Malignant Mesothelioma Patients Treated with Ribonuclease

Mesothelioma News

Onconase Shows Promise in Improving Malignant Mesothelioma Survival Rates

February 8, 2002 — The anticancer drug ranpirnase (Onconase) improved the survival rates of patients with inoperable malignant mesothelioma in a recent clinical trial (Journal of Clinical Oncology, Vol. 20, Issue 1, Jan 2002: 274–281). A ribonuclease isolated from the eggs of the leopard frog, Onconase interrupts protein synthesis and inhibits cell growth. It is manufactured by Alfacell Corporation.

One hundred and five patients with malignant mesothelioma were treated with Onconase. Thirty–seven percent had not responded to prior chemotherapy. The one–year and two–year survival rates of the treated patients were 34.3% and 21.6%. Among 81 mesothelioma patients within that group who met certain cancer definition criteria, the one–year and two–year survival rates were 42% and 26.8%. Within this group of 81 patients, four had partial responses, two had minor regressions, and thirty–five experienced stabilization of what was a previously progressive disease. Median survival rates for malignant mesothelioma patients normally range from 6 to 8 months.

Phase III Clinical Trial Now Underway for Patients with Malignant Mesothelioma

According to the researchers, Onconase was well tolerated in the majority of mesothelioma patients taking part in the study, which was a Phase II clinical trial. As a result, a Phase III clinical trial is now being conducted for mesothelioma patients (see Doxorubicin, Clinical Trials page, National Institute of Health web site for details). The new clinical trial will compare the effects of the anticancer drug doxorubicin with the effects of Onconase plus doxorubicin.

Clinical trial phases are defined by the Food and Drug Administration in the Code of Federal Regulations. In Phase I clinical trials, researchers test a new drug or treatment in a small group of people (20–80) for the first time to evaluate safety, determine dosage range, and identify side effects. In Phase II clinical trials, the study drug or treatment is given to a larger group (100–300 individuals ) to test effectiveness and to further evaluate safety. In Phase III studies, the drug or treatment is given to large groups (1,000–3,000 individuals) to confirm effectiveness, to monitor side effects, to make comparisons to other treatments, and to collect information that will ensure patient safety.