In a significant development on August 11, 2023, the Food and Drug Administration (FDA) granted its approval for the combined use of niraparib and abiraterone acetate, marketed as Akeega by Janssen Biotech, Inc., alongside prednisone. This approval is intended for adult patients grappling with deleterious or suspected deleterious mutations in the BRCA gene, manifesting as castration-resistant prostate cancer (CRPC). The patient’s BRCA-mutated status is determined through an FDA-endorsed test.
This green light from the FDA was based on the efficacy evaluation of Cohort 1 of the MAGNITUDE trial (NCT03748641). The trial encompassed 423 patients diagnosed with homologous recombination repair (HRR) gene-mutated CRPC. These patients were divided into two groups: one receiving the combination of niraparib (200 mg), abiraterone acetate (1,000 mg), and prednisone (10 mg) daily, and the other receiving placebo, abiraterone acetate, and prednisone. Patients in the trial had previously undergone an orchiectomy or were undergoing gonadotropin-releasing hormone (GnRH) analogues. While a short stint of prior abiraterone acetate plus prednisone (up to four months) was allowed, patients in this cohort had not received systemic therapy in the CRPC setting, apart from ongoing androgen deprivation therapy (ADT). Notably, earlier treatments such as docetaxel or androgen receptor (AR) targeted therapies were permitted. The study’s outcomes revealed that patients without HRR gene mutations did not experience benefits from the treatment.
The primary efficacy measure was radiographic progression-free survival (rPFS), determined by an independent central review, while overall survival (OS) was an additional parameter. The study demonstrated a noteworthy enhancement in rPFS among BRCA-mutated patients receiving niraparib and abiraterone acetate plus prednisone compared to the placebo group – with a median of 16.6 months versus 10.9 months. Furthermore, an exploratory OS analysis in the BRCA-mutated patients showcased a median of 30.4 months versus 28.6 months, slightly favoring the investigational arm.
While improvements in rPFS were witnessed across the entire Cohort 1 HRR population, it was primarily attributed to the results seen in the subgroup of patients with BRCA mutations. Common adverse reactions observed included lowered blood cell counts, musculoskeletal pain, fatigue, hypertension, and gastrointestinal symptoms. Notably, 27% of patients treated with niraparib and abiraterone acetate plus prednisone required blood transfusions.
The FDA-approved dose of Akeega entails the oral intake of 200 mg of niraparib, 1,000 mg of abiraterone acetate, and 10 mg of prednisone daily until disease progression or unacceptable toxicity. Patients are concurrently recommended to receive a GnRH analog or have undergone bilateral orchiectomy. This milestone approval represents a promising avenue for managing BRCA-mutated metastatic castration-resistant prostate cancer, ushering in new horizons for treatment.