Collecting duct carcinoma is a rare and aggressive form of kidney cancer that grows in the collecting ducts of the kidney. The collecting duct is the end of a long, twisting tube that collects urine from the kidney where it passes through tubes called the ureters into the bladder. Many people with collecting duct carcinoma have no signs or symptoms until the cancer is at an advanced stage. Symptoms may include flank pain, unexplained weight loss, or blood in the urine.

In this phase 2 clinical trial the effectiveness of cabozantinib was tested in 23 people with collecting duct carcinoma that had spread to other parts of the body (metastatic). In 35% of patients, their cancer responded to treatment by getting smaller. The average time to when the cabozantinib stopped working and the cancer started growing again (progression-free survival) was 4 months and the average overall survival time was 7 months.

Side effects were typical for cabozantinib, such as tiredness, loss of appetite, and hand-foot syndrome, among others.

This trial showed that cabozantinib is effective for collecting duct carcinoma, a rare form of kidney cancer with an unmet need for treatment options. Although patient numbers are low and randomised trials are difficult to do, they would be important to show whether cabozantinib should be considered the standard treatment for collect duct carcinoma, rather than chemotherapy or other tyrosine kinase inhibitors.

Read more in JAMA Oncology here