Introgen Therapeutics Inc announced that a cancer patient with metastatic melanoma has shown regression of multiple tumors including a complete regression of one lesion after treatment with its mda-7 therapeutic, INGN 241.

Dr. John Nemunaitis, of U.S. Oncology and principal investigator of the phase 1 trial said, "The biological activity of INGN 241 in these patients is very exciting to see. This data compels us to continue evaluating the INGN 241 agent for possible treatment of numerous solid tumors."

The administration of INGN 241 was well tolerated in all patients and minimal toxicities were observed such as fever lasting a few hours. A key aspect of the phase 1 evaluation was to establish that intratumoral injection of INGN 241 produced the MDA-7 therapeutic protein both in local and diffusible forms and the resultant biological effects. Study results further indicate that MDA-7 protein was detectable up to 4 cm from the injection site. This wide distribution of MDA-7 protein correlated closely with apoptosis, or cancer cell killing up to 4 cm away from the injection site, at the external edge of the injected tumor. Phase 2 evaluation was done with single and multiple doses in patients with advanced cancers. No tumor responded after a single dose, but tumors in two patients regressed after as few as two doses. The first lesion in a patient with metastatic melanoma completely regressed. A second lesion was injected and this lesion shrank considerably. A third lesion was then treated and this also responded to INGN 241. During the third set of injections, a distant melanoma which had not been treated in the study became markedly inflamed, suggesting a positive immune response. A second patient with melanoma also showed evidence of tumor regression, as did one patient with squamous cell cancer.

According to Dr. James Merritt, Introgen's chief medical officer, the clinical development of INGN 241 was accelerated based on very promising preclinical and clinical data. The phase 1 study confirmed that MDA-7 protein is active, and importantly, has a wide area of biological effect. MDA-7 not only functions as a tumor suppressor, but also as an immune enhancing cytokine which may be significant as a cancer drug.

The mda-7 gene was discovered by the laboratory of Dr. Paul B. Fisher, professor of clinical pathology and the Michael and Stella Chernow Urological Cancer Research Scientist in the Departments of Neurological Surgery, Pathology and Urology at Columbia University. Introgen holds an exclusive worldwide license for all gene therapy applications from the Corixa Corporation.