Prescient Therapeutics expands PTX-200 oncology study
Clinical-stage oncology company, Prescient Therapeutics (ASX:PTX), this morning updated the market on its trial of PTX-200 with cytarabine in relapsed or refractory acute myeloid leukaemia (AML).
PTX-200 — the company’s lead drug candidate — inhibits an important tumour survival pathway known as Akt, which plays a key role in the development of many cancers, including breast and ovarian cancer, as well as leukaemia.
Unlike other drug candidates that target Akt inhibition, which are non-specific kinase inhibitors (and have toxicity problems), PTX-200 has a novel mechanism of action that specifically inhibits Akt, while being comparatively safer.
Encouraging efficacy signals were seen as PTX looks to expand the current study to optimise Akt inhibition in the combination therapy.
The trial completed its Phase 1b enrolment target on schedule with 15 patients recruited and 13 treated in the study.
The study is led by world-renowned AML expert, Professor Jeff Lancet, at the H. Lee Moffitt Cancer Centre in Florida, and including the Yale Cancer Center and Kansas University Medical Centre.
In a very difficult to treat patient population, PTX has reported that two patients had a complete response (CR) to treatment, meaning total eradication of disease. This is an improvement on the already encouraging single agent activity of PTX-200 in the Phase 1 monotherapy study.
Some peculiar toxicities were observed in three AML patients, including stomatitis, appendicitis and a small bowel obstruction, which were not seen in the Phase 1 study of PTX-200 as a monotherapy, nor in the other PTX-200 trials. Transaminase elevation was observed in three subjects, although only one was dose limiting.
Following liaison with investigators, PTX will add an additional exploratory arm to the study to explore PTX-200 in combination with a lower dose of cytarabine in order to best optimise the dose of PTX-200 and best inhibit Akt. A similar modification was made to the PTX-200 study in ovarian cancer, which reduced the amount of chemotherapy (in that case, carboplatin).
PTX aims to enrol 9-12 additional patients under this arm of the study to identify the optimal synergistic dose between PTX-200 and cytarabine. This will also bolster the number of samples for PK and PD analysis.
Prescient’s chief medical officer, Dr Terrence Chew, noted that in studies exploring combination therapies, it is important to identify the synergistic dose between both drugs in a particular patient population.
“The two CRs are encouraging in patients with relapsed and refractory AML, where treatment outcomes are poor,” said Chew. “We look forward to building on this as we optimise the synergistic dose between PTX-200 and cytarabine.”
Of course, it should be noted that PTX is still a speculative stock and anything can happen. Investors should seek professional financial advice if considering this stock for their portfolio.