Flexible sunitinib scheduling improves outcomes
medwireNews: Changing the dosing schedule of sunitinib mitigates toxicity while maintaining efficacy in patients with clear cell metastatic renal cell carcinoma (mRCC) who experience adverse events (AEs) on the traditional dosing schedule, say researchers.
The traditional dosing schedule for sunitinib is 50 mg/day given over a 6-week cycle of 28 days on treatment and 14 days off treatment. And while this schedule is effective for some patients, for others AEs present a substantial barrier to continuing the intensity of medication needed to maintain efficacy.
But researchers Eric Jonasch and colleagues (University of Texas MD Anderson Cancer Center, Houston, USA) report that changing to an alternative schedule, such as 14 days on treatment and 7 days off, without changing the intensity of the dose could help mitigate AEs without comprising efficacy.
“This raises the possibility that toxicity is a marker of a response phenotype, but maintaining a higher level [of] AEs is not necessary to achieve clinical benefit,” the team writes in The Journal of Urology.
The researchers looked back on the sunitinib dosing schedules of 185 patients, 98 (53%) of whom were maintained on a traditional schedule for the duration of sunitinib therapy, whereas 87 (467%) were initiated or transitioned (at a median of 5.6 months) to an alternative schedule, most commonly (87%) 14 days on then 7 days off treatment.
The AEs most often prompting schedule modification were fatigue (64%), hand-foot syndrome (38%), and diarrhea (32%). By the next clinic visit, a median 1.8 months after transition, the rate of AEs was less than 30% for all types.
In addition to mitigating AEs, alternative schedules were associated with improved overall survival, at a median 33.0 months compared with 17.7 months with the traditional schedule. Indeed, the traditional schedule was found to be a predictor of decreased overall survival in multivariate analysis, along with poor Eastern Cooperative Oncology Group performance status, increased lactate dehydrogenase, decreased albumin levels, and unfavorable Heng criteria.
Similarly, progression-free survival was longer in patients on alternative schedules compared with the traditional schedule, at 14.5 months versus 4.3 months.
Findings from a subset analysis ruled out the possibility of a survival bias in patients in the alternative schedule group.
“Our study suggests that a more dynamic approach towards toxicity management in patients receiving sunitinib is warranted and is associated with improved outcomes,” the researchers conclude.
“Prospective validation in the context of a well-designed and controlled randomized trial is the best path forward.”
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By Lucy Piper, Senior medwireNews Reporter