RESEARCH & DEVELOPMENT

Melanoma vaccine shows promising antitumour activity

Polyvalent melanoma cell vaccine therapy is associated with antitumour activity and appears to prolong survival in patients with melanoma, report researchers from the US.

This study involved 66 patients who had undergone resection of regional stage III metastatic melanoma followed by adjuvant intradermal immunotherapy with melanoma cell vaccine. *t

Vaccine constituents The researchers explain that this vaccine consists

of 3 allogeneic human melanoma cell lines that express the melanoma-associated antigens GM3, GD3, GM2 and GD2 on their surface. The cell lines have been irradiated to destroy their capacity for prolonged growth.

In all patients, at 4 weeks after the first immun­isation, IgM antibody responses to all 4 antigens (GM3, GD3, GM2 and GD2) were significantly increased from baseline levels.

Increases in serum antibodies were significantly associated with survival; antibodies to all 4 antigens were significantly higher in the> 5 year, compared with the < 1 year, survival group. Anti-GD2 antibody responses were significantly higher in the 2-5 year, compared with the < 1 year, group, while anti-GD3 and anti-GM3 antibody responses were significantly higher in the> 5 year, compared with the 2-5 year, group.

In addition, results of an inhibition assay conducted in serum from 5 patients with elevated postvaccination serum titres of IgM, using GM2 and GD2 to block binding to M14 target cells, and GM3 and GD3 to block binding to M12 target cells, showed partial or complete inhibition of cytotoxic activity.

* Patients were divided inIo 3 groups of22 patients each, according to durotion ofSUTVivalfolJJJwing initiation ofme1arwma aU vaccine: > 5 years, 2-5 yean or < 1 year.

t The vaccine schedule consists of intradermal injections inIo axillary and inguinal regions every 2 weeksfor 3 cycles,foUowed by monthly injectionsfor 1 year. Thereafter, the vaccine is administered at 3-monthly intervals over a 12-numth perind,folJJJwed by 6-month1y injections.

Takahashi T. Johnson TD. Nishinaka Y. Morton D1., Irie RF. IgM anti-gangIioside antibodies induced by melanoma cell vaccine correlate with survival of melanoma patients. Journal of Investigative Dermatology 112: 205-209. Feb 1999

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Inpharma- 20 Mar 1999 No. 1179