CAR-T Autoimmune Gains and FDA GSK Leucovorin Withdrawal

The U.S. Food and Drug Administration (FDA) has withdrawn the approval application for GSK’s drug leucovorin, marketed as Wellcovorin, for the treatment of cerebral folate deficiency (CFD). CFD is a rare brain disorder characterized by autistic features.

The move concludes a regulatory episode that was influenced in part by political pressure. The withdrawal follows a period of renewed attention toward the decades-old drug after public suggestions were made regarding its potential to treat autism symptoms.

Political Context and Regulatory Timeline

The drug re-entered public discourse in September 2025 when the FDA took the highly unusual step of asking GSK to refile an application for the medication. This request occurred after members of the Trump administration publicly suggested that leucovorin had the potential to treat symptoms associated with autism.

Following this request, GSK eventually filed an application, but the company has now requested to terminate that new drug application. According to a Federal Register notice issued on April 9, 2026, the pharma company requested the termination because the drug products were no longer marketed.

A spokesperson for GSK told The Wall Street Journal on April 10, 2026, that the withdrawal of the application was procedural and not linked to any safety or efficacy issues. The spokesperson further noted that the company had never intended to revive the drug for commercial use.

History of Wellcovorin

Wellcovorin, the brand name for generic leucovorin, was first approved by regulators in 1983. At the time of its original approval, it was used as a treatment to counter the toxic side effects caused by methotrexate, which is a common chemotherapeutic agent used in cancer treatment.

GSK began discontinuing the drug in 1997 and had fully discontinued Wellcovorin by 1999. While the brand-name version was removed from the market, generic versions of leucovorin remained available.

A spokesperson for the Department of Health and Human Services confirmed that GSK’s petition to pull the approval application does not affect the availability of generic leucovorin. The spokesperson stated that the action also does not impact the labeling of leucovorin products currently available on the market.

Developments in CAR-T Cell Therapy

While regulatory focus has been on older medications, the biotechnology sector is seeing a shift in the application of engineered cell therapies. CAR-T therapies, which have been used for more than a decade as a primary tool in oncology, are now gaining traction for the treatment of autoimmune diseases.

For years, CAR-T therapy has been utilized to turn end-stage blood cancers into curable diseases. However, the application of these engineered cells is currently expanding beyond cancer treatment into the autoimmune space, representing a new direction for the regulatory and clinical playbook of cell therapies.