Polaryx Therapeutics, Inc. is a clinical-stage biotechnology company focused on developing disease-modifying therapies for rare pediatric lysosomal storage disorders, including neuronal ceroid lipofuscinoses (CLN2 and CLN3), Krabbe disease, Tay-Sachs and Sandhoff diseases, and Niemann-Pick disease types A and B.
The lead candidate PLX-200, an oral gemfibrozil-based formulation, has extensive preclinical data across multiple animal models, three FDA orphan drug designations and Fast Track status in select NCL indications, with a Phase 2 SOTERIA basket trial in four LSDs expected to start in the second half of 2026.
Additional programs include small molecules PLX-300 and PLX-100 and gene therapy PLX-400, all licensed primarily from Rush University Medical Center, supported by a services agreement with controlling stockholder Mstone. As of February 1, 2026, Polaryx had 47,343,297 common shares outstanding.
Polaryx Therapeutics, Inc. director and Chief Financial Officer Landis G. Michael reported an open-market purchase of common stock. On February 18, 2026, he bought 2,867 shares at an average price of $2.7871 per share, bringing his directly held stake to 228,225 shares.
Polaryx Therapeutics, Inc. received a Schedule 13D reporting that a group led by Mstone entities and Alex Keun Mo Yang beneficially owns 22,744,796 shares of common stock, or 48.0%, based on 47,343,297 shares outstanding as of January 12, 2026.
The group consists of Mstone Partners Healthcare Limited, MBstone Biotech Flagship Limited, Mstone Pediaorphan Singapore I Pte. Limited and Mr. Yang. Mstone holds 22,452,954 shares (47.4%), MBstone 183,560 shares (0.4%) and Mstone Singapore 108,282 shares (0.2%).
The aggregate purchase price for the currently owned shares is $3,000,513, funded from the reporting persons’ general working capital. Mr. Yang is Chief Executive Officer of Polaryx and has voting power over the shares held by the three Mstone entities, though he disclaims beneficial ownership outside Section 13(d) purposes. The group states it has no present specific plans for corporate actions but may reconsider its position over time.