Will the FDA approve lonvoguran ziclumeran in hereditary angioedema before 31 March 2027?
deadline 2027-03-31
confidence medium
tier 4 evidence
75%Asturna estimate
Resolution criterion
Yes if the FDA approves the BLA by 31 March 2027 (Drugs@FDA or an Intellia release). A complete response letter, a postponed PDUFA date, or no decision by that date all count as no. An approval restricted to only type 1 or only type 2 HAE, or excluding adolescents aged 16-17, counts as no; flag for manual review if the label's exact scope is unclear.
Verified starting state
BLA accepted with priority review on 8 September 2026, PDUFA date 10 March 2027, for type 1 or type 2 HAE in adults and adolescents aged 16 and over. No advisory committee planned. Phase 3 HAELO: 87% reduction in monthly attacks versus placebo. This would be the first in vivo gene-editing therapy approved anywhere in the world.
What pushes it up
- The BLA was granted Priority Review with a PDUFA date of 10 March 2027, which falls before the 31 March 2027 deadline [Starting State].
- Phase 3 HAELO trial data demonstrated a robust 87% reduction in monthly HAE attacks compared to placebo [Starting State].
- The FDA has indicated that no advisory committee is currently planned, which often signals regulatory confidence in the submitted data [Starting State].
What pushes it down
- As the first potential in vivo gene-editing therapy, the application faces significant regulatory scrutiny regarding long-term safety and novel platform risks [Starting State].
- The 21-day buffer between the PDUFA date and the deadline is narrow; any major amendment triggering a standard 3-month extension would result in a 'No' resolution [Starting State].
What would move this number most
The primary uncertainty is whether the FDA will require additional data or a major amendment during the review, as a 3-month PDUFA extension would push the decision past the March 31 deadline.
How this number is built
| Deadline | 2027-03-31 |
| Base rate | 73% |
| Best evidence | tier 4 · 3 article(s) used |
| Independent runs | 75 · 75 (spread 0 pts) |
| Confidence | medium |
| Evidence cap | not triggered |
| Last revised | 2026-10-08 09:07 |
| Model | gemini-3-flash-preview |
Sources consulted
Probability history
2026-10-08 09:07 75% 10 article(s) on file · gemini-3-flash-preview
- What pushes it up. The BLA was granted Priority Review with a PDUFA date of 10 March 2027, which falls before the 31 March 2027 deadline [Starting State].
- What pushes it up. Phase 3 HAELO trial data demonstrated a robust 87% reduction in monthly HAE attacks compared to placebo [Starting State].
- What pushes it up. The FDA has indicated that no advisory committee is currently planned, which often signals regulatory confidence in the submitted data [Starting State].
- What pushes it down. As the first potential in vivo gene-editing therapy, the application faces significant regulatory scrutiny regarding long-term safety and novel platform risks [Starting State].
- What pushes it down. The 21-day buffer between the PDUFA date and the deadline is narrow; any major amendment triggering a standard 3-month extension would result in a 'No' resolution [Starting State].
- What would move this number most. The primary uncertainty is whether the FDA will require additional data or a major amendment during the review, as a 3-month PDUFA extension would push the decision past the March 31 deadline.
2026-09-26 09:14 81% 50 article(s) on file · openai/gpt-oss-120b (Groq)
- What pushes it up. BLA accepted with priority review and a PDUFA decision date of 10 March 2027, well before the 31 Mar 2027 deadline [tier 1]
- What pushes it up. Priority review historically yields higher approval odds than standard review [tier 1]
- What pushes it down. Historical first‑cycle approval rate for novel mechanisms is 73% [tier 1]
- What pushes it down. FDA could still issue a complete response letter or postpone the PDUFA date, which would push approval past the deadline [tier 1]
- What would move this number most. Whether the FDA will issue a complete response letter or extend the PDUFA date beyond 31 Mar 2027
2026-09-21 22:23 71% 44 article(s) on file · gemini-3.6-flash
Reasons not recorded for this revision (detailed history has only been kept since recently).
2026-09-19 07:41 77% 36 article(s) on file · gemini-3.5-flash
Reasons not recorded for this revision (detailed history has only been kept since recently).