Prescient Therapeutics Confirms First US Site for PTX-100 Phase 2a Refractory Cutaneous T-Cell Lymphoma Trial

Oncology biotech Prescient Therapeutics (ASX: PTX) has announced the completion of its first US site visit for its Phase 2a trial of PTX-100 for patients with refractory or relapsed cutaneous T-cell lymphoma (r/r CTCL).

The Massey Comprehensive Cancer Centre at Virginia Commonwealth University – ranked as one of the top cancer research centres in the US – joins three Australian sites where four patients are currently enrolled, with the visit marking the start of US patient recruitment to the trial and access to PTX-100 in that country.

The first-in-class targeted therapy recently produced highly-encouraging results from a Phase 1b clinical trial.

Meaningful Impact

Prescient scientific founder Professor Said Sebti was encouraged by the site visit.

“VCU Massey is my academic home and the first US site to open for patient accrual, bringing us a step closer to turning a long-held dream into meaningful impact for patients,” he said.

“As a cancer researcher, there is no greater fulfillment than seeing a drug you co-invented in the laboratory begin to touch patients’ lives [and] the launch of this global clinical trial is a powerful reminder of what science can achieve when driven by purpose and passion.”

SPP Extension

Prescient will fund the Phase 2 trial and potential regulatory approval of PTX-100 through a $7 million share purchase plan with an extended closing date of 22 July.

Under the terms of the raising, Prescient will issue new fully-paid ordinary shares priced at $0.04 each to eligible shareholders in batches of up to $30,000 each.

The company recently announced a seven-day extension to the original 15 July deadline after several shareholders requested additional time to complete their applications.

Proceeds from the raising will support the advancement of PTX-100 Phase 2 clinical trials toward regulatory approval and access for patients with significant unmet medical needs.

GGT-1 Blocker

PTX-100 is a small molecule that can block a cancer growth enzyme known as geranylgeranyltransferase type 1 (GGT-1) by disrupting a cellular signalling pathway known as ‘Ras’.

The disruption is caused by inhibiting the activation of three circuits in cancer cells (Rho, Rac and Ral), leading to their death.

The therapy is able to block multiple pathways and is the only GGT-1 inhibitor of its kind currently in clinical development worldwide.

PTX-100 is administered intravenously and has demonstrated positive clinical data on patients for whom previous treatments have failed or worked temporarily, resulting in a cancer relapse.

Research Beginnings

PTX-100 originated from a research project at Yale University by Professor Sebti and researcher Andrew Hamilton, who were able to show the potential for cancers to be fought by inhibiting GGT-1.

In those days, the therapeutic candidate hung its hat on a Phase 1 trial on 13 patients co-managed by Indiana University and University of Pennsylvania, in which it administered a 30-minute intravenous infusion for a five-day period every 21 days that was found to be well-tolerated, achieving stable disease status in four patients.

In mid-2021, Prescient began investigating the effect of PTX-100 on an expanded cohort of patients with r/r CTCL, with one of them experiencing no disease progression for the next 17 months.

By 2023, 40% of patients in the Phase 1 trial had responded to the treatment and seven of 10 patients evaluated had durations of response exceeding the standard of care.

Phase 2 Trials

The Phase 2a trial of PTX-100 on r/r CTCL, which began in May at 15 sites in Australia, the US and Europe, will be a dose optimisation study on 40 patients while Phase 2b will be an efficacy and safety determination on another 75 patients.

The primary endpoint will be an objective response rate (meaning patients with complete or partial responses), and secondary endpoints will include skin responses, progression-free survival, duration of response, time to next treatment, safety, pharmacokinetics and quality of life.

Prescient is hoping the results of the Phase 2 trial will be sufficiently positive to gain US Food and Drug Administration approval without the need to progress to Phase 3 testing.

The FDA typically considers regulatory approval when the proposed therapy is stronger than the standard of care and lack of current treatment options.

Lucrative Market

Early approval would allow Prescient to target an urgent need within a lucrative market.

T-cell lymphoma is among the deadliest forms of cancer, with overall survival in relapsed or refractory forms of the disease being less than 12 months without expensive stem cell therapy.

While the US market for TCL and its sub-types sits at approximately 6,000 patients, analysts believe the market for Prescient could be as high as US$2.5 billion should PTX-100 attract a high price as a monotherapy.

The clinical and commercial opportunities could be more extensive if Prescient uses PTX-100 as part of a drug combination.