An investigational type of immune therapy that attacks the tissue around a tumor has shown promise in a small study of patients with advanced pancreatic cancer. These results were published in the journal Science.
Immune therapies stimulate the body’s immune system to fight cancer. Traditional approaches to immune therapy have targeted the cancer directly, but recent research suggests that it may also be effective to target the tissue that surrounds and supports the cancer.
In a recent study, scientists evaluated an investigational drug (CP-870,893) that stimulates a protein known as CD40. CD40 plays a role in regulating T cells (types of immune cells). Initially, the scientists expected the drug to stimulate a T-cell attack against the cancer itself.
The drug was given in combination with Gemzar® (gemcitabine) to 21 patients with advanced pancreatic cancer. Information about response to treatment was available for 19 patients: four of the patients experienced a partial reduction in detectable cancer, 11 experienced stable disease, and four experienced cancer progression. This response rate is higher than would be expected with Gemzar alone.
Analysis of tissue removed by biopsy or surgery showed that the immune response seemed to involve macrophages (another type of white blood cell) rather than T cells. To further explore how the drug might be working, researchers conducted studies in mice. These studies showed that the macrophages were attacking the tumor stroma (the tissue that surrounds the tumor).
These studies in humans and mice suggest a novel approach to using the immune system to fight cancer. The drug evaluated in this study is also being evaluated in clinical trials of melanoma. More information about ongoing clinical trials is available from the National Cancer Institute (cancer.gov) as well as eCancerTrials.com.
Reference: Beatty G, Chiroean EG, Fishman MP et al. CD40 agonists alter tumor stroma and show efficacy against pancreatic carcinoma in mice and humans. Science. 2011;331:1612-1616.
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