Long-Term Survival after Complete Surgical Resection and Adjuvant Immunotherapy for Distant Melanoma Metastases.

BACKGROUND: This phase III study was undertaken to evaluate the efficacy of an allogeneic whole-cell vaccine (Canvaxin™) plus bacillus Calmette-Guerin (BCG) after complete resection of stage IV melanoma. METHODS: After complete resection of ≤5 distant metastases, patients were randomly assigned to BCG+Canvaxin (BCG/Cv) or BCG+placebo (BCG/Pl). The primary endpoint was overall survival (OS); secondary endpoints were disease-free survival (DFS), and immune response measured by skin test (ClinicalTrials.gov identifier: NCT00052156). RESULTS: Beginning in May 1998, 496 patients were randomized. In April 2005, the Data Safety Monitoring Board recommended stopping enrollment due to a low probability of efficacy. At that time, median OS and 5-year OS rate were 38.6 months and 44.9%, respectively, for BCG/Pl versus 31.4 months and 39.6% in the BCG/Cv group (hazard ratio (HR), 1.18; p = 0.250). Follow-up was extended at several trial sites through March 2010. Median OS and 5-year and 10-year survival was 39.1 months, 43.3 and 33.3%, respectively, for BCG/Pl versus 34.9 months, 42.5 and 36.4%, in the BCG/Cv group (HR 1.053; p = 0.696). Median DFS, 5- and 10-year DFS were 7.6 months, 23.8 and 21.7%, respectively, for BCG/Pl versus 8.5 months, 30.0%, and 30.0%, respectively, for the BCG/Cv group (HR 0.882; p = 0.260). Positive DTH skin testing correlated with increased survival. DISCUSSION: In this, the largest study of postsurgical adjuvant therapy for stage IV melanoma reported to date, BCG/Cv did not improve outcomes over BCG/placebo. Favorable long-term survival among study patients suggests that metastasectomy should be considered for selected patients with stage IV melanoma.

Intravenous administration of retroviral replicating vector, Toca 511, demonstrates therapeutic efficacy in orthotopic immune-competent mouse glioma model.

Toca 511 (vocimagene amiretrorepvec), a nonlytic, amphotropic retroviral replicating vector (RRV), encodes and delivers a functionally optimized yeast cytosine deaminase (CD) gene to tumors. In orthotopic glioma models treated with Toca 511 and 5-fluorocytosine (5-FC) the CD enzyme within infected cells converts 5-FC to 5-fluorouracil (5-FU), resulting in tumor killing. Toca 511, delivered locally either by intratumoral injection or by injection into the resection bed, in combination with subsequent oral extended-release 5-FC (Toca FC), is under clinical investigation in patients with recurrent high-grade glioma (HGG). If feasible, intravenous administration of vectors is less invasive, can easily be repeated if desired, and may be applicable to other tumor types. Here, we present preclinical data that support the development of an intravenous administration protocol. First we show that intravenous administration of Toca 511 in a preclinical model did not lead to widespread or uncontrolled replication of the RVV. No, or low, viral DNA was found in the blood and most of the tissues examined 180 days after Toca 511 administration. We also show that RRV administered intravenously leads to efficient infection and spread of the vector carrying the green fluorescent protein (GFP)-encoding gene (Toca GFP) through tumors in both immune-competent and immune-compromised animal models. However, initial vector localization within the tumor appeared to depend on the mode of administration. Long-term survival was observed in immune-competent mice when Toca 511 was administered intravenously or intracranially in combination with 5-FC treatment, and this combination was well tolerated in the preclinical models. Enhanced survival could also be achieved in animals with preexisting immune response to vector, supporting the potential for repeated administration. On the basis of these and other supporting data, a clinical trial investigating intravenous administration of Toca 511 in patients with recurrent HGG is currently open and enrolling.