Prescient Therapeutics receives FDA orphan drug status for PTX-100 to treat T-cell lymphomas
Prescient now has seven years of market exclusivity for PTX-100 in treating a broader range of diseases with unmet or poorly unmet clinical need.
Clinical stage oncology company Prescient Therapeutics (ASX: PTX) has secured an orphan drug designation from the US Food and Drug Administration (FDA) for its lead candidate PTX-100 for the treatment of T-cell lymphomas (TCLs) including cutaneous TCL (CTCL).
TCLs are a group of lymphomas that develop when white blood cells (lymphocytes) grow out of control.
Collectively, TCLs represent an area of unmet, or poorly met, patient need, especially in people with relapsed or refractory disease.
Prescient separately received orphan drug designation for peripheral TCL (PTCL) in 2022, and then applied for CTCL to be designated as well.
The FDA has now granted a broader designation than Prescient requested, which encompasses all TCLs.
Orphan drug status
The FDA’s orphan drug designation program provides orphan status to drugs intended for the safe and effective treatment, diagnosis or prevention of rare diseases (defined as those affecting fewer than 200,000 people in the US).
The program provides benefits to incentivise drug development including seven years guaranteed market exclusivity from the granting of regulatory approval; and a waiver of Prescription Drug User Fee Act (PDUFA) fees, which had a value of over US$3.1 million in 2022.
Prescient managing director Steven Yatomi-Clarke welcomed the designation of PTX-100 in treating all TLCs.
“We are delighted to be granted Orphan Drug Designation by the FDA, and we have been pleasantly surprised to receive a designation that was broader than our request,” he said.
“This now confers the certainty of seven years of market exclusivity for PTX-100 in a broader range of diseases with unmet or poorly met clinical need.”
First-in-class compound
PTX-100 is a first in class compound with the ability to block the geranylgeranyl transferase-1 (GGT-1) cancer growth enzyme.
It disrupts oncogenic Ras pathways by inhibiting the activation of Rho, Rac and Ral circuits in cancer cells, leading to apoptosis (or death) of the cells.
PTX-100 is believed to be the only GGT-1 inhibitor in the world in clinical development and has demonstrated safety and early clinical activity in a phase 1 study and recent PK/PD basket study of haematological and solid malignancies.
The drug is now in a phase 1b expansion cohort study in T-cell lymphomas, where it has shown encouraging efficacy signals and safety.
Novel domain inhibitor
Prescient’s other targeted therapy PTX-200 is a novel PH domain inhibitor designed to stop a tumour survival pathway known as Akt, which plays a key role in the development of breast and ovarian cancers, as well as leukaemia.
Unlike other drug candidates which target Akt inhibition, PTX-200 has a novel mechanism of action which specifically inhibits Akt without non-specific kinase inhibition effects.
It is currently in a phase 1b/2 trial in relapsed and refractory acute myeloid leukaemia, where it has resulted in four remissions to date.
PTX-200 has previously generated encouraging results in trials relating to HER2-negative breast cancer and recurrent or persistent platinum-resistant ovarian cancer.