Samsung Pharm Withdraws and Plans to Resubmit Phase 3 Trial Application for PSP Drug GV1001

Samsung Pharm voluntarily withdrew its application to amend the investigational new drug (IND) plan for a Korean phase 3 trial of GV1001, a treatment for progressive supranuclear palsy (PSP). The company made the strategic decision to revise the trial design in response to a request for additional information from the Ministry of Food and Drug Safety (MFDS) and then resubmit the application. With no approved drugs worldwide that treat the underlying cause of PSP, attention is focused on whether GV1001 could become the first disease-modifying treatment in the global market.

Company decides to redesign trial in response to MFDS request

Samsung Pharm said in a Sept. 23 disclosure that it had voluntarily withdrawn the GV1001 phase 3 IND application it submitted to the MFDS on July 1. The company said the MFDS requested additional information during its review and that it had determined it would be appropriate to prepare materials addressing the request in full before resubmitting the application.

The trial was a multicenter, randomized, double-blind, placebo-controlled phase 3 study designed to assess the efficacy and safety of subcutaneous GV1001 0.56mg in patients with progressive supranuclear palsy-Richardson syndrome (PSP-RS). PSP is a rare degenerative brain disease caused by abnormal accumulation of tau protein in the brain. Its symptoms resemble those of Parkinson's disease, but it progresses much faster and is accompanied from early stages by balance problems, vertical gaze palsy and cognitive decline. The disease affects about 6~6.9 people per 100,000.

GV1001 is a drug candidate developed in Korea, with GemVax & Kael leading global development and Samsung Pharm leading domestic rights and clinical trials. The peptide drug has multiple mechanisms of action, targeting both neuroinflammation and tau protein pathology. Data from a recently disclosed 72-week long-term treatment study showed a trend toward slower disease progression compared with placebo. A significant disease-delaying effect was reportedly observed in the PSP-RS patient group targeted in this phase 3 trial.

Unmet global need and market growth outlook

There are currently no approved drugs worldwide that treat the underlying cause of PSP. Only symptom-relieving drugs such as levodopa are used to a limited extent, leaving a substantial unmet medical need for disease-modifying treatments. In a September 2026 report, global market research firm DelveInsight said, "The PSP treatment market will reach a major turning point between 2026 and 2036," and forecast that "if new drugs targeting tau protein are successfully approved, the paradigm will shift completely from symptom relief to mechanism-based treatment."

The global PSP treatment market is estimated at about $172.29 million (about 230 billion won) in 2026 and is projected to grow rapidly at a compound annual growth rate of 12.2~29.6% through 2036, driven by an aging population and development of tau-targeted treatments. The UCSF Memory and Aging Center also said, "Because PSP is a representative tauopathy, targeting the abnormal tau ecosystem is key," adding that "recently launched global PSP platform trials and other efforts will greatly accelerate the evaluation and commercialization of disease-modifying treatments."

Global pharmaceutical companies including Novartis and UCB Biopharma have also entered the race to develop tau-targeted PSP treatments, intensifying competition. Samsung Pharm cautioned investors in its disclosure that the statistical probability of a clinical trial drug ultimately receiving approval as a medicine is about 10% and urged them to exercise caution.

Potential for conditional approval and global market entry

GV1001 was designated a development-stage orphan drug by the Korean MFDS in 2024. Samsung Pharm separately applied to the MFDS in January 2026 for conditional approval as a PSP treatment, and the application is currently under review. The voluntary withdrawal and planned resubmission of the phase 3 IND are understood as part of coordination with regulators to prepare a confirmatory trial, to be conducted after conditional approval, in accordance with international standards.

If conditional approval is granted, GV1001 could reach the Korean market before completion of the phase 3 trial as the world's first commercialized PSP treatment. Samsung Pharm said it plans to revise the phase 3 trial design to reflect MFDS guidance and resubmit the IND in the near term. If GV1001 ultimately demonstrates efficacy in Korean and global clinical trials, attention will turn to whether it can establish itself as a first-in-class drug in the global rare neurodegenerative disease market, which is expected to grow to more than 1 trillion won.