Ribi ImmunoChem Research Inc. said Tuesday that it plans tobegin a multicenter Phase III trial of its Melacine melanomatherapeutic vaccine.
About 27,600 new cases of melanoma and about 6,300 deathsare reported in the United States annually. Median survival forpatients with disseminated melanoma receiving chemotherapyis about 12 months. In a Phase II trial, median survival forpatients receiving Melacine was 29 months.
Life extension will be one of the key end points of the open-label trials. Maintenance of an acceptable quality of life willbe a secondary measurement.
Tumor shrinkage is the traditional measure of clinicalefficacy, but a joint Food and Drug Administration/NationalCancer Institute working group last year recognized lifeextension and quality of life as valid measures of cancertherapeutics.
About 35 percent of patients in Ribi's earlier trial showedeither complete response, partial response, minor response orstabilization of the disease, said Ribi spokesman JeffreyMcDowell. Some patients who receive chemotherapy showhigh-complete or partial responses, but these don't last, andthe recurring cancers are sometimes more aggressive,McDowell said.
Melacine contains tumor cells from two cell lines plus Ribi'sDetox adjuvant to enhance the immune response. The tumorcells, which are killed, lysed and purified, act as antigens thatstimulate an immune response in patients against theirtumors. Detox combines monophosphoryl lipid A, a non-toxicderivative of gram-negative endotoxin, with mycobacterialcell wall skeleton, another immunostimulant.
If the trials are successful, Ribi said it will submit a productlicense application in 1993 to the FDA. The Hamilton, Mont.,company said the drug could be eligible for "fast-track" reviewby the Food and Drug Administration.
Melacine received orphan drug designation in 1989 for patientswith Stage III/IV disseminated melanoma.
Ribi stock (NASDAQ:RIBI) closed unchanged at $7.25 onTuesday.
-- Karen Bernstein BioWorld Staff
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