BioCryst Announces Positive Phase 1 Results with BCX9250, an Oral ALK-2 Inhibitor for Treatment of Fibrodysplasia Ossificans Progressiva

RESEARCH TRIANGLE PARK, NC, USA I December 21, 2020 IBioCryst Pharmaceuticals, Inc. (Nasdaq: BCRX) today announced that in a Phase 1 clinical trial with BCX9250, an oral activin receptor-like kinase-2 (ALK-2) inhibitor discovered and developed by BioCryst for the treatment of fibrodysplasia ossificans progressiva (FOP), BCX9250 was safe and well tolerated at all doses studied, with linear and dose-proportional exposure supporting once-daily dosing.

FOP is an ultra-rare, severely disabling condition characterized by the irregular formation of bone outside the normal skeleton, also known as heterotopic ossification (HO). HO can occur in muscles, tendons and soft tissue. Patients with FOP become bound by this irregular ossification over time, with restricted movement and fused joints, resulting in deformities and premature mortality. There are currently no approved treatments for FOP.

The randomized, double-blind, placebo-controlled dose-ranging trial evaluated safety, tolerability and pharmacokinetics of single ascending doses (SAD) and multiple ascending doses (MAD) of BCX9250 in healthy subjects.

The SAD study was designed to randomize four cohorts of eight subjects each to receive oral BCX9250 (n=6) or placebo (n=2) at dose levels of 5 mg, 10 mg, 15 mg and 25 mg. Subjects in the 15 mg cohort also received a second single dose to evaluate food effect on absorption of BCX9250.

The MAD study was designed to randomize four cohorts of 12 subjects each to receive oral BCX9250 (n=10) or placebo (n=2) at dose levels of 5 mg, 10 mg, 15 mg and 20 mg once daily (QD) for seven days.

Drug exposure increased with dose in an approximately linear and dose-proportional manner. Drug levels after a high fat meal were similar to those after dosing on an empty stomach. Drug exposure (area under the curve) at 20 mg QD in the MAD was similar to that achieved with doses that suppressed HO in a nonclinical model of activity of orally dosed BCX9250. Additional data can be found in slides in the investors section of the company’s website at

In both the SAD and the MAD studies, oral BCX9250 was safe and well tolerated, with no serious adverse events, no study discontinuations due to adverse events, no grade 3 or 4 adverse events and no clinically significant changes in vital signs, electrocardiograms or safety laboratory parameters. No safety signals were seen.

“FOP is a devastating condition with no approved treatments. These encouraging Phase 1 results provide hope for patients and their families, and we look forward to speaking with expert physicians, patient advocates and regulators about the next steps to advance the program,” said Dr. Bill Sheridan, chief medical officer of BioCryst.

In preclinical studies, BCX9250 demonstrated potency for the target kinase, selectivity, safety and strong suppression of HO in animal models.

About BCX9250

Discovered by BioCryst, BCX9250 is a novel, oral, inhibitor of the ALK-2 enzyme. The ALK-2 enzyme is a part of the normal signaling pathway for bone formation and responds to binding its specific ligands (bone morphogenic proteins, BMPs) by stimulating normal bone growth and renewal in healthy children and adults. Specific activating mutations of the ALK-2 gene are seen in all cases of FOP. An activating mutation in ALK-2 is necessary for the disease to occur, making the ALK-2 enzyme an ideal drug target for treatment of FOP.

About BioCryst Pharmaceuticals

BioCryst Pharmaceuticals discovers novel, oral, small-molecule medicines that treat rare diseases in which significant unmet medical needs exist and an enzyme plays a key role in the biological pathway of the disease. Oral, once-daily ORLADEYO™ (berotralstat) is approved in the United States for the prevention of HAE attacks in adults and pediatric patients 12 years and older, and under regulatory review for approval in Japan and the European Union. BioCryst has several ongoing development programs including BCX9930, an oral Factor D inhibitor for the treatment of complement-mediated diseases, galidesivir, a potential treatment for COVID-19, Marburg virus disease and Yellow Fever, and BCX9250, an ALK-2 inhibitor for the treatment of fibrodysplasia ossificans progressiva. RAPIVAB® (peramivir injection), a viral neuraminidase inhibitor for the treatment of influenza, is BioCryst’s first approved product and has received regulatory approval in the U.S., Canada, Australia, Japan, Taiwan and Korea. Post-marketing commitments for RAPIVAB are ongoing. For more information, please visit the Company’s website at

SOURCE: BioCryst Pharmaceuticals

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