly assigned in a 2:1 ratio to receive weekly intravenous ontuxizumab (8 mg/kg) or placebo plus best supportive care until progression or unacceptable toxicity. Tissue and blood biomarkers were evaluated for their ability to identify a patient population that was responsive to ontuxizumab. Results: A total of 126 patients were enrolled. No significant difference between the ontuxizumab and placebo groups was evident for the primary endpoint of progression-free survival (PFS), with a median PFS of 8.1 weeks in each group (HR, 1.13; 95% confidence interval, 0.76–1.67; P = 0.53). There were no significant differences between groups for overall survival (OS) or overall response rate (ORR). The most common treatment-emergent adverse events (TEAEs) in the ontuxizumab group (vs. the placebo group, respectively) were fatigue (53.7% vs. 47.5%), nausea (39.0% vs. 35.0%), decreased appetite (34.1% vs. 27.5%), and constipation (28.0% vs. 32.5%). The most common grade 3/4 TEAE in the ontuxizumab group versus placebo was back pain (11.0% vs. 0%). No single biomarker clearly identified patients responsive to ontuxizumab. Conclusions: No benefit with ontuxizumab monotherapy compared with placebo for clinical response parameters of PFS, OS, or ORR was demonstrated. Ontuxizumab was well tolerated. Clin Cancer Res; 24(2); 316–25. ©2017 AACR.

Purpose Treatment options for neuroendocrine tumors (NETs) remain limited. This trial assessed the progression-free survival (PFS) of bevacizumab or interferon alfa-2b (IFN-α-2b) added to octreotide among patients with advanced NETs. Patients and Methods Southwest Oncology Group (SWOG) S0518, a phase III study conducted in a US cooperative group system, enrolled patients with advanced grades 1 and 2 NETs with progressive disease or other poor prognostic features. Patients were randomly assigned to treatment with octreotide LAR 20 mg every 21 days with either bevacizumab 15 mg/kg every 21 days or 5 million units of IFN-α-2b three times per week. The primary end point was centrally assessed PFS. This trial is registered with ClinicalTrials.gov as NCT00569127. Results A total of 427 patients was enrolled, of whom 214 were allocated to bevacizumab and 213 to IFN-α-2b. The median PFS by central review was 16.6 months (95% CI, 12.9 to 19.6 months) in the bevacizumab arm and was 15.4 months (95% CI, 9.6 to 18.6 months) in the IFN arm (hazard ratio [HR], 0.93; 95% CI, 0.73 to 1.18; P = .55). By site review, the median PFS times were 15.4 months (95% CI, 12.6 to 17.2 months) for bevacizumab and 10.6 months (95% CI, 8.5 to 14.4 months) for interferon (HR, 0.90; 95% CI, 0.72 to 1.12; P = .33). Time to treatment failure was longer with bevacizumab than with IFN (HR, 0.72; 95% CI, 0.58 to 0.89; P = .003). Confirmed radiologic response rates were 12% (95% CI, 8% to 18%) for bevacizumab and 4% (95% CI, 2% to 8%) for IFN. Common adverse events with bevacizumab and octreotide included hypertension (32%), proteinuria (9%), and fatigue (7%); with IFN and octreotide, they included fatigue (27%), neutropenia (12%), and nausea (6%). Conclusion No significant differences in PFS were observed between the bevacizumab and IFN arms, which suggests that these agents have similar antitumor activity among patients with advanced NETs.

348 Background: Neuroendocrine tumor progression is associated with decline in quality of life, both due to tumor and hormone-related symptoms. The Phase III NETTER-1 trial randomized patients with advanced, progressive midgut NETs to receive treatment with 177Lu-DOTATATE (177Lu; Lutathera) versus high-dose (60 mg) Octreotide LAR (Oct). EORTC questionnaires C30 and GINET21 were assessed during the trial in order to determine the impact of treatment on health-related quality of life (HRQoL). Methods: Patients completed EORTC QLQ-30 and QLQ-G.I.NET21 questionnaires at baseline and every 12 weeks thereafter until disease progression. Raw scores were converted to a 100-point scale and individual changes from baseline scores were assessed. Clinically relevant ( ≥ 10 point) deterioration/improvement was considered clinically significant. Results: Clinically and statistically significant improvements in QoL were observed in the 177Lu arm versus the Oct arm at certain time points in key domains of HRQoL including global health status and diarrhea. In mean, global health status improved in 28% of patients on 177Lu arm vs. 15% on Oct, and worsened in 18% of patients on 177Lu vs. 26% on Oct. Diarrhea improved in 39% of patients on 177Lu vs. 23% on Oct, and worsened in 19% of patients on 177Lu vs. 23% on Oct. There was a trend towards improvement in pain that was not statistically significant. Flushing appeared to improve compared to baseline in both arms of the study with no clear advantage to treatment with 177Lu vs. Oct. Conclusions: QoL analysis suggests benefit in important domains associated with 177Lu treatment compared to high-dose octreotide in patients with advanced midgut NETs, and confirms the treatment value of 177Lu on patient QoL, in addition to the meaningful increase in progression-free survival already reported. Clinical trial information: NCT01578239.

194 Background: Currently, there are limited therapeutic options for patients with advanced midgut neuroendocrine tumors progressing on first-line somatostatin analog therapy. Methods: NETTER-1 is the first Phase III multicentric, randomized, controlled trial evaluating 177Lu-DOTA0-Tyr3-Octreotate (Lutathera) in patients with inoperable, progressive, somatostatin receptor positive midgut NETs. 230 patients with Grade 1-2 metastatic midgut NETs were randomized to receive Lutathera 7.4 GBq every 8 weeks (x4 administrations) versus Octreotide LAR 60 mg every 4-weeks. The primary endpoint was PFS per RECIST 1.1 criteria, with objective tumor assessment performed by an independent reading center every 12 weeks. Secondary objectives included objective response rate, overall survival, toxicity, and health-related quality of life. Results: Enrolment was completed in February 2015, with a target of 230 patients randomized (1:1) in 36 European and 15 sites in the United States. At the time of statistical analysis, the number of centrally confirmed disease progressions or deaths was 23 in the Lutathera group and 67 in the Octreotide LAR 60 mg group. The median PFS was not reached for Lutathera and was 8.4 months with 60 mg Octreotide LAR [95% CI: 5.8-11.0 months], p < 0.0001, with a hazard ratio of 0.21 [95% CI: 0.13-0.34]. Within the current evaluable patient dataset for tumor responses (n = 201), the number of CR+PR was 19 (18.8%) in the Lutathera group and 3 (3.0%) in the Octreotide LAR 60 mg group (p < 0.0004). Although the OS data were not mature enough for a definitive analysis, the number of deaths was 13 in the Lutathera group and 22 in the Octreotide LAR 60 mg group (p < 0.019 at interim analysis) which suggests an improvement in overall survival. Conclusions: The Phase III NETTER-1 trial provides evidence for a clinically meaningful and statistically significant increase in PFS and ORR, and also suggests a survival benefit in patients with advanced midgut NETs treated with Lutathera. Clinical trial information: NCT01578239.

260 Background: Recent placebo-controlled phase III trials of the mTOR inhibitor everolimus and the VEGF/ PDGF receptor inhibitor sunitinib in PNET noted improved progression-free survival (PFS). However, objective response rates (RR) with these agents are <10%. Preclinical studies suggest enhanced anti-tumor effects with combined mTOR and VEGF targeted therapy. Methods: We conducted a phase II trial of the mTOR inhibitor TEM (25 mg IV q week) and the VEGF-A monoclonal antibody BEV (10 mg/kg IV q 2 weeks) in patients (pts) with well or moderately differentiated PNET and progressive disease by RECIST within 7 months of study entry. Co-primary endpoints were RR and 6-month PFS. Planned enrollment is 50 patients, with interim analysis after the first 25 evaluable pts. Pts had no prior mTOR or VEGF targeted agents, ECOG PS 0-1, and adequate hematologic and organ function. Continued octreotide was allowed, but not required. Prior interferon, embolization, and ≤ 2 chemotherapy regimens were allowed. Results: Confirmed PR was documented in 11 of the first 25 (44%) evaluable patients. 20 of 25 (80%) patients were progression-free at 6 months. Both endpoints exceeded pre-defined criteria to continue enrollment. For 35 evaluable patients, the most common grade 3-4 adverse events attributed to therapy were leukopenia (12%), hypertension (12%), hyperglycemia (12%), mucositis (9%), and fatigue (9%). Conclusions: The combination of TEM/BEV has substantial activity in a multi-center phase II trial with RR of 44%, well in excess of single targeted agents in PNET. 6-month PFS was a notable 80% in a population of patients with RECIST criteria progression within 7 months of study entry. Accrual is ongoing. Supported by NCI N01 Contracts: 662205, 62203, 62208, 62209, 62206, 62204, 62207, 62201.

Purpose There are few effective therapies for pancreatic neuroendocrine tumors (PNETs). Recent placebo-controlled phase III trials of the mammalian target of rapamycin (mTOR) inhibitor everolimus and the vascular endothelial growth factor (VEGF)/platelet-derived growth factor receptor inhibitor sunitinib have noted improved progression-free survival (PFS). Preclinical studies have suggested enhanced antitumor effects with combined mTOR and VEGF pathway–targeted therapy. We conducted a clinical trial to evaluate combination therapy against these targets in PNETs. Patients and Methods We conducted a two-stage single-arm phase II trial of the mTOR inhibitor temsirolimus 25 mg intravenously (IV) once per week and the VEGF-A monoclonal antibody bevacizumab 10 mg/kg IV once every 2 weeks in patients with well or moderately differentiated PNETs and progressive disease by RECIST within 7 months of study entry. Coprimary end points were tumor response rate and 6-month PFS. Results A total of 58 patients were enrolled, and 56 patients were eligible for response assessment. Confirmed response rate (RR) was 41% (23 of 56 patients). PFS at 6 months was 79% (44 of 56). Median PFS was 13.2 months (95% CI, 11.2 to 16.6). Median overall survival was 34 months (95% CI, 27.1 to not reached). For evaluable patients, the most common grade 3 to 4 adverse events attributed to therapy were hypertension (21%), fatigue (16%), lymphopenia (14%), and hyperglycemia (14%). Conclusion The combination of temsirolimus and bevacizumab had substantial activity and reasonable tolerability in a multicenter phase II trial, with RR of 41%, well in excess of single targeted agents in patients with progressive PNETs. Six-month PFS was a notable 79% in a population of patients with disease progression by RECIST criteria within 7 months of study entry. On the basis of this trial, continued evaluation of combination mTOR and VEGF pathway inhibitors is warranted.