Researchers found an increase in invasive disease-free survival (iDFS) in patients with early-stage breast cancer treated with Puma Biotechnology’s Nerlynx (neratinib) after initial treatment with Herceptin (trastuzumab). Quality of life was similar in patients on extended Nerlynx therapy compared with women receiving a placebo, in spite of a drop at the start of treatment.
Some of the findings of the Phase 3 ExteNET trial (NCT00878709) were presented at the European Society for Medical Oncology (ESMO) 2017 Congress in Madrid, Spain.
The presentation, “Neratinib after trastuzumab (T)-based adjuvant therapy in early-stage HER2+ breast cancer (BC): 5-year analysis of the phase III ExteNET trial,” was announced in a press release.
The U.S. Food and Drug Administration approved the use of Nerlynx to treat women with early stage, HER2-positive breast cancer who have previously been treated with Herceptin.
HER2-positive breast cancer tests positive for a protein called human epidermal growth factor receptor 2 (HER2), which promotes the growth of cancer cells.
Women with early-stage breast cancer who had been previously treated with Herceptin were followed for about five years. The difference in iDFS rates in 2,117 patients was compared for women treated with Nerlynx and women taking a placebo. iDFS is the period during which no invasive disease caused by the cancer is observed.
The study showed increased five-year iDFS rates in the Nerlynx group (90.2%) compared with the placebo group (87.7%). The rates in Nerlynx-treated women who had HER2-positive breast cancer were even higher.
In another part of the trial, a health-related quality of life (HRQoL) questionnaire was used to assess the participants’ quality of life for a period of one year. Most of the women in the Nerlynx group experienced a drop in quality of life at the one-month mark, whereas women taking a placebo did not. An HRQoL questionnaire is used to assess a patient’s perception of their physical, mental, emotional, and social functioning.
The researchers attributed this drop to diarrhea, which occurred briefly in many women in the Nerlynx group at the start of treatment. These patients then reported a similar quality of life as the placebo group for the remainder of the study period.
Hope S. Rugo, professor of medicine and director of breast oncology and clinical trials education at the University of California San Francisco’s Comprehensive Cancer Center, who discussed the results of ExteNET trial, said that the study demonstrated long-term clinical benefit, particularly among women with high-risk, HR-positive disease.
She said that diarrhea is a limiting factor, but it can be reduced significantly with preventative treatment, which is required in any case.
The trial was sponsored by Puma Biotechnology.