Merck KGaA / Debiopharm

Locally advanced squamous cell carcinoma of the head and neck (LA SCCHN)

66K US cases/yr · $3.5B Global head & neck cancer therapeutics market 2021 (USD MM) · 55 5-year overall survival in LA SCCHN (%)

Disease Overview

Squamous cell carcinoma of the head and neck (SCCHN) encompasses malignancies of the oral cavity, oropharynx, hypopharynx, and larynx, with approximately 66,470 new US cases and 15,050 deaths estimated for 2022 (NCI SEER). Globally, head and neck cancers are the seventh most common cancer with approximately 890,000 new cases annually. Risk factors include tobacco, alcohol, and HPV (especially HPV-16 in oropharyngeal cancer, accounting for ~70% of US oropharyngeal cases). Approximately 60% of SCCHN patients present with locally advanced (stage III/IVA-B) disease at diagnosis, where standard-of-care is platinum-based concurrent chemoradiotherapy (CRT) with cisplatin 100 mg/m2 every three weeks plus 70 Gy radiation. Despite curative intent, 5-year overall survival in LA SCCHN is approximately 50-60%, and 30-50% of patients experience locoregional recurrence within 2-3 years. The unmet need is acute: no new agent had been added to the cisplatin-radiotherapy backbone in over two decades since the 2006 cetuximab approval, and post-operative cisplatin/RT (Bernier and Cooper trials) remains standard for high-risk resected disease. Recurrent/metastatic SCCHN is treated with pembrolizumab (Keytruda, anti-PD-1) +/- platinum-fluorouracil (KEYNOTE-048) or nivolumab monotherapy.

Competitive Landscape

Xevinapant (Debio 1143) is a first-in-class oral, small-molecule inhibitor of apoptosis proteins (IAP) antagonist that mimics the natural IAP antagonist Smac/DIABLO, sensitizing tumor cells to chemoradiotherapy-induced apoptosis. At deal date (March 2021), Debiopharm had reported positive Phase 2 data in 96 LA SCCHN patients showing significant improvement in locoregional control at 18 months (54% vs 33% placebo, HR 0.51, p=0.026) and 3-year overall survival (66% vs 51%) when added to standard cisplatin-CRT. The Phase 3 TrilynX study (NCT04459715) was enrolling at deal close. Subsequent Phase 3 readouts disappointed: TrilynX missed primary endpoint of event-free survival (EFS) in October 2023, leading Merck KGaA to discontinue xevinapant development in February 2024 — wiping the asset's commercial value. Competitive landscape in LA SCCHN intensification: pembrolizumab (Keytruda) tested in KEYNOTE-412 adjuvant CRT (failed primary endpoint 2022), avelumab (Bavencio) in JAVELIN Head & Neck 100 (failed 2020), nivolumab in CheckMate 651 (1L R/M failed 2021), Roche/Genentech atezolizumab in IMpower150 (negative LA setting). EGFR-targeted: cetuximab (Erbitux, RTOG 1016 showed inferior to cisplatin in HPV+ 2018). HRA-Pharma's pemigatinib, ISA Pharma ISA-101 HPV vaccine, Bicycle Therapeutics BT8009 are adjacent. Other IAP antagonists include Astex/Ono ASTX660 (tolinapant, discontinued), AstraZeneca/Astex ASTX295, Birinapant (TetraLogic, discontinued).