Myelofibrosis Clinical Trial Running for New ‘First in Class’ Drug

Pharmaxis has several promising products at various stages of clinical development. These compounds have been invented and developed in our laboratories in Sydney where we employ 70 staff. We have numerous collaborations with research institutions across Australia.

One drug, PXS-5505, is a selective and irreversible inhibitor of a family of enzymes called lysyl oxidases which are involved in the final stage of fibrosis where they cause cross-linking of collagen and elastin. Fibrotic disease is caused by the excessive accumulation of these proteins which if left untreated ultimately progress to failure of the affected organ/s. PXS-5505 has successfully cleared pre‐clinical safety including 6‐month toxicity studies and has shown significant reductions in fibrosis in in‐vivo models of myelofibrosis1 and other cancers. PXS‐5505 has shown to be well tolerated in Phase 1 single and multiple ascending dose studies in humans with an excellent pharmacokinetic and pharmacodynamic profile.

There is a large unmet medical need in current treatments of myelofibrosis. At this time the only approved treatment for myelofibrosis are Janus kinase (JAK) inhibitors such as ruxolitinib (Jakavi®) which have limited long-term efficacy. Patients can develop resistance to JAK inhibitors and experience disease progression. Currently, there are no approved treatments for patients who experience disease progression with JAK inhibitors. PXS-5505 has the potential to reduce the bone marrow fibrosis caused by myelofibrosis and thereby have beneficial effects on blood cell production and consequently other aspects of the disease.

The purpose of the new PXS-5505 study is to test its effects in patients with intermediate or high-risk myelofibrosis who have previously been treated with JAK inhibitors and are now unsuitable for treatment with ruxolitinib, or who have failed treatment with ruxolitinib and who still experienced disease progression. The study will determine the safety and effects on disease of PXS-5505, during a six-month treatment period. The study is open label so all patients eligible for inclusion will be treated with PXS-5505.

Further information on the clinical trial can be found on at 

We are looking for people living with myelofibrosis to take part, click here to find out more.

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