CHICAGO – Retreatment with cabazitaxel demonstrated encouraging activity and acceptable toxicity when used in combination with a new hormonal therapy and docetaxel among men with heavily pretreated, metastatic, castration-resistant prostate cancer, according to findings presented at the ASCO Annual Meeting.
“Only two chemotherapies have shown an OS benefit in metastatic, castration-resistant prostate cancer: docetaxel and cabazitaxel,” the researchers wrote. “In patients previously treated with a new hormonal therapy (enzalutamide or abiraterone), docetaxel and cabazitaxel, therapeutic options are limited.”
MD, of the Georges Pompidou European Hospital in Paris, and colleagues performed a retrospective study in patients with metastatic, castration-resistant prostate cancer. Enrollment required prior treatment with docetaxel, cabazitaxel and a novel hormonal therapy (enzalutamide or abiraterone), as well as a positive response to cabazitaxel. The researchers examined the records of 70 patients from 17 centers in France, Italy, the United Kingdom and Austria.
Most patients (n = 52) were treated with docetaxel first, followed by a new hormonal therapy and then cabazitaxel. An additional 15 patients received docetaxel first, but were treated with cabazitaxel second and a new hormonal therapy last. The remaining 3 patients were treated with a new hormonal therapy first, followed by docetaxel and then cabazitaxel.
When treatment with cabazitaxel resumed, high-volume disease was reported in most patients (83%) and 10% had visceral metastases. Narcotic analgesics had been prescribed for 66% of patients and the majority (68%) had an ECOG performance status of zero to one. The median neutrophil-to-lymphocyte ratio was 3.1.
Treatment with cabazitaxel was reinstituted for a median number of 6 cycles, with a median duration of 8.6 months since the last cycle of cabazitaxel. Most patients (59%) received 25 mg/m2 every 3 weeks; 27% were treated with 20 mg/m2 every 3 weeks and 11% of patients received 16 mg/m2 every 3 weeks. Prophylactic treatment with granulocyte colony-stimulating factor was administered to 47% of patients.
Median PFS was 11.3 months among patients treated with docetaxel, 12 months among patients who received a novel hormone therapy, 11.9 months after initial treatment with cabazitaxel (median number of cycles = 8) and 7.8 months after resuming treatment. Median OS “calculated from the first life-extending therapy was 59.9 months (95% CI, 47.8-66.4),” the researchers wrote.
The toxicities after reinstituting treatment were reported to be tolerable; 7 patients (10%) experienced grade 3-4 neutropenia.
“Cabazitaxel rechallenge might be an option in heavily treated patients still fit to receive chemotherapy,” the researchers wrote. – by Julia Ernst, MS
Thibault C, et al. Abstract 5033. Presented at: ASCO Annual Meeting: June 2-6, 2017; Chicago.
Disclosures: Thibault reports that she serves as a consultant or adviser for Novartis and Sanofi and that she receives travel, accommodations and expenses from Novartis and Sanofi. Please see the full study for a list of all other researchers’ relevant financial disclosures.