GQ-203 is a gene transfer vector for the treatment of osteoarthritis in humans. It is almost identical to GQ-201 and GQ-202 except that it carries the human version of the therapeutic protein. The mechanism of action is exactly the same as for GQ-201 and GQ-202. In December 2017, GQ-203 was acquired by Flexion Therapeutics, Inc. and is now designated FX201. Pending positive preclinical studies, FX201 anticipated to enter clinical trials in 2019.