The Korean biotechnology company ViroMed Co., Ltd. has announced the publication of a Phase 2 study that evaluated their VM202 product in patients with critical limb ischemia. This study involved 52 patients in the United States and showed that VM202 is not only safe, but also produced significant clinical benefits.
VM202 is a plasmid (small circle of DNA) that encodes the human hepatic growth factor (HGF) gene. When injected into muscles, VM202 is readily taken up by nearby cells that then quickly synthesize the two isoforms of HGF. Heightened HGF concentrations can treat ischemic cardiovascular diseases by inducing the formation of new blood vessels (angiogenesis). These new collateral vessels increase blood flow and tissue perfusion in the sick tissue, which effectively treats any tissue ischemia.
Severe obstruction of the arteries that feed the extremities (hands, feet and legs) is the cause of critical limb ischemia (CLI). The term “ischemia” refers to the starvation of a tissue for oxygen. The lack of sufficient blood flow to an organ or tissue can cause severe pain and even skin ulcers, sores, or gangrene. CLI-induced pain can awaken the patient during the night, and, therefore, is called “rest pain.” Rest pains often occur in the leg and is usually temporarily relieved by dangling the leg over the bed or getting up and walking.
CLI does not improve on its own. It is a severe condition that requires immediate by a vascular surgeon or vascular specialist.
In this Phase 2 study, patients were divided into three groups, one of which received a placebo treatment, the second of which received a low-dose treatment VM202, and a third group that received a high-dose of VM202.
Both patient groups that received VM202 showed improvement compared to the placebo group, but patients in the higher-dose group showed significantly better ulcer healing and higher tissue oxygen levels than the placebo group. For example, 62 percent of the ulcers healed in patients treated with high-dose VM202 compared to only 11 percent of ulcers in patients who were treated with the placebo. Also, 71 percent of patients who received the high-dose VM202 showed improved oxygen concentrations in their tissues, compared to only 33 percent of patients who were treated with the placebo.
Emerson C. Perin, Director of the Stem Cell Center at the Texas Heart Institute and the principal investigator of this Phase 2 study, said: “These positive results are exciting, and VM202 shows great promise for treating patients with this debilitating disease who often have limited therapeutic options. We are looking forward to conducting a phase III trial to better understand the potential of this novel approach, especially in treating non-healing ulcers, which is a serious symptom that often leads to amputation because of the lack of medical therapies available.”
ViroMed has already been granted an IND or Investigational New Drug approval by the USFDA to initiate a Phase 3 study in diabetic patients who suffer from non-chronic ischemic foot ulcers. This study will enroll 300 subjects who will be divided into a VM202 group and a placebo group. The treatment regiment will mimic that of this smaller Phase 2 study and will only follow patients for seven months. This time, ViroMed is interested in determining if VM202 helps wound closure, which will constitute the primary efficacy endpoint on this new study.