PURPOSE: Pembrolizumab and pembrolizumab-chemotherapy demonstrated efficacy in recurrent/metastatic head and neck squamous cell carcinoma in KEYNOTE-048. Post hoc analysis of long-term efficacy and progression-free survival on next-line therapy (PFS2) is presented. METHODS: Patients were randomly assigned (1:1:1) to pembrolizumab, pembrolizumab-chemotherapy, or cetuximab-chemotherapy. Efficacy was evaluated in programmed death ligand 1 (PD-L1) combined positive score (CPS) ≥ 20, CPS ≥ 1, and total populations, with no multiplicity or alpha adjustment. RESULTS: The median study follow-up was 45.0 months (interquartile range, 41.0-49.2; n = 882). At data cutoff (February 18, 2020), overall survival improved with pembrolizumab in the PD-L1 CPS ≥ 20 (hazard ratio [HR], 0.61; 95% CI, 0.46 to 0.81) and CPS ≥ 1 populations (HR, 0.74; 95% CI, 0.61 to 0.89) and was noninferior in the total population (HR, 0.81; 95% CI, 0.68 to 0.97). Overall survival improved with pembrolizumab-chemotherapy in the PD-L1 CPS ≥ 20 (HR, 0.62; 95% CI, 0.46 to 0.84), CPS ≥ 1 (HR, 0.64; 95% CI, 0.53 to 0.78), and total (HR, 0.71; 95% CI, 0.59 to 0.85) populations. The objective response rate on second-course pembrolizumab was 27.3% (3 of 11). PFS2 improved with pembrolizumab in the PD-L1 CPS ≥ 20 (HR, 0.64; 95% CI, 0.48 to 0.84) and CPS ≥ 1 (HR, 0.79; 95% CI, 0.66 to 0.95) populations and with pembrolizumab-chemotherapy in the PD-L1 CPS ≥ 20 (HR, 0.64; 95% CI, 0.48 to 0.86), CPS ≥ 1 (HR, 0.66; 95% CI, 0.55 to 0.81), and total (HR, 0.73; 95% CI, 0.61 to 0.88) populations. PFS2 was similar after pembrolizumab and longer after pembrolizumab-chemotherapy on next-line taxanes and shorter after pembrolizumab and similar after pembrolizumab-chemotherapy on next-line nontaxanes. CONCLUSION: With a 4-year follow-up, first-line pembrolizumab and pembrolizumab-chemotherapy continued to demonstrate survival benefit versus cetuximab-chemotherapy in recurrent/metastatic head and neck squamous cell carcinoma. Patients responded well to subsequent treatment after pembrolizumab-based therapy.

PURPOSE: The phase III KEYNOTE-048 (ClinicalTrials.gov identifier: NCT02358031 ) trial of pembrolizumab in recurrent or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) included planned efficacy analyses in the total population and in participants with programmed death ligand-1 (PD-L1) combined positive score (CPS) ≥ 1 and CPS ≥ 20. To further characterize the predictive value of PD-L1 expression on outcome, we conducted efficacy analyses in the PD-L1 CPS < 1 and CPS 1-19 subgroups in KEYNOTE-048. METHODS: Participants with R/M HNSCC and no prior systemic therapy for R/M disease were randomly assigned 1:1:1 to pembrolizumab, pembrolizumab-chemotherapy, or cetuximab-chemotherapy. Post hoc efficacy analyses of the PD-L1 CPS < 1 and CPS 1-19 subgroups were performed. RESULTS: Of 882 participants enrolled, 128 had PD-L1 CPS < 1 and 373 had CPS 1-19. For pembrolizumab versus cetuximab-chemotherapy, the median overall survival was 7.9 versus 11.3 months in the PD-L1 CPS < 1 subgroup (hazard ratio [HR], 1.51 [95% CI, 0.96 to 2.37]) and 10.8 versus 10.1 months in the CPS 1-19 subgroup (HR, 0.86 [95% CI, 0.66 to 1.12]). For pembrolizumab-chemotherapy versus cetuximab-chemotherapy, the median overall survival was 11.3 versus 10.7 months in the PD-L1 CPS < 1 subgroup (HR, 1.21 [95% CI, 0.76 to 1.94]) and 12.7 versus 9.9 months in the CPS 1-19 subgroup (HR, 0.71 [95% CI, 0.54 to 0.94]). CONCLUSION: Increased efficacy of pembrolizumab or pembrolizumab-chemotherapy was observed with increasing PD-L1 expression. PD-L1 CPS < 1 subgroup analysis was limited by small participant numbers. Results from the PD-L1 CPS 1-19 subgroup support previous findings of treatment benefit with pembrolizumab monotherapy and pembrolizumab-chemotherapy in patients with PD-L1 CPS ≥ 1 tumors. Although PD-L1 expression is informative, exploration of additional predictive biomarkers is needed for low PD-L1–expressing HNSCC.

At the first interim analysis of the phase 3 KEYNOTE-426 trial, first-line pembrolizumab plus axitinib showed superior overall survival (OS), progression-free survival (PFS) and objective response rate (ORR) over sunitinib for advanced renal cell carcinoma (RCC). To assess long-term durability of clinical outcomes and elucidate predictive biomarkers for RCC, we performed efficacy and prespecified exploratory biomarker analyses from KEYNOTE-426 with ≥5 years of follow-up. Pembrolizumab plus axitinib showed sustained benefits in OS (hazard ratio: 0.84; 95% confidence interval: 0.71–0.99), PFS (hazard ratio: 0.69; 95% confidence interval: 0.59–0.81) and ORR (60.6% versus 39.6%) compared to sunitinib. An 18-gene T-cell-inflamed gene expression profile (Tcell_infGEP) was positively associated with OS (P = 0.002), PFS (P < 0.0001) and ORR (P < 0.0001) within the pembrolizumab plus axitinib arm. An angiogenesis signature was positively associated with OS (P = 0.004) within the pembrolizumab plus axitinib arm and with OS (P < 0.0001), PFS (P < 0.001) and ORR (P = 0.002) within the sunitinib arm. Across arms, programmed cell death ligand 1 combined positive score was only associated (negatively) with OS within the sunitinib arm (P = 0.025). Additionally, PBRM1 (polybromo-1) mutation had a positive association with ORR (P = 0.002) within the pembrolizumab plus axitinib arm. Within the sunitinib arm, OS was positively associated with VHL (von Hippel–Lindau tumor suppressor gene) (P = 0.040) and PBRM1 (P = 0.010) mutations and was negatively associated with BAP1 (BRCA1-associated protein 1) mutation (P = 0.019). Results showed a sustained clinical benefit with pembrolizumab plus axitinib over sunitinib and provide valuable information on biomarkers for immunotherapy-based treatment combinations in advanced RCC. Prospective clinical investigations are needed for biomarker-directed treatment for advanced RCC. ClinicalTrials.gov identifier: NCT02853331.

Several small studies indicated that the genotype of KIT or platelet-derived growth factor receptor-α (PDGFRA) contributes in part to the level of clinical effectiveness of sunitinib in gastrointestinal stromal tumor (GIST) patients. This study aimed to correlate KIT and PDGFRA mutational status with clinical outcome metrics (progression-free survival [PFS], overall survival [OS], objective response rate [ORR]) in a larger international patient population. This is a non-interventional, retrospective analysis in patients with imatinib-resistant or intolerant GIST who were treated in a worldwide, open-label treatment-use study (Study 1036; NCT00094029) in which sunitinib was administered at a starting dose of 50 mg/day on a 4-week-on, 2-week-off schedule. Molecular status was obtained in local laboratories with tumor samples obtained either pre-imatinib, post-imatinib/pre-sunitinib, or post-sunitinib treatment, and all available data were used in the analyses regardless of collection time. The primary analysis compared PFS in patients with primary KIT exon 11 versus exon 9 mutations (using a 2-sided log-rank test) and secondary analyses compared OS (using the same test) and ORR (using a 2-sided Pearson χ2 test) in the same molecular subgroups. Of the 1124 sunitinib-treated patients in the treatment-use study, 230 (20 %) were included in this analysis, and baseline characteristics were similar between the two study populations. Median PFS was 7.1 months. A significantly better PFS was observed in patients with a primary mutation in KIT exon 9 (n = 42) compared to those with a primary mutation in exon 11 (n = 143; hazard ratio = 0.59; 95 % confidence interval, 0.39–0.89; P = 0.011), with median PFS times of 12.3 and 7.0 months, respectively. Similarly, longer OS and higher ORR were observed in patients with a primary KIT mutation in exon 9 versus exon 11. The data available were limited to investigate the effects of additional KIT or PDGFRA mutations on the efficacy of sunitinib treatment. This large retrospective analysis confirms the prognostic significance of KIT mutation status in patients with GIST. This analysis also confirms the effectiveness of sunitinib as a post-imatinib therapy, regardless of mutational status. NCT01459757.

Two phase III clinical trials (CheckMate 141 and KEYNOTE 040) have independently demonstrated that overall survival (OS) in recurrent and/or metastatic head and neck squamous cell carcinoma (R/M HNSCC) patients, who have failed platinum-based therapy, can be improved with anti-PD1 monotherapy. Treatment with nivolumab or pembrolizumab in R/M HNSCC patients led to an improved OS with a hazards ratio (HR) of 0.70 (95%CI 0.51–0.96; p = 0.01) and HR of 0.80 (95%CI 0.65–0.98, p = 0.0161), respectively, as compared to standard of care (SOC) chemo monotherapy regimens (specifically, cetuximab, docetaxel, or methotrexate). The gain in OS was similar in both studies, underscoring the role of anti-PD1 drugs in R/M HNSCC patients. One of the striking discrepancies between CheckMate 141 and KEYNOTE 040 was the OS observed in the control SOC arms (6.9 months median in KEYNOTE 040 versus 5.1 months in CheckMate 141), which inadvertently set a higher threshold in the bio-statistical analysis of KEYNOTE 040 so that the clinical outcome of every patient was influential in the analysis. We perform a comparative analysis of the two studies to identify potential factors in the control arm that can impact clinical trial bio-statistical outcomes and which may have implications for future immunotherapy clinical trial designs.