During the European Cancer Congress, Vienna, Austria, Genentech announced positive results from two Phase II studies of atezolizumab in patients with advanced non-small cell lung cancer (NSCLC). Atezolizumab was effective in individuals with NSCLC expressing PD-L1 in the BIRCH trial. Additional follow-up in the POPLAR trial demonstrated that atezolizumab use resulted in superior overall survival when compared to the chemotherapy agent docetaxel.
Atezolizumab is a monoclonal antibody that blocks the activity of a protein known as PD-L1 (Programmed death 1), specifically on tumor cells and tumor-infiltrating immune cells. PD-L1 suppresses the immune system, which can be useful in conditions such as pregnancy, but it can also contribute to disease as is the case with cancer. Through inhibition of PD-L1, atezolizumab may activate T cells, helping the patient’s immune system to fight tumors. The efficiency of this novel immunotherapy greatly relies on the amount of PD-L1 present in tumor cells. “Unlike other biomarkers, there have not been large-scale epidemiological studies of PD-L1 prevalence. However, because of our studies and others we are beginning to gain a better understanding. In the POPLAR trial, about two-thirds of NSCLC tumors expressed some level of PD-L1, with about one-third expressing medium to high levels of the biomarker. Data from these pivotal studies showed that PD-L1 expression correlated with a person’s response to atezolizumab. The level of PD-L1 overexpression that correlates with use of PD-L1 as a biomarker may be different for each disease and requires validation in each tumor type”, Holli Kolkey, Associate Director, Corporate Relations, Genentech, told Immuno-Oncology News in an exclusive interview.
In the BIRCH study, atezolizumab shrank tumors in up to 27 percent of people whose cancer had gotten worse while they took previous medicines and who also had the highest levels of PD-L1. In the Phase II POPLAR study, atezolizumab was better at increasing survival than standard chemotherapy in individuals with recurring NSCLC and whose tumors expressed moderate to high levels of PD-L1. Overall, people taking atezolizumab lived 7.7 months longer when compared to individuals who received docetaxel chemotherapy.
When asked if atezolizumab could be used in early stages of the disease, as a first line of therapy, Ms. Kolkey told Immuno-Oncology News that, “This year at ECC we presented results from the BIRCH study that included patients who received atezolizumab in the first line. We also have five ongoing Phase III studies of atezolizumab as a first-line treatment in NSCLC. We are also currently studying atezolizumab in multiple treatment settings in advanced cancer, including as a first-line treatment across tumor types, such as triple negative breast cancer. Additionally, we are studying atezolizumab in the early stages of the disease where the goal of treatment is to prevent the cancer from coming back after surgery (adjuvant setting). Currently, we have an adjuvant Phase III study of atezolizumab for both invasive bladder cancer and separately, NSCLC.”
In both of the studies of atezolizumab, side effects were consistent with those observed in previous studies. “Results from both of our studies in non-small cell lung cancer showed that measuring PD-L1 may help identify people most likely to respond to atezolizumab, and the majority of responses continued when these data were assessed,” noted Sandra Horning, M.D., chief medical officer and head of Global Product Development. “Durable responses are meaningful for people whose cancer has progressed on other medicines, and we plan to submit these results to global health authorities to bring this potential new option to people as soon as possible.”
Atezolizumab has received Breakthrough Therapy Designation from the US Food and Drug Administration (FDA). The designation speeds up developmental of treatments for serious diseases, specifically medications that are substantial improvements from what is currently available. “We are discussing results from our lung studies with the FDA, under atezolizumab’s Breakthrough Therapy Designation (BTD), so that we can bring this medicine to people with advanced bladder and lung cancers as soon as possible”, Ms. Kolkey told Immuno-Oncology News.
Based on American Cancer Society statistics, over 221,000 Americans will receive a lung cancer diagnosis in 2015. NSCLC accounts for most forms of lung cancers, at 85 percent. Unfortunately, about 60 percent of lung cancer is diagnosed in the United States when the disease is in advanced stages, therefore effective treatments that work in later disease stages are greatly needed.