PURPOSE Patients with relapsed or refractory primary mediastinal large B-cell lymphoma (rrPMBCL) have a poor prognosis, and their treatment represents an urgent and unmet need. Because PMBCL is associated with genetic aberrations at 9p24 and overexpression of programmed cell death-1 (PD-1) ligands (PD-L1), it is hypothesized to be susceptible to PD-1 blockade. METHODS In the phase IB KEYNOTE-013 (ClinicalTrials.gov identifier: NCT01953692 ) and phase II KEYNOTE-170 (ClinicalTrials.gov identifier: NCT02576990 ) studies, adults with rrPMBCL received pembrolizumab for up to 2 years or until disease progression or unacceptable toxicity. The primary end points were safety and objective response rate in KEYNOTE-013 and objective response rate in KEYNOTE-170. Secondary end points included duration of response, progression-free survival, overall survival, and safety. Exploratory end points included association between biomarkers and pembrolizumab activity. RESULTS The objective response rate was 48% (7 complete responses; 33%) among 21 patients in KEYNOTE-013 and 45% (7 complete responses; 13%) among 53 patients in KEYNOTE-170. After a median follow-up time of 29.1 months in KEYNOTE-013 and 12.5 months in KEYNOTE-170, the median duration of response was not reached in either study. No patient with complete response experienced progression, including 2 patients with complete response for at least 1 year off therapy. Treatment-related adverse events occurred in 24% of patients in KEYNOTE-013 and 23% of patients in KEYNOTE-170. There were no treatment-related deaths. Among 42 evaluable patients, the magnitude of the 9p24 gene abnormality was associated with PD-L1 expression, which was itself significantly associated with progression-free survival. CONCLUSION Pembrolizumab is associated with high response rate, durable activity, and a manageable safety profile in patients with rrPMBCL.

Preclinical evidence suggests that concomitant BRAF and EGFR inhibition leads to sustained suppression of MAPK signaling and suppressed tumor growth in BRAF V600E colorectal cancer (CRC) models. Patients with refractory BRAF V600–mutant metastatic CRC (mCRC) were treated with a selective RAF kinase inhibitor (encorafenib) plus a monoclonal antibody targeting EGFR (cetuximab), with (n = 28) or without (n = 26) a PI3K-alpha inhibitor (alpelisib). The primary objective was to determine the maximum tolerated dose (MTD) or a recommended phase 2 dose. Dose-limiting toxicities were reported in three patients receiving dual- and two patients receiving triple-treatment. The MTD was not reached for either group and the Phase 2 doses were selected as 200 mg encorafenib (both groups) and 300 mg alpelisib. Combinations of cetuximab and encorafenib show promising clinical activity and tolerability in patients with BRAF-mutant mCRC; confirmed overall response rates of 19% and 18% were observed, and median progression-free survival was 3.7 and 4.2 months, for the dual- and triple-therapy groups, respectively.

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1 Background: For patients (pts) with ASCC, second-line or later treatment options have been limited. Pembrolizumab (pembro), an anti-PD-1 monoclonal antibody, has demonstrated antitumor activity in several tumor types (including ASCC) in the multicohort phase 1b KEYNOTE-028 study. KEYNOTE-158 (NCT02628067) is an open-label, phase 2, multicohort study that evaluates antitumor activity and safety of pembro in pts with previously treated advanced cancer. Results from the ASCC cohort are presented. Methods: Eligible pts were ≥18 y with histologically/cytologically documented metastatic and/or unresectable ASCC with prior treatment failure on or intolerance to standard first-line therapy, measurable disease per RECIST v1.1, ECOG PS of ≤1, and evaluable tissue sample for PD-L1 and biomarker analysis. PD-L1 expression was assessed by the PD-L1 IHC 22C3 pharmDx assay (Agilent Technologies). Pts received pembro 200 mg Q3W until disease progression, unacceptable AE, or completion of 35 cycles. The primary endpoint was ORR per RECIST v1.1 (assessed every 9 wk for 12 mo, then every 12 wk thereafter) by independent central review. Secondary endpoints were DOR, OS, PFS and safety. Results: 112 pts with ASCC were enrolled (81.3% women; median age, 61 y [range 32–79]; ≥2 prior therapies, 73.2%). At database cutoff (Dec 6, 2018) 10 pts (8.9%) had completed 35 cycles and 102 discontinued; median follow-up was 12.0 mo (range, 0.8–33.0) Five pts had CR and 8 had PR; ORR was 11.6% (95% CI, 6.3–19.0). Median DOR was not reached (range, 6.0+ to 29.1+ mo). Responses occurred in 11/75 pts (14.7%) with PD-L1 combined positive score (CPS) ≥1 and 2/30 pts (6.7%) with PD-L1 CPS < 1. Among all pts, median OS was 12.0 mo (95% CI, 9.1–15.4), and median PFS was 2.0 mo (95% CI, 2.0–2.1). 68 (60.7%) pts had treatment-related AEs, including 21 (18.8%) who had grade 3–5 events; there were no treatment-related deaths. 4 pts (3.6%) discontinued due to treatment-related AEs. 27 pts (24.1%) had immune-mediated AEs/infusion reactions. Conclusions: Pembro demonstrated antitumor activity and manageable toxicity in pts with heavily pretreated advanced ASCC, regardless of PD-L1 status. Clinical trial information: NCT02628067.