Genentech has issued a letter to healthcare professionals warning that its anticancer agent Herceptin (trastuzumab) can increase the risk of heart problems.

The news follows data from the 2,000-patient National Surgical Adjuvant Breast and Bowel Project, which showed a significant increase in cardiotoxicity amongst Herceptin receivers compared to those who were given chemotherapy alone. Overall, a significant increase in the three-year cumulative incidence of congestive heart failure and cardiac death was observed in the Herceptin group (4.1%) versus the chemotherapy arm (0.8%), although Genentech was quick to stress that actually there were no reports of cardiac death amongst patients given its drug.

Sales of Herceptin climbed 29% to $152 million in the second quarter of the year [[12/07/05a]].