Gene therapy applied to peripheral arterial disease

By Piriya Mahendra, MedWire Reporter

Hepatocyte growth factor (HGF) gene therapy could be used to treat patients with severe peripheral arterial disease (PAD), suggest results of a phase I clinical trial.

This finding could be "cautiously interpreted" to indicate that intramuscular injection of naked plasmid DNA encoding HGF is safe, feasible, and can achieve successful improvement of ischemic limbs as sole therapy, remark Ryuichi Morishita (Osaka University, Japan) and team.

In a previous study by the researchers, ankle-brachial pressure index (ABI) was significantly increased in patients with PAD who were treated with HGF from 0.46 at baseline to 0.59 at 8 weeks after injection.

In the current study, which included 22 patients with PAD or Buerger disease staged by Fontaine IIb (n=7), III (n=4), and IV (n=11), ABI increased 2 years on from treatment, to 0.61.

A significant improvement in rest pain (defined as >2 cm on the VAS) was observed in all patients 2 years after transfection, from 5.92 at baseline to 0.39 on a visual analog scale (VAS).

Moreover, at 2 years, 9 of 10 ischemic ulcers were reduced by more than 25%. The size of the largest ulcer had reduced from 3.08 cm at baseline to 0.61 cm at 2 years.

There were no severe complications or adverse effects caused by HGF therapy in any patient.

"The most striking point from the present study is that an improvement in ABI, ulcer size, and rest pain continued up to 2 years before transfection," comment Morishita and team in Arteriosclerosis, Thrombosis and Vascular Biology.

"To our knowledge, such an improvement has not previously been obtained spontaneously or with medical therapy in patients with CLI [critical limb ischemia]."

The authors say that a possible explanation for their findings could be that an increase in the number of blood vessels induced by HGF at an early time point may enlarge collateral at a later time point "over the transient expression of exogenous HGF."

They conclude that larger studies to determine whether HGF therapy can avoid major amputation and decrease mortality in patients with CLI are warranted.

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