The Food and Drug Administration has declined for now to approve a copycat version of Amgen’s blockbuster drug Neulasta.

Reuters reported July 19 that the FDA sent a letter to Swiss pharmaceutical Novartis at the end of June saying it was declining to approve the drug for now. Neulasta, made by Thousand Oaks-based biotech giant Amgen, stimulates the growth of white blood cells to fight infections. With $4.7 billion in sales it was second only to Amgen’s Enbrel, which had $5.3 billion in sales.

Biosimilars are new, lower-cost treatments and similar to generics but are made with living organisms and aren’t identical to the complex compounds they replicate. Because the compounds are not identical, extensive testing must still take place to ensure their safety, which does not lower the cost of the drugs as much as generics.

In December, Novartis said its Neulasta biosimilar worked just as well as Neulasta. Novartis said in a news release at the time a study showed that there were no clinically meaningful differences between the proposed biosimilar pegfilgrastim and Neulasta.

“Adverse events were similar and consistent with the known safety profile of pegfilgrastim,” Novartis’ news release said at the time.

Neulasta has the same generic name pegfilgrastim.

In November, Novartis submitted the drug for approval. The FDA apparently disagreed for now. The representative Reuters spoke to did not elaborate on why Novartis’ biosimilar was not approved. The FDA typically sends such letters to companies when more information is needed to make a final decision.

• Contact Philip Joens at pjoens@pacbiztimes.com.