Pharmaxis Announces First Patient Enrolled In Clinical Trial For New Cancer Treatment

Pharmaceutical research company Pharmaxis Ltd (ASX: PXS) today announced it has enrolled the first patient in a clinical trial studying a potential new treatment for the bone marrow cancer myelofibrosis.

The phase 1c/2a trial cleared by the FDA under the Investigational New Drug (IND) scheme aims to demonstrate that PXS‐5505, the lead asset in Pharmaxis’ drug discovery pipeline, is safe and effective as a monotherapy in myelofibrosis patients who are intolerant, unresponsive or ineligible for treatment with approved JAK inhibitor drugs.

Pharmaxis has completed site initiation at several Australian and South Korean hospitals and the first patient has been enrolled. The dose escalation phase of the study that aims to select the optimum dose of PXS‐5505. This first phase, that will recruit up to 18 patients, is expected to conclude and report in 2H 2021 and will be followed by a six‐month dose expansion phase (24 patients) to evaluate safety and efficacy. Sites in other countries including the USA will be added for the dose expansion phase.

PXS‐5505 is an orally taken drug that inhibits the lysyl oxidase family of enzymes. In pre‐clinical models of myelofibrosis PXS‐5505 reversed the bone marrow fibrosis that drives morbidity and mortality in myelofibrosis and reduced many of the abnormalities associated with this disease.

Pharmaxis CEO Gary Phillips said, “PXS‐5505 has demonstrated good tolerability and highly effective inhibition of the enzyme in phase 1 studies. Its potential to modify the course of the disease by directly targeting bone marrow fibrosis will make PXS‐5505 an ideal monotherapy or adjunct to approved therapies in this indication. There remains a high level of unmet need in myelofibrosis and many other drugs in development have challenging side effect profiles.” 

While Pharmaxis’ primary focus is the development of PXS‐5505 for myelofibrosis, the drug also has potential in several other cancers including liver and pancreatic cancer where it aims to breakdown the fibrotic tissue in the tumour and enhance the effect of chemotherapy treatment.

Trial Design

Name of trial: PXS5505‐MF‐101: A phase 1/2a study to evaluate safety, pharmacokinetic and pharmacodynamic dose escalation and expansion study of PXS‐5505 in patients with primary, post‐polycythaemia vera or post‐essential thrombocythemia myelofibrosis
Trial number: NCT04676529
Primary endpoint: To determine the safety of PXS‐5505 in patients with myelofibrosis
Secondary endpoints: Determine appropriate therapeutic dose, Characterize pharmacokinetic and pharmacodynamic parameters, Determine reduction in bone marrow fibrosis, Determine response rates as defined by International Working Group (IWG)‐ Myeloproliferative Neoplasms Research and Treatment criteria, Evaluate efficacy of PXS‐5505 in spleen size reduction measured by CT or MRI scan, Evaluate the efficacy of PXS‐5505 on MF related symptoms based on MF‐SAF scores (Myelofibrosis Symptom Assessment Form)
Blinding status: Open label
Placebo controlled: No
Trial design: Randomised, multicentre, 4 week duration phase 1 (dose escalation) followed by 6 month phase 2 (dose expansion)
Treatment route: Oral
Treatment frequency: Twice daily
Dose level: Dose escalation: three escalating doses, Dose expansion: one dose
Number of subjects: Dose escalation: minimum of three patients to maximum of 18 patients, Dose expansion: 24 patients
Subject selection criteria: Patients with primary or secondary myelofibrosis who are intolerant, unresponsive or ineligible for treatment with approved JAK inhibitor drugs
Trial locations: Dose escalation: Australia (2 sites) and South Korea (4 sites), Dose expansion: Australia, Korea, USA
Commercial partners involved: No commercial partner