Frankie Ann Holmes, MD, FACP from Texas Oncology-US Oncology Research speaks about Puma Biotechnology Presents Final Overall Survival Analysis from the Phase III ExteNET Trial at the 2020 SABCS.
Link to Poster –
https://www.pumabiotechnology.com/docs/120920_PD3_03_Holmes_ExteNET_OS_SABCS_2020_poster_FINAL.pdf
LOS ANGELES, Calif., December 11, 2020 / B3C newswire / — Puma Biotechnology, Inc. (NASDAQ: PBYI), a biopharmaceutical firm, announced that at the current 2020 Virtual San Antonio Breast Cancer Symposium (SABCS) the efficacy findings of neratinib in HER2-positive early-stage breast cancer (eBC) from the Phase III ExteNET trial were presented. A presentation entitled ‘Continued efficacy of neratinib in HER2-positive early-stage breast cancer patients: Final overall survival review from the randomized phase 3 ExteNET trial,’ will be presented by Frankie Ann Holmes, M.D., FACP, Texas Oncology Houston-US Oncology Research, a study investigator, at a Spotlight Poster Discussion Session. Please find a copy of this poster presentation on the Puma website.
ExteNET was a multicenter, randomized, double-blind, phase III trial of 2,840 HER2-positive eBC patients who received neratinib with chemotherapy and trastuzumab after neoadjuvant and/or adjuvant treatment. Patients were stratified by hormone receptor status and randomly allocated to either 240 mg/day oral neratinib or placebo for one year of care. Invasive disease-free survival was the primary endpoint of the trial (iDFS). Overall survival and cumulative occurrence of CNS metastases provide secondary endpoints. A descriptive study was performed that evaluated the free survival of CNS disease, which was described as the period from randomization to any CNS recurrence or death from any cause.
Neratinib is approved within the European Union in patients with hormone receptor-positive (HR+) breast cancer who have begun treatment within one year of completion of the adjuvant regimen containing trastuzumab.
The endpoints for three clinical interest groups were analyzed: I the intent-to-treat (ITT) population; (ii) patients with HR+ breast cancer who started treatment within one year of completion of the adjuvant trastuzumab-containing regimen; and (iii) patients with HR+ breast cancer who began treatment within one year of completion of the adjuvant trastuzumab-containing regimen and who did not undergo treatment within one year of completion of the adjuvant trastuzumab-containing regimen. In the October 5, 2020 issue of Clinical Breast Cancer, findings from the Phase III ExteNET trial were released. HTTPS:/www.clinical-breast-cancer.com/article/S1526-8209(20)30258-5/fulltext is available online for the manuscript.
127 of 1420 patients (8.9 percent) in the neratinib group and 137 of 1420 patients (9.6 percent) in the placebo group died in the ITT population at the cut-off date of the study (July 2019). In the neratinib and placebo classes, the median 8-year overall survival (OS) rates were 90.1 percent and 90.2 percent (stratified HR 0.95; 95 percent confidence interval [CI] 0.75-1.21; p=0.69). The cumulative incidence of CNS metastases at 5 years was 1.3% in the neratinib arm (95% CI 0.8-2.1) and 1.8% (95% CI 1.2-2.7%) in the placebo arm, while the median 5-year CNS disease-free survival was 97.5% in the neratinib group and 96.4% in the placebo group (stratified HR 0.73; 95 percent CI 0.45-1.17).
53 of 670 patients (7.9 percent) in the neratinib group and 68 of 664 patients (10.2 percent) in the placebo group died in the HR+ /< 1-year patient population. The median 8-year OS rates in the neratinib group and 89.4 percent in the placebo group were 91.5 percent, leading to an absolute gain of 2.1 percent (HR 0.79; 95 percent CI 0.55-1.13). The cumulative incidence of CNS metastases at 5 years in the neratinib arm was 0.7% (95% CI 0.2-1.7) and 2.1% (95% CI 1.1-3.5) in the placebo arm, while the median 5-year CNS disease-free survival was 98.4% in the neratinib group and 95.7% in the placebo group (stratified HR 0.41; 95 percent CI 0.18-0.85).
No patient pCR subgroup (n=295) in the HR+/<1 year, 8-year OS rates were 91.3% in the neratinib group and 82.2% in the placebo group, leading to 9.1% absolute gain (HR 0.47; 95% CI 0.23–0.92). 8-year OS rates were 93.3 percent in the neratinib group and 73.7 percent in the placebo group in the HR+/<1 year, with a pCR (n=38), leading to 19.6 percent absolute gain (HR 0.40; 95 percent CI 0.06–1.88). The cumulative incidence of CNS metastases at 5 years was 0.8% in the neratinib arm (95% CI 0.1-4.0) and 3.6% (95% CI 1.3-7.8%) in the placebo arm, while the median 5-year CNS disease-free survival was 98.4% in the neratinib group and 92.0% in the placebo group (stratified HR 0.24; 95 percent CI 0.04-0.92).