A study by Prescient Therapeutics (ASX: PTX) into the effects of lead drug PTX-100 on relapsed and refractory T-cell lymphomas (TCL) continues to show encouraging clinical activity in a difficult-to-treat patient population.

The study comprises an expansion cohort and is being conducted at Melbourne’s Epworth Hospital under the leadership of haematologist Professor H Miles Prince.

The expansion cohort includes 12 patients, seven of whom have been dosed with PTX-100 to date.

Four patients have peripheral T-cell lymphoma (PTCL) and three have cutaneous T-cell lymphoma (CTCL).

Patients received a median of four prior lines of therapy and up to six prior lines of therapy to treat their lymphomas.

PTX-100 was administered at the highest dose of 2000 milligrams per cubic metres of body surface.

Safety profile

Prescient said PTX-100 has exhibited a favourable safety profile with very few adverse events and no serious ones reported to date.

Two of the PTCL patients who commenced therapy withdrew from the study for reasons unrelated to the trial.

Another PTCL patient passed away due to reasons not associated with the study.

Such events are reported to be a frequent occurrence in studies of advanced malignancies.

Prescient said while all three patients were not on the study long enough to observe responses, relevant pharmacokinetic and safety data were still collected.

Four patients remain on therapy and additional patients are being recruited.

The company said the study would remain open while patients continue to derive clinical benefit from PTX-100.

Impressive responses

Prescient chief executive officer and managing director Steven Yatomi-Clarke said the study continues to produce impressive responses in systemic and cutaneous TCL.

“It is very exciting to see PTX-100 show clinical activity in a patient population which is notoriously difficult to treat and where these patients have failed several lines of prior therapies,” he said.

“PTX-100 continues to exhibit an excellent safety profile, which is uncharacteristic of available TCL therapies… it is exciting to see encouraging responses in CTCL patients and we will aim to recruit more of them over time.”