Fast Track Designation Granted to Investigational Treatment for Kennedy Disease

The Food and Drug Administration (FDA) has granted Fast Track designation to AJ201 (AnnJi Pharmaceutical Company, Taipei City, Taiwan) for investigation as a treatment for the rare X-linked inherited neuromuscular disorder, spinal and bulbar muscular atrophy (SBMA), also referred to as “Kennedy disease.” Currently, there are no therapies approved by the FDA for the treatment of SBMA, which affects approximately 1 in 40,000 individuals globally.

AJ201 is a novel, orally delivered investigational compound that is designed to target and support the degradation of pathogenic androgen receptor (AR) proteins caused by mutations of the AR gene associated with SBMA. According to a statement released by AnnJi Pharmaceuticals, preclinical research suggests that treatment with AJ201 may have the potential to improve motor function.

In the spring of 2025, AnnJi Pharmaceutical Company announced positive topline data from a phase 1/2 clinical trial (NCT05517603) assessing the safety, tolerability, pharmacokinetics, and pharmacodynamics of treatment with AJ201 for individuals with SBMA. In this first-in-patient study, participants were randomly assigned to receive either AJ201 600 mg or placebo daily for 12 weeks. The primary end point assessed safety in terms of treatment-emergent adverse events (AEs) and serious AEs. While the study was not intended to assess efficacy and biomarker results, exploratory end point data were reported.

Compared with placebo, AJ201-treated individuals showed the following:

• An average 17.6-meter improvement in 6-Minute Walk Test (6MWT).
• An average 0.8-point increase in score on the SBMA Functional Rating Scale (SMBAFRS).
• A significant improvement in physical function as reported on the SF36v2 quality of life questionnaire (P=.026).
• Reduction in serum levels of creatine kinase and myoglobin, proteins that are typically elevated in those with SBMA.

Additionally, 53% of participants treated with AJ201 vs 17% of those treated with placebo showed a >50% reduction in mutant AR protein levels on muscle biopsy, which are a proposed biomarker for SBMA.

“Receiving the Fast Track Designation for AJ201 marks a significant milestone for AnnJi,” said Wendy Huang, PhD, CEO and Chair of the Board at AnnJi Pharmaceutical Company. “Alongside the Orphan Drug Designations granted by both the US FDA and EMA, this recognition reinforces AJ201's potential to address the unmet needs of patients with SBMA. Backed by a strong global patent portfolio, we remain committed to advancing AJ201 into Phase 3 development and to working closely with the FDA to potentially deliver the first approved treatment for SBMA in more than two decades.”

Source: AnnJi Pharmaceutical Co. Ltd. AnnJi Pharmaceutical Company announces positive phase 1/2a results for AJ201 in spinal and bulbar muscular atrophy (SBMA) patients. PR Newswire. Published May 21, 2025. Accessed October 28, 2025. https://www.prnewswire.com/news-releases/annji-pharmaceutical-company-announces-positive-phase-12a-results-for-aj201-in-spinal-and-bulbar-muscular-atrophy-sbma-patients-302462634.html

AnnJi Pharmaceutical Co. Ltd. FDA grants Fast Track Designation for AJ201, a first-in-class therapy for Kenndy's (sic) disease. PR Newswire. Published October 22, 2025. Accessed October 28, 2025. https://prnmedia.prnewswire.com/news-releases/fda-grants-fast-track-designation-for-aj201-a-first-in-class-therapy-for-kenndys-disease-302592267.html