NPC-31 (P092 maleate), Gifu University anti-prion small-molecule chaperone licensed to Nobelpharma

Key facts

• Nobelpharma's English pipeline table (heading dated March 2026) lists NPC-31 (P092 maleate) for prion disease at phase PI/II, status in preparation, with Gifu University as partner and marketing approval timing TBD.
• US patent 9809563 covers a crystalline maleic acid salt of an anti-prion compound; inventor Kazuo Kuwata, first assigned to Gifu University, assignment to Nobelpharma recorded 2022-02-11; priority 2014-02-10, filed 2015-02-03, granted 2017-11-07.
• The patent says the salt dissolves well enough in water to be made as an injection and reports a cell-culture IC50 of about 0.46 micromolar; a distribution study cited there found more radioactivity in cerebrum and cerebellum than in blood. Whether the patent compound is the one named NPC-31 is not stated in the text read.
• Kuwata's 2025 Japanese-language article says the chaperone binds normal prion protein, crosses the blood-brain barrier when given into a peripheral vein, has an IC50 near 500 nM against one strain, clears from blood within a week yet stays in brain with a half-life over one month, and that preclinical work is finished with a trial to start shortly.
• Nobelpharma's project manager told the July 2025 CJD Foundation conference that several essential non-clinical studies were done and that clinical studies were expected to start probably the next year; no trial was listed.
• A one-slide Nobelpharma PDF dated 14 July 2025 is titled as a P092 kick-off meeting with Dunn Regulatory; only metadata could be read, so its content and Dunn Regulatory's role are unverified.
• Earlier lineage: the same group reported in 2007 that GN8, found by computer screening against PrPC hot spots, lowered abnormal prion protein in cells and modestly lengthened survival of infected mice; GN8 was proposed to act as a chemical chaperone. The link from GN8 to NPC-31 is not stated in any opened source.
• Searches of the Japanese registry and the web found no registered NPC-31 trial; the only prion drug record seen in jRCT was Ionis ION717, a different drug. The registry itself was not queried directly.

Timeline

1. 2007Kuwata group publishes GN8 and the hot-spot chaperone concept in PNAS.
2. 2014Priority date of the maleate salt patent.
3. 2017US patent 9809563 granted.
4. 2022Patent assignment to Nobelpharma recorded.
5. 2025Nobelpharma speaks at the CJD Foundation Family Conference; slide file dated 14 July 2025.
6. 2025Kuwata's trial-start article goes online on J-STAGE.
7. 2026Pipeline table shows NPC-31 phase I/II in preparation.