The efficacy and tolerability of a sunitinib 3-week administration schedule in metastatic renal cell carcinoma patients: report of three cases

Tolerability of Alternative Dosing Schedules for Sunitinib: A Systematic Review and Meta-Analysis

PURPOSE

The standard schedule for sunitinib treatment is 4 weeks on and 2 weeks off (4/2) in first-line treatment for metastatic renal cell carcinoma (mRCC). Schedule modifications, including 2 weeks on and 1 week off (2/1), appear to reduce the total number of treatment-related adverse events (TRAEs) without compromising efficacy. Even though TRAEs can qualitatively differ from each other, it is not clear as to what effects a 2/1 schedule has on individual TRAEs.

MATERIALS AND METHODS

This meta-analysis included one randomized controlled trial (RCT) and four non-randomized controlled studies (non-RCTs) that compared the two schedules in parallel. The primary objective was to estimate risk of individual adverse events (AEs) with a sunitinib 2/1 schedule versus a 4/2 schedule. Seven representative AEs were evaluated as standard data for the RCT and as weighted pooling data of the non-RCTs. Random effects modelling with Review Manager v5.3 was used to pool study-level data using the inverse-variance of each study as the weight.

RESULTS

The five selected studies included a total of 484 patients with mRCC. Risk ratios for fatigue for a 2/1 schedule were significantly lower than those for a 4/2 schedule {0.69 [95% confidence intervals (CI), 0.51, 0.95] in the RCT and 0.77 (95% CI, 0.63, 0.94) in the non-RCTs}. Other TRAEs, except diarrhea and anorexia, also tended to decrease in both sets. Efficacy outcomes were comparable between 2/1 and standard schedules.

CONCLUSION

This meta-analysis suggests that a 2/1 schedule of sunitinib lowers the risk of fatigue and the occurrence other AEs without compromising efficacy.

Sunitinib in the treatment of metastatic renal cell carcinoma

Sunitinib is an oral multi-targeted tyrosine kinase inhibitor (TKI) that targets various receptors, including vascular endothelial growth factor receptors (VEGFRs). Sunitinib received approval in 2006 and became a standard treatment option in the first-line treatment of metastatic renal cell cancer (mRCC) after a phase III trial showed superiority compared with interferon alpha (IFN-α). Sunitinib has also shown activity in second-line treatment in several trials. Most of the combination trials with sunitinib with various agents have led to considerable toxicity without improving efficacy. Sunitinib alone causes significant side effects and has a distinct profile with diarrhoea, hypertension, skin effects hypothyroidism, fatigue and nausea of special interest. The recommended dose of sunitinib in mRCC is 50 mg orally daily for 4 weeks, followed by 2 weeks off treatment (4/2 schedule). An alternative 2 weeks on, 1 week off schedule (2/1 schedule) seems to be of similar efficacy and better tolerability and could be more widely used in the future. An intermittent treatment strategy with a stop in remission and re-induction after progression showed efficacy in smaller trials and is currently being evaluated in a phase III trial. Direct comparison of sunitinib with pazopanib in first-line treatment showed a similar efficacy for both TKIs with a distinct toxicity profile. Data from two phase II trials showed that sunitinib has also activity in non-clear cell cancer and is an option due to a lack of better alternatives. Currently, after immune checkpoint inhibitors have shown very promising results in the second-line treatment of RCC, they are being tested in a number of phase III trials in the first-line setting. The future will show the position of sunitinib in the first-line treatment of RCC in the era of the immune checkpoint inhibitors.

Efficacy and tolerability of a low-dose, 2-week administration of sunitinib followed by a week rest (2/1 schedule) for metastatic renal cell carcinoma: a single center experience of six cases

Background

Sunitinib, an oral multitarget tyrosine kinase inhibitor and standard first-line treatment for metastatic renal cell carcinoma (mRCC), is generally administered on a 6-week schedule (4 weeks on/2 weeks off). However, drug toxicity often leads to temporary treatment interruption, resulting in reduced treatment efficacy. In this report, we investigated whether sunitinib administration of at a dose of 25 mg/day in a 2-weeks-on/1-week-off cycle would reduce the incidence of drug-related side effects while maintaining drug efficacy.

Findings

A total of six patients with mRCC were orally administered sunitinib at a dose of 25 mg/day in a 2-weeks-on/1-week-off regimen until intolerable toxicities occurred. All enrolled patients were assessed for toxicity and response. The median treatment period was 24 months (range, 9–40 months). Objective responses were as follows: disease stabilization of >6 months was achieved in all patients. The most important toxicities were neutropenia, fatigue, and proteinuria, but all were controlled.

Conclusions

Oral sunitinib at 25 mg/day in a 2-weeks-on/1-week-off regimen to Japanese patients can avoid drug-related toxicities while achieving the same dose intensity as a 6-week schedule. Because these data were derived from a small number of patients, future prospective studies of modified sunitinib administration schedules are warranted.