Alligator Bioscience

Regulatory Filings • Sep 9, 2020

Alligator Bioscience presents an update regarding the Phase I study with the drug candidate ATOR-1015

Lund, Sweden, September 9, 2020 – Alligator Bioscience (Nasdaq Stockholm: ATORX) announced today updated timelines indicating 3-6 months delay for the planned Phase Ib study with ATOR-1015, its tumor-localizing, bispecific CTLA-4 and OX40 antibody developed for treatment of metastatic cancer.

As previously communicated, preliminary data from the ongoing Phase I study have shown that ATOR-1015 is well tolerated at doses up to 600 mg (about 10 mg/kg), which is believed to be a clinically relevant dose range. At the current dose of 750 mg (~12.5 mg/kg), some grade 3 infusion related reactions have been reported which is expected to result in further dose evaluations.

"While the infusion related reactions will lead to the selection of a Phase Ib dose below 750 mg, we are still considerably higher in dose than our competitors and well within clinically relevant dose levels", commented Per Norlén, CEO at Alligator Bioscience.

The ongoing Phase I dose escalation will be completed during the fourth quarter 2020 as previously communicated. The start of the Phase Ib expansion in malignant melanoma will be pushed into 2021 due to study amendments to adjust for the observed reactions. Recruitment will start as soon as regulatory approval has been obtained.

For further information, please contact:

Cecilia Hofvander, Director Investor Relations & Communications Phone: +46 46 540 82 06 E-mail: cecilia.hofvander@alligatorbioscience.com

Per Norlén, Chief Executive Officer Phone: +46 540 82 00 E-mail: per.norlen@alligatorbioscience.com

This information is such information as Alligator Bioscience AB (publ) is obliged to make public pursuant to the EU Market Abuse Regulation. The information was submitted for publication, through the agency of the contact person set out above, at 1:40 p.m. CEST on September 9, 2020.

About ATOR-1015

ATOR-1015 is a tumor-localizing, bispecific CTLA-4 and OX40 antibody developed for treatment of metastatic cancer. Promising data from the ongoing ATOR-1015 Phase I clinical trial was presented at ASCO in June 2020 and dose escalation continued at the higher dose 750 mg. The next step in the ATOR-1015 clinical development plan is a Phase Ib study for demonstration of single-agent activity.

About Alligator Bioscience

Alligator Bioscience AB is a clinical-stage biotechnology company developing tumordirected immuno-oncology antibody drugs. Alligator's pipeline includes five lead clinical and preclinical drug candidates: Mitazalimab, ATOR-1015, ATOR-1017, ALG.APV-527 (codeveloped with Aptevo Therapeutics Inc.) and AC101 (in clinical development by Shanghai Henlius Biotech Inc.). Alligator's shares are listed on Nasdaq Stockholm (ATORX). The Company is headquartered in Lund, Sweden. For more information, please visit www.alligatorbioscience.com.