Tecentriq with carboplatin and etoposide led to a median overall survival rate of 12.3 months versus 10.3 months in those assigned placebo, carboplatin and etoposide, although the death rate was high at a median follow-up of 22.9 months.
Study results demonstrated that the immunotherapy Tecentriq (atezolizumab) with carboplatin and etoposide safely improved overall survival (OS) in patients with extensive-stage small-cell lung cancer.
“This combination of chemotherapy and immunotherapy is now our preferred standard of care,” said Dr. Stephen V. Liu, associate professor of medicine and director of thoracic oncology at Georgetown University in Washington, D.C., in an interview with CURE®. “It offers better outcomes overall and, for some patients, provides an opportunity for long-term survival.”
Treatment for patients with extensive-stage small-cell lung cancer is not often studied in the clinical trial space.
“Extensive-stage small-cell lung cancer is an exceptionally lethal cancer with limited survival in need of better therapy,” said Liu. “In fact, prior to this study, no trial had improved survival outcomes in over three decades despite dozens of randomized studies attempting to do so. It’s an extremely challenging cancer to study. But based on our early experience combining immunotherapy with chemotherapy in other cancers, we felt this strategy had tremendous promise in small-cell lung cancer.”
In the Impower133 study, 403 patients with untreated extensive-stage small-cell lung cancer were randomly assigned either 1,200 mg of Tecentriq intravenously on the first day (201 patients) or placebo (202 patients). Both treatments were administered in addition to carboplatin (four 21-day cycles) plus etoposide. Maintenance doses of Tecentriq or placebo were continued until disease progression, unacceptable toxicity or when clinical benefit was lost.
Researchers retrieved tumor specimens in all patients. Primary end points for this study included OS and progression-free survival (PFS).
Follow-up for OS was conducted for a median of 22.9 months, during which 302 deaths occurred. The Tecentriq group had a median OS of 12.3 months compared with 10.3 months for the placebo group. At 18 months, 34% of patients assigned Tecentriq were alive versus 21% of those assigned placebo.
Adding Tecentriq benefited patients regardless of blood-based tumor mutational burden status (or the number of mutations within the DNA of cancer cells, which may predict the best treatment option for a patient) or PD-L1 immunohistochemistry (or the amount of a specific protein that controls the body’s immune response).
Despite the findings in this study, more research is needed in this area.
“We need biomarkers to help us understand exactly why the long-term benefit of immunotherapy is achieved by only a fraction of patients and not all of the patients,” said Liu. “We also need better drugs for patients with this devastating disease.”
Liu emphasized the importance of participating in clinical trials. He said, “Small-cell lung cancer has historically been treated with chemotherapy alone. While the chance of an initial response is high, these cancers tend to relapse quickly. I would strongly encourage patients and physicians to consider clinical trials as part of initial therapy because we know we can do better than the standard approach. Even though the addition of (Tecentriq) to chemotherapy is definitely superior to chemotherapy alone and is a new standard of care, there is clearly room for improvement, and we have some very promising trials ongoing right now.”
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