The US Food and Drug Administration has given a tentative green light to Merck & Co’s follow-on biologic basal insulin Lusduna Nexvue.

The decision means that the drug has met all required regulatory standards for follow-on biologics of clinical and nonclinical safety, efficacy and quality, but is subject to an automatic stay due to a lawsuit from Sanofi claiming that it infringes on patents for its diabetes therapy Lantus (insulin glargine).

As per the Hatch-Waxman Act, Sanofi’s lawsuit, which was filed in September 2016 alleging infringement of 10 patents, prevents a final approval from the FDA on Lusduna Nexvue for either 30 months or in the event a court finds in favour of Merck, whichever comes sooner.

“The tentative approval of Lusduna Nexvue is an important milestone, bringing us closer to offering this medicine to patients,” noted Sam Engel, associate vp, Merck clinical research, diabetes, endocrinology, and women’s health.

Lusduna won clearance from the European Commission on January 4 as a biosimilar of Lantus, and can be used in patients aged at least two years for the treatment of diabetes.