Alligator Bioscience Announces Completion of 600 mg Dose Cohort for ATOR-1017, Dose-escalation and Enrollment for 900 mg dose Cohort Commences

Lund, Sweden, April 1, 2022 – Alligator Bioscience (Nasdaq Stockholm: ATORX) today announced the completion of the patient enrollment for the 600 mg dose cohort from Alligator’s Phase I, 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 Phase I study with ATOR-1017 is an open-label, dose escalation study in patients with histologically confirmed, advanced and/or refractory solid cancer (NCT04144842). The primary objective of the study is to investigate the safety and tolerability of ATOR-1017, and to determine the recommended dose for subsequent Phase II studies.

The data indicate that for doses up to 600 mg, there were no significant safety concerns with stable disease as the best tumor response. Patient enrollment and treatment for the highest planned dose cohort, 900 mg, has commenced.

As previously announced in December 2021, results from the early readout for ATOR-1017 showed that the drug candidate has an encouraging safety profile. In this readout, there was no dose-limiting toxicity or severe immune-related adverse events (link to press release).

For further information, please contact:

Julie Silber, Investor Relations

Phone: +46 46-540 82 23

E-mail: jur@alligatorbioscience.com

About Alligator Bioscience

Alligator Bioscience AB is a clinical-stage biotechnology company developing tumor-directed immuno-oncology antibody drugs. Alligator’s pipeline includes the two key assets mitazalimab, a CD40 agonist, and ATOR-1017, a 4-1BB agonist. Furthermore, Alligator is co-developing ALG.APV-527 with Aptevo Therapeutics Inc., several undisclosed molecules based on its proprietary technology platform, Neo-X-Prime™, and novel drug candidates based on the RUBY™ bispecific platform with Orion Corporation. Out licensed programs include AC101, in phase II development, by Shanghai Henlius Biotech Inc. and an undisclosed target to Biotheus Inc. Alligator Bioscience’s shares are listed on Nasdaq Stockholm (ATORX) and is headquartered in Lund, Sweden.

For more information, please visit http://www.alligatorbioscience.com.

Updated 2022-04-01