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Background Resistance to immune checkpoint inhibitors and targeted treatments for cancer is common; thus, novel immunotherapy agents are needed. Urelumab is a monoclonal antibody agonist that binds to CD137 receptors expressed on T cells. Here, we report two studies that evaluated urelumab in combination with cetuximab or nivolumab in patients with select, advanced solid tumors.Methods CA186-018: Patients with metastatic colorectal cancer or metastatic squamous cell carcinoma of the head and neck (SCCHN) were treated in a dose-evaluation phase with urelumab 0.1 mg/kg (urelumab-0.1) every 3 weeks (Q3W)+cetuximab 250 mg/m2 (cetuximab-250) weekly; and in a dose-expansion phase with urelumab 8 mg flat dose (urelumab-8) Q3W+cetuximab-250 weekly. CA186-107: The dose-escalation phase included patients with previously treated advanced solid tumors (or treated or treatment-naive melanoma); patients received urelumab 3 mg flat dose (urelumab-3) or urelumab-8 every 4 weeks+nivolumab 3 mg/kg (nivolumab-3) or 240 mg (nivolumab-240) every 2 weeks. In the expansion phase, patients with melanoma, non-small cell lung cancer, or SCCHN were treated with urelumab-8+nivolumab-240. Primary endpoints were safety and tolerability, and the secondary endpoint included efficacy assessments.Results CA186-018: 66 patients received study treatment. The most frequent treatment-related adverse events (TRAEs) were fatigue (75%; n=3) with urelumab-0.1+cetuximab-250 and dermatitis (45%; n=28) with urelumab-8+cetuximab-250. Three patients (5%) discontinued due to TRAE(s) (with urelumab-8+cetuximab-250). One patient with SCCHN had a partial response (objective response rate (ORR) 5%, with urelumab-8+cetuximab-250).CA186-107: 134 patients received study treatment. Fatigue was the most common TRAE (32%; n=2 with urelumab-3+nivolumab-3; n=1 with urelumab-8+nivolumab-3; n=40 with urelumab-8+nivolumab-240). Nine patients (7%) discontinued due to TRAE(s) (n=1 with urelumab-3+nivolumab-3; n=8 with urelumab-8+nivolumab-240). Patients with melanoma naive to anti-PD-1 therapy exhibited the highest ORR (49%; n=21 with urelumab-8+nivolumab-240). Intratumoral gene expression in immune-related pathways (CD3, CD8, CXCL9, GZMB) increased on treatment with urelumab+nivolumab.Conclusions Although the addition of urelumab at these doses was tolerable, preliminary response rates did not indicate an evident additive benefit. Nevertheless, the positive pharmacodynamics effects observed with urelumab and the high response rate in treatment-naive patients with melanoma warrant further investigation of other anti-CD137 agonist agents for treatment of cancer.Trial registration numbers NCT02110082; NCT02253992.

BACKGROUND:Intensity-modulated radiation therapy (IMRT) has been used to limit treatment-related toxicity for patients with anal squamous cell carcinoma (SCC). The treatment outcomes and HPV characteristics for a cohort of patients receiving definitive concurrent chemotherapy and IMRT are reported. MATERIALS AND METHODS:52 patients with anal SCC were treated with IMRT and concurrent chemotherapy. Radiation was delivered sequentially to the pelvis and inguinal lymph nodes (45 Gy) and anal tumor (median dose, 54 Gy). Multiplex real-time PCR for 7 high-risk HPV subtypes (n = 22) and p16 immunohistochemistry (n = 21, rated on a 0, 1, and 2+ scale) were performed on available specimens. Survival was estimated using Kaplan-Meier analysis, and toxicities were recorded. RESULTS:Median follow-up was 33 months. Three-year freedom from locoregional failure (FFLRF), freedom from distant metastasis (FFDM), freedom from colostomy (FFC), and overall survival (OS) were 94%, 85%, 91%, and 90%, respectively. Acute grade 2+ skin, GI, and GU toxicities occurred in 83%, 71%, and 19% of evaluable patients, respectively. The rates of late grade 2+ GI and GU toxicities for evaluable patients (n = 32) were 28% and 9%, respectively. Of patients with available pathology, 91% and 71% were positive for HPV and p16 (2+), respectively. HPV genotypes included 16 (n = 17), 33 (n = 2), 18 (n = 1), and 45 (n = 1). HPV and p16 status were associated on Chi-square analysis (p = 0.07). Neither HPV nor p16 status was significantly associated with any clinical outcome. For HPV+ patients, 3-year FFLRF, FFDM, FFC, and OS were 100%, 69%, 100%, and 88%, respectively. CONCLUSIONS:In this patient cohort, disease control was excellent for anal SCC treated with definitive concurrent chemotherapy and IMRT, and treatment was well tolerated. HPV and p16 status were not prognostic for treatment outcomes which may be related to our small sample size.

[This corrects the article DOI: 10.1371/journal.pone.0194234.].

Purpose Stereotactic body radiotherapy (SBRT) may stimulate innate and adaptive immunity to augment immunotherapy response. Multisite SBRT is an emerging paradigm for treating metastatic disease. Anti-PD-1-treatment outcomes may be improved with lower disease burden. In this context, we conducted a phase I study to evaluate the safety of pembrolizumab with multisite SBRT in patients with metastatic solid tumors. Patients and Methods Patients progressing on standard treatment received SBRT to two to four metastases. Not all metastases were targeted, and metastases > 65 mL were partially irradiated. SBRT dosing varied by site and ranged from 30 to 50 Gy in three to five fractions with predefined dose de-escalation if excess dose-limiting toxicities were observed. Pembrolizumab was initiated within 7 days after completion of SBRT. Pre- and post-SBRT biopsy specimens were analyzed in a subset of patients to quantify interferon-γ-induced gene expression. Results A total of 79 patients were enrolled; three patients did not receive any treatment and three patients only received SBRT. Patients included in the analysis were treated with SBRT and at least one cycle of pembrolizumab. Most (94.5%) of patients received SBRT to two metastases. Median follow-up for toxicity was 5.5 months (interquartile range, 3.3 to 8.1 months). Six patients experienced dose-limiting toxicities with no radiation dose reductions. In the 68 patients with imaging follow-up, the overall objective response rate was 13.2%. Median overall survival was 9.6 months (95% CI, 6.5 months to undetermined) and median progression-free survival was 3.1 months (95% CI, 2.9 to 3.4 months). Expression of interferon-γ-associated genes from post-SBRT tumor biopsy specimens significantly correlated with nonirradiated tumor response. Conclusion Multisite SBRT followed by pembrolizumab was well tolerated with acceptable toxicity. Additional studies exploring the clinical benefit and predictive biomarkers of combined multisite SBRT and PD-1-directed immunotherapy are warranted.

Purpose: The optimal end point for randomized phase II trials of anticancer therapies remains controversial. We simulated phase II trials by resampling patients from N9741, a randomized phase III trial of chemotherapy regimens for metastatic colorectal cancer, and compared the power of various end points to detect the superior therapy (FOLFOX [infusional fluorouracil, leucovorin, and oxaliplatin] had longer overall survival than both IROX [irinotecan plus oxaliplatin] and IFL [irinotecan and bolus fluorouracil plus leucovorin])., Methods: Tumor measurements and progression-free survival (PFS) data were obtained for 1,471 patients; 1,002 had consistently measured tumors and were resampled (5,000 replicates) to simulate two-arm, randomized phase II trials with α = 0.10 (one sided) and 20 to 80 patients per arm. End points included log ratio of tumor size at 6, 12, and 18 weeks relative to baseline; time to tumor growth (TTG), estimated using a nonlinear mixed-effects model; and PFS. Arms were compared using rank sum tests for log ratio and TTG and a log-rank test for PFS., Results: For FOLFOX versus IFL, TTG and PFS had similar power, with both exceeding the power of log ratio at 18 weeks; for FOLFOX versus IROX, TTG and log ratio at 18 weeks had similar power, with both exceeding the power of PFS. The best end points exhibited > 80% power with 60 to 80 patients per arm., Conclusion: TTG is a powerful end point for randomized phase II trials of cytotoxic therapies in metastatic colorectal cancer; it was either comparable or superior to PFS and log ratio at 18 weeks. Additional studies will be needed to clarify the potential of TTG as a phase II end point., (© 2014 by American Society of Clinical Oncology.)