ESMO 2020: Ipatasertib Plus Abiraterone in Metastatic Castration-Resistant Prostate Cancer
Posted: Tuesday, September 22, 2020
According to Johann de Bono, MB, ChB, PhD, of The Institute of Cancer Research and the Royal Marsden Hospital, London, and colleagues, patients with loss of phosphatase and tensin homolog (PTEN) metastatic castration-resistant prostate cancer may derive a radiographic progression-free survival benefit from treatment with the AKT inhibitor ipatasertib plus abiraterone. The results of the phase III IPATential150 trial were presented during the European Society for Medical Oncology (ESMO) Virtual Congress 2020 (Abstract LBA4).
“PI3K/AKT and androgen receptor signaling are dysregulated in metastatic castration-resistant prostate cancer. PTEN loss results in activation of AKT, the ipatasertib target, and worse outcomes,” the investigators commented. “Preclinically, dual pathway inhibition has greater antitumor activity than androgen receptor inhibition.”
In a 1:1 ratio, a total of 1,101 patients with castration-resistant prostate cancer were randomly assigned to receive either first-line ipatasertib plus abiraterone and prednisone (n = 547) or placebo plus abiraterone and prednisone (n = 554). The loss of PTEN was defined as the loss of PTEN protein expression in at least 50% of the tumor cells on immunohistochemical analysis. Follow-up data were provided for a median of 19 months.
In tumors with loss of PTEN, the median radiographic progression-free survival with ipatasertib and with the placebo were 18.5 versus 16.5 months, respectively (P = .0335). Similarly, in the intention-to-treat population, the median radiographic progression-free survival was longer with ipatasertib than without (19.2 vs. 16.6 months; P = .0431). Serious adverse events were reported in 40% of the ipatasertib arm and in 23% of the placebo arm; adverse events leading to treatment discontinuation occurred in 21% and 5% of patients, respectively.
Disclosure: For full disclosures of the study authors, visit oncologypro.esmo.org.
