Aviragen Therapeutics, a company focused on the discovery and development of the next generation of direct-acting antivirals to treat infections that have limited therapeutic options, today announced top-line data from its Phase 2b SPIRITUS trial, a multi-center, randomized, double-blind, placebo-controlled, dose-ranging study of vapendavir in moderate to severe asthmatics with a rhinovirus (RV) infection. Vapendavir did not demonstrate a statistically significant reduction in the asthma control questionnaire-6 (ACQ-6) at day 14, the primary endpoint, for either the 264 mg or 528 mg cohorts compared to placebo.
“We are disappointed that the SPIRITUS trial did not meet its primary endpoint in this patient population. There was evidence of an antiviral effect in patients that received vapendavir within the first day following the onset of their symptoms, and as such, we plan to take time to fully analyze the data before making a decision on whether to initiate a study in hematopoietic stem cell transplant patients, where the ability to stop the progression of the RV infection could be beneficial,” stated Joseph Patti, PhD, President and Chief Executive Officer of Aviragen. “We are sincerely grateful for the patients, investigators and staff that participated in the trial.”
The Phase 2b SPIRITUS clinical trial of vapendavir was conducted at approximately 68 sites in North America and Europe. Patients aged 18-70 years that had an established history of moderate-to-severe asthma and a history of losing asthma control as a result of an upper respiratory tract infection were eligible for enrollment. The intent-to-treat (ITT) patient population consisted of 455 randomized patients and from this group there were 168 laboratory-confirmed HRV-infected patients (ITT-infected; ITT-I).
- Primary Endpoint Data: Subjects that received 264 mg (n=54) or 528 mg (n=57) vapendavir had a least square means change in ACQ-6 at day 14 of -0.75 and -0.79, respectively, compared to placebo of -0.94 (n=57). A 0.5 point change in ACQ-6 is considered clinically relevant. The improvement of ACQ-6 in the placebo cohort was larger than expected for this patient population.
- Secondary Endpoint Data: The results of the SPIRITUS study demonstrated statistically significant antiviral effects for patients that received vapendavir within 24 hours of first symptoms, consistent with previous studies. Secondary endpoints evaluating the lung function measure FEV1 and reduction in asthma exacerbations did not show significant differences between the treatment groups and placebo.
- Safety Data: Vapendavir was shown to be generally well tolerated and the safety profile was consistent with previous clinical studies.