More than three years after approving two biosimilars referencing Sanofi’s long-acting insulin Lantus, the FDA has signed off on a rapid-acting insulin biosimilar for the first time.

The agency has given a thumbs up to Sanofi’s Merilog (insulin-aspart-szjj) as the first biosimilar to Novo Nordisk’s NovoLog for patients with diabetes. Insulin aspart is delivered by a subcutaneous shot 5 to 10 minutes before mealtime to help patients control glucose and limit blood sugar spikes.

Merilog will be provided by prefilled pen in a 3 mL dose or in a multiple-dose 10 mL vial. It is for adults and pediatric patients age 6 and older.

The approval is backed by a phase 3 trial of 597 patients with type 1 and type 2 diabetes who received multiple shots daily. At week 26, blood sugar levels were similar for those who received the biosimilar and those on the reference product, confirming Merilog’s non-inferiority.

Of the roughly 38 million in the U.S. with diabetes, 8.4 million use either a rapid-acting or long-acting insulin, or both, the FDA said. The high cost of insulin has led some patients to ration their use, triggering high-profile calls from U.S. lawmakers for companies to drop their prices.

In 2023, Eli Lilly revealed a plan to cut the cost of most of its insulins by 70%. Less than two weeks later, Novo Nordisk announced a planned 75% reduction in the cost of NovoLog.

Then a few days later, Sanofi followed suit with a 78% slashing of the price of Lantus. The company also said it would cap the monthly out-of-pocket cost for Lantus at $35 for those with commercial insurance. 

NovoLog and Novo Nordisk’s other rapid-acting insulin follow-on Fiasp are among the drugs subject to government price negotiations under the Inflation Reduction Act. The new prices will be enacted at the start of next year.

In July 2021, the FDA approved Biocon and Viatris’ Semglee (insulin glargine-yfgn) as the first biosimilar to Lantus. Five months later, the U.S. regulator endorsed Eli Lilly’s version of the drug, called Rezvoglar (insulin glargine-aglr).