The FDA conditionally approved Veloxis Pharmaceuticals’ organ-rejection drug Envarsus XR, but says the company must wait until the patent on a rival’s product has expired before launching; a decision that the company disputes.

Tentative approval, announced last week, stemmed from results of a Phase III study in which Envarsus XR (tacrolimus) extended-release tablets proved equal to Astellas Pharma’s Prograf (tacrolimus). Envarsus, indicated to prevent organ rejection in kidney transplant patients, had a treatment failure rate of 10.4 percent compared to Prograf’s 14.2 percent, and had a similar safety profile.

Before it can market Envarsus XR, however, Veloxis has to wait until Astellas’ patent on Astagraf XL (tacrolimus) extended-release tablets expires on July 19, 2016, the FDA said.

This decision came as a surprise, company representatives said during a conference call, as Astagraf’s patent protection was never mentioned during the review process. The company stressed that Envarsus XR is not a “me, too” drug, but rather, an innovative product.

The drug is based on a specific manufacturing technique that dissolves the active ingredient, sprays it on a carrier particle and then compresses it into a tablet, President and CEO William Polvino said. This leads to slower absorption of the drug along the GI tract, he said, which helps patients maintain higher levels of the drug in their blood for longer periods.

Veloxis says it is currently in discussions with the FDA to get the issue resolved.

The drug was granted orphan designation in the U.S., which would give it an extra seven years of patent protection. It was approved in the EU for liver and kidney transplant patients. — Lena Freund

Originally appeared in Drug Industry Daily, the pharmaceutical industry’s number one source for regulatory news and information. Click here for more information.