ORCHESTRA: minzasolmin

The research record

This is the project's file for this landmark, as written and checked. Sources are listed at the end; anything not yet confirmed is marked "Not yet verified".

Who

UCB (Belgium), which says it developed minzasolmin in partnership with Novartis. Preclinical work by Diana Price, Anja-Leona Biere, Martin Citron and colleagues.

What happened

Minzasolmin is a small molecule taken by mouth that is meant to block the early misfolding of alpha-synuclein, the first step of clumping. In mice carrying the human gene (the "Line 61" strain) three months of dosing lowered synuclein pathology and improved gait and balance (npj Parkinson's Disease, 2023). ORCHESTRA (NCT04658186, Phase 2a) then ran from 30 December 2020 to 6 September 2024: 496 people with early Parkinson's were randomised to placebo (165), 180 mg a day (166) or 360 mg a day (165) for 18 months. The primary measure was the change in the MDS-UPDRS parts I-III sum score. On 16 December 2024 UCB announced that the trial missed its primary and secondary endpoints, with no evidence of clinical benefit and no new safety risks, and began ending the extension phase. A preliminary signal in biomarker data was still being analysed. The registry posted results on 31 October 2025. It gives raw group means at month 18 of 37.9 (placebo), 35.6 (180 mg) and 34.9 (360 mg) on the MDS-UPDRS I-III sum, with no test shown there; these are not adjusted comparisons, and UCB reports the endpoint was missed. A Phase 1/1b paper (healthy volunteers and 31 people with Parkinson's) found acceptable safety and predictable drug levels (Mov Disord 2022).

Why it moved us toward a cure

It tested a different idea from antibodies: stop the first misfolding step inside the neuron rather than clear clumps outside. The result does not prove the idea wrong; why it failed (dose, brain exposure, timing, or the idea itself) is not answered in the sources read. UCB moved to a drug aimed at synuclein spread outside cells (UCB7583). Compare landmark 29, which lowers synuclein production instead, and landmark 27 on what the misfolded protein looks like.

Outcome

Dead end for minzasolmin in early Parkinson's.

Sources

• UCB press release, 16 Dec 2024
• ClinicalTrials.gov NCT04658186 (496 enrolled, Phase 2, re-read via API 22 Oct 2026; results posted 31 Oct 2025)
• Phase 1/1b studies of UCB0599, Mov Disord 2022;37:2045-2056, PMID 35959805
• Price et al., npj Parkinsons Dis 2023, DOI 10.1038/s41531-023-00552-7
• Not yet verified: a peer-reviewed publication of ORCHESTRA (none found in PubMed on 19 Oct 2026; UCB said it would submit one); the registry's adjusted analysis (not shown in the posted record); the biomarker signal; the enrolment figure (UCB says "more than 450", the registry 496, which is used above).