| The following article is part of conference coverage from the 17th St. Gallen International Breast Cancer Symposium, which is being held virtually from March 7-21, 2021. The team at Cancer Therapy Advisor will be reporting on the latest research conducted by leading experts in breast cancer. Check back for more from the 17th St. Gallen International Breast Cancer Symposium. |
Niraparib showed antitumor activity in a small group of patients with localized HER2-negative breast cancer harboring a BRCA1/2 mutation who were enrolled in a single-arm pilot study. The study results were reported at the 17th St. Gallen International Breast Cancer Conference 2021.
The trial (ClinicalTrials.gov Identifier: NCT03329937) enrolled 21 treatment-naive patients with localized HER2-negative breast cancer harboring a BRCA1/2 mutation. All patients received niraparib, a poly (ADP-ribose) polymerase (PARP) inhibitor.
Most patients (71.4%) had triple-negative breast cancer, and the rest (28.6%) had hormone receptor-positive disease. Two-thirds of patients had a BRCA1 mutation, and 28.6% had a BRCA2 mutation. One patient had both a BRCA1 and a BRCA2 mutation.
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The tumor response rate was 90.5%, which included 2 complete responses and 17 partial responses, as assessed by magnetic resonance imaging (MRI). Tumor response was also assessed by ultrasound, which yielded a 95.2% response rate that included 1 complete response and 19 partial responses.
A median reduction in tumor volume of 86.4% (range, 26-100) was seen on MRI, and ultrasound showed a similar median reduction of 87.2% (range, 23-100).
The most common treatment-related adverse events of any grade were nausea (66.7%), fatigue (47.6%), and anemia (23.8%). One-third of patients reported a grade 3 or worse treatment-related adverse event, the most common being anemia (14.3%), neutropenia (9.5%), and decrease in neutrophil count (9.5%).
Overall, 19% of patients required a reduction in niraparib dose. No treatment discontinuations due to a treatment-related adverse event were reported.
The study authors concluded that niraparib showed “promising” antitumor activity in the neoadjuvant treatment of patients with localized HER2-negative, BRCA-mutated breast cancer.
Disclosure: Study authors declared affiliations with and receipt of funding from the pharmaceutical industry, and this study was funded by GlaxoSmithKline. Please refer to the original article for a full list of disclosures.
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Reference
Spring LM, Han H, Hamilton E, et al. Neoadjuvant niraparib in patients with HER2-negative, BRCA-mutated resectable breast cancer. Poster presentation at: 17th St. Gallen International Breast Cancer Conference 2021; March 17-21, 2021. Abstract P095.
