On July 12, 2023 Pharmaxis Ltd (ASX: PXS) reported details of a final interim analysis of data from 10 patients who have completed 6 months’ treatment with PXS‐5505 in an open label phase 2 clinical trial in patients with the bone marrow cancer myelofibrosis (Press release, Pharmaxis, JUL 12, 2023, View Source;utm_campaign=Final%20set%20of%20interim%20data%20from%20PXS-5505%20trial%20in%20patients%20with%20MF&utm_content=Final%20set%20of%20interim%20data%20from%20PXS-5505%20trial%20in%20patients%20with%20MF+CID_f4f969d97c9cee20a80ec95d7772c8bb&utm_source=Campaign%20Monitor&utm_term=View%20Full%20Media%20Release [SID1234633179]). The phase 2 trial known as MF‐101 aims to demonstrate that PXS‐5505, an inhibitor of all lysyl oxidase enzymes (LOX), is safe and effective as a monotherapy in myelofibrosis patients who are intolerant, unresponsive or ineligible for treatment with approved JAK inhibitor drugs. These patients have very limited treatment options and a life expectancy of approximately 1 year1.

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A total of 21 patients have been enrolled in the cohort expansion phase of the study with 10 patients having completed 24 weeks of treatment. PXS‐5505 has shown to be well tolerated, with no serious treatment related adverse events reported, and has promising signs of clinical efficacy including improved symptom scores, stable or improved hematological parameters and reduced bone marrow fibrosis. 10 patients have dropped out of the study due to a lack of clinical response or adverse events unrelated to the drug.

Of the 10 patients completing 6 months treatment:
 5/9 evaluable patients2 had improved bone marrow fibrosis scores of ≥1 grade with 4 out of 5 fibrosis responders demonstrating stable hematological parameters and 3 out of 5 patients reporting symptomatic improvement

 4 had an improvement in symptom score of >20%

 7 had stable/improved hemoglobin (Hb) counts

 8 had stable/improved platelet counts of which 3 patients had Grade 4 (potentially life‐ threatening) thrombocytopenia at baseline

 No spleen volume response (SVR35) was identified

Dr. Lucia Masarova, Assistant Professor, Department of Leukemia at MD Anderson Cancer Center, Houston said, "PXS‐5505 continues to show not only an excellent safety profile but also promising clinical activity. The effect on bone marrow fibrosis is particularly exciting for a disease like myelofibrosis, where despite numerous years of research, we do not have any effective anti‐fibrotic drugs. It is encouraging to see that majority of 10 patients who completed 24 weeks of therapy also had improvements of symptoms and more importantly, stable or improved blood counts; including in those patients with severe thrombocytopenia.

"These results support plans to continue clinical investigation of the agent, including combinations with JAK inhibitors where the lack of overlapping hematological toxicity would make PXS‐5505 an ideal add‐on candidate."

The final results from this cohort will be submitted for presentation at the American Society of Haematology conference later this year. "Pharmaxis is the only company with pan‐LOX inhibitors in clinical development," said Pharmaxis CEO Mr Gary Phillips.

"The results from this trial with an oral LOX inhibitor showing significant improvements in fibrosis grade in bone marrow biopsies corroborate the findings of the trial of our topical LOX inhibitor in established skin scars where we saw a 30% reduction in collagen in skin biopsies after only 3 months treatment. Further to the published pre‐clinical research showing disease modification in several different indications, this is a mechanism which is now proven to be anti‐fibrotic in patients."

Mr Phillips continued, "The excellent safety profile of PXS‐5505 makes it an ideal candidate to combine with JAK inhibitors, the current standard of care in myelofibrosis. We anticipate that the impact on bone marrow fibrosis and other clinical parameters from the antifibrotic and intracellular effects of LOX inhibition should lead to improved outcomes for patients. We look forward to FDA feedback on our protocol and expect to start recruitment of this next cohort later this year."

Pharmaxis will host an investor briefing at 11.00am today, 12 July 2023, to discuss the interim data. Join the briefing at View Source;erS0mNkhUJfjiITg.

A recording will be uploaded to the Pharmaxis Investor Centre after the call at View Source;centre/investor‐briefing/.