Pembrolizumab and nivolumab are immune checkpoint inhibitors targeting PD-1 that have recently been approved in pretreated recurrent and/or metastatic head and neck squamous cell carcinoma (R/M HNSCC) patients. In the clinic, some patients seem not only not to benefit from anti-PD-L1/PD-1 agents but rather to experience an acceleration of tumor growth kinetics (TGK). We retrospectively compared TGK on immunotherapy and TGK on last treatment in patients with R/M HNSCC treated with PD-1/PD-L1 inhibitors in four French centers. The TGK ratio (TGK_R, ratio of the slope of tumor growth before treatment and the slope of tumor growth on treatment) was calculated. Hyperprogression was defined as a TGK_R ≥ 2. From September 2012 to September 2015, 34 patients were identified. Patterns of recurrence included exclusive loco-regional recurrence in 14 patients, exclusive distant metastases in 11 patients, and both in 9 patients. No pseudo-progression was observed. Hyperprogression was observed in 10 patients (29%), including 9 patients with at least a locoregional recurrence, and only 1 patient with exclusively distant metastases. Hyperprogression significantly correlated with a regional recurrence (TGK_R ≥ 2: 90% versus TGK_R < 2: 37%, P = 0.008), but not with local or distant recurrence. Hyperprogression was associated with a shorter progression-free survival (PFS) according to RECIST (P = 0.003) and irRECIST (P = 0.02), but not with overall survival (P = 0.77). Hyperprogression was observed in 29% of patients with R/M HNSCC treated with anti-PD-L1/PD-1 agents and correlated with a shorter PFS. It occurred in 39% of patients with at least a locoregional recurrence and 9% of patients with exclusively distant metastases. No pseudo-progressions were reported. Mechanisms and causality of hyperprogression should further be assessed through prospective controlled studies.

The benefit of the addition of perioperative pembrolizumab to standard care with surgery and adjuvant therapy for patients with locally advanced head and neck squamous-cell carcinoma (HNSCC) is unclear. In this phase 3, open-label trial, we randomly assigned participants with locally advanced HNSCC in a 1:1 ratio to receive 2 cycles of neoadjuvant pembrolizumab and 15 cycles of adjuvant pembrolizumab (both at a dose of 200 mg every 3 weeks) in addition to standard care (pembrolizumab group) or standard care alone (control group). Standard care was surgery and adjuvant radiotherapy with or without concomitant cisplatin. The primary end point was event-free survival, sequentially assessed in participants whose tumors expressed programmed death ligand 1 (PD-L1) with a combined positive score (CPS) of 10 or more (CPS-10 population), participants whose tumors expressed PD-L1 with a CPS of 1 or more (CPS-1 population), and all the participants. A higher CPS indicates a higher proportion of cells that express PD-L1. A total of 363 participants (234 with a CPS of ≥10 and 347 with a CPS of ≥1) were assigned to the pembrolizumab group and 351 (231 with a CPS of ≥10 and 335 with a CPS of ≥1) to the control group. Surgery was completed in approximately 88% of the participants in each group. At the first interim analysis, the median follow-up was 38.3 months. Event-free survival at 36 months was 59.8% in the pembrolizumab group and 45.9% in the control group (hazard ratio for progression, recurrence, or death, 0.66; 95% confidence interval [CI], 0.49 to 0.88; two-sided P = 0.004) in the CPS-10 population; 58.2% and 44.9%, respectively (hazard ratio, 0.70; 95% CI, 0.55 to 0.89; two-sided P = 0.003), in the CPS-1 population; and 57.6% and 46.4%, respectively (hazard ratio, 0.73; 95% CI, 0.58 to 0.92; two-sided P = 0.008), in the total population. Grade 3 or higher treatment-related adverse events occurred in 44.6% of the participants in the pembrolizumab group and in 42.9% of those in the control group, including death in 1.1% and 0.3%, respectively. Potentially immune-mediated adverse events of grade 3 or higher occurred in 10.0% of the participants in the pembrolizumab group. The addition of neoadjuvant and adjuvant pembrolizumab to standard care significantly improved event-free survival among participants with locally advanced HNSCC. Neoadjuvant pembrolizumab did not affect the likelihood of surgical completion. No new safety signals were identified. (Funded by Merck Sharp and Dohme, a subsidiary of Merck [Rahway, NJ]; KEYNOTE-689 ClinicalTrials.gov number, NCT03765918.).

Novel patterns of response and progression to immunotherapy have been reported that are not observed with conventional cytotoxic or targeted anticancer treatments. A major breakthrough with immunotherapy is its potential to achieve durable responses in a subset of patients with advanced cancer that can be maintained several years even after stopping the treatment. No standardized definition of durable response exists in the literature, and the optimal duration of treatment in case of durable response is not clearly established. However, the majority of patients do not respond to immunotherapy. Initially reported in advanced melanoma patients, pseudoprogression occurs when tumor index lesions regress after initial progression, supporting the concept of treating some patients beyond progression. Overall, reported rates of pseudoprogression never exceeded 10%, meaning that the large majority of patients who have a disease progression will not eventually respond to treatment. The decision to pursue treatment beyond progression must therefore only be taken in carefully selected patients with clinical benefit, who did not experience severe toxicities with immunotherapy. Conversely, rapid progressions, called hyperprogressions, were reported by several teams with rates ranging from 4% to 29%. These observations need to be confirmed from randomized trials. It is essential to interrupt the treatment in patients with hyperprogression, in order to switch to another potentially active treatment. Finally, some patients experience dissociated responses, with some lesions shrinking and others growing. Local treatment with surgery or radiotherapy for growing lesions may be considered. Several immune-specific-related response criteria were developed to better capture benefits of immunotherapy. These criteria only address the pseudoprogression pattern of response, and do not capture the other patterns of response such as hyperprogression and dissociated response. The classic RECIST remains a reasonable and meaningful method to assess response to immunotherapy in the clinic.

Background We assessed the efficacy and safety of avelumab, an anti-programmed death ligand 1 (PD-L1) antibody, in patients with previously treated metastatic adrenocortical carcinoma (mACC). Methods In this phase 1b expansion cohort, patients with mACC and prior platinum-based therapy received avelumab at 10 mg/kg intravenously every 2 weeks. Continuation of mitotane was permitted; however, mitotane levels during the study were not recorded. Tumor response was assessed by Response Evaluation Criteria In Solid Tumors v1.1. Results Fifty patients received avelumab and were followed for a median of 16.5 months. Prior treatment included ≥2 lines in 74.0%; mitotane was continued in 50.0%. The objective response rate (ORR) was 6.0% (95% CI, 1.3% to 16.5%; partial response in 3 patients). Twenty-one patients (42.0%) had stable disease as best response (disease control rate, 48.0%). Median progression-free survival was 2.6 months (95% CI, 1.4 to 4.0), median overall survival (OS) was 10.6 months (95% CI, 7.4 to 15.0), and the 1-year OS rate was 43.4% (95% CI, 27.9% to 57.9%). In evaluable patients with PD-L1+ (n = 12) or PD-L1− (n = 30) tumors (≥5% tumor cell cutoff), ORR was 16.7% vs 3.3% (P = .192). Treatment-related adverse events (TRAEs) occurred in 82.0%; the most common were nausea (20.0%), fatigue (18.0%), hypothyroidism (14.0%), and pyrexia (14.0%). Grade 3 TRAEs occurred in 16.0%; no grade 4 to 5 TRAEs occurred. Twelve patients (24.0%) had an immune-related TRAE of any grade, which were grade 3 in 2 patients (4.0%): adrenal insufficiency (n = 1), and pneumonitis (n = 1). Conclusions Avelumab showed clinical activity and a manageable safety profile in patients with platinum-treated mACC. Trial registration Clinicaltrials.gov NCT01772004; registered January 21, 2013.