Addition of Perjeta to Standard Care Improves Survival in HER2-Positive Early Breast Cancer

An updated analysis from the six-year follow-up of the phase 3 APHINITY trial demonstrated that the addition of Perjeta (pertuzumab), when given in addition to adjuvant Herceptin (trastuzumab) and chemotherapy, reduced the risk of recurrence and death in patients with HER2-positive early breast cancer.

“The addition of trastuzumab (Herceptin) to chemotherapy after surgery has revolutionized treatment outcomes for patients with HER2-positive early breast cancer, yet roughly 30% of patients will still experience recurrence of their disease, a condition for which effective treatments are now available, but cure is no longer possible,” lead study author, Dr. Martine Piccart, said in a press release.

In the randomized multicenter, double-blind, placebo-controlled study, 2,400 patients were randomly assigned to receive Perjeta plus Herceptin and chemotherapy and 2,405 patients received placebo plus the previous standard of care. Patients were treated from November 2011 to August 2013. Data cutoff for updated OS was June 19, 2019, with a median follow-up of 74.1 months.

Previously reported findings, which were published in the New England Journal of Medicine, showed that the addition of Perjeta improved three-year invasive disease-free survival, compared with placebo (94.1% vs. 93.2%, respectively). In addition, those with node-positive disease experienced improved three-year invasive disease-free survival, compared with placebo (92% vs. 90.2%, respectively). Disease recurrence occurred in 171 patients (7.1%) in the Perjeta group and 210 patients (8.7%) in the placebo group.

After the six-year follow-up, which was presented during a press briefing held at the annual meeting of the San Antonio Breast Cancer Society (SABCS) on Dec. 11, in San Antonio, Texas, the researchers conducted a descriptive analysis of invasive-disease-free survival (the length of time after primary treatment for cancer ends that a patient survives without any signs of symptoms of that cancer) in the overall patient population of the study.

They found that the addition of Perjeta to the previous standard of care led to a 24% reduction in the relative risk for breast cancer recurrence, compared with placebo. In addition, the regimen yielded a 15% reduction in the risk for death. Piccart noted that the overall survival benefit remains to be seen because the data are still immature; however, an additional follow-up study is expected to be presented in two-and-a-half years.

In their updated analysis, the researchers found that patients whose cancer had spread to their lymph nodes continued to derive the greatest clinical benefit with the addition of Perjeta to standard treatments in the six-year follow up. Among patients with node-positive disease, the invasive-disease-free survival in the Perjeta arm was 87.9%, but just 83.4% in the placebo arm, marking a 4.5% improvement. Therefore, adding Perjeta to Herceptin and chemotherapy after surgery translated to a reduced relative risk of invasive disease recurrence by 28% in this cohort.

“By adding a different yet complimentary HER2 inhibitor, pertuzumab (Perjeta), to this treatment regimen, we hope to further reduce the risk of recurrence and advanced disease in this patient population,” Piccart said in the release.