Weight and skeletal muscle loss with cabozantinib in metastatic renal cell carcinoma

BACKGROUND

Cabozantinib, a standard of care metastatic renal cell carcinoma (mRCC), may be associated with weight and muscle loss. These effects of new generation VEGFR tyrosine kinase inhibitor on muscle mass loss are poorly described.

METHODS

All cabozantinib-treated mRCC patients from January 2014 to February 2019 in our institution were included. Clinical data including weight were collected during therapy. Computed tomography images were centrally reviewed for response assessment, and axial sections at the third lumbar vertebrae were used to measure the total muscle area. Toxicities and cabozantinib outcomes were evaluated. Co-primary endpoints included skeletal muscle loss and weight loss (WL), longitudinally evaluated during treatment. WL has been classified according to CTCAEv5.0: Grade 1 (loss of 5 to <10% of baseline body weight), Grade 2 (loss of 10% to <20% of baseline body weight), and Grades 3-4 (loss >20% of baseline body weight).

RESULTS

Patients were mostly men (70.3%), median age was 59.2 (range: 22.0-78.0) years, and median baseline body mass index was 25.0 (range: 16.4-49.3) kg/cm² . Prognosis according to International Metastatic RCC Database Consortium score was good, intermediate, and poor for 13 (13.0%), 63 (63.0%), and 24 (24.0%) patients, respectively. Out of a total of 120 patients, 101 patients with a median follow-up of 22.3 months (range: 4.5-62.2) were eligible for analysis; 85 experienced muscle loss and muscle loss >10% increased during cabozantinib exposition, especially after 6 months of treatment. At cabozantinib baseline, 71 patients (70.3%) had sarcopenia, and 16/30 (53.3%) non-sarcopenic patients developed sarcopenia during treatment. Baseline sarcopenia was associated with lower response rates (P = 0.031) and higher grades 3-4 toxicities (P = 0.001). Out of 92 patients included in the WL analysis, 44 (47.8%) and 12 (13.0%) experienced grades 2 and 3 WL, respectively.

CONCLUSIONS

We report a high incidence of grades 3-4 WL, fourth times higher than reported in prior pivotal trials, and half of the patients developed sarcopenia while on cabozantinib treatment. Weight and muscle mass loss with cabozantinib are underreported and may require further investigations and early management.

Activity of Systemic Treatments After Cabozantinib Failure in Advanced Metastatic Renal Cell Carcinoma

BACKGROUND

Cabozantinib, a potent multityrosine kinases inhibitor (TKI), has demonstrated overall survival (OS) benefit over everolimus in patients previously treated with VEGFR TKI for metastatic Renal Cell Carcinoma (mRCC). The efficacy of systemic treatments after cabozantinib failure has not been investigated.

MATERIALS AND METHODS

We conducted a retrospective study on patients receiving systemic treatment after cabozantinib failure in heavily pretreated patient with mRCC. We assessed Time to Treatment Failure (TTF), OS and objective response rate (ORR).

RESULTS

Among 150 patients treated with cabozantinib in our institution, 56 (37.3%) received subsequent systemic therapy and were eligible for the analysis. IMDC prognostic group was good, intermediate and poor in 11 (19.6%), 24 (42.9%) and 11 (19.6%) patients, respectively. Cabozantinib was administered mainly as a second (41.1%), or third (33.9%) line treatment. axitinib or immune-checkpoint inhibitors were the subsequent treatment in 18 (34.8%) patients for each everolimus (n:16, 28.6%), other angiogenesis inhibitors (n:4, 7.1%) TTF and OS from subsequent systemic therapy after cabozantinib failure were 2.8 months (95%CI 1.9-3.7) and 7.7 months (95%CI 4.4-10.8), respectively. ORR was 8.7% and 2 patients with axitinib and 2 patients treated with Immune checkpoint inhibitors achieved a partial response.

CONCLUSION

Overall, activity of systemic therapies after cabozantinib was limited.