MannKind Corp. announced Tuesday that Sanofi-Aventis U.S. has terminated its agreement to manufacture and market MannKind’s sole commercial product, Afrezza Inhalation Powder, an inhalable insulin.

With the bad news, MannKind’s shares plummeted Tuesday, closing down 70 cents or more than 48 percent to 75 cents on the Nasdaq.

The Valencia biotech said it is reassessing its strategic plan for Afrezza.

Sanofi-Aventis’ departure from the deal was expected as its sales of the product have proved disappointing. The pharmaceutical company, headquartered in Bridgewater, N.J., reported a little over $2 million in Afrezza sales for the third quarter of last year.

Additionally, this past November, Hakan Edstrom stepped down as chief executive of MannKind, and founder Alfred Mann was elected as interim chief executive until a permanent replacement could be found.

The transition out of Sanofi is expected to take place over the next 90 to 180 days and will occur no later than six months after the termination date of the agreement, which will be July 4.