New Clinical Data Demonstrate Strong Synergy between Cancer Vaccine ISA101 and Chemotherapy
10 Apr 2014

ISA Pharmaceuticals B.V., a clinical-stage immunotherapy company focusing on rationally designed therapeutic vaccines against cancer and persistent viral infections, has announced new clinical data on its lead product candidate ISA101. ISA101 is a therapeutic cancer vaccine for the treatment of high-risk, HPV16-induced diseases, such as cervical cancer. The data were presented by principal investigator Prof. Sjoerd van der Burg, Ph.D., at this year’s American Association for Cancer Research (AACR) Annual Meeting in San Diego.

The data demonstrate strong synergy between ISA101 and chemotherapy, offering potential new treatment options for cervical cancer patients scheduled to receive standard chemotherapy with carboplatin/paclitaxel.

Prof. van der Burg and his group evaluated the immunological and clinical responses of patients with advanced cervical carcinoma in a Phase I combination trial. In this pilot trial, patients received ISA101 in combination with standard chemotherapy cycles (carboplatin/paclitaxel). Almost all patients showed a strong immune response to the ISA101 vaccine. Comprehensive immune monitoring confirmed the beneficial effect of myeloid suppressor cell depletion associated with a robust induction of HPV16-specific T-cell responses that were sustained throughout several cycles of chemotherapy.

The observation that depletion of myeloid suppressor cells by a carboplatin/paclitaxel chemotherapy regimen enhances the immune response to ISA101 is in line with prior observations that tumors promote immune tolerance starting early in the disease and that chemotherapy can restore immune competence in cancer patients.

Based on these results ISA has initiated a phase I/II study (CervISA) in October last year testing ISA101 in combination with carboplatin, paclitaxel and pegylated interferon alpha in women with advanced or recurrent cervical cancer.

“The findings of the pilot study are remarkable,” said Sjoerd van der Burg. “They clearly demonstrate that chemotherapy was able to restore the T cell immune response capacity to the ISA101 vaccine. The outcome also supports a new paradigm in cancer immunotherapy, wherein cancer vaccination might be more effective in combination with certain chemotherapies rather than as monotherapy.”

“These data underline the value of ISA101 as a therapy complementing chemotherapy,” said Kees Melief, CSO of ISA Pharmaceuticals. “The results make us very hopeful for our ongoing CervISA trial in cervical cancer, as the strength of the T-cell responses induced in the pilot study could be increased to a level previously observed in a phase II trial with ISA101 in patients with vulvar intraepithelial neoplasia (VIN). This study produced lasting clinical responses in about half of the patients."

The presentation titled “Synergistic effects of properly timed HPV16 SLP vaccination during standard carboplatin/paclitaxel chemotherapy in animals and patients with metastatic cervical carcinoma“ was given at the Minisymposium MS.IM02.01 "Immune-based Therapies: Responses, Biomarkers, and Mechanisms" on Monday, April 07, 2014, at 3:20 PM in Room 6CF at the San Diego Convention Center.

The abstract # 2938 is available at the AACR website www.aacr.org.

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Michelle Maxwell
Drug Discovery Editor