Imfinzi May Contribute to Long-Term Survival Improvements in Unresectable Non-Small Cell Lung Cancer

Five-year follow-up data demonstrated that the use of Imfinzi (durvalumab) in patients with unresectable stage 3 non-small cell lung cancer is associated with strong and sustained improvements to survival, compared to placebo.

The data, which were presented during the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting, are a follow-up to results from the phase 3 PACIFIC trial. Previously, findings from that trial led the Food and Drug Administration (FDA) to approve the PD-L1 inhibitor in 2018 for the treatment of patients with unresectable stage 3 non-small cell lung cancer whose disease did not worsen after chemoradiation.

At the time of the FDA approval, Imfinzi was shown to have improved median progression-free survival (time that a patient lives with cancer without disease worsening) by 11.2 months compared with placebo (16.8 months vs. 5.6 months). Moreover, 12-month (55.9% vs. 35.3%) and 18-month (44.2% vs. 27%) progression-free survival rates favored the Imfinzi treatment group. However, the overall survival (time that a patient with cancer is still alive) was immature and not included in that analysis.

“For patients with stage 3 lung cancer that cannot be removed surgically, the current approach to prevent progression is chemoradiation,” said Dr. Richard Pazdur, director of the FDA’s Oncology Center of Excellence, in a statement at the time the drug was approved. “Although a small number of patients may be cured with the chemoradiation, the cancer may eventually progress. Patients now have an approved therapy that has been shown to keep the cancer from progressing for a longer time after chemoradiation.”

“These findings transformed the treatment landscape for unresectable stage 3 disease and established (Imfinzi) following chemoradiotherapy as the new standard of care,” said lead study author Dr. David R. Spigel, chief scientific officer at Sarah Cannon Cancer Institute in Nashville, of the initial study results while presenting the updated findings.

Here, Spigel presented that updated analyses of overall survival and progression-free survival data assessed at five years after the last patient was randomized to treatment.

Of note, the last patient completed treatment in May 2017 and the data cutoff was January 2021. As of data cutoff, 58.8% of all patients had died — 55.5% of whom received Imfinzi and 65.4% of whom received placebo).

An estimated 42.9% of patients randomized to Imfinzi remained alive at five years as opposed to 33.4% of patients who received placebo. Moreover, approximately 33.1% of Imfinzi-treated patients remained alive without disease progression compared to 19% of the placebo group.

“These updated results based on five-year data from the PACIFIC trial demonstrate robust and sustained overall survival and durable (progression-free survival) benefits with the PACIFIC regimen,” Spigel concluded. “This establishes a new benchmark for the standard of care in the unresectable stage III non-small-cell lung cancer setting.”

Spigel highlighted that Imfinzi is being investigated in combination with various chemoradiotherapy regimens as well as other agents following treatment with chemoradiotherapy.

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