Aim: Aim of the study was to evaluate the safety, tolerability, and efficacy of AUP1602-C, a genetically engineered lactic acid bacterium producing three human therapeutic proteins: fibroblast growth factor-2 (FGF-2), interleukin-4 (IL-4), colony stimulating factor-1 (CSF-1), addressing all aspects of chronic wound healing. The maximum tolerated dose (MTD), dose-limiting toxicities (DLTs), and recommended phase-2 dose (RP2D) were also evaluated. Method: A phase-1, open-label, single-arm, dose-escalation study was initiated to treat non-healing DFU patients. Four dosecohorts were evaluated in a 3+3 design. Dosing frequency was three times-a-week for six-weeks. A cohort review committee was established to monitor safety and recommend dose-escalation. Wound area was measured by an independent evaluator using digital planimetry. Assessment of systemic toxicity, biodistribution and shedding, and wound microbiology were performed. Results / Discussion: Fifteen patients received AUP1602-C treatment. No DLTs were observed, MTD was not reached, and the hightherapeutic dose was selected as the RP2D. Local and systemic safety and tolerability were confirmed with no serious adverse events (SAEs), systemic toxicity or immunogenicity related to AUP1602-C. Maceration was the most frequent adverse-event. 83% of patients in the RP2D cohort achieved total wound closure with a median healing time of 47 days. During the 2-weeks run-in period without AUP1602-C, mean wound area increased by 17% with standard-of-care treatment, versus >30% reduction in the first 2-weeks of RP2D treatment. Conclusion: Encouraging safety and efficacy data, from the first ever study for a GTMP of this nature to be tested in DFU patients, enabled a phase-2 clinical study, now under preparation.