Leap Therapeutics Inc. said a combination of its experimental drug DKN-01 and Merck & Co. Inc.'s blockbuster therapy Keytruda extended the lives of certain patients with a type of stomach cancer in a study testing the therapy.
The combination was being examined to treat patients with advanced gastroesophageal junction — the point where the esophagus joins the stomach — and gastric cancer whose tumors expressed high levels of the DKK1 protein.
Leap's DKN-01 is designed to target certain signaling pathways that are often implicated in cancer, enabling cancer cells to grow and divide and to suppress the immune system. Merck's Keytruda boosts the immune system's ability to kill cancer cells by blocking healthy cells' PD-1 protein from linking up with a partner arm on the surface of cancer cells known as the PD-L1 protein.
The DKN-01 plus Keytruda combination therapy was tested in 63 patients across all arms and dose groups of the study. Of these, 53 patients had not previously received PD-1/PD-L1 therapies and 10 patients had not responded to such treatments.
Results from the study showed that 10 patients whose tumors expressed high levels of DKK1 lived for a median of 22 weeks without the disease spreading, while the overall survival was 32 weeks on the combination therapy. In addition, 50% of these patients saw shrinkage in their tumors, and the disease remained stable in 80% of these patients.
Moreover, 15 patients whose tumors expressed low levels of DKK1 survived for nearly six weeks without disease progression and over 17 weeks overall, with a 20% disease control rate. Previously, the therapy showed tumor shrinkage in 23.5% of certain evaluable patients and the disease was controlled in 58.8% of these patients.
Leap, which develops targeted immune therapies for cancer, is studying DKN-01 in patients with esophagogastric, hepatobiliary, gynecologic and prostate cancers.