Sobi’s plan to introduce a challenger to Amgen’s blockbuster gout drug Krystexxa has been put on hold by the FDA.
The FDA has issued a complete response letter to Sobi’s application for NASP as a treatment for uncontrolled gout, the Swedish company announced Friday.
In rejecting NASP, the FDA is delaying the launch of a product that Sobi projected could reach between 4 billion Swedish kroner (about $410 million) and 6 billion Swedish kroner ($620 million) in peak sales.
The FDA cited deficiencies at a contract manufacturing facility and is requiring additional data related to manufacturing control strategy of the biological component of the drug, according to Sobi. The agency identified no concerns regarding the drug’s clinical efficacy-safety profile, the company said.
“The FDA's feedback provides a clear and actionable path forward and we will work closely with them towards a resubmission,” Lydia Abad-Franch, M.D., chief medical officer of Sobi, said in a June 26 statement.
NASP is a sequential combination of nanoencapsulated sirolimus, which prevents the formation of anti-drug antibodies, and pegadricase, a pegylated recombinant uricase enzyme that reduces serum uric acid (SUA). High levels of SUA are a primary driver of gout.
In two phase 3 trials, Dissolve I and II, Sobi and its partner Selecta Biosciences reported a higher percentage of patients who achieved SUA levels below 6 mg/dL, a target for the treatment of gout, for at least 80% of the sixth month of treatment, for NASP than placebo.
With NASP, Sobi’s prime competitor is Amgen’s Krystexxa, another recombinant uricase that brought $1.34 billion in U.S. sales last year. Krystexxa is an every-other-week intravenous infusion that requires weekly oral methotrexate as its immunomodulator. NASP is administered monthly, and it could offer an option for patients for whom methotrexate is contraindicated, including those with severe liver or kidney disease.
Besides NASP, Sobi recently acquired another gout program. Through its up-to-$1.5 billion acquisition of Arthrosi Therapeutics, Sobi is advancing pozdeutinurad, a once-daily oral URAT1 inhibitor that reported positive topline results from one of its phase 3 trials in gout last month. The company expects readout from a second trial later this year, plus additional follow-up from the current six months to a year.
Sobi has higher expectations for pozdeutinurad, forecasting it to generate blockbuster peak sales exceeding 10 billion Swedish kroner ($1.03 billion).