ESMO: Exelixis triumphantly unveils Cabometyx neuroendocrine data that led to early trial end

Exelixis touted last month that its Cabometyx proved so successful in neuroendocrine tumors (NETs) that the trial ended early. Now, we get to see what one analyst had already heralded as the “dramatic improvements” in data unveiled at the European Society for Medical Oncology Congress.

The Ipsen-partnered tyrosine kinase inhibitor was tested in 290 participants split into two cohorts of previously treated NETs, one consisting of patients with advanced pancreatic neuroendocrine tumors (pNETs) and another with extra-pancreatic neuroeconomic tumors (epNETs).

In the pNET group, Cabometyx (cabozantinib) helped patients live longer without their disease getting worse for a median of 11.4 months compared with just three months on placebo.

The results were just as impressive in the epNET cohort, which saw Cabometyx treatment nearly triple placebo's median of 3.2 months of progression-free survival with 8.3 months. 

The trial, called CABINET, was cut early and unblinded based on a unanimous vote from an independent data and safety monitoring board in August.

In a disease area with few treatment options, an approval for Cabometyx could be crucial. More than 12,000 people in the U.S. are diagnosed with NETs each year at an increasing rate, according to Exelixis. NETs that start in the pancreas are often more aggressive, and the advanced stage has a survival rate of only 23%.  

“Although progress has been made in recent years, there remains a critical need for new and effective therapies for patients with advanced neuroendocrine tumors,” CABINET’s study chair Jennifer Chan, M.D., said in an Exelixis release. “Given that there is no standard treatment for patients with progressive disease, these results showing notable improvements in progression-free survival are highly encouraging for patients and their physicians.”

Now, the company will discuss the findings with the FDA, Exelixis Chief Medical Officer Amy Peterson, M.D., added.

William Blair analysts were “pleasantly surprised” by the win pre-readout when the company unblinded the study and teased “dramatic improvements.” The team noted that an FDA review in the disease setting would likely take about a year.

Elsewhere, the drug recently put up mixed data in pretreated metastatic castration-resistant prostate cancer as a combination therapy with Roche’s Tecentriq. The combo was able to prolong progression free-survival, but overall survival rates didn’t meet statistical significance despite a “trend toward improvement.”