Treatment with Imfinzi (durvalumab) significantly prolongs overall survival among patients with stage III, inoperable non-small-cell lung cancer (NSCLC) in comparison to those given a placebo, according to new data from a Phase 3 clinical trial.
The updated results from the PACIFIC trial (NCT02125461) were presented by AstraZeneca and its global biologics research and development arm, MedImmune, at the recent IASLC 19th World Conference on Lung Cancer hosted by the International Association for the Study of Lung Cancer in Toronto.
Findings of the study, “Overall Survival with Durvalumab after Chemoradiotherapy in Stage III NSCLC,” were also published in the New England Journal of Medicine.
Previous data from the PACIFIC trial had demonstrated that Imfinzi significantly extended the time to disease progression or death among patients whose disease did not progress after platinum-based chemotherapy and radiation therapy.
The newly released data, from a subsequent independent interim analysis, revealed that Imfinzi significantly increased overall survival — another primary trial goal — reducing the risk of death by 32% over two years among treated patients. (Median follow-up for overall survival was 25.2 months, the study noted.)
“The five-year survival rate in this setting has historically been around 15% after concurrent chemoradiation therapy. The significant survival benefit observed using the PACIFIC regimen [32%] provides confidence and clear rationale for a new standard of care,” Scott J. Antonia, MD, PhD, chair of the Thoracic Oncology Department at Moffitt Cancer Center in Tampa, Florida, and principal investigator for the PACIFIC trial, said in a press release.
Updated trial findings were also consistent with what had been previously reported regarding the safety and tolerability of Imfinzi.
“Updated analyses regarding progression-free survival were similar to those previously reported, with a median duration of 17.2 months in the durvalumab group and 5.6 months in the placebo group. The median time to death or distant metastasis was 28.3 months in the durvalumab group and 16.2 months in the placebo group,” the researchers wrote.
Although Imfinzi can lead to serious, sometimes fatal, side effects, most adverse reactions reported in this analysis of treated patients compared to placebo were cough (35.2% vs. 25.2%), fatigue (24.0% vs. 20.5%), shortness of breath (22.3% vs. 23.9%) and radiation pneumonitis (a type of lung injury linked to repeat radiation treatment; 20.2% vs. 15.8%).
But the percentage of Imfinzi-treated patients experiencing grade 3 or 4 adverse events was higher than those given a placebo (30.5% vs. 26.1%). More of these patients also stopped treatment due to side effects than did those on placebo (15.4% vs. 9.8%).
“These data establish Imfinzi as the first immunotherapy to demonstrate an overall survival benefit for patients with [inoperable], Stage III non-small cell lung cancer following chemoradiation therapy. Today’s announcement brings new hope to patients in a setting where survival rates have not changed in decades,” said Sean Bohen, AstraZeneca’s executive vice president for Global Medicines Development and chief medical officer.
Imfinzi was approved in the U.S. to treat advanced and inoperable NSCLC patients who remain stable after platinum-based chemotherapy and radiation therapy in February, based on results obtained in the course of the PACIFIC trial. It was also approved for these patients in the EU, Canada, Switzerland, India, Japan, and Brazil. Health authority requests for similar approval elsewhere are ongoing.