Pseudovax hydrochloride

Table of contents

• What is pseudovax hydrochloride?
• How does pseudovax hydrochloride work?
• Which conditions is it studied for?
• How is pseudovax hydrochloride given?
• What do the clinical trials show?
• What side effects are known?

What is pseudovax hydrochloride?

Pseudovax hydrochloride is a protein-based, investigational cancer vaccine. It is a chemically synthesised substance of protein origin, developed as a therapeutic vaccine rather than a preventive one. The substance appears in the EU Clinical Trials Information System (CTIS) product records under the name Pseudovax, with the registry name pseudovax hydrochloride.^[1]

Pseudovax hydrochloride has no marketing authorisation in the product records, meaning it is still an investigational substance and not yet approved as a medicine. The authorisation holder listed in the registry is Oslo University Hospital.^[1] The product is classified in the therapeutic area of neoplasms (cancers) and pathological conditions, signs and symptoms.

How does pseudovax hydrochloride work?

Pseudovax hydrochloride is designed as a cancer vaccine targeting mutated GNAS, a gene that is frequently altered in pseudomyxoma peritonei. The vaccine aims to stimulate the immune system to recognise and attack cancer cells carrying this mutation. In the registered trial, Pseudovax is combined with immune checkpoint inhibition using tislelizumab, a drug that helps the immune system attack cancer cells.^[1]

The trial also includes molgramostim and sargramostim, both forms of GM-CSF, a protein that stimulates the immune system. These are given together with Pseudovax to enhance the immune response against the vaccine peptide. The study measures T cell responses against the vaccine peptide in blood samples and skin, which indicates whether the vaccine activates the immune system as intended.^[1]

Which conditions is it studied for?

• Pseudomyxoma peritonei — a rare cancer that causes a build-up of mucin (a jelly-like substance) in the abdominal cavity. It usually starts in the appendix and spreads within the abdomen. The registered trial studies pseudovax hydrochloride specifically in this condition.^[1]

How is pseudovax hydrochloride given?

Pseudovax hydrochloride is given as an injection by the intradermal route, meaning it is injected into the top layer of the skin. In the registered trial, the dose used is 100 micrograms per injection. The pharmaceutical form listed in the product records is injection.^[1]

The trial also involves other drugs given by different routes: tislelizumab is given as an intravenous infusion at a dose of 200 milligrams, while molgramostim (30 micrograms) and sargramostim (75 micrograms) are given by intradermal injection as immune stimulants.^[1]

What do the clinical trials show?

There is one registered clinical trial for pseudovax hydrochloride in the EU Clinical Trials Information System. It is a Phase 1 study, which means it is an early-stage trial primarily designed to assess safety and tolerability in a small number of participants. The trial has an enrolment of 10 participants and is currently authorised, meaning it has received regulatory approval to proceed.^[1]

The primary outcomes measured in this trial are the incidence and rate of adverse events related to the investigational medicinal products, and T cell responses against the vaccine peptide in blood samples and skin. The trial is interventional, meaning participants receive the study treatments as part of the protocol. The study assesses sequential treatment with Pseudovax/GM-CSF and tislelizumab to measure immune activation following treatment.^[1]

What side effects are known?

No side effect data from supplementary sources are available for pseudovax hydrochloride. The registered Phase 1 trial measures the incidence and rate of adverse events related to the investigational medicinal products as a primary outcome, but results have not yet been reported in the registry.^[1]