In addition to tissue biopsy, a liquid biopsy test can be used to better identify patients who may benefit from niraparib and abiraterone acetate.
The FDA has approved the use of a liquid biopsy test, FoundationOne Liquid CDx, for use as a companion diagnostic for niraparib and abiraterone acetate dual action tablets (Akeega) to treat BRCA-mutated metastatic castration-resistant prostate cancer (CRPC), according to a news release published by the developer, Foundation Medicine Inc.1
The approval of the liquid biopsy test comes after the approval of FoundationOne CDx, a tissue-based comprehensive genomic profiling (CGP) test to better identify patients who may benefit from use of niraparib and abiraterone acetate, in August 2023.2 For those with insufficient tumor tissue available, the minimally invasive liquid biopsy is available where a tissue biopsy may not be viable.
“We know how challenging it can be to obtain a tissue sample for testing in advanced cancers such as [metastatic] CRPC, making liquid biopsy an incredibly important tool in a provider’s toolbox for the development of personalized treatment plans for their patients,” Mia Levy, MD, PhD, chief medical officer at Foundation Medicine said.1 “The approval of our liquid biopsy test, along with the previous approval for our tissue biopsy test, will enable more patients to access this important therapy option. Additionally, with the ability to leverage a liquid-based test and reflex to a tissue-based test if needed, healthcare providers can feel confident they have accurate genomic information at their fingertips to guide treatment decisions for patients.”
Additionally, the FDA previously approved niraparib and abiraterone acetate with prednisone for patients with BRCA-positive metastatic CRPC in August 2023.3 Supporting data for the approval came from the phase 3 MAGNITUDE study (NCT03748641), in which investigators reported a 47% risk reduction in radiographic progression-free survival (rPFS) with the niraparib combination (HR, 0.53; p = 0.001). Furthermore, with a median follow-up of 24.8 months in the BRCA-positive subgroup at the second interim analysis, the median rPFS was 19.5 months in the experimental arm vs 10.9 in the placebo arm (HR, 0.55; 95% CI, 0.39-0.78).
"As a physician, identifying patients with a worse prognosis is a priority, especially those whose cancers have a BRCA mutation. We prospectively designed the MAGNITUDE study to identify the subset of patients most likely to benefit from targeted treatment with [ niraparib and abiraterone acetate] and to help us understand how we can potentially achieve better health outcomes for patients," principal investigator Kim Chi, MD, a medical oncologist at BC Cancer – Vancouver, said in a press release at the time of the dual action tablet’s approval.3
The FoundationOne Liquid CDx analyzes more than 300 cancer-related genes across several companion diagnostic indications. It is used for detection of substitutions, insertion and deletion alterations, as well as copy number alterations in genes and select gene rearrangements, along with genomic signatures.
According to the news release, use of the test does not guarantee a patient-treatment match, and a negative result does not rule out the presence of an alteration. Furthermore, patients who test negative for mutations with the companion diagnostic should undergo tumor tissue testing using an FDA-approved tumor tissue test.
The FDA approved the FoundationOne Liquid CDx assay in August 2020, which included an indication for rucaparib (Rubraca) as a treatment for patients with BRCA-mutated metastatic CRPC.4 The FDA also approved the FoundationOne Liquid CDx as a companion diagnostic for identifying patients with metastatic CRPC harboring a BRCA1/2 and/or ATM alteration who may be eligible to receive treatment with olaparib (Lynparza) in November 2020.5