Lund, Sweden, 30 September, 2022 - Alligator Bioscience (Nasdaq Stockholm: ATORX) today announces positive safety data from the 900 mg dose cohort in its Phase 1, first-in-human clinical trial with the 4-1BB (CD137) targeting drug candidate, ATOR-1017, which is being developed as a tumor-directed therapy for advanced/metastatic cancer.

The data show that for doses up to 900 mg there were no significant safety concerns with durable stable disease as the best tumor response, confirming previously announced signs of clinical benefit. No dose-limiting toxicity was observed and the maximum tolerated dose (MTD) of ATOR-1017 has not been reached.

The Phase 1 open-label dose-escalation study of ATOR-1017 in patients with histologically confirmed, advanced, and/or refractory solid cancer (NCT04144842) has completed enrollment. The primary objective of the study to investigate the safety and tolerability of ATOR-1017 at therapeutic doses has been successfully met. Two patients remain on the study benefitting from ATOR-1017 treatment.

"We welcome the latest data from the 900 mg dose cohort, the highest dose tested in this trial, which confirm the good safety profile of ATOR-1017," said Søren Bregenholt, PhD, CEO of Alligator Bioscience. "We have observed activation of peripheral T cells and increased levels of soluble 4-1BB across all active dose levels of ATOR-1017, demonstrating biological activity and proof of mechanism, further validating the therapeutic potential of this drug candidate in solid tumors. This Phase 1 study has now succesfully fulfilled its purpose and provides a strong foundation for further clinical development."

The information was submitted for publication, through the agency of the contact person set out below, at 11:00 a.m. CET on September 30, 2022.