MannKind Corp. stock dipped below $1 Wednesday after the Valencia biomed announced the termination Tuesday of its marketing deal for Afrezza, MannKind’s inhalable insulin.

MannKind’s deal with the European distributor Sanofi effectively ends July 4. Meantime the two companies will “promptly commence transition discussions in order to effect a smooth and orderly transition in the development and commercialization of Afrezza,” a statement from MannKind said.

It took several years and three tries, but the FDA eventually approved MannKind’s treatment for diabetes in mid-2014.

Investor expectations were high because the treatment didn’t require needles; instead the drug is dispensed through an inhaler. With the FDA approval, MannKind’s stock price shot up above $10.

The frenzy was short-lived. Sales never took off and many investors started to question whether Sanofi, which markets a broad portfolio of medicines, was really committed to promoting and selling the product.

But analyst Brian Feroldi, writing for the Motley Fool, suggested the decision was Sanofi’s. “Despite throwing tens of millions of dollars behind the product each quarter,” he writes, “Sanofi was only able to sell about $5.5 million worth of the drug through its first three quarters on the market. That sales figure came up well short of what Sanofi was projecting, so the company decided (Tuesday) to cut its losses.”

Law firms were fishing for clients Wednesday in hopes of filing class-action suits. As an example, Khang & Khang LLP of Irvine said it was investigating “whether (MannKind) violated securities laws by issuing misleading information to investors.”