Preliminary findings from a Phase II study with intramuscular (im) injection of peramivir, the company’s product candidate for the treatment of seasonal and life-threatening influenza, found that the drug failed to meet its primary endpoint of symptom reduction.
The study randomized 344 patients who had a positive rapid antigen test indicating acute influenza illness to receive intramuscular injections of either placebo or one of two dose levels of peramivir (150mg and 300mg) as a single dose administered within 48 hours of symptom onset. The primary endpoint of the study was the time to alleviation of symptoms in the patients with confirmed influenza infection.
While the results indicate that in the evaluable population of 313 subjects, a single dose of peramivir demonstrated a treatment improvement over placebo, the improvement was not statistically significant. With regard to the primary endpoint of median time to alleviation of symptoms, the improvement over placebo was 22.9 hours with the 150mg dose and 21.1 hours with the 300mg dose.
BioCryst said that it believed that the introduction of a shorter injection needle in the Phase II trial compared to the Phase I trial, only one-third of subjects received an adequate intramuscular injection, based on preliminary results.
At both doses studied, peramivir demonstrated a safety and tolerability profile similar to placebo, both in the total population and in the population showing evidence of intramuscular delivery.
“We are clearly disappointed that we did not achieve the primary endpoint across the entire study population. However, the goal of this Phase II study was to explore the efficacy of peramivir and establish its safety profile in subjects with acute influenza infections as we plan for the Phase III trial. In subjects that we believe received the intended dosing of peramivir, we saw patients achieve symptom relief up to 2.6 days faster than placebo, a result that exceeded our expectations. In addition, peramivir demonstrated a safety profile similar to placebo,” said Jon Stonehouse, president and CEO of BioCryst Pharmaceuticals.
“Based on these results, we have a clear and concise plan to correct the issues identified in this study and continue our preparations to initiate our Phase III program by year end.”