Vitespen(Agenus, Inc)

BACKGROUND. Heat shock protein peptide complex-96 (HSPPC-96) triggers adaptive and innate antitumor immune responses. The safety and efficacy of HSPPC-96 vaccination was examined in patients with newly diagnosed glioblastoma multiforme (GBM). METHODS. In this open-label, single-arm, phase I study, adult patients were vaccinated with HSPPC-96 in combination with the standard treatment for newly diagnosed GBM after surgical resection. Primary endpoints were frequency of adverse events and progression-free survival (PFS) at 6 months. Secondary endpoints included overall survival (OS), PFS, and tumor-specific immune response (TSIR). RESULTS. A total of 20 patients with newly diagnosed GBM were enrolled from September 2013 to February 2015. No grade 3 or 4 vaccine-related adverse events were noted. After a median follow-up of 42.3 months, PFS was 89.5% (95% CI, 66.9%–98.7%) at 6 months, median PFS was 11.0 months (95% CI, 8.2–13.8), and median OS was 31.4 months (95% CI, 14.9–47.9). TSIR was significantly increased by 2.3-fold (95% CI, 1.7–3.2) after vaccination. Median OS for patients with high TSIR after vaccination was >40.5 months (95% CI, incalculable) as compared with 14.6 months (95% CI, 7.0–22.2) for patients with low TSIR after vaccination (hazard ratio, 0.25; 95% CI, 0.071–0.90; P = 0.034). A multivariate Cox regression model revealed TSIR after vaccination as a primary independent predicator for survival. CONCLUSION. The HSPPC-96 vaccination, combined with the standard therapy, is a safe and effective strategy for treatment of newly diagnosed GBM patients. TSIR after vaccination would be a good indicator predicting the vaccine efficacy. TRIAL REGISTRATION. ClinicalTrials.gov NCT02122822. FUNDING. National Key Technology Research and Development Program of the Ministry of Science and Technology of China (2014BAI04B01, 2014BAI04B02), Beijing Natural Science Foundation (7164253), Beijing Talents Fund (2014000021469G257), and Shenzhen Science and Technology Innovation Committee (JSGG20170413151359491).

Outcomes for patients with recurrent glioblastoma multiforme (GBM) are poor and may be improved by immunotherapy. We investigated the safety and efficacy of an autologous heat-shock protein peptide complex-96 (HSPPC-96) vaccine for patients with recurrent GBM.

In this open-label, single-arm, phase II study, adult patients with surgically resectable recurrent GBM were given vaccine after gross total resection. The primary endpoint was overall survival at 6 months. Secondary endpoints included overall survival, progression-free survival, safety, and immune profiling. Outcome analyses were performed in the intention-to-treat and efficacy populations.

Between October 3, 2007 and October 24, 2011, 41 patients underwent gross total resection of recurrent GBM and received a median of 6 doses of HSPPC-96 vaccine. Following treatment, 90.2% of patients were alive at 6 months (95% confidence interval [CI]: 75.9-96.8) and 29.3% were alive at 12 months (95% CI: 16.6-45.7). Median overall survival was 42.6 weeks (95% CI: 34.7-50.5). Twenty-seven (66%) patients were lymphopenic prior to therapy, and patients with lymphocyte counts below the cohort median demonstrated decreased overall survival (hazard ratio: 4.0; 95% CI: 1.4-11.8; P = .012). There were no treatment-related deaths. There were 37 serious (grades 3-5) adverse events reported, with 17 attributable to surgical resection and a single grade 3 constitutional event related to the vaccine.

The HSPPC-96 vaccine is safe and warrants further study of efficacy for the treatment of recurrent GBM. Significant pretreatment lymphopenia may impact the outcomes of immunotherapy and deserves additional investigation.