- Amgen on Wednesday said the Food and Drug Administration has rejected its treatment for a type of hormonal imbalance in patients with chronic kidney disease (CKD), an unexpected outcome for a drug seen as a successor to the company's blockbuster Sensipar.
- The big biotech offered little detail on the complete response letter issued by the FDA but said it anticipated meeting with the regulator later this year to discuss the rejection.
- Called Parsabiv, the experimental drug is designed for treatment of secondary hyperparathyroidism (sHPT) in adult patients with CKD who are on hemodialysis. Patients with the condition have overly high levels of the parathyroid hormone, leading to faster loss of calcium and phosphorus from the bones.
Amgen's existing drug for sHPT, Sensipar, is one of the company's top-earners, pulling in $1.4 billion in revenue last year, mostly in the U.S. Higher net selling prices and increased demand further buoyed sales 13% higher in the second quarter, compared to the same period a year prior.
But some of Amgen's patents on Sensipar expire soon. A patent on the methods of treatment expires this December, for example, according to regulatory filings.
Generic drugmakers Teva and Barr Pharmaceuticals have both received tentative approval from the FDA for their copies of Sensipar, although the companies are currently blocked from selling the drugs until the expiry of Amgen's patents.
Amgen also faces new branded competition in the sHPT market. The FDA in June approved a drug from Opko Health for treatment of sHPT in adults with CKD, but only those with vitamin D insufficiency.
Parsabiv would give Amgen a successor to Sensipar to help offset any losses in sales from generics or Opko's drug. But those plans are on hold, at least for now.
Jefferies, an investment bank, noted Parsabiv is only a "small part" of Amgen's current valuation and didn't change any of its current estimates, despite the initial rejection. Analysts at the bank had forecast sales of the drug to reach about $500 million by 2022.