Women suffering from HER2-positive breast cancer have reason to rejoice. The drug Trastuzumab has been found to show strong immune response on a subtype of the HER2-positive breast cancer tumor.
Case Western University researchers say that the immune response can be measured after a single dose of the drug.
The National Cancer Institute lists Trastuzumab, sold under the brand name Herceptin, as also being used to treat adenocarcinoma and metastasized cancer.
"Our study showed, for the first time, that the immune-cell-activating properties of Trastuzumab are likely related to the subtypes of breast cancer. Knowing this can inform future trials studying the usefulness of adding immunotherapy drugs to Trastuzumab," Vinay Varadan, assistant professor at Case Western Reserve University School of Medicine and member of the Case Comprehensive Cancer Center, said in a press release.
But not all women will respond to Trastuzumab, as this is determined by the patient's own immune system. "We found that higher Immune Index evaluated after just one dose of Trastuzumab predicted the tumor's response," Varadan said. In patients given single doses of other chemotherapy drugs, the researchers could not establish any correlation between immune activity and the subtype of breast cancer.
"Also, the predictive ability of the Immune Index test was not observed in patient tumors before any therapy was given, suggesting that just a single dose exposure may be a beneficial way to identify which patients are most likely to benefit from trastuzumab-based chemotherapy and, thus, do not need additional anti-HER2 treatment," Varadan added.
Seeking to identify the immune cells which responded to trastuzumab, researchers found that PD-1 expression, a marker of T-cells, was higher in women with the HER2-enriched subtype of disease who had been administered trastuzumab.
"Given that the subtypes of HER2-positive disease and the immune signatures predict response to trastuzumab-based therapy, the next question is whether these signatures can also predict response to dual-HER2 targeted therapy. Additionally, we would like to understand why certain breast cancers have a strong immune response when treated with anti-HER2 therapy while others escape immune surveillance," Vardaan said, explaining the direction of research on the drug and its effect on HER2-positive breast cancer tumor.
The study was published in the Clinical Cancer Research journal.
