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26-04-2022 | Oncology | News | Article

Cabozantinib shows promise for untreated collecting duct RCC

Author: Shreeya Nanda

medwireNews: The BONSAI trial has demonstrated encouraging efficacy and manageable toxicity of cabozantinib in treatment-naïve patients with metastatic collecting duct renal cell carcinoma (RCC).

The study met its primary endpoint of objective response rate (ORR), “reaching a noticeable ORR of 35%,” say Giuseppe Procopio (Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy) and co-investigators in JAMA Oncology.

They therefore propose that “cabozantinib may be considered as a therapeutic option” for this uncommon type of non-clear cell RCC “with poor prognosis and no standard treatment.”

In the single-center, phase 2 trial, 23 patients with previously untreated metastatic collecting duct carcinoma received oral cabozantinib at a daily dose of 60 mg until disease progression or unacceptable toxicity.

Of the 22 evaluable patients, one achieved a complete response and seven had a partial response, giving an ORR of 35%. An additional three patients had stable disease and the remaining 11 had progressive disease.

The median progression-free survival (PFS) was 4 months and median overall survival (OS) was 7 months; 43% of patients were alive and 23% were continuing treatment at the 12-month mark.

All participants experienced at least one grade 1–2 adverse event (AE), with the most common being fatigue (60%), followed by anorexia (39%), hand–foot syndrome (30%), hypothyroidism (30%), mucositis (30%), diarrhea (22%), and hypertension (13%).

There were six AEs of grade 3 – two cases each of arterial hypertension and fatigue, and one each of pulmonary thromboembolism and bleeding – but there were no grade 4 or 5 AEs.

A total of 17% of patients required a dose interruption due to AEs and an identical proportion needed a dose reduction to 40 mg/day, but no participant discontinued treatment permanently as a result of toxicity.

Discussing the results, Procopio and colleagues say that “[p]laced in the context of the little prospective evidence available, the results of the BONSAI trial are promising.”

They highlight the need for caution with cross-trial comparisons, but note that single-agent cabozantinib “appeared to be more active than platinum-gemcitabine chemotherapy” in this setting “and resulted in similar antitumor activity compared with the combination of platinum-based chemotherapy plus sorafenib.”

Furthermore, the toxicity profile of cabozantinib appeared to be more favorable than platinum–gemcitabine without or with sorafenib, say the researchers.

medwireNews is an independent medical news service provided by Springer Healthcare Ltd. © 2022 Springer Healthcare Ltd, part of the Springer Nature Group

JAMA Oncol 2022; doi:10.1001/jamaoncol.2022.0238

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