Key Takeaways

  • The FDA issued a CRL for idebenone in LHON, citing the need for additional clinical data

  • Chiesi Global Rare Diseases plans to evaluate next steps following the agency’s feedback

  • Patient advocates emphasized the importance of continued research and collaboration to advance future treatment options

Chiesi Global Rare Diseases announced that the FDA has issued a Complete Response Letter (CRL) regarding its application for idebenone, a proposed treatment for adolescents and adults with Leber Hereditary Optic Neuropathy (LHON).

In the CRL, the FDA stated it is unable to approve the application in its current form, citing the need for additional clinical data from adequate and well-controlled studies to further establish the drug’s safety and effectiveness. The agency also requested clarification and updates related to chemistry, manufacturing, and nonclinical information. Additionally, issues tied to a referenced "Drug Master File" must be resolved before the application can move forward.

The FDA noted that no new safety concerns were identified.

In a news release, Chiesi emphasized its ongoing commitment to the LHON community and to advancing research in rare diseases.

“Although this outcome is not what we hoped for, we’re deeply grateful to the patients, families, and investigators whose dedication has enabled critical advancements in LHON research,” said Giacomo Chiesi, Executive Vice President of Chiesi Global Rare Diseases. “Their contributions have generated important insights that will continue to inform future scientific efforts. We remain committed to championing the needs of the LHON community and to supporting ongoing research efforts that may one day lead to new treatment options and improved care pathways.”

The regulatory submission for idebenone was supported by data from two key studies: the pivotal RHODOS trial, a randomized, double-blind, placebo-controlled study, and LEROS, a phase 4 open-label interventional study. Both trials evaluated the safety and efficacy of idebenone in adolescent and adult patients with LHON across primary mitochondrial DNA mutations.

Chiesi has not yet disclosed its next regulatory steps but indicated it will review the FDA’s feedback and determine the appropriate path forward.