(RxWiki News) Lung cancer is the leading cause of cancer-related death in the US. Advanced lung cancers have spread to other areas of the body and are extremely tough to beat. An experimental therapy may be a game changer.
Researchers discovered that when the experimental therapy — called Imprime PGG — was added to conventional therapies, patients with advanced lung cancer lived up to three years.
This therapy works by priming the body’s immune system to target and kill the cancer cells.
And while promising, more research will be needed before Imprime PGG is available to patients.
"Research clinical trials testing new cancer medications."
This phase II trial looking at the effectiveness of Imprime PGG was led by Richard D. Huhn, MD, medical director and senior vice president at Biothera Inc., the company that’s developing Imprime PGG.
Imprime PGG is what’s known as an immunotherapy, which means it works with the body’s own defense system to find and destroy cancer cells.
Roughly 65 percent of immune cells are what scientists call neutrophils and monocytes. These cells kill foreign invaders such as bacteria and yeast.
Imprime PGG is made from yeast and is designed to attach to a specific spot on the neutrophil, which enables the immune cell to become a cancer killer.
In this study, Dr. Huhn and team found that certain people had a high level of a type of antibody (molecule that identifies specific foreign invaders) that helps Imprime PGG bind to neutrophils and monoctyes.
Patients with the antibody responded better to the experimental therapy and were called biomarker-positive. Patients who did not have the antibody were classified as biomarker-negative.
A total of 90 patients with stage 3 or stage 4 non-small cell lung cancer (NSCLC) participated in this trial. NSCLC is the more common form of lung cancer.
The researchers randomly assigned 30 patients to the control group, and they received the antibody medication cetuximab (brand name Erbitux), and 60 patients received both cetuximab and Imprime PGG.
All participants also received two conventional chemotherapy medications — carboplatin (brand name Paraplatin) and paclitaxel (brand names Abraxane, Taxol).
Among the 46 participants who received Imprime PGG and were evaluated in the trial, 15 were biomarker-positive (BM+), meaning they had sufficient levels of the binding antibody, and 31 were biomarker-negative (BM-) and didn’t have the specific antibody.
BM+ participants who received Imprime PGG had a median overall survival of 16.5 months, compared to 9.1 months for BM- participants in the Imprime group.
A total of 7 percent of all participants and 17 percent of BM+ patients in the Imprime group were still alive after three years, while none of the BM- patients in the Imprime group nor any participants in the control group survived that long.
The overall response rate (ORR) to the therapy was 23 percent in the control group patients, as compared to 48 percent of the entire Imprime group, 67 percent of the BM+ patients and 39 percent of the BM- Imprime group. All responses were partial.
The median overall survival was 11.2 months for the control group and 10.2 months for all participants in the Imprime PGG group.
Adverse effects experienced were consistent with those seen in patients receiving chemotherapy agents or cetuximab.
"In summary, the addition of Imprime PGG to chemoimmunotherapy with carboplatin, paclitaxel and cetuximab resulted in improved outcomes in BM+ subjects with respect to increased ORR and extended survival compared to control subjects and had a good safety profile," the researchers wrote.
“We believe that Imprime PGG can change the way cancer is treated,” Dr. Huhn said in a statement.
Findings from this study were presented at AACR-IASLC Joint Conference on the Molecular Origins of Lung Cancer.
Biothera Inc., the developer of the Imprime PGG, funded the research.