In Year 4 of the Strategic Partnership, the open-label VC01-101 STEP ONE clinical trial continued. After nineteen subjects were implanted in the US and Canada, ViaCyte and its clinical sites paused enrollment. During Year 4 no additional subjects were implanted with the VC-01 product candidate in the STEP ONE trial. The majority of subjects in the STEP ONE trial have reached their 2-year time point and have had all remaining implanted VC-01 units removed. Subjects who completed the STEP ONE trial enrolled in the mandatory observational Follow-Up Study. Following the additional year of study in the STEP ONE trial, the preliminary observations previously reported continue to be supported: (1) the VC-01 product candidate appears to be safe and well tolerated; (2) the Encaptra Cell Delivery System is providing immune protection, as designed, with no allogeneic or autoimmune rejection of the implanted cells, nor patient sensitization, observed; and (3) there is potential for prolonged cell survival and differentiation to insulin-expressing beta cells in patients with type 1 diabetes, but this is limited in some cases by a foreign body response which negatively impacts engraftment. Accordingly, further non-clinical work is being performed to explore modifications to the product and procedures before the STEP ONE trial resumes enrollment. ViaCyte has teamed up with WL Gore & Associates to pursue and optimize such VC-01 product modifications.