Fresh off reporting final interim data from their Phase 2 clinical trials for PXS-5505 to treat myelofibrosis, biotech company Pharmaxis (ASX: PXS) has quickly jumped forward in the commercialisation process having been cleared by the US Food and Drug Administration (FDA) to commence a combination arm of the trial.

The clearance of the amended trial protocol comes following earlier discussions held between Pharmaxis and the FDA which suggested the Aussie biotech combine their PXS-5505 drug with the current standard of care – JAK inhibitor, ruxolitinib.

As a monotherapy, PXS-5505 has proven safe and effective in improving the fibrosis scores of myelofibrosis patients that have completed 6 months of treatment.

Myelofibrosis is a life-altering cancer characterised by the development of scar tissue, or fibrosis in the bone marrow, which interferes with the body’s ability to produce healthy blood cells. Symptoms of this disease can include fatigue, weakness, enlarged spleen, and anaemia, significantly affecting the patients’ quality of life. With the current standard of care, the average life expectancy upon diagnosis is just five years, emphasising the desperate need for a disease-modifying treatment.

These existing treatment options generate more than USD $1 billion of sales per annum without addressing the underlying disease and largely focus on alleviating symptoms rather than targeting the underlying cause of the disease. This is where Pharmaxis CEO Gary Phillips sees the brightest potential for PXS-5505 which has been designed to target fibrotic tissue directly and inhibit the enzymes responsible for the scarring of bone marrow.

“PXS‐5505 is a first in class drug and as such there is no precedent for the company or the FDA to consider when reviewing the data from the first phase 2 study in patients,” said Phillips.

“After a positive type C meeting in quarter one which was the first look at our trial data, I am delighted to report that the FDA has agreed Pharmaxis can progress to the next stage of development.”

The combo arm of the trial will take place over 12 months, targeting 15 patients who are already undergoing treatment with ruxolitinib, and be recruited to combine it with PXS-5505.

“This study will be run as an extra cohort of the ongoing monotherapy study and therefore we can get a very fast start with no need to set up new trial centres,” added Phillips.

“Recruitment is scheduled to commence later this year and take approximately 6 months to complete. This combination holds much promise for myelofibrosis patients with the potential to deliver a disease modifying effect. We should be reviewing significant data that has both regulatory and commercial value in the second half of 2024.”

While the road to full FDA approval and widespread availability may still be years away, the approval to expand Phase 2 clinical trials of PXS-5505 represents a promising step towards transforming myelofibrosis treatment and providing new hope for patients around the world.

Pharmaxis is scheduled to present its final data from the monotherapy treatment of PXS-5505 at the upcoming American Society of Hematology Conference in the United States. The event is attended by the world’s leading blood disease researchers and pharmaceutical scientists.

At 30 June 2023 the Company had $9.2m of cash on hand and a FY 23 $5.2m R&D tax credit refund expected in H2 CY 23. In addition, the Company expects to receive a ~$1.7 million grant milestone payment in the next quarter from Parkinson’s UK when it doses the first patient in a clinical trial for isolated Rapid Eye Movement Sleep Behaviour Disorder (iRBD) – a precursor of Parkinson’s Disease.