The FDA has approved a Portola Pharmaceuticals drug that reverses the effect of blood thinners in cases of life-threatening bleeding. The decision comes two years after the regulator rejected the drug due to manufacturing concerns.
The agency still has some concerns about the drug, andexanet alfa (Andexxa). The drug’s label must carry a boxed warning about its cardiovascular risks. In its announcement of the approval late Thursday, South San Francisco, CA-based Portola (NASDAQ: PTLA) said continued approval for the injectable drug may be contingent on post-marketing study results.
But investors welcomed the news, boosting shares of Portola 19 percent to $40.23 Friday morning.
Regulatory approval of andexanet alfa puts Portola in line for a $100 million payment from HealthCare Royalty Partners. Last year, Portola entered a royalty agreement with the company, which paid Portola $50 million at the closing of the deal, and pledged another $100 million upon the drug’s approval. In exchange, Healthcare Royalty Partners will receive royalties on worldwide sales of the drug.
The Portola drug was developed to be an antidote for patients being treated with two blood thinning drugs, rivaroxaban and apixaban. In some cases, these patients can experience uncontrolled or life-threatening bleeds. Portola studied its drug in two Phase 3 studies that showed the drug was able to quickly reverse the blood-thinning effect of the blood thinners in healthy volunteers.
The FDA also reviewed interim data from an ongoing study testing the Portola drug in patients with major bleeding. A total of 185 patients have been evaluated in that study so far. In those that had received initially rivaroxaban, the decrease in anti-clotting activity observed following treatment with the Portola drug was 90 percent. In those that had received apixaban, the decrease in anti-clotting activity following administration of the Portola drug was 93 percent.
But the Portola drug comes with risks of its own. The warning on the andexanet alfa label says the drug’s risks include blood clots, restriction of blood supply to tissues, cardiac arrest, and sudden death. Investigators will look out for those complications in the post-marketing study, which will randomize patients to receive either the Portola drug, or the standard of care. Portola said this study is scheduled to start next year. Data are expected in 2023.
In rejecting andexanet alfa in 2016, Portola said the FDA cited concerns with one of two manufacturing for the lines that a third-party company, AGC Biologics, used to produce the drug. Portola has since entered an agreement with another company, Lonza, to develop a higher-capacity, lower-cost manufacturing process for the drug.
Portola says it plans to launch andexanet alfa with quantities of the drug made by AGC. A broader commercial launch is expected in early 2019 after the FDA approves Lonza’s manufacturing process for the drug. The drug is also under review in Europe, where a regulatory decision is expected early next year.
The andexanet alfa approval is Portola’s second regulatory nod in the past year. Last June, the FDA approved betrixaban (Bevyxxa), a drug developed to prevent blood clots in hospitalized patients.