Prothena Guides $50–55M 2026 Cash Burn; Partner Drugs Enter Phase 3 After 40% and 48% Endpoint Reductions
Prothena guided 2026 cash burn of $50–55M, excluding up to $105M in partner milestones, after spending $163.7M in 2025. Partner programs prasinezumab and coramitug moved into phase 3 trials enrolling ~900 and ~1,280 patients after phase 2 data reported 40% and 48% reductions in key endpoints.
1. Cash Guidance and 2025 Financials
Prothena reported using $163.7M in cash for operations and investing during 2025 and ended the year with $308.4M on hand and no debt. The company now forecasts net cash burn of $50–55M in 2026, noting this outlook excludes up to $105M of potential partner clinical milestones.
2. Phase 3 Advances for Prasinezumab and Coramitug
Roche advanced prasinezumab into the PARAISO phase 3 trial in early Parkinson’s disease, targeting enrollment of approximately 900 participants with primary completion expected in 2029. Novo Nordisk’s coramitug entered the CLEOPATTRA phase 3 ATTR-CM trial, aiming to enroll around 1,280 patients and also reach primary completion in 2029.
3. Phase 2 Efficacy Readouts
In a levodopa-stable subset from the PADOVA phase 2 trial, prasinezumab treatment achieved a 40% relative reduction in MDS-UPDRS part 3 progression versus placebo at 24 months (nominal p=0.0177). Coramitug’s 60 mg/kg dose in a 12-month, 105-patient phase 2 ATTR-CM study produced a 48% NT-proBNP reduction compared with placebo (p=0.0017).
4. BMS Partnerships and Preclinical Pipeline
Prothena’s collaboration with Bristol Myers Squibb saw BMS-986446 complete enrollment in a ~310-patient phase 2 Alzheimer’s trial and receive FDA Fast Track designation. The company will share phase 1 PRX019 results with BMS following program exercise and continues to advance its CYTOPE intracellular-targeting platform and PRX012-TfR anti-Aβ approach in preclinical studies.