Telomerase is an active enzyme that produces and maintains telomeres which are located at the end of chromosomes. In general, telomeres become shorter as the number of cell divisions increases, leading to apoptosis. However, telomerase prolongs and maintains the length of the telomere so that tumor cells continue proliferation without cell death. When the telomerase is reduced, the telomere DNA is not produced and maintained and the chromosomes become shorter and shorter. Telomerase is not well observed in normal cells and are known to act as a specific antigen by over-expression in various cencer cell types. The riavex(GV1001) which is 16-amino acid sequence from the telomere combines with HLA class I to induce an immune response through activation of CD4 T cells.
We analyzed 50 patients who were injected with riavex. The riavex was provided through the application for emergency medication from the Korea Food and Drug Administration. Most patients who were given riavex failed several standard chemotherapies. The administration methods was injection of riavex 0.2ml intradermally three times at the first week and one time at 2 weeks, 3 weeks, 4 weeks, 6 weeks and then once per 28 days. A total of 12 doses were given to each patient. After the end of the administration, we evaluated anti-tumor response by RECIST 1.1 and quality of life by EORTC QLO-C30 and EQ-5D.
Partial response was found in one patient with renal cell carcinoma. The rest of the patients showed a stable or progressive response. However, quality of life was significantly improved in 19 patients, and 15 of them have applied for re-treatment. Only three patients had a fever of more than 38oC, and no significant side effects were observed in other patients
In conclusion, riavex as an anti-cancer vaccine is relatively safe in heavily pre-treated solid cancer patients and is assessed to improve quality of life, although the treatment response is not promising.
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The author has declared no conflicts of interest.