One year of adjuvant trastuzumab should remain the standard of care for patients with HER2-postive early-stage breast cancer, according to data from the phase III HERA trial, which compared the efficacy and safety of one year and two years of treatment.

“Giving trastuzumab for a longer duration (two years) did not improve disease-free or overall survival compared with one year of trastuzumab treatment,” said Martine J. Piccart, M.D., Ph.D., chief of the medicine department at the Jules Bordet Institute in Brussels, Belgium, president of the European Society for Medical Oncology and chair of the Breast International Group (BIG).

Piccart presented these data at the 2012 CTRC-AACR San Antonio Breast Cancer Symposium.

Piccart and colleagues took part in the HERA trial, an international, multicenter, phase III, randomized trial run by BIG and Roche that spanned several countries.

They followed 5,102 women with HER2-positive early-stage breast cancer randomly assigned to trastuzumab every three weeks for one year or two years, or to observation.

All women completed primary therapy of surgery, chemotherapy and radiotherapy as indicated.

Disease-free status and overall survival rates were comparable between the one and two year trastuzumab arms. In addition, while the primary cardiac endpoint of symptomatic congestive heart failure was comparable in both arms, the secondary cardiac endpoint of asymptomatic cardiac dysfunction was higher in the two-year arm, at 7.2 percent compared with 4.1 percent in the one-year arm.

Most of the cardiac events occurred during trastuzumab administration, and the majority were reversible when the trastuzumab was stopped.

“The HERA trial showed the sustainability of the efficacy of trastuzumab, proving that a significant proportion of patients treated with trastuzumab in the adjuvant setting are alive and free of disease recurrence after a median follow-up of eight years,” Piccart said.

“It is also reassuring with regard to the low cardiac toxicity of trastuzumab when given after adjuvant chemotherapy. Finally, it confirms that one year of adjuvant trastuzuamb should remain the standard of care in women with HER2-positive early breast cancer."

Source: SABCS