Pharmaxis Ltd (ASX:PXS, OTC:PMXSF) has concluded an interim analysis of data from six patients who have completed six months’ treatment with PXS-5505 in its Phase 2 clinical trial in the bone marrow cancer myelofibrosis.
Overall, PXS-5505 continues to be well tolerated and there have been encouraging signs of clinical benefit in patients ineligible for a JAK inhibitor.
The company has recruited 15 out of a total of 24 patients and expects to have full recruitment completed by the end of the year and results in Q3 2023.
Phase 2 cancer trial provides confidence
The phase 2 trial known as MF-101 was cleared by the FDA under the Investigational New Drug (IND) scheme and 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 the only drugs approved for myelofibrosis; JAK inhibitors.
These patients have very limited treatment options and a life expectancy of approximately one year.
So far, a total of 15 patients have been enrolled in the study with six patients completing 24 weeks of treatment.
Four patients have dropped out of the study due to a lack of clinical response.
Highlights of the study so far show:
- PXS-5505 has been well tolerated with no serious treatment-related adverse events reported.
- 2/6 patients had clinically important improvement in symptoms.
- 5/6 patients had either stable or improved bone marrow fibrosis scores of ≥1 grade.
- 5/6 have stable or improved platelet and/or haemoglobin scores.
- No reductions were seen in spleen volume.
Dr Gabriela Hobbs MD, assistant professor, Medicine, Harvard Medical School & clinical director, Leukemia Service, Massachusetts General Hospital said: “PXS-5505 continues to be very well tolerated in the clinic with no serious treatment-related adverse events reported.
"Though still early in the dose expansion phase of the study, PXS-5505 appears to be stabilising and in some cases, improving the haemoglobin and platelet counts, which has also been associated with symptom improvements in those patients that were treated to 24 weeks.
“This is encouraging given the poor prognoses seen after ruxolitinib discontinuation with a median overall survival of only 11-14 months, typical of this study population.
“These results support further clinical investigation of PXS-5505 in myelofibrosis.”
There are now 18 clinical trial sites actively recruiting in Australia, South Korea, Taiwan and the US with two more sites due to open in Q4. Recruitment is expected to be done by the end of 2022 with top-line results available in Q3 2023.
“We are confident that these results, if repeated in the whole study population, will satisfy regulatory requirements to continue the development of PXS-5505 in myelofibrosis and also excite clinicians, patients and industry groups who are closely following our progress with this novel mechanism," Pharmaxis CEO Mr Gary Phillips said.
"The excellent target enzyme inhibition and safety profile seen in previous studies has been maintained when the treatment periods have been extended to six months and the signs of efficacy to date are compatible with the disease-modifying effect witnessed in the preclinical studies.”
Pharmaxis’ primary focus is the development of PXS-5505 for myelofibrosis, however, the drug also has potential in several other cancers including liver and pancreatic cancer where it aims to break down the fibrotic tissue in tumours and enhance the chemotherapy treatment.
An investigator-led phase 1c study in newly diagnosed hepatocellular cancer patients, where PXS-5505 will be used in addition to immunotherapy standard of care, is due to start recruitment at Rochester University New York in Q4 2022.
Raising $10 million
PXS is also raising $10 million in a two-tranche placement to a small group of international and domestic institutional investors, which will give it a $30 million pro-forma cash balance post-raising.
The money will be used to advance the company’s current clinical study in myelofibrosis (as above), and other clinical studies in or close to recruitment in skin scarring, liver cancer and Parkinson’s disease.
PXS has received commitments from institutional investors to subscribe for approximately 82.4 million fully paid ordinary shares at A$0.06 per share, to raise approximately A$4.9 million via the placement (Tranche 1).
Further commitments from institutional investors for approximately 84.3 million shares at A$0.06 per share, to raise approximately A$5.1 million have also been made (Tranche 2).
“The positive preliminary data from Pharmaxis phase 2 clinical study in myelofibrosis has impressed global clinical experts and has driven interest from the specialist healthcare investors who have participated in this capital raise," Phillips said.
"I am delighted by the strong support seen from existing substantial shareholders and would also like to welcome our new institutional investors.
"The company is now well positioned to build on the positive preliminary data from both the ongoing clinical studies in myelofibrosis and skin scarring to deliver full results during 2023,” he added.
The shares to be issued under the placement will be issued at a price of $0.06 per share, which is a discount of approximately 23.1% to the last close of $0.078 on Monday, October 17, 2022.
Settlement of shares under Tranche 1 is expected to take place on Tuesday, October 25, 2022. New shares will be allotted and traded around Wednesday, October 26, 2022.
Settlement of new shares issued under Tranche 2 is expected to take place on Friday, December 2, 2022, following the Pharmaxis Annual General Meeting on Tuesday, November 29, 2022.
Allotment, quotation and trading of the new shares issued under Tranche 2 are expected to take place on Monday, December 5, 2022.