TTCC-2022-01: Niraparib and dostarlimab in locally-advanced head and neck squamous cell carcinoma treated with (chemo) radiotherapy (RADIAN).
Authors: Oliva Marc , Llop Sandra , Vidales Zara , Arrazubi Virginia , Baste Neus , Brana Irene , Cirauqui Beatriz , Cacicedo Jon , Giralt Jordi , Marruecos Jordi , Plana Serrahima María , De Blas Rodolfo , Navarro Valentín , Pujana Miguel Angel , Rodriguez Bel Laura , Tierraseca Vanessa , Durán Marisa , Montalbán Carmen , Lozano Alicia , Mesia Ricard 
Published: August 2024

TPS6125

Background: The prognosis of locally-advanced head and neck squamous cell carcinoma (LA-HNSCC) remains poor, with a 60% 5-year overall survival (OS) rate despite curative-intent therapies. Treatment intensification strategies with antiPD-(L)1 agents given concurrently to (chemo)radiotherapy (CRT) have failed to improve survival. New radiosensitizing agents such as PARP inhibitors have shown encouraging results in early studies, and are of special interest in cisplatin-unfit patients (pts) (Moutafi et al. 2021). Beyond radiation sensitization, PARP inhibition is predicted to trigger immune responses via STING pathway activation, and synergize with anti-PD-(L)1 agents (Sen T et al., 2019). We hypothesize that niraparib will enhance antitumor immune responses when combined with dostarlimab before and after definitive CRT and will boost RT response ultimately leading to higher disease-free survival (DFS). Methods: Trial design: RADIAN is an investigator-initiated, multi-center, non-randomized two-cohort phase 1b study of niraparib and dostarlimab in LA-HNSCC pts candidates for CRT (cohort A) or RT alone (cohort B – cisplatin unfit). Dostarlimab 500mg is given intravenously 3 weeks(w) before RT and then q/3w starting w4 post-RT for up to 14 cycles. Niraparib 200 or 300mg is given orally once daily 1w after dostarlimab until start of CRT (cohort A) or continuously until last dose of RT (Cohort B) and then continuously in 3w cycles from w4 post-RT for up to a year (14 cycles). Intensity-modulated RT (70 Grays:2Gray/fraction) and high-dose cisplatin are given as per standard-of-care. Study procedures include collection of baseline archival or fresh tumor sample for molecular profiling, PD-L1 expression and immunophenotyping; serial blood samples for circulating tumor (ct) DNA and clinical/endoscopic photographs of the tumor (baseline, pre-niraparib, pre-RT, 12w post-RT, end-of treatment, and at progression). Imaging and follow-up procedures are conducted as per standard-of-care. Key eligibility criteria: untreated, stage III to IVB laryngeal, hypopharyngeal, HPV-negative oropharyngeal SCC (stage III only if HPV-positive), and stage IVB oral cavity SCC as per TNM 8th edition;adequate organ function; no autoimmune disorders; no immunosuppressive therapy. Study objectives: primary objective is to evaluate 1-year disease free survival. Secondary objectives: safety/tolerability including RT delay/completion; locoregional and distant control, event-free survival, OS and ctDNA dynamics correlation with efficacy endpoints. Sample size: 32 evaluable pts for correlative studies are planned for enrollment (16/cohort). It is expected that experimental treatment will provide an increase of efficacy of 0.64 in terms of HR (1-year DFS of 75.9 % in cohort A and 68.2% in cohort B). Study activation: Nov 11th 2023, with 2 pts enrolled as of Feb 6th 2024. Clinical trial information: NCT05784012 .