Phase II (Alliance A091802) Randomized Trial of Avelumab Plus Cetuximab Versus Avelumab Alone in Advanced Cutaneous...

Continued improvement in outcomes is needed for advanced cutaneous squamous cell carcinoma (cSCC).

Alliance A091802 is a randomized phase II trial of avelumab (800 mg IV once every 2 weeks) plus cetuximab (500 mg/m² IV once every 2 weeks) versus avelumab alone once every 2 weeks for up to 2 years. Cetuximab was given for 1 year in the avelumab + cetuximab arm. Crossover at progression to avelumab + cetuximab was allowed. Randomization was 1:1, stratified by PD-L1 and HIV status. Patients had distant metastatic or unresectable locally advanced cSCC, were anti-PD-1/PD-L1 monoclonal antibody-naive, had no previous cetuximab in the advanced setting, had an Eastern Cooperative Oncology Group performance status of 0-2, and could be HIV+ (CD4 >200, viral load <200). Patients with chronic lymphocytic leukemia, immunosuppression, or active autoimmune diseases were excluded. The primary end point was progression-free survival (PFS; null hypothesis: median = 12 months v alternative hypothesis: 21 months or a 75% improvement, power of 80% with one-sided alpha .2, n = 57, 37 PFS events required). Secondary end points were overall survival, objective response rates (ORRs), clinical benefit rate, and toxicity.

Sixty patients were enrolled; 57 patients were evaluable. The median age was 72 years, all were HIV-; 75.4% was PD-L1+, 84.2% had head/neck origin, 47.4% had distant metastasis, and there were no differences in baseline characteristics by arm. Avelumab + cetuximab significantly improved PFS versus avelumab (median, 11.1 [7.6-not reached (NR)] v 3.0 months [2.7-13.6] hazard ratio, 0.48 [95% CI, 0.23 to 0.97], P = .018). Avelumab patients who crossed over (n = 9) to combination had a median PFS after crossover of 11.3 months (5.8-NR). The confirmed ORR was 27.6% with avelumab + cetuximab and 21.4% with avelumab. Grade 3 treatment-related adverse events occurred in 48.3% and 21.5% of patients with avelumab + cetuximab (most common: rash [20.7%], infusion reaction [20.7%]) and avelumab, respectively.

Avelumab + cetuximab significantly improved PFS versus avelumab alone in patients with advanced cSCC. Alliance A091802 supports a larger confirmatory study with the combination of cetuximab and PD-1:PD-(L)1 blockade.