Sanofi and US biopharmaceutical company Mannkind have finally thrashed out an agreement to terminate their licensing deal for Afrezza inhalable insulin. The agreement will likely cost Sanofi more than $100 million. The Paris-headquartered drug company handed back the rights to Mannkind in January this year after sales failed to reach expectations.

Under terms of the deal, Sanofi will buy $10.2 million worth of insulin from Mannkind in December 2016 and will also pay $30.6 million in cash by Jan. 9, 2017, for more insulin that the California-based firm will not be required to deliver. Sanofi will also cancel Mannkind’s promissory note, forgiving the outstanding loan balance of $71.6 million.

According to both companies, “all issues arising out of the license and collaboration agreement, the supply agreement, the promissory note, the security agreement and the transition agreement are resolved.” Launched in 2014, the partnership was formed to market Afrezza shortly after it was approved. At that time, revenues were estimated at $600 million annually. However, sales never really took off, with Mannkind shipping only $17 million worth of the insulin during the first nine months of their partnership.

Mannkind has now taken over all of the commercial manufacturing responsibilities at its plant in Danbury, Connecticut, USA, which had been producing the drug for Sanofi. In its third-quarter results presentation, Mannkind said it had starting shipping Afrezza in late July and had sold $600,000 worth during that quarter. It also recorded another $2 million in deferred revenue from products it had shipped but which had yet to be sold by wholesalers.

The US company is now working on an inhalable form of epinephrine – a treatment for allergic reactions – that is aimed to take market share from Mylan’s injectable EpiPen version, which has been at the center of a pricing scandal.