Milhem, Mohammed

11007 Background: Patients (pts) with metastatic sarcoma (SAR) have limited options. Nivolumab(N), a fully human anti-PD-1 mAb and ipilimumab (I), a humanized anti-CTLA-4 mAb, have favorable safety & efficacy in other tumors. Pembrolizumab demonstrated a response rate (RR) of 12% in SAR pts. We evaluated N, independently from N+I, in SAR pts. Methods: This open-label multi-center phase II study enrolled pts failing prior regimens. Randomized (non-comparative) pts received either N3 [N (3 mg/kg q2W)] or N3+I1 [N(3 mg/kg Q3W x4, then Q2W) & [I(1 mg/kg q3W x4)]. Treatment continued beyond progressive disease (PD) in 1st12 weeks. 5 confirmed responses in 38 evaluable pts yielded 90% power (0.05 1-sided alpha) to detect a 20% (vs 5%) confirmed RR. Other endpoints: adverse events (AEs), progression-free, overall survival (PFS, OS), and correlative studies including PD-L1 expression by IHC, mutational burden/neoantigen analysis, TCR clonality and TIL characterization. Results: 85 pts (43 - N3; 42 - N3+I1) were enrolled [mean age 54 yrs (21–81), 52% female). No significant differences in histological subtypes across cohorts: 36% LMS, 4% LPS, 10% UPS/MFH, 6% synovial, 5% bone, 5% Ewing’s, and 34% other. Pts were refractory to 1(20%), 2(22%), and ≥3 (58%) regimens. Grade 3-4 treatment related adverse events (TRAE) occurred in 7% (N3) and 14% (N3+I1) and 0 Gr 5 TRAEs. 8% of pts stopped due to AEs (2% N3, 14% N3+I1). 2/3 confirmed responses on N3, with 2 ongoing (range 1.1-3.2 months). 6/7 confirmed responses (2 complete) on N3+N1, with 5 ongoing (range 6-13 months). Responses occurred in 7 histologies. See Table for pt outcomes. Conclusions: N + I showed acceptable safety and encouraging antitumor activity with most responses ongoing across multiple SAR histologies, passing efficacy criteria. There was minimal activity observed with N alone. Increased TRAEs were observed in N3+I1. Correlative analyses ongoing. NCT02500797. Support: U10CA180821, U10CA180882, Conquer Cancer Foundation, BMS. Clinical trial information: NCT02500797. [Table: see text]

Purpose We evaluated the combination of talimogene laherparepvec plus ipilimumab versus ipilimumab alone in patients with advanced melanoma in a phase II study. To our knowledge, this was the first randomized trial to evaluate addition of an oncolytic virus to a checkpoint inhibitor. Methods Patients with unresectable stages IIIB to IV melanoma, with no more than one prior therapy if BRAF wild-type, no more than two prior therapies if BRAF mutant, measurable/injectable disease, and without symptomatic autoimmunity or clinically significant immunosuppression were randomly assigned 1:1 to receive talimogene laherparepvec plus ipilimumab or ipilimumab alone. Talimogene laherparepvec treatment began in week 1 (first dose, ≤ 4 mL × 10 6 plaque-forming units/mL; after 3 weeks, ≤ 4 mL × 10 8 plaque-forming units/mL every 2 weeks). Ipilimumab (3 mg/kg every 3 weeks; up to four doses) began week 1 in the ipilimumab alone arm and week 6 in the combination arm. The primary end point was objective response rate evaluated by investigators per immune-related response criteria. Results One hundred ninety-eight patients were randomly assigned to talimogene laherparepvec plus ipilimumab (n = 98), or ipilimumab alone (n = 100). Thirty-eight patients (39%) in the combination arm and 18 patients (18%) in the ipilimumab arm had an objective response (odds ratio, 2.9; 95% CI, 1.5 to 5.5; P = .002). Responses were not limited to injected lesions; visceral lesion decreases were observed in 52% of patients in the combination arm and 23% of patients in the ipilimumab arm. Frequently occurring adverse events (AEs) included fatigue (combination, 59%; ipilimumab alone, 42%), chills (combination, 53%; ipilimumab alone, 3%), and diarrhea (combination, 42%; ipilimumab alone, 35%). Incidence of grade ≥ 3 AEs was 45% and 35%, respectively. Three patients in the combination arm had fatal AEs; none were treatment related. Conclusion The study met its primary end point; the objective response rate was significantly higher with talimogene laherparepvec plus ipilimumab versus ipilimumab alone. These data indicate that the combination has greater antitumor activity without additional safety concerns versus ipilimumab.

Abstract Background: The indoleamine 2,3-dioxygenase (IDO) pathway is a key counter-regulatory mechanism that normally inhibits immune responses when appropriate. In the setting of cancer, IDO pathway-mediated immune suppression is exploited by tumors in order to prevent and defeat anti-tumor immunity. Small-molecule inhibitors of the IDO pathway, such as indoximod, are an increasingly validated class of potential cancer therapeutics. Additionally, pre-clinical tumor models have shown complementary effects with indoximod / anti-PD1 checkpoint inhibitor treatment combinations. A clinical trial was developed based upon these data. Methods: Upon successful completion of a Phase 1b dose escalation cohort, metastatic melanoma patients were enrolled in a single arm Phase 2 trial evaluating the addition of indoximod to standard of care checkpoint inhibitors approved for melanoma. Treating physicians were allowed to administer their choice of approved checkpoint inhibitor. The large majority of patients received indoximod with pembrolizumab and this interim report is limited to those patients. Indoximod was administered continuously in 21 days cycles (1200mg po twice daily) concurrently with pembrolizumab (3mg/kg q21 days). Study endpoint is best overall response (objective response rate (ORR) = complete response rate (CR) + partial response rate (PR)) per site reported RECIST criteria. Results: At time of data cut-off, 60 patients had received indoximod /pembrolizumab and were evaluable for response, defined as having at least one follow-up imaging study performed. The ORR was 52% (31/60) with a CRR of 8% (5/60). The combination was well tolerated. The most frequently reported adverse events (regardless of attribution), occurring in ≥ 20% of subjects, were fatigue, diarrhea, nausea, arthralgia, headache, cough, rash, pruritus, and hypertension. The most frequently reported laboratory abnormalities (regardless of attribution), were anemia (17%) and hyperglycemia (17%). Conclusions: The interim analysis of the combination of indoximod and pembrolizumab demonstrates an ORR of 52% which compares favorably with the established ORR for pembrolizumab alone. Updated data to be presented. NCT02073123. Citation Format: Yousef Zakharia, Robert McWilliams, Monaster Shaheen, Kenneth Grossman, Joseph Drabick, Mohammed Milhem, Olivier Rixie, Samir Khleif, Ryan Lott, Eugene Kennedy, David Munn, Nicholas Vahanian, Charles Link. Interim analysis of the Phase 2 clinical trial of the IDO pathway inhibitor indoximod in combination with pembrolizumab for patients with advanced melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr CT117. doi:10.1158/1538-7445.AM2017-CT117

CRA9003 Background: Gq/11 mutations are early oncogenic events in UM resulting in MAPK pathway activation. We demonstrated decreased viability in UM cell lines harboring Gq/11 mut with sel, a small molecule inhibitor of MEK1/2 (Ambrosini, CCR 2012). Methods: We conducted a 16 center randomized phase II study of hyd-sulfate sel 75 mg BID vs TMZ 150 mg/m2 daily for 5 days in 28-day cycles (or DTIC 1000 mg/m2 q21 days) for patients (pts) with metastatic UM with a Q209 Gq/11 mut who have not received prior TMZ/DTIC. The primary endpoint was progression free survival (PFS). Secondary endpoints included overall survival (OS) and response rate (RR). Select pts underwent tumor biopsies at baseline and after 14 (+/- 3 days) of sel. Our statistical plan required ≥80 pts randomized and ≥68 events to detect a PFS hazard ratio of 0.6 (p=0.1). Randomization was stratified by mut (Gq vs G11), M stage and number of prior therapies (tx). Tumor assessment occurred every 4 weeks (wks) for 8 wks and then every 8 wks using RECIST 1.1. Pts receiving TMZ who progressed could receive sel (TMZ→sel). Results: 80 pts were randomized. Sel (n=39): median age 66 (range 32-86), 54% male, 54% G11 mut, median ECOG PS 0 (range 0-1), 97% M1c, median prior tx 0 (range 0-2). TMZ (n=41): median age 60 (range 34-81), 63% male, 58% G11 mut, median ECOG PS 0 (range 0-1), 93% M1c, median prior tx 0 (range 0-2). 11/39 (28%) pts on sel experienced grade (gr) 3 toxicity (tox) manageable with dose modification (5 CPK elevation, 3 LFT elevation, 1 rash, 1 lymphopenia, 1 edema). 1/41 (2%) pt on TMZ experienced gr 3 tox (neutropenia). No gr 4/5 tox occurred. 28 pts on sel underwent paired tumor biopsies with inhibition of pERK and cyclinD1 observed by Western blot at day 14. At interim analysis (9/25/12), 55 pts were evaluable with 45 progression events and 16 deaths. Sel (n=27): median PFS 16 wks (95% CI 8-30.9), RR 11%, median OS 11.8 months (95% CI 4.8-not reached). TMZ (n=28): median PFS 4 wks (95% CI 3.7-15), RR 0%, median OS 4.7 months (95% CI 4.3-14.3). TMZ→sel (n=25): median PFS 8.1 wks (95% CI 7-15), RR 0%. Conclusions: Sel is the first drug to ever show improved clinical activity in UM relative to TMZ. Sustained target inhibition is observed with sel. Final results will be presented. Clinical trial information: NCT01143402.