Tenax Cleared to Start Clinical Testing of Oral Imatinib for PAH
The U.S. Food and Drug Administration (FDA) has cleared Tenax Therapeutics to begin clinical testing of its new oral formulation of imatinib in people with pulmonary arterial hypertension (PAH).
The company is planning to conduct a small pharmacological study this year — and then launch a Phase 3 clinical trial by June 2022 to test the therapy’s efficacy.
“Tenax is thrilled we can now advance our imatinib PAH program towards pivotal testing,” Christopher Giordano, Tenax’s CEO, said in a press release. “We remain on track to be the first company to commence a Phase 3 trial of a new formulation of imatinib in patients with PAH.”
Imatinib is a small molecule that blocks the activity of signaling proteins in the body that are involved in driving the growth of certain kinds of cells.
An oral formulation of imatinib — 100 mg and 400 mg tablets, marketed as Gleevec by Novartis — is approved to treat certain types of blood cancers, in which the growth of cancer cells is driven by these signaling molecules. These signals also are thought to contribute to the abnormal growth of blood vessel cells that occurs in PAH, which is the theoretical basis for using imatinib in PAH.
“Imatinib has been shown to block several growth factors that regulate endothelial and vascular smooth muscle cell proliferation in PAH,” said Stuart Rich, MD, chief medical officer of Tenax.
Novartis conducted clinical trials testing the original formulation in PAH patients in the early 2010s. Those results indicated that the treatment improved certain blood flow characteristics, as well as exercise capacity. However, the medicine had a poor safety and tolerability profile, leading many trial participants to discontinue treatment. Gastrointestinal issues, including nausea and vomiting, were especially common.
Ultimately, Novartis discontinued the development of imatinib for PAH, deciding that the safety concerns outweighed any potential benefit.
The formulation of imatinib that Tenax is now developing is meant to be taken by mouth, like Novartis’ original formulation. However, it has been specifically designed to avoid irritating the digestive tract, which the company expects to lead to fewer safety problems.
“A suboptimal oral formulation of the drug [imatinib] has limited its therapeutic utility in PAH. Tenax’ reformulation of imatinib directly addresses this issue,” Rich said.
“We expect that our formulation will be the first drug therapy to show conclusively a disease modifying impact, due to the inhibition of the pulmonary vascular remodeling seen in PAH,” he said.
Tenax is planning to now launch a small clinical trial that will compare the pharmacological properties of its new imatinib formulation against Novartis’ original version. The company expects to have results by the end of this year, and hopes to start Phase 3 clinical testing in the second quarter of 2022.
“Imatinib has already been clinically proven to be effective in PAH, and with our unique formulation, we anticipate a better tolerated, and thus more effective, treatment option with the potential to advance the current standard of care,” Giordano said.
Of note, Tenax acquired PH Precision Med, the original developer of the new formulation, earlier this year.
An inhaled formulation of imatinib, dubbed AER-901, is currently being developed for PAH by Aerami Therapeutics. Clinical testing started earlier this year.
Both of these investigational formulations of imatinib have been granted orphan drug designation by the FDA. The designation gives certain benefits to a therapy’s developer, with the aim of incentivizing companies to develop treatments for rare diseases.
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