Abstract 685P
Background
Anti–PD1–based immune checkpoint blockade (ICB) treatment (Tx) is the standard therapy for R/M HNSCC but the objective response rate is low (<20%). Currently, PD-L1 expression is the only biomarker used in the clinic, however, the predictive value is low. The data on the correlation between ICB outcomes and genomic characteristics is scant. Here, we report a single institutional data of clinical outcomes and genomic characteristics of patients (pts) with R/M HNSCC treated with ICB-based therapy.
Methods
We performed a retrospective analysis of data of pts with R/M HNSCC treated with ICB (without concurrent chemo) who had next-generation sequencing-based molecular test results at Massachusetts General Hospital. Patient clinicopathologic and genomic data, treatment response, and survival data were analyzed with descriptive statistics.
Results
A total of 82 pts with available data were identified. Median age was 65 years and 64 (78%) were male. 29 (35%) were HPV positive. 44 (54%) had ICB as 1st-line. Median PD-L1 combined positive score (CPS) was 20. The most commonly altered genes were TP53 (43%), CDKN2A (29%), and PIK3CA (29%). Other frequent (> 10%) genetic alterations include TERT promoter, NOTCH1, and H/K/NRAS mutations. With a median follow-up of 14.4 months (mo), median overall survival (OS) and progression-free survival were 14.4 and 3.7 mo, respectively. Radiographic response was seen in 25%. Clinicopathologic factors which correlated with survival include radiographic response (HR 3.86, P < 0.001) and ECOG status (1/2 vs 3/4) (HR 3.6, P < 0.001). The survival trend related to PD-L1 (CPS ≥20 vs < 20) did not meet statistical significance. Interestingly, PIK3CA alteration was negatively correlated with OS (HR 1.99, P = 0.027), while TERT promoter mutation showed a positive correlation with OS (HR 0.44, P = 0.05).
Conclusions
Our single institution data with anti-PD-1 ICB Tx in R/M HNSCC is consistent with registration study results. The correlation between PIK3CA and TERT promoter gene alterations and ICB outcome warrants further investigation.
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.