Efficacy and Safety Exposure-Response Relationships of Apalutamide in Patients with Nonmetastatic Castration-Resistant Prostate Cancer.

To evaluate the relationship between exposure of apalutamide and its active metabolite, N-desmethyl-apalutamide, and selected clinical efficacy and safety parameters in men with high-risk nonmetastatic castration-resistant prostate cancer. An exploratory exposure-response analysis was undertaken using data from the 1,207 patients (806 apalutamide and 401 placebo) enrolled in the SPARTAN study, including those who had undergone dose reductions and dose interruptions. Univariate and multivariate Cox regression models evaluated the relationships between apalutamide and N-desmethyl-apalutamide exposure, expressed as area under the concentration-time curve at steady state, and metastasis-free survival (MFS). Univariate and multivariate logistic regression models assessed the relationship between apalutamide and N-desmethyl-apalutamide exposure and common treatment-emergent adverse events including fatigue, fall, skin rash, weight loss, and arthralgia. A total of 21% of patients in the apalutamide arm experienced dose reductions diminishing the average daily dose to 209 mg instead of 240 mg. Within the relatively narrow exposure range, no statistically significant relationship was found between MFS and apalutamide and N-desmethyl-apalutamide exposure. Within apalutamide-treated subjects, skin rash and weight loss had a statistically significant association with higher apalutamide exposure. The use of apalutamide at the recommended dose of 240 mg once daily provided a similar delay in metastases across the SPARTAN patient population, regardless of exposure. The exploratory exposure-safety analysis supports dose reductions in patients experiencing adverse events

Phase II study of the efficacy and tolerability of two dosing regimens of the farnesyl transferase inhibitor, R115777, in advanced breast cancer

Phase II study of the efficacy and tolerability of two dosing regimens of the farnesyl transferase inhibitor, R115777, in advanced breast cancer. Purpose : R115777 is an orally active farnesyl transferase inhibitor that specifically blocks farnesylation of proteins involved in growth-factor-dependent cell-signal-transduction pathways. We conducted a phase II study in 76 patients with advanced breast cancer. Patients and Methods: Two cohorts of patients were recruited sequentially. The first cohort (n = 41) received a continuous dosing [CD] regimen of R115777 400 or 300 mg bid. The second cohort (n = 35) received 300 mg bid in a cyclical regimen of 21 days of treatment followed by 7 days of rest (intermittent dosing [ID]). Results: In the CD cohort, four patients (10%) had a partial response (PR) and six patients (15%) had stable disease at greater than or equal to 24 weeks (SD). In the ID cohort, five patients (14%) had a PR and three patients (9%) had prolonged SD. The first six patients in the CD cohort treated at 400 mg bid all developed grade 3 to 4 neutropenia, so the subsequent 35 patients were treated at 300 mg bid. The incidence of hematologic toxicity was significantly lower in the ID than in the CD (300-mg bid) cohort: grade 3 to 4 neutropenia (14% v 439/6, P = .016) and grade 3 to 4 thrombocytopenia (3% v 26%, P = .013). One patient in the ID cohort developed grade 2 to 3 neurotoxicity compared with 15 patients in the CD cohort (3% v 37%; P = .0004). Conclusion: The farnesyl transferase inhibitor R115777 has demonstrated clinical activity in patients with metastatic breast cancer, and the ID regimen has a significantly improved therapeutic index compared with the CD regimen. (C) 2003 by American Society of Clinical Oncology