Aurinia Pharmaceuticals has presented a mixed bag of midphase data on its challenger to Allergan’s blockbuster dry eye drug Restasis. The challenger, VOS, failed to better the tolerability of Restasis but delivered better efficacy on secondary endpoints, suggesting it may have an unexpected edge over its rival.
Canada’s Aurinia designed the head-to-head clinical trial to compare the tolerability of its voclosporin ophthalmic solution (VOS) and Restasis, which Allergan has turned into a blockbuster despite some patients suffering eye irritation that drives them to discontinue treatment. VOS is free from the oil that causes eye irritation in patients taking Restasis, leading Aurinia to speculate that its candidate may be more tolerable.
Data from the 100-patient phase 2 trial undermine that theory. Aurinia found scores on a discomfort scale were comparable across the VOS and Restasis arms. The finding leaves Aurinia without data to support its efforts to position VOS as a more tolerable alternative to Restasis.
If that were the end of the data, VOS could be on its way to the scrapheap. However, the drug could be saved by the secondary efficacy endpoints Aurinia included in the trial. Having gone into the trial looking for a tolerability advantage, Aurinia has emerged from the study with evidence suggesting it has an efficacy edge.
Aurinia picked out four-week data on three secondary efficacy endpoints to make its case. Compared to baseline, the worst eyes of patients in the VOS arm produced 8.6 mm more tears after four weeks. The figure for Restasis was 3.3 mm, resulting in the study hitting the Schirmer tear test endpoint.
VOS also beat Restasis on a secondary endpoint that looked at the percentage of subjects who achieved a 10 mm or more improvement on the Schirmer test. Additionally, it bettered the Allergan drug against another measure that indicates the integrity of the corneal epithelium. All three measures are hard endpoints that are accepted by the FDA.
The surprise nature of the findings and relatively small size of the trial will provoke skepticism about whether the divergence between the VOS and Restasis arms is replicable or a fluke. But Aurinia Chief Medical Officer Neil Solomons publicly has no doubts about the significance of the results.
“We are extraordinarily excited with the superior efficacy shown by VOS when compared to Restasis, which is the current market leader for the treatment of DES in the U.S.,” Solomons said in a statement. “The efficacy endpoints exceeded our expectations and provide further validation of the potential of VOS to provide a highly differentiated and efficacious treatment option for the more than 16 million patients living with this all-too-common disease.”
Buoyed by the data, Aurinia plans to “aggressively advance” VOS as a treatment for dry eye disease. That means bigger tests of the efficacy of VOS—and potentially threats to the market dominance of Restasis—are set to come.