FDA Proposes New Pathway for Approving Customized Rare Disease Treatments

The proposed system aims to spur development of bespoke therapies for hard-to-treat conditions.

Feb. 23, 2026 at 9:33pm

Got story updates? Submit your updates here. ›

The U.S. Food and Drug Administration has laid out a proposal to create a new pathway for approving customized treatments for patients with rare genetic diseases and other hard-to-treat conditions. The proposed "plausible mechanism" system would allow experimental therapies to be commercialized even if they have only been tested in a small number of patients, a shift long sought by patient advocates and researchers focused on rare diseases.

Why it matters

This new approach aims to address the challenges rare disease patients face, as pharmaceutical companies often lack incentive to invest in developing treatments for conditions that affect only a tiny fraction of the population. The proposed pathway could spur more innovation and access to customized therapies for those with limited medical options.

The details

Under the FDA's draft guidelines, the "plausible mechanism" pathway would require researchers to confirm that an experimental therapy successfully targeted the patient's genetic or biological abnormality, even if the treatment has only been tested in a handful of people. This is a departure from the FDA's traditional drug approval process, which typically requires larger clinical trials demonstrating safety and efficacy. The new system would also allow companies to commercialize these customized treatments, addressing a key barrier that has discouraged investment in rare disease therapies.

  • The FDA announced the proposed guidelines on February 23, 2026.
  • The agency will accept public comments on the draft guidance for 60 days before finalizing the new pathway.

The players

Marty Makary

FDA Commissioner who stated that the new pathway is a priority to "remove barriers and exercise regulatory flexibility" to deliver more treatments for rare disease patients.

Children's Hospital of Philadelphia and the University of Pennsylvania

A research team at these institutions designed a CRISPR-based therapy to treat a rare disease that causes ammonia buildup in the blood.

Got photos? Submit your photos here. ›

What they’re saying

“It is our priority to remove barriers and exercise regulatory flexibility to encourage scientific advances and deliver more cures and meaningful treatments for patients suffering from rare diseases.”

— Marty Makary, FDA Commissioner (wbal.com)

What’s next

The FDA will finalize the new "plausible mechanism" pathway after reviewing public comments over the next 60 days.

The takeaway

This proposed FDA system represents a significant shift in how the agency approaches approving customized treatments for rare and hard-to-treat diseases. By providing a more flexible pathway, it aims to spur innovation and increase access to life-changing therapies for patients with limited options.