MannKind Corp. said Thursday that it has suspended attempts to find a partner for its inhalable insulin product “given the current market sentiment.”

The announcement comes a day after shares in the Valencia-based company plunged more than 60 percent after Pfizer Inc. said it found increased instances of lung cancer among users of its inhalable insulin product Exubera.

After reviewing clinical trial data and following up with clinical participants, Pfizer said it found six instances of lung cancer out of 4,740 Exubera-treated patients as compared with one case out of 4,292 patients not given the drug. The six patients with cancer either had been or were current smokers.

MannKind’s Technosphere is the only remaining inhalable insulin product still in development after two other companies dropped their programs over the past few months. MannKind has said its inhaler, which is in late-stage clinical trials, is more effective and safer than its competitors.

MannKind has no products for sale and has been seeking a partner for Technosphere.

“We believe that we will be unable to achieve an appropriate valuation for Technosphere insulin” until the ongoing human tests “confirm our belief in the safety and efficacy” of the drug, MannKind’s statement said.

Shares in MannKind were flat at $2.37 in early trading Thursday.