Will the FDA approve bezuclastinib in advanced systemic mastocytosis before 31 July 2027?
deadline 2027-07-31
confidence high
tier 4 evidence
48%PolySignal estimate
⚠ Evidence cap applied: the model proposed 85%, brought back to 48% for lack of sources solid enough to justify the departure from the base rate.
Resolution criterion
Yes if the FDA approves this specific NDA, for the advanced systemic mastocytosis indication, by 31 July 2027. Decisions on the two other bezuclastinib NDAs (non-advanced mastocytosis, GIST) do not count. A complete response letter, a postponed PDUFA date, or no decision by that date all count as no.
Verified starting state
NDA accepted under standard review, PDUFA date 29 June 2027, no advisory committee planned. Pivotal APEX trial: overall response rate of 65%. Two other NDAs are pending: non-advanced mastocytosis (PDUFA 30 December 2026) and GIST (PDUFA 30 November 2026). A single-arm trial against an established competitor. (15 September 2026)
What pushes it up
- NDA accepted under standard review and PDUFA date set for 29 June 2027, indicating a high likelihood of approval before 31 July 2027 [tier 1]
- Strong pivotal trial results with 65% overall response rate [tier 1]
- No advisory committee planned, reducing potential delays [tier 1]
What pushes it down
- Risk of a complete response letter or additional data requests could delay approval beyond the PDUFA date [tier 1]
- Potential regulatory or safety concerns could arise, leading to a postponed PDUFA date [tier 1]
What would move this number most
Whether the FDA will issue a complete response letter or postpone the PDUFA date beyond 29 June 2027.
How this number is built
| Deadline | 2027-07-31 |
| Base rate | 40% |
| Best evidence | tier 4 · 0 article(s) used |
| Independent runs | 48 · 48 (spread 0 pts) |
| Confidence | high |
| Evidence cap | applied: 85% brought back to 48% |
| Last revised | 2026-09-27 09:13 |
| Model | openai/gpt-oss-20b (Groq) |
Probability history
2026-09-27 09:13 48% 52 article(s) on file · openai/gpt-oss-20b (Groq)
- What pushes it up. NDA accepted under standard review and PDUFA date set for 29 June 2027, indicating a high likelihood of approval before 31 July 2027 [tier 1]
- What pushes it up. Strong pivotal trial results with 65% overall response rate [tier 1]
- What pushes it up. No advisory committee planned, reducing potential delays [tier 1]
- What pushes it down. Risk of a complete response letter or additional data requests could delay approval beyond the PDUFA date [tier 1]
- What pushes it down. Potential regulatory or safety concerns could arise, leading to a postponed PDUFA date [tier 1]
- What would move this number most. Whether the FDA will issue a complete response letter or postpone the PDUFA date beyond 29 June 2027.
2026-09-26 09:18 48% 50 article(s) on file · openai/gpt-oss-120b (Groq)
- What pushes it up. NDA accepted under standard review with a PDUFA date of 29 June 2027, well before the 31 July 2027 deadline [tier 1]
- What pushes it up. No advisory committee is planned, which lowers the chance of a delay or negative recommendation [tier 1]
- What pushes it down. The FDA could issue a complete response letter or extend the review if safety or efficacy concerns arise [tier 1]
- What pushes it down. The generic base‑rate for similar drugs is only 40 %, indicating inherent uncertainty [tier 1]
- What would move this number most. Whether the FDA will encounter any major safety, efficacy, or manufacturing issues that trigger a complete response letter or a PDUFA extension
2026-09-21 22:27 48% 44 article(s) on file · openai/gpt-oss-120b (Groq)
Reasons not recorded for this revision (detailed history has only been kept since recently).
2026-09-20 09:01 81% 37 article(s) on file · gemini-3-flash-preview
Reasons not recorded for this revision (detailed history has only been kept since recently).