PXS‐5505 is an oral drug that inhibits all lysyl oxidase family members (LOX, LOXL1, 2, 3 & 4).
The compound successfully cleared pre‐clinical safety including 6‐month toxicity studies and has shown significant reductions in fibrosis in in‐vivo models of myelofibrosis 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.
Orphan designation qualifies the sponsor of the drug for various development incentives such as reduced regulatory fees and extended periods of market exclusivity.
“Market with high unmet need and significant deal values”
Pharmaxis chief executive officer Gary Phillips said: “We are very pleased with the FDA orphan drug designation for PXS‐5505.
“Pharmaxis believes that the current treatments for myelofibrosis can be augmented by a pan‐LOX inhibitor and be disease modifying in a market with high unmet need and significant deal values for programs with clinical proof of concept.
“We expect to file an investigational new drug (IND) application with the FDA shortly and will provide an update on the clinical trial plans at that time.”
Current standard of care is inadequate
Myelofibrosis is a rare cancer in which normal bone marrow tissue is gradually replaced with a fibrous scar‐like material.
Over time, this leads to progressive bone marrow failure preventing the production of adequate numbers of red cells, white cells and platelets.
Myelofibrosis has a poor prognosis and limited therapeutic options.
Apart from a small group of patients eligible for stem cell transplantation, current standard of care are JAK1/2 inhibitors which provide mainly symptomatic relief but carry a risk of worsening blood cell counts.
A recent publication reported that Pharmaxis pan‐LOX inhibitor compounds significantly decreased the bone marrow fibrotic burden in two different models of primary myelofibrosis.