What happened

Shares of ImmunoGen (IMGN) jumped 13.7% today on no apparent news. The biotech is scheduled to release earnings on Friday morning, but without any revenue-generating drugs, there isn't likely to be anything on the profit-loss statement that would drive its valuation higher.

So what

Instead, investors are likely jumping in ahead of expected data from the phase 3 Forward I study that's testing mirvetuximab in patients with ovarian cancer.

Management has previously guided for data to be available in the first half of this year. Six months is a fairly wide range for a data release, but the primary endpoint of the study is progression-free survival, so ImmunoGen has to wait for patients to progress before the measurement -- time to progression or death, whichever comes first -- can be taken. The time frame for data release is just an estimate based on the progression of the previous patients with some time added on to process the data.

It's possible that ImmunoGen might have the data processed and ready for release during its earnings report on Friday, but it's just as likely to come on a random day sometime between now and the end of June. Or perhaps later. It's just an estimate, after all.

Check out the latest ImmunoGen earnings call transcript.

Woman holding hands with a woman in a head scarf

Image source: Getty Images.

Now what

Long-term investors can ignore today's move. While the double-digit jump is nice, ImmunoGen's long-term valuation will be determined by the results of the Forward I study. If positive, the data should be enough to gain FDA approval for mirvetuximab in late-stage patients while also increasing the potential for the drug to work in combination with other cancer drugs in earlier-stage patients.