CAMBRIDGE, MA, USA I April 16, 2018 I Leap Therapeutics, Inc. (NASDAQ:LPTX) today presented nonclinical and clinical data on DKN-01, Leap’s anti-DKK1 monoclonal antibody, at the American Association for Cancer Research (AACR) 2018 Annual Meeting. The presentation highlighted the immunomodulatory activity of DKN-01 in nonclinical experiments and preliminary results from the dose escalation phase of the clinical study evaluating DKN-01 in combination with the Merck (known as MSD outside the United States and Canada) anti-PD-1 therapy, KEYTRUDA® (pembrolizumab), in patients with advanced esophagogastric cancer.

Nonclinical Data:

Nonclinical studies demonstrated the activity of DKK1 inhibition in enhancing innate immunity and the potential for combination with immune checkpoint inhibitors. mDKN-01, the murine form of DKN-01, reduced myeloid-derived suppressor cells (MDSCs), increased PD-L1 levels on MDSCs, and enhanced expression of T-cell chemoattractants. These innate mechanisms, promoting an inflammatory tumor microenvironment, are complementary to immune checkpoint inhibition. In a syngeneic tumor model, mDKN-01 had additive activity with anti-PD-1 therapy as compared to either antibody administered alone.

Clinical Data:

Preliminary results from the dose escalation phase of the clinical study evaluating the combination of DKN-01 and KEYTRUDA in patients with advanced esophagogastric cancer demonstrated that the combination was well tolerated with early signals of clinical activity:

  • Four out of five patients enrolled at the highest tested dose of DKN-01 were naïve to anti-PD-1/PD-L1 therapy and evaluable for response. One patient had a partial response with a 66% reduction in target tumor volume. This patient had progressed on two prior systemic therapies and had a tumor that was known to be KRAS amplified, microsatellite stable (MSS), and PD-L1 negative; a phenotype typically less responsive to anti-PD-1 therapy. Three patients had stable disease, two of whom remain on study through at least four cycles.
  • Two patients enrolled in the escalation phase were refractory to anti-PD-1/PD-L1 therapy and currently have had a best response of stable disease. One of these patients also had a tumor that was KRAS amplified, MSS, and PD-L1 negative and has been on study for six cycles with an initial 10% reduction in tumor burden.

The DKN-01 and KEYTRUDA expansion combination continues to enroll patients who are naïve to anti-PD-1/PD-L1 therapy (n=40) and patients who are refractory to anti-PD-1/PD-L1 therapy (n=15).

About Leap Therapeutics

Leap Therapeutics (NASDAQ:LPTX) is focused on developing targeted and immuno-oncology therapeutics. Leap’s most advanced clinical candidate, DKN-01, is a humanized monoclonal antibody targeting the Dickkopf-1 (DKK1) protein, a Wnt pathway modulator. DKN-01 is in clinical trials in patients with esophagogastric cancer, biliary tract cancer, and gynecologic cancers, with an emerging focus on patients with defined mutations of the Wnt pathway and in combination with immune checkpoint inhibitors. Leap’s second clinical candidate, TRX518, is a novel, humanized GITR agonist monoclonal antibody designed to enhance the immune system’s anti-tumor response that is in two advanced solid tumor studies. 

SOURCE: Leap Therapeutics