Prolia and Xgeva Biosimilar Companies Are Queuing Up

There is nothing like having FDA approval for a drug and not being able to launch it.

Such is the case — two times over — for Sandoz, which in early March received FDA approval for its biosimilars of Amgen’s blockbuster osteoporosis drugs, Prolia (denosumab) and Xgeva (denosumab).

Amgen has gone to Sandoz's home state of New Jersey to contest the company's rights to market those biosimilars, alleging 21 patent infringements and requesting a jury trial to resolve the dispute. This could take a while. The court filing was on May 1, 2023.

Prolia is approved as a treatment for osteoporosis in individuals with an elevated risk for bone fractures. Xgeva is used to strengthen bone in patients with multiple myeloma and others cancers that weaken skeletal bone. The active ingredient in both is denosumab, although Xgeva is a higher dose. Wyost is the name that Sandoz has given to its biosimilar to Prolia ,and Jubbonti is its biosimilar to Xgeva.

The market for osteoporosis medication is enormous. More than 10 million U.S. individuals over age 50 live with osteoporosis, according to Sandoz, and Prolia and Xgeva are expensive.. They sport list prices of roughly $1,700 and $3,400 per injection (once every 6 months and once every 4 weeks, respectively).

For this reason, the anteroom is filling up with potential Prolia and Xgeva biosimilar candidates, similar to the pileup that preceded last year's cluster of Humira (adalimumab) biosimilar launches.

If Amgen is feeling any pressure from this pending competition, it is not showing it. “Prolia sales grew 12% year-over-year to a record $1.1 billion for the fourth quarter,” Amgen’s Executive Vice President Murdo Gordon said in the company’s most recent earnings call. Xgeva sales climbed 6% for the full year. The company predicts more growth ahead.

In November, Celltrion became the second company to file for FDA approval of its Prolia and Xgeva denosumab biosimilars. There are at least 10 other pharma companies with denosumab biosimilar candidates in various stages of development. Several of these have finished or are close to finishing phase 3 trial development, including Samsung Bioepis/Biogen, Teva, Fresenius Kabi and Gedeon Richter.

FDA approval can take a year or longer, and Sandoz and Celltrion have each sought interchangeable status, which gives pharmacists the option to substitute lower-cost biosimilars when presented with a physician's script for the originator products. Interchangeability has become a decided marketing advantage in the biosimilar market

According to life sciences data company IQVIA, Prolia and Xgeva have a 17% share of the osteoporosis market compared with 66% for market-leader Fosamax (alendronate).

Some research findings suggest that Prolia and Xgeva are superior to Fosamax in building bone density. But Prolia and Xgeva are administered as injections, while Fosamax is an oral drug, which patients often prefer. Fosamax generics are relatively inexpensive. On the Mark Cuban Cost Plus Drug website, 30, 10-milligram tablets are priced at $8.00, plus the website’s 15% markup and dispensing fee.