What happened

ImmunoGen (NASDAQ:IMGN) closed the day up 10.4% on no obvious news to support a double-digit gain.

So what

BIO, the biotech industry's annual trade show, is going on this week, so it's possible that ImmunoGen has been talking to investors at the conference, which could be driving the share price higher. The company has done a good job at cutting costs and generating some much-needed cash by selling off IMGN529 to Debiopharm and amending its license agreement with Sanofi (NYSE:SNY) to forgo a limited co-promotion option as well as future milestones or royalties in exchange for a $30 million payment now. Perhaps investors are finally paying attention.

It's also possible that ImmunoGen is just trading on sentiment rather than on fundamentals; we've seen that story before. Shares start moving, and the day traders jump in to play their game. Shares of ImmunoGen are up nearly 20% over the past three trading days, and the only news I could find was an analyst reiterating an "outperform" rating with an increase in his already-exaggerated price target.

A cancer patient holds hands with a friend.

Image source: Getty Images.

Now what

Long-term investors will want to focus on enrollment of the phase 3 trial called FORWARD I that's testing mirvetuximab soravtansine in women with ovarian cancer, which started in January. The faster the enrollment happens, the faster the trial can read out and potentially get approved.

Brian Orelli has no position in any stocks mentioned. The Motley Fool recommends ImmunoGen. The Motley Fool has a disclosure policy.