AB680 is a potent and selective inhibitor of CD73, the enzyme responsible for the extracellular production of adenosine within the tumor micro-environment. Adenosine is a powerful immunosuppressive substance produced inside tumors as a result of rapid cancer cell turnover and, in some cases, in connection with certain anti-tumor interventions, such as chemotherapy and radiation.

Inhibition of adenosine production is an alternative, perhaps complementary, therapeutic strategy to the use of adenosine receptor antagonists such as AB928. AB680 was the first small molecule CD73 inhibitor to enter clinical development.  Initiated a Phase 1 trial to evaluate AB680 in healthy volunteers in the second half of 2018. We anticipate initiating clinical trials in patients in the first half of 2019.

AB680 Clinical Trials Currently Enrolling

Trial Summary

This is a double-blind, randomized, placebo-controlled, single-ascending dose study to investigate the safety, tolerability, and pharmacokinetic profile of AB680 in healthy volunteers.

Trial Identifier

Publications and Abstracts

September 30-October 3, 2018

Preclinical Pharmacokinetic and Pharmacodynamic Characterization of AB680, a Small-Molecule CD73 Inhibitor for Cancer Immunotherapy. Tan JBL, Chen J, Ginn E, Ashok D, Anderson AE, Banuelos J, Zhang K, Pham A, Park T, Chen A, Zhao X, Jin L, Lawson KV, Jeffreys J, Kalisiak J, Leleti MR, Walters MJ, and Powers JP. CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; New York, New York; abstract No. A157.

View Poster

April 14-18, 2018

CD73 inhibitors (CD73i) reverse the AMP/adenosine-mediated impairment of immune effector cell activation by Immune Checkpoint Inhibitors (ICI). Becker A, Narasappa, N, Yin F, Zhang K, Park T, Kalisiak J, Lawson K, Jeffrey J, Powers JP, Schindler U, Walters, MJ, Tan JBL. Annual Meeting of the American Association of Cancer Research; Chicago, Illinois; abstract No. 710.

View Poster

April 14-18, 2018

Discovery and characterization of AB680, a potent and selective small-molecule CD73 inhibitor for cancer immunotherapy. Lawson KV, Jin L, Jeffrey J, Kalisiak J, Yin F, Zhang K, Chen A, Swinarski D, Walters MJ, Young S, Schindler U, Powers JP. Annual Meeting of the American Association of Cancer Research; Chicago, Illinois; abstract No. 4886.

View Poster