In just 72 words, BioCryst Pharmaceuticals announced it would pause enrollment for three phase 2 trials of its rare disease candidate BCX9930, sending shares tumbling 30%.
The extremely brief statement said enrollment in the trials would be paused as the company investigates elevated serum creatinine levels, which is a sign of impaired kidney function.
No new patients will be enrolled in the Redeem-1, Redeem-2 and Renew trials. The Redeem studies are testing BCX9930 in paroxysmal nocturnal hemoglobinuria, or PNH, a rare blood disease that causes the destruction of red blood cells. Renew features patients with C3 glomerulopathy (C3G), immunoglobulin A nephropathy (IgAN) and primary membranous nephropathy (PMN), all diseases that lead to kidney malfunction.
Enrollment in the proof-of-concept Renew study just got underway in February, while Redeem-1 began in January and Redeem-2 kicked off in November 2021.
Patients currently enrolled in the trials will continue to receive BCX9930, BioCryst said.
In going after PNH, BioCryst is up against AstraZeneca unit Alexion, which has dominated in the disease for years with approved meds Ultomiris and Soliris. BioCryst is trying to develop a therapy with an easier treatment regimen that could tackle the disease in several different ways.
BCX9930 has been granted a fast track and orphan drug tag from the FDA for PNH.
Shares of BioCryst were down 32% to $12.06 Friday morning as the markets opened, compared to a prior close of $17.88.
RBC Capital Markets said the short statement did not provide clarity on whether the creatinine signal appeared in the PNH or kidney disease populations. This is a new safety issue not previously seen in earlier trials.
"It remains to be seen whether the drug may still be viable at least in the PNH population," RBC said in a Friday afternoon note.
The firm said the stock tumble "may be excessive," despite the obvious setback for the company's lead pipeline program.