Effects of cabozantinib monotherapy starting dose on treatment outcomes in metastatic renal cell carcinoma: A real-world cohort study from Southwest Finland
Sakari Kosola, Laura Ahtiainen, Judith Miedema, Ann-Charlotte Mårdby, Julia Rockberg, Valerie Perrot, Tommi Kauko, Lotta Tapana, Kalle E. MattilaBackground
Cabozantinib is a treatment for metastatic renal cell carcinoma (mRCC), typically recommended at a 60 mg daily starting dose. However, a lower dose is often used in clinical practice to improve tolerability.
Objectives
This study investigates the impact of cabozantinib starting dose on survival and safety in a real-world cohort from Southwest Finland.
Design and Methods
This study utilized electronic healthcare data from the Hospital District of Southwest Finland, including adult patients with mRCC initiating cabozantinib monotherapy between March 2018 and December 2021. Patients were stratified by treatment line (first-line [1L] or second/later line [2L+]) and starting dose (40 mg or 60 mg daily). Outcomes assessed were overall survival (OS), time to next treatment (TTNT), and safety (CTCAE v5.0).
Results
Of 71 patients, 34 (48%) received cabozantinib as 1L and 37 (52%) as 2L+ treatment. Median OS was 24 months for 1L and 10 months for 2L+, with no significant difference between starting doses. Median follow-up was 16 months (IQR 9.9, 23.4) for 1L and 9 months (IQR 3.6, 16.5) for 2L+. Median treatment duration was 11 months (IQR 4.3, 15.8) for 1L and 6 months (IQR 3.0, 10.0) for 2L+. At 8 months, 86% of 1L and 92% of 2L+ patients did not start the next treatment line. Dose reduction or schedule modification was needed for 79% of patients starting 1L cabozantinib at 60mg daily, compared to 45% at 40mg. Diarrhea and hand-foot syndrome were more common than elevated liver enzymes, with grade 3 adverse events being rare.
Conclusion
This study suggests that no statistically significant difference in survival outcomes was observed between patients starting cabozantinib at 40 mg versus 60 mg, while fewer dose modifications and adverse events were observed with the lower starting dose.