This morning, FDA announced that it will now release complete response letters (CRLs) “promptly after they are issued to sponsors.” Alongside that announcement, it released 89 previously unpublished CRLs that were issued since 2024.
That tranche includes the CRL that the agency issued to Lykos Therapeutics last August, when it rejected the company’s MDMA for PTSD application.
Access the CRL: You can retrieve a PDF copy of the Complete Response Letter here. ∎
In the letter, the agency first identifies several issues that precluded approval:
- Failure to collect ‘positive’ adverse events (“FDA inspections also identified several unreported adverse events for at least two sites”, the agency added, “which increased our concerns about the reliability of safety data.”)
- Lack of durability data (“Overall, the data contained in your application fails to establish how MDMA should be used to treat this chronic disease”, the agency wrote.)
- High rates of prior MDMA use among participants, and high rates of prescreening failures (“Together these two factors suggest the possibility of selection bias”, FDA said.)
The CRL goes on to suggest that Lykos conduct a new clinical trial in order to address these issues, which it says should focus on:
- Demonstrating durability of effect
- Minimising potential for bias
- Adequately characterising the safety of MDMA
The agency provides more specific guidance for each of those broad areas of focus. It also recommended that Lykos “consider an independent third-party data audit of all study records and reports”, noting that FDA would still consider the existing data in the event of a future resubmission.
Once again, you can retrieve a PDF copy of the letter here.
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