Last year’s roller-coaster ride for inhaled-insulin developer MannKind Inc. left its stock down 70 percent after regulators balked at approving the company’s product until it agreed to additional costly clinical trials.

But now investors are looking at recouping some of those losses.

So far this year, the Valencia biotech’s shares are up by nearly half, with much of the gain coming in the last week when it was one of the top gainers on the LABJ Stock Index. (See page 40.) And there is little to account for it – aside from investors taking a flier on a beaten-down stock.

“I haven’t heard anything on the name for weeks, no sell-side chatter and there’s no deadline I know of coming up” that might cause short sellers to cover their positions by accumulating shares, said analyst Jason Butler at JMP Securities in New York.

MannKind’s stock closed up 13 percent to $3.09 for the week ended Jan. 25. The next day it rose further to $3.41. That’s 45 percent higher than the beginning of the year.

If anything, Butler pointed out, MannKind shareholders should be settling into a wait-and-see period that could extend until two new clinical trials are completed at year’s end. Other big news could be a significant debt financing or a long-awaited partnership deal with a big drug maker.

In January last year, the Food and Drug Administration told MannKind that the company had wrongly assumed that previous study results for its older insulin dispenser would apply to its next-generation dispenser. The company was told to conduct new head-to-head studies if it wanted to switch dispensers. In August, regulators approved the design of two new studies and MannKind in the fall began recruiting diabetics to participate.

Chief Financial Officer Matthew Pfeffer said he couldn’t comment on last week’s stock activity, but said partnership talks with larger drug companies are continuing. Also still in the works is a sale of debt that could either take the company through the end of the clinical study period or even as far as the next FDA approval deadline.

MannKind founder and Chief Executive Alfred Mann provided an update to investors earlier this month at a JP Morgan conference in San Francisco, but Butler said the presentation included no game-changing information that would spur buyers.

In Southern California, studies are just getting under way at the Diabetes Research Center in Tustin, where principal investigator Dr. Jean Louis Selam is interested to learn whether MannKind’s second-generation inhaler will work as well, or better, than the earlier model he studied a few years ago.

“There is a real need for a drug that will prevent the blood sugar spikes that diabetics get after eating a meal, which is hard to prevent only using injected insulin,” Selam said. “Can MannKind’s new inhaler do this? We’ll see. Hopefully, yes.”