Aquinox Pharmaceuticals is abandoning development of its lead drug candidate, rosiptor, after it was unable to beat placebo in a phase 3 clinical trial in chronic bladder pain. The disappointing topline results come less than two months after Astellas agreed to purchase R&D rights to the drug in several Asia-Pacific countries for $25 million upfront.
That includes the halting of a phase 2 proof-of-concept study of rosiptor in chronic prostatitis, which began dosing in the past few weeks. The news sent Aquinox’s stock down 80% in premarket trading.
“This is a disappointing result for Aquinox and for patients,” said David Main, president and CEO of the Vancouver, Canada-based Aquinox. “We will be undertaking a thorough evaluation of our pipeline and other strategic options available to the company and will be in a position to provide further guidance later this year.”
Main told investors on a conference call that Aquinox had $93 million cash on hand at the end of the last quarter, plus Astellas’ $25 million, giving it a somewhat healthy balance sheet as the biotech plans its next steps. The company will also aim to publish the full study data if possible.
The phase 3 trial, LEADERSHIP 301, randomized 341 female patients with interstitial cystitis or bladder pain syndrome to two oral, daily doses or placebo for its primary endpoint analysis. While generally well tolerated, rosiptor failed to significantly reduce average maximum daily pain scores after 12 weeks, with a p-value of 0.41.
“Patients improved from start to finish, but it didn’t matter whether you took placebo or drug,” Main said.
The company described the trial as robust and well conducted, and that it believed the results were definitive. “We have conducted a number of sensitivity, subpopulation, and secondary endpoint analyses and none demonstrate a benefit of rosiptor over placebo,” Main said.
Rosiptor activates the SHIP1 pathway, which can help reduce overactive PI3K immune system signaling and the inflammatory process, and hopefully the pain that can come with it.
The drug has had a rocky development: The most-recent trial enrolled a population very similar to a prior phase 2 study in bladder pain, which missed its primary endpoint in 2015, but saw some success against secondary endpoints. Also known as AQX-1125, rosiptor also failed mid-phase studies in chronic obstructive pulmonary disease and atopic dermatitis.
Astellas’ deal included up to $130 million in development and commercial milestones for exclusive rights to rosiptor in all diseases in Japan, South Korea, Australia, Taiwan, Indonesia and Malaysia. Astellas has not yet responded to a request for comment.
On the conference call, Main said Aquinox plans to discuss the results with Astellas later today. “It will be in their court, with what they’d like to do next,” Main said.