What happened

ImmunoGen (NASDAQ:IMGN) closed up 12% today on no apparent good news. In fact, there was a bit of bad news on Friday after partner Bayer revealed that anetumab ravtansine, which ImmunoGen helped develop with its antibody-drug-conjugate technology failed a phase 2 trial testing the drug in patients with mesothelioma.

So what

Perhaps investors are looking on the bright side because Bayer hasn't killed the anetumab ravtansine program completely. While the drug didn't help patients with mesothelioma, Bayer is still testing the drug as monotherapy and in combination with other drugs, including a phase 1b trial that's enrolling patients with six different types of advanced solid tumors, and another phase 1b combination study in patients with recurrent platinum-resistant ovarian cancer.

Last year, ImmunoGen earned a milestone payment from Bayer after the company initiated a phase 2 trial of anetumab ravtansine. At the time, ImmunoGen noted that it was entitled to receive milestone payments potentially totaling up to $170 million and royalties on sales of the drug.

Doctor and patient

Image source: Getty Images.

Now what

Today's move, like so many in the past, is just noise in the bigger long-term picture for ImmunoGen. While partnered drugs offer some potential benefit to ImmunoGen, most of the biotech's valuation lies in its wholly owned mirvetuximab soravtansine. Investors should be focused on the drug's phase 3 trial, called FORWARD I, which is currently enrolling patients, and how the company is generating cash toward paying for the trial.

Investors will hopefully get an update on both when ImmunoGen reports earnings on Friday.

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