Clinical report: Calliditas data provide mixed support for anti-fibrotic cancer mechanism

The idea that breaking down the tumor matrix to allow immune cells to access solid tumors gained mixed clinical support this week with data from a head-and-neck-cancer study of setanaxib from Calliditas Therapeutics AB (SSE:CALTX; NASDAQ:CALT).

In a Phase II study of 55 patients with recurrent or metastatic squamous cell carcinoma of the head and neck (SCCHN) who had moderate or high cancer-associated fibroblast (CAF) density — indicating a fibrotic tumor microenvironment — NOX enzyme inhibitor setanaxib plus Keytruda pembrolizumab increased progression-free survival (5.0 months vs. 2.9 months) and overall survival (88% vs. 58% nine-month OS) over Keytruda alone. The combination failed, however, to shrink tumors to a greater extent than the PD-1 inhibitor alone, missing the trial’s primary endpoint of objective response rate (ORR)...