Telomerase is expressed in 85-90 % of pancreatic adenocarcinomas and might be a 
target for active cancer immunotherapy. A study was conducted to investigate 
safety and immunogenicity in non-resectable pancreatic carcinoma patients using 
a 16-amino acid telomerase peptide (GV1001) for vaccination in combination with 
GM-CSF and gemcitabine as first line treatment. Three different vaccine 
treatment schedules were used; [A (n=6), B (n=6) and C (n=5)]. Groups A/B 
received GV1001, GM-CSF and gemcitabine concurrently. Group C received initially 
GV1001 and GM-CSF while gemcitabine was added at disease progression. Group D 
(n=4) was treated with gemcitabine alone. Adverse events (AE) related to 
vaccination were mild (grades I-II). Grade III AEs were few and transient. An 
induced GV 1001‑specific immune response was defined as an increase ≥2 above the 
baseline value in one of the assays (DTH, proliferation, ELISPOT and cytokine 
secretion assays, respectively). A telomerase‑specific immune response was noted 
in 4/6 patients in group A, 4/6 patients in group B and 2/5 patients in group C. 
An induced ras‑specific immune response (antigenic spreading) was seen in 5 of 
the 17 patients. The cytokine pattern was that of a Th1-like profile. A 
treatment induced telomerase or ras response was also noted in group D. All 
responses were weak and transient. A significant decrease in regulatory T-cells 
over time was noted in patients in groups A and B (p<0.05). Telomerase 
vaccination (GV1001) in combination with chemotherapy appeared to be safe but 
the immune responses were weak and transient. Measures have to be taken to 
optimize immune responses of GV1001 for it to be considered of clinical 
interest.