Prescient Therapeutics’ PTX-100 continues showing promising results in clinical T cell lymphoma trial

Clinical-stage oncology company Prescient Therapeutics (ASX: PTX) has announced continuing positive results in the PTX-100 phase 1b expansion cohort for relapsed and resistant T cell lymphomas (TCL).

The study, led by renowned haematologist Professor H Miles Prince at Melbourne’s Epworth Hospital, has demonstrated promising clinical activity and excellent safety.

Since the last update in November 2022, two new complete responses have been observed in patients with relapsed and refractory peripheral TCL (PTCL).

In addition, seven out of 10 evaluable patients had durations of response that exceeded the standard of care, and the reported safety profile remains “excellent”.

Study results

PTX-100 has been administered to 13 TCL patients, eight with PTCL and five with cutaneous TCL (CTCL).

At the highest dose of 2,000mg/m2, PTX-100 has continued to demonstrate an “excellent safety profile”, with very few serious adverse events.

Some patients experienced adverse events of grade 3, including neutropenia, thrombocytopenia, and anaemia, which were possibly related to PTX-100. However, these adverse events resolved and are considered manageable.

Although the primary objective of the current study is to assess safety, Prescient describes the clinical activity of PTX-100 in this difficult-to-treat patient population as “encouraging” compared to current standards of care.

Following these ongoing “encouraging results”, regulatory advisors have recommended Prescient enrols seven additional patients to create a more robust data package for a meeting with the US Food and Drug Administration.

Potential expedited FDA approval

The company intends to submit an application to the FDA for accelerated approval in an orphan indication, which, if gained, could expedite the regulatory process for PTX-100.

If accelerated approval is not granted, a phase 2 trial will follow standard drug development procedures.

Under the FDA’s Project Optimus, Prescient will request clarification on dose optimisation and dose schedule considerations for the phase 2 study.

A meeting with the FDA is scheduled for later this year, and if the outcome is favourable, the registrational phase 2 trial could begin within 12 months if the phase 1b study.

In advance, Prescient will conduct another PTX-100 manufacturing campaign to facilitate further research. To support later-stage trials and regulatory submissions, the manufacturing process will be meticulously documented.

Prescient chief medical officer Dr Terrence Chew said he was pleased with the encouraging efficacy and safety results in the difficult-to-treat patient population.

Meanwhile, Prescient chief executive officer and managing director Steven Yatomi-Clarke added that the encouraging clinical data for PTX-100 in relapsed and refractory T cell lymphomas, as well as its excellent safety profile, presents an exciting opportunity for the company and TCL patients awaiting more effective therapies.

“It is very exciting to see this clinical data for PTX-100 continue to unfold so favourably, especially in these relapsed and refractory T cell lymphomas, which are particularly difficult to treat and where other therapies have failed,” he stated.

This follows Prescient’s news last week it had secured designated orphan drug status from the FDA for PTX-100 to treat T-cell lymphomas.