Nearly Half of Imfinzi-treated NSCLC Patients Alive After 4 Years, PACIFIC Update Shows

Nearly Half of Imfinzi-treated NSCLC Patients Alive After 4 Years, PACIFIC Update Shows

Imfinzi (durvalumab) continues to demonstrate a sustained survival benefit in patients with inoperable, locally advanced non-small cell lung cancer (NSCLC) who had not progressed after platinum-based chemotherapy and radiation therapy, a four-year analysis shows.

Updated findings from the PACIFIC Phase 3 trial (NCT02125461) demonstrate that, at four years, more participants receiving Imfinzi were alive, compared with those on a placebo. In addition, nearly double the number of participants were alive and without signs of disease progression.

These results “set a new survival benchmark,” José Baselga, MD, PhD, executive vice president, oncology R&D, at AstraZeneca said in a press release. AstraZeneca developed Imfinzi.

The findings were shared at the 2020 European Society for Medical Oncology (ESMO) Virtual Congress, recently held online, in a presentation titled “Durvalumab after chemoradiotherapy in stage III NSCLC: 4-year survival update from the phase III PACIFIC trial.”

Imfinzi is an antibody that binds the PD-L1 protein on cancer cells, which prevents tumors from evading immune attacks. 

PACIFIC was designed to evaluate Imfinzi against a placebo in people with inoperable, locally advanced NSCLC that had not progressed following concurrent chemotherapy and radiation therapy. It enrolled 713 patients across 26 countries, regardless of their PD-L1 status — whether or not they carried this marker of responses to immune checkpoint inhibitors like Imfinzi.

Previous data from PACIFIC had demonstrated that, compared with a placebo, Imfinzi significantly extended the time to disease progression or death, and prolonged overall survival. Those results had led to the therapy’s 2018 approval by the U.S. Food and Drug Administration for this NSCLC patient population. The treatment was approved in the EU for the same patient population, by the European Commission, in September 2020, following other trial results.

Later analyses of the PACIFIC trial found that Imfinzi’s survival benefits continued to be observed after three years, with the therapy maintaining a 31% reduction in the risk of death compared with the placebo.

The new updated findings presented at the ESMO meeting were based on data collected after a median follow-up of 34.2 months — almost four years after the last patient entered the trial.

The results revealed that individuals receiving Imfinzi lived a median of 47.5 months, or almost one and a half years longer, than those on a placebo, who had a median 29.1-month survival rate. This represented a 29% reduction in the risk of death.

After four years, almost half of patients on Imfinzi (49.6%) were still alive, compared with a little over one third (36.3%) of the placebo-treated patients.

Further, Imfinzi nearly doubled the proportion of patients who survived four years without ever showing signs of disease progression (35% vs. 19.5% for placebo). The median time these patients lived without disease worsening also was almost one year longer with Imfinzi. 

“Previously, only 15 to 30 percent of patients with [inoperable], stage III non-small cell lung cancer survived five years, and the majority eventually progressed to metastatic disease,” said Corinne Faivre-Fin, MD, PhD, professor at the University of Manchester and a lead investigator in PACIFIC.

“These data show about half of patients treated with IMFINZI survived four years, and an estimated 35 percent had not progressed, a remarkable advance in this curative-intent setting,” Faivre-Fin said.

Common adverse events reported from PACIFIC among treated patients versus placebo were cough (35.2% vs. 25.2%), fatigue (24.0% vs. 20.5%), shortness of breath (22.3% vs. 23.9%), and inflammation of the lung caused by radiation therapy (20.2% vs. 15.8%). 

Serious adverse events were experienced by 30.5% of patients treated with Imfinzi compared with 26.1% for placebo. A total of 15.4% of patients on Imfinzi discontinued treatment due to adverse events compared with 9.8% for placebo. No new adverse events were reported. 

Imfinzi continues to be investigated in other types of cancer, either alone or in combination with other medications. 

“These unprecedented four-year results reinforce Imfinzi as the established standard of care in [inoperable, locally advanced] non-small cell lung cancer and set a new survival benchmark in a setting where cure is the treatment goal,” Baselga said.