What happened

Shares of the clinical-stage biotech Geron Corporation (GERN 1.36%) lost 12.5% of their value last month, according to S&P Global Market Intelligence. What went wrong?

After a tremendous start to the year following a positive clinical update for the company's blood cancer drug imetelstat that's being co-developed with Johnson & Johnson (JNJ 0.67%), Geron became a popular target for short-sellers at the start of last month. Although overall short interest did fall as the month progressed, Geron kicked off April as one of the most heavily shorted stocks in the entire market. 

Man in a business suit looking over a ledge with a downward trending chart in the background.

Image source: Getty Images.

So what

Geron has been on a wild ride since the start of the year, thanks to the uncertainty surrounding its partnership with J&J. While all the outward signs suggest that the collaboration is going well, the lack of concrete info from either company has allowed short-sellers to control the narrative in many ways. Unfortunately, this situation probably isn't going to change anytime soon.

Now what

Geron is scheduled to hold its annual stockholder meeting on May 15. However, investors probably shouldn't expect any major news from this meeting. After all, Geron and J&J have repeatedly stated that the next clinical update won't occur until sometime in the late second quarter, or perhaps even the third quarter of this year.

Going one step further, the options market clearly expects imetelstat's next major update to occur around September based on the number of open contracts on both the call and put side of the ledger. So, until then, this stock will likely trade sideways for the most part.