BioVie's stock dropped 50% after its Parkinson's trial leaned on a new scorecard instead of its planned measure

BioVie's stock lost roughly half its value on Thursday after the company made its case for a mid-stage Parkinson's drug, bezisterim, on a custom 15-part scorecard it calls the Early Parkinson's Neuro-Inflammatory Composite 15, or EPNIC-15, rather than on the motor-signs measure the trial was actually designed around, according to FierceBiotech.

The trial's stated primary endpoint, per the federal ClinicalTrials.gov database, was change from baseline in MDS-UPDRS Part III, the motor-signs portion of the standard Parkinson's rating scale. That number is not in BioVie's press release. BioVie put the MDS-UPDRS Part III data in a separate, updated investor presentation, while the press release led with EPNIC-15 instead. Leading with a custom composite in place of the trial's planned measure is a flag, not a routine marketing choice, and the roughly 50% stock move is the market's read on that flag.

EPNIC-15 pulls 15 subdomains from four standard rating tools: UPDRS Parts I, II, and III, plus the Parkinson's Disease Sleep Scale 2, or PDSS-2. The MDS-UPDRS Part III items inside the composite are a narrow subset: speech, toe tapping right, toe tapping left, leg agility left, posture, and rest-tremor constancy. BioVie says most patients on bezisterim improved on EPNIC-15, while placebo patients worsened, per the FierceBiotech report.

The provenance line in BioVie's release is thin. The company says EPNIC-15 was "constructed based on learnings" from a 2025 peer-reviewed paper on composite scales for assessing Parkinson's drugs, coauthored by Biohaven researchers. That paper does not mention EPNIC-15, and it does not frame Parkinson's in inflammatory terms. BioVie's release frames bezisterim's mechanism around neuroinflammation; the cited paper does not. That gap, more than any absolute number in the release, is what the market saw.

On the planned primary itself, the picture is muddier. Placebo numerically beat bezisterim at lower baseline platelet counts; bezisterim beat placebo numerically at higher counts; the upper bound of the 95% confidence interval for the overall treatment effect stayed above zero. None of those statements is a hit on the trial's own pre-specified measure. They are a non-result, dressed in subgroup detail, as FierceBiotech laid out.

BioVie CEO Cuong Do, on the company's October 2025 earnings call, had said the trial's goal was to show bezisterim could help "slow the progression of muscle loss" in Parkinson's patients. On Thursday, the company framed the readout as a foundation for further clinical development, not as a primary-endpoint win.

The pattern here is one any biotech reader can reuse on the next disclosure. When a press release leads with a custom composite, three checks follow. First, is the trial's pre-specified primary named in the release itself, or is it parked in a separate deck? Second, where is the supporting paper, and does it actually describe the composite being used, or only adjacent methods? Third, how thin is the prior footprint of the new measure online, in trial registries and prior investor materials? When all three answers tilt toward omission and adjacency, the market usually reads the gap the same way it did on Thursday.

The clinical stakes for Parkinson's patients are narrower than the stock move implies. Bezisterim remains a mid-stage candidate. The roughly 50% drop is about trial design and disclosure, not about a new safety signal. Patients and families watching the headlines should hold the news for what it is: a single mid-stage readout whose framing the market rejected, not a verdict on the underlying science.

BioVie's next test is whether the MDS-UPDRS Part III data in the investor presentation will support a larger phase 3 program, or whether the company will pivot the regulatory strategy around EPNIC-15 itself. The ClinicalTrials.gov record, the BioVie press release, and the investor presentation are the three documents a careful reader should keep side by side.