BioCryst Pharmaceuticals Inc. (NASDAQ: BCRX) is getting crushed after announcing results from OPuS-2 for the treatment of hereditary angioedema (HAE) attacks. Unfortunately, the company said that this treatment failed to demonstrate a statistically significantly lower mean attack rate than a placebo. This was a liquid-filled soft gel formulation for the prophylactic treatment of HAE.

HAE is a rare and severely debilitating and potentially fatal genetic condition that occurs in about one in 10,000 to one in 50,000 people. It is also worth noting that BioCryst said that the company is still talking up HAE test results by midyear and by the end of this year.

The primary goals of the trial were to characterize the efficacy of avoralstat in reducing the frequency of angioedema attacks, and to evaluate the safety and tolerability of 12 weeks of avoralstat treatment. The primary efficacy endpoint was angioedema attack frequency.

Secondary efficacy endpoints included measures of quality of life, attack duration and attack severity. BioCryst did say that statistically significant improvements in duration of attacks and in the angioedema quality of life total score, and its domains, were observed comparing the 500 mg three times a day avoralstat arm to a placebo.

Thirty-eight subjects received avoralstat 500 mg, 36 subjects received avoralstat 300 mg and 36 subjects received the placebo. Treatment with 500 mg and 300 mg of avoralstat three times daily failed to demonstrate a statistically significantly lower mean attack rate versus the placebo. The mean (standard deviation) attack rates per week were 0.63 (0.57) on avoralstat 500 mg, 0.71 (0.66) on avoralstat 300 mg, and 0.61 (0.41) on placebo.

BioCryst did say that oral administration of avoralstat in OPuS-2 was generally safe and well tolerated. It also noted that the adverse event profile was similar to that for the placebo, and no safety signals were observed. Unfortunately, safety profiles just do not matter if the overall endpoints are not met.

Jon P. Stonehouse, president and chief executive officer of BioCryst, said:

OPuS-2 was a well-designed and executed trial that gave us a clear answer; this dosage form of avoralstat is not a viable formulation to move forward. While we are disappointed in the study results, we learned that meaningfully better exposure is needed for avoralstat to succeed. We expect results from a relative bioavailability study testing a novel solid dosage form of avoralstat by mid-year – the primary goals of this study are to achieve much higher exposures and twice daily dosing. Our other opportunity to achieve higher exposure of an oral kallikrein inhibitor is with BCX7353 – we expect results from the BCX7353 APeX-1 dose ranging study in HAE patients by year end.

BioCryst shares were last seen down over 66% at $2.05 on Monday morning. Its new 52-week low, also put in on Monday, was $1.96, versus a 52-week high of $16.83. Its new market cap is right at $150 million.

At the end of last September, BioCryst had almost $72 million between its cash and short-term securities and it had almost $48 million in long-term investments.

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