(Reuters) - Mylan NV on Monday beat a clutch of drugmakers racing to get a biosimilar to Amgen Inc’s blockbuster drug, Neulasta, to market, with U.S. health regulators approving its version of the infection-fighting treatment.

Mylan’s shares rose 5.2 percent to $40.50 after the bell, while Amgen fell 1.7 percent to $182.30.

Mylan and its partner - India’s Biocon - expect to launch the drug, Fulphila, in the coming weeks, the companies said.

Neulasta, which is used to fight infections in cancer patients, brought Amgen revenue of $4.53 billion last year and accounted for nearly 21 percent of total product sales.

While competition for the drug has long been expected, Monday’s approval positions Mylan favorably, according to analysts.

“Mylan is thus far the only approved biosimilar, and may therefore fill the channel ahead of competition,” Mizuho Securities analyst Irina Koffler said in a note.

Koffler estimates that Fulphila could bring in peak sales of $554 million in 2022.

Fulphila is the second biosimilar from Mylan and Biocon to be approved in six months, after the FDA gave its nod to the companies’ version of Roche’s blockbuster breast cancer treatment, Herceptin, in December.

In 2017, the FDA declined to approve Fulphila and asked for more data related to manufacturing facilities of the drug’s developers.

The FDA has also previously rejected biosimilars to Neulasta from Novartis AG and Coherus BioSciences Inc.

Biologic drugs such as Neulasta are made inside living cells, and it is impossible to make exact generic copies. As a result, regulators are approving products deemed “similar” enough as biologics. in the hope that they .

In the wake of widespread criticism of corporate greed in the pharmaceutical industry, the agency has prioritized the approval of cheaper copies of branded medicines to increase competition in the market and tackle soaring branded drug prices.

Mylan's Fulphila can cause serious side effects including a rupture of the spleen, acute respiratory distress syndrome, and serious allergic reactions, the FDA said here&u=urn:newsml:reuters.com:20180604:nPn20lMSma.