Prescient Therapeutics Ltd (ASX:PTX, OTC:PSTTF) is trading higher after receiving a green light from the US Food and Drug Administration (FDA) to proceed with its Phase 2 clinical trial of PTX-100 — the company’s first-in-class Ras pathway inhibitor.
The FDA cleared the Investigational New Drug (IND) application for the Phase 2 trial 100 — a significant milestone for Prescient — paving the way for the commencement of the Phase 2 study which will focus on relapsed and refractory cutaneous T-cell lymphomas (r/r CTCL).
The planned Phase 2 study builds on compelling Phase 1b data that demonstrated PTX-100’s potential to address key unmet medical needs in T-cell lymphomas (TCL), including r/r CTCL.
PTX-100 has Orphan Drug Designation from the US FDA for all T-cell lymphomas.
Shares have jumped by as much as 53.7% in early ASX trading to A$0.063.
Transformative milestone
Prescient CEO and managing director Steven Yatomi-Clarke said: “The FDA’s clearance of our IND for PTX-100 is a transformative milestone for Prescient.
“This achievement is the culmination of tireless work from the Prescient team this year, and builds upon years of rigorous preclinical and clinical development, positioning us to unlock the therapeutic and commercial potential of PTX-100.
“Prescient thanks the clinical and industry experts who have provided valuable feedback into the study design, which adds to the confidence we have of this program.
“We look forward to commencing the study with world leaders in CTCL, and hope to bring a safe and effective therapy to this area of unmet patient need.”
Building on Phase 1 success
The Phase 1b study has enrolled 19 TCL patients and reported an excellent safety profile of PTX-100 at 500, 1,000 and 2,000 mg/m2.
To date, there has been a 42% overall response rate amongst all evaluable TCL patients. Five out of 7 evaluable CTCL patients received clinical benefit.
Responders had a median progression-free survival (PFS) of 12.2 months, surpassing the typical median PFS of around 3.1 months associated with standard care treatment vorinostat.
The Phase 1b trial remains open, with one patient — a complete responder — remaining on treatment.
Phase 2 protocol summary
Target (NYSE:TGT) patient population - relapsed and refractory cutaneous T-cell lymphomas (r/r CTCL) patients with advanced disease. Patients must have received and failed at least two prior lines of systemic therapy.
Study sites - 15 sites globally, including Australia, US and eventually Europe. The trial will be led out of Melbourne under the principal investigator, global TCL expert professor H. Miles Prince, AM.
The trial will be in two parts - dose optimisation (optimal biologically effective dose) and efficacy. Prescient remains hopeful that the FDA will consider the Ph2b data as a registrational study.
Phase 2a - Dose optimisation of up to 40 patients, with two groups of up to 20 patients randomised either 500 or 1,000 mg/m² of PTX-100 A safety review committee (SRC) will meet to determine the optimum dose for Phase 2b. An interim analysis may be undertaken.
Phase 2b - Efficacy and safety determination in approximately 75 r/r CTCL patients.
Primary endpoint - Objective response rate (ie proportion of patients with complete or partial responses).
Secondary endpoints - Skin responses, progression-free survival; duration of response; time to response; complete response rate; overall survival; time to next treatment; safety; pharmacokinetics and quality of life.