Study of Weekly Cabazitaxel for Advanced Prostate Cancer

The efficacy of three-weekly cabazitaxel is accompanied by an appreciable rate of serious side effects and toxic deaths. The toxicity rates observed, including grade III-IV neutropenia, febrile neutropenia and diarrhea, could be an obstacle to the use and management of a drug that, on the other hand, has demonstrated great activity. In the treatment of patients with prostate cancer, who have a larger number of morbidities than patients with breast cancer, we assume the risk that in the transition from clinical trial to clinical practice the drug will not be used much because of the risk of side effects, cost, the discomfort derived from the routine use of G-CSF and the lack of patient compliance with this type of regimens. Rates of neuropathy, nail and conjunctive toxicity with this new taxane are not relevant, which suggests that weekly administration will not produce relevant toxicity problems. Weekly administration of other taxanes improved hematologic tolerance along with a better therapeutic range in some cases, increasing the dose intensity and activity without increasing the associated toxicity. Phase I study has been reported studying weekly administration of cabazitaxel, recommended dose is 10 mg/m2, administered on days 1, 8, 15 and 22 every 5 weeks in a 1-hour infusion, being diarrhea the dose-limiting toxicity observed in this study. Given the pharmacokinetic characteristics of this taxane and its activity and toxicity profile, cabazitaxel might be a good candidate for studying in a weekly administration regimen in patients with prostate cancer with a greater risk of toxicity associated with treatment every 3 weeks, such as patients who have received previous pelvic radiation therapy that affects more than 25% of the bone marrow reserve, patients over 75 years with a worse performance status (ECOG 2) or who have already experienced important hematologic toxicity in the previous treatment with docetaxel.