Altering sunitinib dosing schedule improves tolerability

By Sara Freeman, medwireNews Reporter

mewireNews: Shortening the time that patients with advanced renal cell carcinoma are on and off treatment with sunitinib improves the drug’s overall tolerability without affecting its efficacy, say Japanese researchers.

Similar oncological outcomes were seen in patients treated with sunitinib in cycles of 2 weeks on and 1 week off treatment (2/1) as compared to those given the standard dosing schedule of 4 weeks on and 2 weeks off therapy (4/2)

Importantly, the 2/1 schedule was associated with significantly fewer (27 vs 53%) dose interruptions and a lower incidence of some side effects than the 4/2 schedule, the team from the Tokyo Women’s Medical University reports in the Japanese Journal of Clinical Oncology.

“The tolerability of sunitinib is a major issue, so modification of the dosing schedule was investigated,” write Tsunenori Kondo and colleagues. They add that “recent retrospective studies showed higher tolerability of Schedule 2/1 than Schedule 4/2 and that Schedule 2/1 may end up providing longer treatment and, thereby, longer overall survival.”

Kondo and team looked at data on 48 patients who had been treated with sunitinib for metastatic renal cell carcinoma at their institution. Twenty-six patients in the study had received the shorter sunitinib dosing schedule and 22 patients the 4/2 schedule.

Adverse events occurred to a similar extent, with the exception of hand–foot syndrome and diarrhoea, which were more frequent with the 4/2 schedule. These two side effects are the most likely to affect patients’ quality of life, say the researchers, and could determine how long patients are able to tolerate therapy.

Objective response rates (ORR) were higher with the standard doing schedule (50 vs 32%) but median progression-free survival (PFS) was longer in patients on the 2/1 schedule than the 4/2 schedule (18.4 vs 9.1 months). However, there was no statically significant differences in these efficacy markers between the schedules.

The initial dose of sunitinib given did not seem to affect the PFS results and the team suggests that a lower starting dose of 37.5 mg/day rather than 50 mg/day might be reasonable, particularly for elderly patients.

The researchers conclude: “The alteration of dosing schedule may increase treatment compliance and maximize the potential of sunitinib, although a prospective randomized study is required for further confirmation.”

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