PTC:VS-TC

Table of contents

• What is PTC:VS-TC?
• How does PTC:VS-TC work?
• Which conditions is it studied for?
• How is PTC:VS-TC given?
• What do the clinical trials show?
• What side effects are known?

What is PTC:VS-TC?

PTC:VS-TC is an investigational cell therapy consisting of virus-specific T lymphocytes. These are immune cells selected in the laboratory from a family donor to recognise and attack particular viruses.^[1] The substance is not an authorised medicine; it is being studied in a clinical trial setting only. In the EU Clinical Trials Information System (CTIS) record, the full name of the product is given as PTC:VS-TC for intravenous use.^[1]

How does PTC:VS-TC work?

Virus-specific T lymphocytes are a type of white blood cell that can recognise cells infected by a particular virus and destroy them. In this therapy, T cells are taken from a family donor and selected in vitro — meaning outside the body, in a laboratory — for their ability to target specific viruses: cytomegalovirus (CMV), adenovirus (ADV), Epstein-Barr virus (EBV) and BK virus.^[1] The idea is that giving these selected cells to a patient whose own immune system has not controlled the infection may help clear the virus when antiviral drugs have failed.^[1]

Which conditions is it studied for?

• Post-transplant viral reactivation resistant to drug therapy — after an allogeneic haematopoietic stem cell transplant, viruses such as CMV, adenovirus, EBV and BK can reactivate and cause illness when the new immune system is still weak. The trial studies patients whose infection has not responded to available antiviral medicines.^[1]
• Severe primary or secondary immunodeficiency — the trial title also mentions patients with severe immunodeficiency of primary (inherited) or secondary (acquired) origin, although the brief summary focuses on transplant recipients.^[1]

How is PTC:VS-TC given?

PTC:VS-TC is given by intravenous infusion, meaning the cells are delivered directly into a vein.^[1] The registry record does not specify the dose or the number of infusions in this trial.

What do the clinical trials show?

The single trial registered for PTC:VS-TC is a Phase 1 study, which is the earliest stage of testing in people and focuses mainly on safety.^[1] The trial is currently authorised, meaning it has received regulatory approval to begin but may not yet be recruiting participants.^[1] It plans to enrol 10 participants aged between 0 and 30 years.^[1]

The primary outcome, the main thing the study measures, is the collection of adverse events. An adverse event is any significant change in vital signs or organ function, seen in clinical findings, blood tests or imaging, and is graded according to version 5 of the Common Terminology Criteria for Adverse Events (CTCAE).^[1] This means the trial is designed first and foremost to find out whether the treatment is safe to give to these patients.

The trial enrols patients who have received an allogeneic haematopoietic stem cell transplant — a transplant of blood-forming stem cells from a donor — and who have developed a viral reactivation that is resistant to pharmacological therapies.^[1] The viruses included are CMV, adenovirus, EBV and BK virus.^[1]

What side effects are known?

The registry record does not report side effects from completed studies, because this trial is still in its early safety-testing phase. The primary aim of the trial is precisely to collect information on adverse events.^[1]