Pain and Health-related Quality of Life with Biweekly Versus Triweekly Cabazitaxel Schedule in Older Men with Metastatic Castration-resistant Prostate Cancer in the Multicenter, Randomized CABASTY Trial.

BACKGROUND AND OBJECTIVE: The CABASTY study showed that more frequent administration of a lower dose of cabazitaxel (CBZ) reduced toxicity in older men with metastatic castration-resistant prostate cancer (mCRPC), without compromising efficacy. Here, we investigated the impact of a biweekly CBZ schedule on patient-reported pain and health-related quality of life (HRQoL). METHODS: We randomized 196 patients from 25 centers (1:1, stratified by age and G8 score) to the biweekly CBZ16 (CBZ 16 mg/m2) experimental arm or the triweekly CBZ25 (CBZ 25 mg/m2) control arm (CABASTY study, NCT02961257). We assessed pain using the Numeric Pain Rating Scale and HRQoL using the Functional Assessment of Cancer Therapy-Prostate (FACT-P) questionnaire. KEY FINDINGS AND LIMITATIONS: A total of 141 patients were available for a pain and 160 for an HRQoL analysis. Median time to pain progression (stratified hazard ratio [HR]: 1.7, confidence interval [CI]: 0.67-4.22, p = 0.3) and median time to first opiate use (stratified HR: 1.05, CI: 0.44-2.55, p = 0.9) did not differ between arms. We did not see a significant difference in median time to deterioration of FACT-P total score between treatments (stratified HR: 0.88, CI: 0.47-1.7, p = 0.7). Interestingly, the time to onset of several adverse events was significantly longer in the biweekly CBZ16 group. CONCLUSIONS AND CLINICAL IMPLICATIONS: HRQoL did not significantly differ between the biweekly CBZ16 and the standard schedule. Additionally, onset of some adverse events was delayed. These results may increase health care providers' confidence in using CBZ in older patients with mCRPC who are denied chemotherapy. PATIENT SUMMARY: Androgen receptor pathway inhibitors are often preferred to taxane chemotherapy as a treatment of second or subsequent line in older metastatic castration-resistant prostate cancer patients due to more frequent treatment-related toxicities. Here, we showed that quality of life and pain did not differ significantly with an adapted schedule of cabazitaxel (CBZ), compared with the standard regimen. This CBZ schedule could increase eligibility of older patients for chemotherapy.

Targeted Inhibition of CYP11A1 in Castration-Resistant Prostate Cancer.

BACKGROUND: Prostate cancer is regulated by steroid hormones, even in castration-resistant disease. ODM-208, a novel inhibitor of cytochrome P450 11A1 (which catalyzes the first step of steroid-hormone biosynthesis), was investigated in patients with heavily pretreated metastatic castration-resistant prostate cancer (mCRPC). METHODS: CYPIDES is a first-in-human phase 1 (3 + 3 design) and phase 2 study. We administered ODM-208 twice daily with glucocorticoid/mineralocorticoid replacement and ongoing androgen deprivation therapy to adults with previously treated mCRPC, regardless of androgen receptor gene (AR) ligand-binding domain mutations (phase 1) and with activating AR ligand-binding domain mutations (ARmut; phase 2). Safety, pharmacokinetics, steroid-hormone pharmacodynamics, and preliminary efficacy were the key outcomes. RESULTS: Ninety-two patients received one or more doses of ODM-208: 47 in phase 1 (20 [42.6%] with ARmut) and 45 in phase 2 (all ARmut). A dose of ODM-208 of 5 mg twice a day with dexamethasone 1 mg/fludrocortisone 0.1 mg provided a balance between decreased steroidogenesis and toxicity. Treatment-related adrenal insufficiency was the most common toxicity in phase 1 (n=17, 36.2%; necessitating ODM-208 discontinuation in one patient); this toxicity occurred in six patients (13.3%) at 5 mg twice a day in phase 2. Median circulating testosterone levels declined from 3.0 ng/dl (interquartile range, 1.3 to 6.2 ng/dl) at baseline to undetectable levels within the first week of ODM-208 5 mg twice a day treatment in 46 of 53 (87%) patients. A decrease in prostate-specific antigen levels of 50% or more occurred in 14 of 19 (73.7%) patients with ARmut and 2 of 23 (8.7%) patients with AR wild type in phase 1 and in 24 of 45 (53.3%) patients with ARmut in phase 2. CONCLUSIONS: ODM-208 potently inhibited steroid-hormone biosynthesis with the expected toxicity of adrenal insufficiency. Evidence of antitumor activity was observed in this heavily pretreated mCRPC population, especially in those with ARmut. (Funded by Orion Pharma; ClinicalTrials.gov number, NCT03436485.)