Geron reports striking cancer vaccine results

The results show that the vaccination protocol successfully generated telomerase-specific T-cell responses in 19 of 20 subjects. The vaccine was well tolerated with no major treatment-related toxicities, and peak immune responses to vaccination were remarkably high with 1% to 2% of circulating CD8+ T-cells demonstrating anti-telomerase specificity. Vaccination was also associated with a significant increase in PSA doubling time and clearance of circulating tumor cells.

The data show that telomerase vaccination was associated with a significant impact on PSA doubling time and a reduction or elimination of circulating tumor cells during the time that a measurable, telomerase-specific T-cell response was detectable in the patient’s blood.

The modified vaccine produced a central T-cell memory response which should enable recall responses to additional vaccinations. These observations suggest that continued vaccination (boosting) to maintain the telomerase-specific T-cell response may enhance clinical impact.

“These results are very exciting,” said senior author, Dr Johannes Vieweg. “The high levels of telomerase T-cell immunity generated in these advanced cancer patients is striking. The temporal association between immunity and surrogate clinical response suggests a potential clinical impact of the vaccine. We are currently optimizing the vaccination protocol to extend the durability of the immune response to telomerase.”