Multi-center, open-label, non-randomized, non-comparative two-cohort study for patients with locally-advanced squamous cell carcinoma arising from the larynx, hypopharynx, oropharynx (Stage III, IVA and IVB according to 8th TNM/AJCC ed.) and oral cavity (unresectable, stage IVB according to 8th TNM/ American Joint Committee on Cancer (AJCC) ed.) who are candidates for definitive radiotherapy plus cisplatin (Cohort A) or as single-modality (in cisplatin unfit patient population) (Cohort B) and will receive dostarlimab and niraparib in combination pre-, during and post- radiation.
Study has three parts:
1. Neoadjuvant phase (immune-conditioning phase): patients will receive 1 dose of dostarlimab day -21; niraparib from day -14 prior to radiotherapy (up to 48h prior to radiotherapy (RT) in Cohort A; Cohort B niraparib is uninterrupted until the end of study treatment).
2. Concurrent phase (radiosensitization): patients will receive definitive radiotherapy (70Gy in 35 fractions) with concurrent cisplatin (Cohort A) or with concurrent niraparib (Cohort B).
3. Maintenance: Following radiotherapy, patients will receive adjuvant dostarlimab plus niraparib until Cycle 14 day1(dostarlimab) and day21(niraparib).