940P - Salvage chemotherapy after progression on nivolumab in patients with squamous cell carcinoma of the head and neck included in the phase II TOPNIVO trial

Background

Immune checkpoint inhibitors (ICIs) changed the treatment landscape of patients with recurrent and/or metastatic squamous cell carcinoma of the head and neck (R/M SCCHN) and approved in first-line setting as monotherapy or in combination with chemotherapy as well as in platinum refractory disease. Recent retrospective data showed that salvage chemotherapy (SCT) after progressing on ICIs was associated with an overall response rate (ORR) of 30%. We report herein data of patients with R/M SCCHN included in the TOPNIVO phase II trial who progressed on nivolumab (N) and received SCT.

Methods

TOPNIVO is a multicenter phase II safety trial of nivolumab in patients (pts) with platinum refractory R/M SCCHN, ECOG 0-2. Pts received N 3mg/kg every 2 weeks intravenously. Overall, 343 pts received N.

Results

143 pts (84% male, 17% ≥70 years) received SCT after a median of 7 injections of N [range 1-47]. Best response under N was complete response for 2%, partial response for 14%, stable disease for 27%, progression for 56%. The ORR of SCT of the 143 pts was 22% (95% confidence interval (CI) 16;30) and the disease control rate was 38%. The median overall survival (OS) since SCT start was 7.9 months (mo) (95% CI 5.4;9.7) and the 12-mo OS rate was 34%. The median OS was 9.1 mo in 96 pts treated with cetuximab (C) or taxanes (T) based SCT vs 3.9 mo in 31 pts treated with methotrexate or other regimens (p=0.0007). The median OS was 18.3 mo in 17 pts treated with C and T based SCT vs 7.5 mo in 58 pts treated T based SCT without C (p=0.09). 40 pts received C-based SCT with an ORR of 25%, and 79 pts received T-based SCT with an ORR of 30%. In C-based SCT, the ORR was 29% (7/24) in those who already received C prior to N vs 19% (3/16) in those who did not receive, and the median OS was 17.7 mo vs 9.4 mo (p=0.17). In T-based SCT, the ORR was 27% (4/15) in patients who already received T prior to N versus 31% (20/64) in those who did not already receive T and the median OS was 5.7 mo vs 8.8 mo (p=0.37).

Conclusions

SCT was associated with an ORR of 22% in pts with SCCHN who progressed on nivolumab confirming previous results. Re-challenge with cetuximab was associated with ORR of 29%, and re-challenge with taxanes was associated with ORR of 27%.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.