Cubist Pharmaceuticals has acquired an exclusive option to buy San Francisco-based biotech Adynxx on completion of the Phase II study of the company’s lead compound AYX1 in acute post-surgical pain. Adynxx will receive an undisclosed payment for granting the option with additional payments upon option exercise. If Cubist elects to exercise its option, Adynxx will be the second company backed by venture capital firm Domain Associates that it has acquired following its 2009 purchase of antibiotic drug developer Calixa Therapeutics.