Shares of ImmunoGen plunged 37 percent in premarket trading Friday after a breast cancer treatment from drug development partner Roche failed to deliver significant improvement in a key late-stage study measurement of cancer patients.
The drug Kadcyla uses ImmunoGen technology and is already approved to treat patients with a form of breast cancer that has spread, and who have already tried another treatment.
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The drug combines Roche's Herceptin and a powerful chemotherapy drug as well as a third chemical, developed by ImmunoGen, which links the medicines together. The chemical keeps the drugs together until they bind to a cancer cell, delivering a potent dose of anti-tumor poison.
Roche tested the combination in patients with previously untreated cases of the cancer. The Swiss drugmaker said Friday that patients taking Kadcyla did not experience a significantly better progression-free survival period than those who received another treatment regimen.
Progression-free survival measures the time from the start of treatment until a patient's cancer begins advancing again, or the patient dies.
ImmunoGen CEO Daniel Junius said that the company was disappointed, but he also noted that Roche has several other Kadcyla studies underway, including one related to gastric cancer.
The study results won't affect the company's 2015 guidance or the approved use of Kadcyla, according to ImmunoGen Inc.
Shares of the Waltham, Massachusetts, company tumbled $4.05, to $6.80 before the opening bell. The stock had already dropped 26 percent so far this year.