Will the FDA approve bezuclastinib in advanced systemic mastocytosis before 31 July 2027?
deadline 2027-07-31
confidence medium
tier 4 evidence
45%Asturna estimate
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
- The FDA accepted the NDA with a PDUFA date of June 29, 2027, which is before the July 31, 2027 deadline [tier 1].
- No advisory committee is currently planned, which may suggest a more straightforward review process [tier 1].
- The pivotal APEX trial demonstrated a strong overall response rate of 65% [tier 1].
What pushes it down
- The pivotal trial is a single-arm study against an established competitor, which carries higher regulatory risk than a randomized trial [tier 1].
- With a PDUFA date of June 29, 2027, any standard three-month extension would push the decision past the July 31, 2027 deadline [tier 1].
What would move this number most
The outcomes of the two earlier bezuclastinib NDAs (GIST in November 2026 and non-advanced mastocytosis in December 2026) will provide critical signals regarding the drug's safety and regulatory viability.
How this number is built
| Deadline | 2027-07-31 |
| Base rate | 40% |
| Best evidence | tier 4 · 3 article(s) used |
| Independent runs | 45 · 45 (spread 0 pts) |
| Confidence | medium |
| Evidence cap | not triggered |
| Last revised | 2026-10-08 09:21 |
| Model | gemini-3.5-flash |
Sources consulted
Probability history
2026-10-08 09:21 45% 11 article(s) on file · gemini-3.5-flash
- What pushes it up. The FDA accepted the NDA with a PDUFA date of June 29, 2027, which is before the July 31, 2027 deadline [tier 1].
- What pushes it up. No advisory committee is currently planned, which may suggest a more straightforward review process [tier 1].
- What pushes it up. The pivotal APEX trial demonstrated a strong overall response rate of 65% [tier 1].
- What pushes it down. The pivotal trial is a single-arm study against an established competitor, which carries higher regulatory risk than a randomized trial [tier 1].
- What pushes it down. With a PDUFA date of June 29, 2027, any standard three-month extension would push the decision past the July 31, 2027 deadline [tier 1].
- What would move this number most. The outcomes of the two earlier bezuclastinib NDAs (GIST in November 2026 and non-advanced mastocytosis in December 2026) will provide critical signals regarding the drug's safety and regulatory viability.
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).