The body’s immune system can be directed to shrink tumors and prevent new ones from forming. Data presented at the 2008 Annual Meeting of the American Association for Cancer Research (AACR) detail how cellular strategies and new vaccines are changing the cancer treatment landscape.
First Live Listeria Cancer Vaccine in Humans
Phase I/II trial results have shown that the live Listeria cancer vaccine, Lovaxin C, is safe for humans. In addition, three women in the cervical cancer trial had approximately 20 percent tumor reductions, researchers report.
“We are using Listeria to deliver tumor-specific antigens to the immune system in a manner that results in maximal immune and tumor-clearing response,” said John Rothman, Ph.D., vice president of clinical development at Advaxis, which is developing Lovaxin C.
Abstract 225: The first use of a live listeria cancer vaccine in man
Improved Immune Response for Prostate Cancer
Blocking CTLA-4, a cellular molecule on lymphocytes that inhibits immune response, produced meaningful clinical benefits in patients with prostate cancer that hadn’t responded to hormone therapy, according to researchers.
“CTLA-4 blockade works by removing the brakes on the immune system. Our results show that enhancing immune responses in prostate cancer patients can lead to clinical responses,” said Lawrence Fong, M.D., a hematology/oncology researcher at University of California, San Francisco.
Abstract 2539: CTLA-4 blockade for hormone refractory prostate cancer: dose-dependent induction of CD8+ T cell activation and clinical responses
Two Therapies Lower PSA Levels in Metastatic Prostate Cancer Patients
Researchers have found a promising synergy of two therapies to treat metastatic prostate cancer that is resistant to hormone therapy. In a Phase 1 trial, they observed that a combination of GVAX immunotherapy with ipilimumab lowered prostate-specific antigen (PSA) levels in some patients.
“Higher doses of ipilimumab combined with the GVAX vaccine is showing a lot of success in increasing anti-tumor activity in these patients,” said Saskia J.A.M. Santegoets, Ph.D., a researcher in the Department of Pathology and Division of Immunotherapy at the Vrije Universiteit Medical Center in the Netherlands. “We’re encouraged by the results of this phase I trial and expect ongoing analyses to yield more valuable data about the GVAX/ ipilimumab combination.”
Abstract 2538: Dendritic and T cell functions in patients with metastatic hormone-refractory prostate cancer treated with GVAX immunotherapy for prostate cancer and ipilumumab
Antibody-directed Enzyme Prodrug Therapy Show Promise
A two-step drug therapy that selectively targets tumors may hold promise for some patients with advanced cancers, according to results of a clinical trial directed by researchers in London.
Scientists at the University College London’s Cancer Institute and the Royal Free Hospital used a technique called antibody-directed enzyme prodrug therapy (ADEPT) in 43 patients with previously treated, advanced colorectal, gastro-esophageal, breast, gallbladder, peritoneal, appendix, or pancreatic cancers, or cancers of unknown primary site. The patients received one, two or three ADEPT treatments over a period of two to 10 days, at dosages ranging from 37 mg/m2 to 3,226 mg/m2.
“We found clinically significant responses in 44 percent of patients,” said senior author Richard H. Begent, M.D., professor of oncology at the University College London’s Cancer Institute. “These results support the case for conducting a randomized Phase II clinical trial.”
Abstract LB-200: Evidence of Efficacy of Antibody Directed Enzyme Prodrug Therapy (ADEPT) in a Phase I Trial in Patients with Advanced Carcinoma
Filed Under: Drug Discovery