Abstract 930P
Background
Immune-checkpoint inhibitors (ICI) are currently the standard of care as a first line treatment for pts with R/M HNSCC. There is limited data on the impact of adding PT to ICI in this population.
Methods
We retrospectively analyzed pts with R/M HNSCC who received first line ICI alone or along with PT, between July 1st 2016 and November 1st 2022. We collected data on original tumor site, P-16 status, combined positive score (CPS), absolute lymphocyte count (lymph) prior to starting ICI, time elapsed between finishing radiation to the original tumor site and starting ICI (RT-ICI), response to therapy, progression free survival (PFS), and overall survival (OS). PFS was defined as the time from ICI initiation and disease progression or death. OS was defined as the time from ICI initiation and death. Descriptive statistics were used to explore study variables.
Results
Of the 207 pts analyzed, 81% were male, median age 61 years (IQR: 56, 68). Tumor site: Oropharynx 85 (41%), oral cavity 54 (26%), others 68 (33%). 138 pts (67%) received ICI alone, 69 (33%) PT+ICI triweekly. 64 pts (31%) had RT-ICI of less than 6 months (mo). 144 pts (70%) had CPS available. CPS values: 0 (43 [30%]), 1-20 (50 [35%]), 21-100 (51 [35%]). Median follow-up: PFS: 4.4 mo (IQR: 2.3, 9.8), OS: 8.5 mo (IQR: 3.7, 17.7). Overall response rate (ORR): PT+ICI (33%), ICI (16%), p=0.002. Median survival time: PFS: 4.5 mo (95% CI: 4, 6.2), OS: 11 mo (95% CI: 8.8, 14.3). Median OS: PT+ICI: 15.4 mo (95% CI: 11.3, –), ICI: 9.1 mo (95% CI: 7.1, 13), p=0.062. On multivariable analysis for OS: PT+ICI had reduced hazard compared to ICI (HR: 0.79, 95% CI: 0.53, 1.17, p=0.2); P-16 positive had reduced hazard compared to p-16 negative (HR: 0.46, 95% CI: 0.31, 0.68, p <0.001); high lymph compared to low lymph (HR: 0.48, CI: 0.32, 0.73, p <0.001); CPS of 1-20 and 21-100 had reduced hazard compared to CPS of 0 (HR: 0.72, 95% CI: 0.44, 1.2; HR: 0.48, 95% CI: 0.29, 0.82; respectively, p=0.024); RT-ICI of more than 6 mo had reduced hazard compared to 0-6 mo (HR: 0.68, 95% CI: 0.47, 0.99; p=0.11).
Conclusions
In pts with R/M HNSCC, the addition of PT to ICI was associated with better ORR. Negative P-16, low lymph, CPS of 0, and relapse within 6 mo of finishing RT, were all associated with worse survival outcomes.
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.
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