ExpreS2ion Biotech: Austrian milestone

Phase 1 trial ready to start shortly

ExpreS2ion Biotechnologies has received final approval by the Austrian Agency for Health and Food Safety, BASG, to start a first-in-human, phase 1 trial with ES2B-C001, the most advanced vaccine candidate in the ExpreS2ion pipeline.

This decision follows a clinical trial application which was submitted by the company in August. The trial will be conducted at the Oncology department of Medical University of Vienna.

HER2 positive cancer patients to be included

Participants are diagnosed with metastatic or locally advanced HER2 positive breast cancer and will receive five doses of ES2B-C001, either adjuvanted by Montanide or unadjuvanted. Participants are no longer responding to Herceptin, the standard anti-HER2 treatment in breast cancer.

Depending on the final number of patients, we expect enrollment to be ongoing during the course of 2025 and a topline result ready by the first half of 2026. The primary endpoint will be safety and tolerability, but signs of clinical activity in the participants will also be measured.

The promise of a vaccine immunotherapy

ES2B-C001 will be studied as a therapeutical agent, not in the preventive setting generally assigned to vaccines. The vaccine antigen is designed to overcome treatment resistance that limits the current monoclonal standard treatments by producing polyclonal antibodies binding to the entire HER2 protein instead of a single epitope.

ES2B-C001 may also show a longer protection to relapsed disease, which needs to be studied over a longer time span. If these properties can be proven in a phase 3 study by a future partner, we expect sales of ES2B-C001 to surpass USD 3bn.

Fair value at SEK 91 offers substantial upside

The recent slump in the share price of ExpreS2ion Biotechnologies makes the outcome of the TO10 less impressive, adding gross proceeds of SEK 10m. We expect the company to enter next year with a cash position of SEK 70m, which should extend beyond the TO11.

Our assumption in ES2B-C001 is 11 percent likelihood of approval, reflecting a better chance of approval than the average oncology drug initiating a phase 1 study. Fair value is trimmed at 91 SEK (96), offering a substantial upside once the phase 1 study starts to generate a positive news flow.