TDM1 info
 

—ImmunoGen: The Waltham, MA-based biotech (NASDAQ: IMGN) has developed technology to make a “souped-up” version of Genentech’s and Roche’s trastuzumab (Herceptin) for breast cancer. This product, called trastuzumab DM1 or TDM1, aims to make the original antibody drug more potent by attaching a tumor-killing toxin to it.

One out of four patients (25 percent) who got the experimental drug had partial or complete tumor shrinkage, according to a final analysis of the trial cited by ImmunoGen in a statement. That figure was impressive, because the trial involved patients whose cancer had spread and who had relapsed after taking the original Herceptin.

More than half had also relapsed after taking a competing drug from GlaxoSmithKline, lapatinib (Tykerb). The most common severe side effects were lowered potassium levels, and lowered counts of platelet cells in the blood, although researchers didn’t see the heart damage that has been observed in other Herceptin trials.

A preliminary look in December at the data from 107 patients suggested this drug might be doing even better—with 40 percent showing partial or complete tumor shrinkage after taking the drug. One difference is that the final numbers on tumor shrinkage were judged by an independent review facility—not the treating physicians who might be inclined to see something positive that isn’t there.

Regardless, Genentech and Roche considered these results intriguing enough to begin a 580-patient global clinical trial next February to hopefully amass enough proof to bring TDM1 to the market.