Abiraterone Approaches EU Approval for Newly Diagnosed Hormone-Sensitive Prostate Cancer

Karim Fizazi, MD, PhD

The European Medicines Agency’s Committee for Medicinal Products for Human Use (CHMP) has recommended expanding the existing marketing authorization for abiraterone acetate (Zytiga) to include use in combination with prednisone/prednisolone and androgen deprivation therapy (ADT) in men with newly diagnosed, high-risk metastatic hormone-sensitive prostate cancer.

The European Commission (EC) has already approved abiraterone acetate, in combination with prednisone or prednisolone, for the treatment of metastatic castration-resistant prostate cancer (mCRPC) in adult men who are asymptomatic or mildly symptomatic after failure of ADT in whom chemotherapy is not yet clinically indicated, and for mCRPC in adult men whose disease has progressed on or after a docetaxel-based chemotherapy.

Janssen Biotech, the developer of abiraterone acetate, reported in a press release that the CHMP’s positive opinion was based on findings from the phase III LATITUDE trial. Results from the study showed that abiraterone combined with prednisone/prednisolone and ADT reduced the risk for death by 38% compared with ADT and placebo in men with high-risk metastatic, castration-sensitive prostate cancer.^1,2 The median overall (OS) survival was not reached with abiraterone acetate versus 34.7 months with placebo (hazard ratio [HR], 0.62; 95% CI, 0.51-0.76; P <.001).

“As shown by the results from the LATITUDE study, adding abiraterone acetate plus prednisone/prednisolone to ADT alone significantly improves overall survival and radiographic progression-free survival in men with metastatic hormone-sensitive prostate cancer and high-risk features in comparison to treating patients with ADT alone, where median survival is currently less than three years,” Karim Fizazi, MD, PhD, principal investigator of the LATITUDE trial, head of the medical oncology department at Institute Gustave Roussy, said in a press release. “Today’s decision means we are one step forward in ensuring men [with metastatic hormone-sensitive prostate cancer] across Europe may be able to benefit from this treatment soon.”

The LATITUDE trial randomly assigned 1199 newly diagnosed patients with high-risk metastatic prostate cancer to abiraterone acetate, prednisone, and ADT (n = 597) or ADT and placebo (n = 602). Abiraterone acetate was administered at 1000 mg daily and prednisone was given at 5 mg daily. Patients had either a positive bone scan or a metastatic lesion at the time of diagnosis on CT or MRI. Patients had not previously received ADT therapy and had at least 2 of 3 risk factors: Gleason score greater than or equal to 8, measurable visceral metastases, or 3 or more bone lesions.

The radiographic progression-free survival with abiraterone acetate was 33.0 months compared with 14.8 months for ADT alone, representing a 53% reduction in the risk of progression or death (HR, 0.47; 95% CI, 0.39-0.55; P <.001). The OS rate at 3 years was 66% in the abiraterone acetate group versus 49% with ADT.

The time to pain progression was also reduced by 31% with abiraterone acetate versus ADT (HR, 0.695; 95% CI, 0.583-0.829; P <.0001). Additionally, the risk of developing a skeletal-related event was 30% lower with abiraterone acetate versus ADT (HR, 0.703; 95% CI, 0.539-0.916; P = .0086). The risk of starting chemotherapy was reduced by 56% with abiraterone acetate versus ADT alone (HR, 0.443; 95% CI, 0.349-0.561; P <.0001).

The most common grade 3/4 adverse events with abiraterone acetate versus placebo, respectively, were hypertension (20.3% vs 10.0%); hypokalemia (10.4% vs 1.3%); elevated alanine aminotransferase (5.5% vs 1.3%), and elevated aspartate aminotransferase (4.4% vs 1.5%).

Abiraterone acetate was first approved in 2011 in combination with prednisone for the treatment of men with metastatic castration-resistant prostate cancer following chemotherapy. It has since gained approval earlier in the treatment paradigm for use prior to chemotherapy.

References

1. Fizazi K, Tran N, Fein LE, et al. the LATITUDE investigators. LATITUDE: A phase 3 double-blind, randomized trial of androgen deprivation therapy (ADT) with abiraterone acetate (AA) plus prednisone (P) or placebos (PBOs) in newly diagnosed high-risk metastatic hormone-naïve prostate cancer (mHNPC) patients (pts). J Clin Oncol. 2017;35 (suppl; abstr LBA3).
2. Fizazi K, Tran N, Fein LE, et al. Abiraterone plus Prednisone in Metastatic, Castration-Sensitive Prostate Cancer. N Engl J Med. 2017;377:352-360.