A large cohort of patients around the world diagnosed with myelofibrosis (aka bone marrow cancer) will soon be able to access a new treatment which has already shown to be effective in a small group of patients undergoing treatment of PXS-5505 in Phase 2 clinical trials.

Myelofibrosis is a rare cancer of the bone marrow affecting 15 per 1 million people worldwide. The main driver of illness is fibrosis, or scar tissue buildup within the bone marrow, which in turn disrupts production of normal blood cells. Upon diagnosis, the average life expectancy is just five years, which emphasises the urgent need for new treatments. Many patients go on to develop acute myeloid leukaemia.

The good news for myelofibrosis patients comes following discussions between the drug’s developer – Pharmaxis (ASX: PXS), and the US Food & Drug Administration (FDA) after data was presented from the current Phase 2 trial which has dosed 21 patients. The MF-101 trial program has already reported encouraging interim data from 6 patients and attracted interest from institutional investors which purchased $10m in PXS shares via a private Placement in October 2022.

After meeting with the FDA to discuss the pathway towards regulatory approval, Pharmaxis will submit a study design update which will create a new arm of the MF-101 trials where PXS-5505 will be offered to patients already receiving a JAK inhibitor – the current standard of care.

This new arm will be an extension of the current trial with the existing 21 patients receiving only PXS-5505 as a monotherapy over a 24-week treatment program. The drug has already been demonstrated to be well-tolerated and led to stable or improved conditions in those that have been dosed with PXS-5505 on its own.

To now be offered to patients already on a treatment plan with the existing standard of care, Pharmaxis expects that the FDA feedback will open up PXS-5505 to many more patients around the world, to a drug that has the potential to modify the disease rather than just mask its symptoms.

Pharmaxis CEO, Gary Phillips said, “The agreement with the FDA to expand the patient population in the ongoing phase 2 study to include those patients currently on a JAK inhibitor is an important step forward in realising the benefits of lysyl oxidase inhibition for all myelofibrosis patients and in maximising the commercial opportunity for PXS-5505.

“We are already in discussion with the existing trial site investigators who have welcomed the opportunity to extend the patient population for the study and anticipate significantly accelerated recruitment.”

The study design will be submitted as a protocol amendment to global regulators, including the FDA, and Pharmaxis expects the treatment for patients in this combination arm to commence in the second half of 2023.

Based on the substantial advancement of PXS-5505 over the past two years and highly encouraging interim data recorded in its Phase 2 trials to treat bone marrow cancer and interest from researchers around the world, Pharmaxis will focus its immediate efforts on commercialising the drug. To facilitate this, the Company has elected to put its liver cancer trials in collaboration with the University of Rochester on hold to allocate resources towards PXS-5505 and its potential to modify blood cancer diseases like myelofibrosis and others where data to date has been highly encouraging and potentially life changing for patients.

The myelofibrosis treatment market is conservatively estimated at USD $1 billion per annum with no current product on the market that can modify the disease.

The increased allocation of resources to PXS-5505 in will have no impact on Pharmaxis’ anti-scarring trials led by Professor Fiona Wood which is scheduled to report trial data from PXS-6302 by June 2023.