Babu and Adamson Clinical studies Due to the success of PEPvIII-KLH in in vivo studies, several clinical trials were designed. The first clinical trial (Phase I; VICTORI) was conducted at the Duke University Medical Center and enrolled 15 adults with newly diagnosed GBM.87 However, as three patients had tumor progression during external beam radiotherapy and were not vaccinated, the data of 12 patients were analyzed. The median age was 42 years, with the majority of patients (58.3%) having a KPS of 100 (mean: 95.8). Patients underwent leukapheresis to obtain peripheral blood mononuclear cells (PBMC) for the generation of DCs and immunologic monitoring. DCs were then pulsed with PEPvIII-KLH and administered intradermally every 2 weeks at doses up to 1.1 X 108 DCs in three equal doses. Patients were monitored for tumor progression and toxicity. There were no cases with serious adverse effects beyond grade II toxicity. While patients had increased erythrocyte sedimentation rate and rheumatoid factor levels, these increases were minimal and did not result in clinical symptoms. Immunization was seen to induce antigen-specific cellular and humoral immune responses (as detected ex vivo). The median time to progression was 10.2 months (95% confidence interval [CI]: 5.7–12.6) and median survival was 22.8 months (95% CI: 17.5–29). Patient survival was compared to that based on recursive partition analysis.93 Of the 12 trial patients, eight were in group III, with the remaining in group IV. As patients in these groups have an expected survival of 17.9 and 11.1 months, respectively, nine of 12 study patients were seen to exceed these expectations. While this difference did not reach statistical significance (P = 0.083), the results may have been negatively biased as EGFRvIII expression was not a criterion for inclusion. The promising results of PEPvIII-KLH in the Phase I toxicity trial led to the initiation of a second clinical trial. Due to the expense and variability associated with the use of DCs, further studies only administered PEPvIII- KLH in combination with GM-CSF. The second trial, A Complimentary Trial of an Immunotherapy Vaccine Against Tumor Specific EGFRvIII (ACTIVATE), was performed at the Duke University Medical Center and MD Anderson Cancer Center.88 Eighteen patients with newly diagnosed EGFRvIII expressing GBM (as detected via immunohistochemistry on paraffin-embedded tissue) having a gross total resection (.95%), Karnofsky performance status (KPS) $80, and not exhibiting radiographic progression following external beam radiotherapy and concurrent temozolomide were included in the trial. The median age of the cohort was 52 years, with a mean KPS of 91.7. Patients were intradermally 98 submit your manuscript | www.dovepress.com Dovepress 1.0 0.8 y t i l i ab 0.6 b o r p l iva 0.4 v r u S 0.2 0.0 Dovepress ACT III ACT II ACTIVATE Matched historical control 0 10 20 30 40 50 60 70 OS from diagnosis (months) 80 90 Figure 3 Kaplan–Meier overall survival curves showing higher overall survival in vaccinated patients in each of the Phase II clinical trials. Note: Lai RK, Recht LD, Reardon DA, et al. Long-term follow-up of ACT III: A Phase II trial of rindopepimut (CDX-110) in newly diagnosed glioblastoma. Neuro Oncol. 2011;13(Suppl 3): iii34–iii40, by permission of Oxford University Press.95 administered PEPvIII-KLH/CDX-110 in GM-CSF, receiving three vaccinations every 2 weeks and monthly thereafter until progression. Toxicity was mostly limited to injection site reactions and was never more severe than grade II toxicity. One patient developed asymptomatic areas of T2-signal hyperintensity which was thought to be grade I leukoencephalopathy toxicity. The median time to progression was 14.2 months and median OS was 26.0 months. This survival was significantly better than that seen in a temozolomide-treated matched control group (hazard ratio [HR]: 5.1; 95% CI: 1.9–13.9; P = 0.001) (Figure 3). As seen in the in vivo studies, the majority of recurrent tumors (82%) had lost EGFRvIII expression at recurrence. The serum of 14 patients was analyzed for EGFRvIII-specific humoral responses, with six inducing such a response. The median OS of patients who developed EGFRvIII-specific antibody responses was 47.7 months, compared to 22.8 months in those who did not develop antibody responses (P = 0.025). Assessment of cellular immune responses showed three of 17 patients to have a positive delayed-type hypersensitivity (DTH) response. Patients who developed PEPvIII-specific DTH responses had a significantly longer PFS and OS (P = 0.03). A third clinical trial (Phase II; ACTII) was designed to assess the efficacy of PEPvIII-KLH with standard-dose (STD) and dose-intensified (DI) temozolomide regimens in 22 patients.94 Patients in group A were assigned to receive temozolomide at a dose of 200 mg/m2 for 5 days of a 28 day cycle, with those in group B receiving 100 mg/m2 for 21 days of a 28 day cycle. Immunization with PEPvIII-KLH Core Evidence 2012:7