ASCO spotlight: Antibody-drug conjugates arrive

 June 1, 2012 | By Ryan McBrideThe past year has been one worth celebrating for developers of antibody-drug conjugates (ADCs), which are drugs that marry an anti-cancer toxin to a targeted antibody to kill tumors with fewer side effects than traditional treatments. In a New York Times article, veteran reporter Andrew Pollack features this emerging class of therapies and the long haul required to advance some of the drugs. At the major American Society of Clinical Oncology meeting this weekend in Chicago, plan to hear a lot about T-DM1 from Roche's ($RHHBY) Genentech and partner ImmunoGen ($IMGN). Genentech plans to present Phase III data on the drug, which is made by linking its blockbuster antibody Herceptin with a chemotherapy agent. The drug has already shown that it provides longer progression-free survival in patients with HER2-positive breast cancer with about half the cases of serious side effects as treatment with Herceptin and chemotherapy given together but not linked, the Times reported. ImmunoGen provides the linker and anti-cancer toxin in the treatment, and T-DM1 could become the first approved drug that uses the developer's technology. ImmunoGen could follow in the footsteps of rival Seattle Genetics ($SGEN), which gained its first approval last summer for an ADC called Adcetris to combat forms of lymphoma. As Pollack writes, a key for these companies has been keeping the anti-cancer toxins linked to the antibodies in the bloodstream until the treatments reach their targets. In 2010 Pfizer ($PFE) pulled from the market an ADC called Mylotarg, which had difficulty staying intact before it hit cancer cells.