AstraZeneca‘s Imfinzi (durvalumab) decreases the spread of cancer to other parts of the body, explaining the enhanced survival in patients with stage 3 inoperable non-small-cell lung cancer (NSCLC), according to a new analysis of Phase 3 data.
This analysis of survival data was gathered from the Phase 3 PACIFIC trial (NCT02125461) where treatment with Imfinzi — an immunotherapy agent that unblocks the immune system allowing it to attack cancer — after radiation and chemotherapy extended the time in which a patient lived without the disease progressing and significantly improved overall survival rates.
These new results were recently discussed at the 2019 American Society for Radiation Oncology (ASTRO) Annual Meeting in Chicago, in a presentation titled, “Patterns of Disease Progression with Durvalumab in Stage III Non-small Cell Lung Cancer (PACIFIC).”
The analysis was conducted by an independent team of researchers who re-analyzed computerized tomography (CT) scans — combined X-ray images from different angles around the body — from the PACIFIC study.
At the time of the analysis, fewer than half (45.4%) of those being treated with Imfinzi had experienced disease progression or died, compared with 64.6% of patients taking a placebo.
When new cancer lesions appeared, regardless of treatment, it occurred mostly within the chest area (intrathoracic) — 36.6% of patients treated with Imfinzi had new cancer growth in this area alone compared with 48.1% of untreated patients. However, in Imfinzi-treated patients, it took longer on average (25.2 months) for the cancer to come back in the chest compared with the placebo-treated group (9.2 months).
Imfinzi decreased the number of patients with new cancer growth outside the chest area (extrathoracic) as well — 6.9% of treated patients versus 13.1% of patients taking a placebo. It also delayed the appearance of these extrathoracic lesions.
The number of patients with new cancers both inside and outside the chest was also lowered with Imfinzi (1.9% of Imfinzi-treated patients versus 3.4% on placebo). Of the treated patients, 8.8% had new cancer growth outside the chest first, compared with 16.5% of patients on placebo.
When cancer reappeared outside the chest area, regardless of treatment, it mostly occurred in one organ (95.2% versus 94.9%) — and primarily in the brain (61.9% versus 66.7%). New cancer growth occurred in other single organs as well such as bone and liver.
“It is helpful to know that cancer didn’t commonly come back in multiple different places,” Andreas Rimner, MD, study author and radiation oncologist at Memorial Sloan Kettering Cancer Center in New York, said in a press release. “When cancer returns in just one or two areas, it can be amenable to aggressive local therapies.”
“To have a treatment that truly reduces the rate of lesions developing distantly, and reduces the frequency of these distant lesions, is a major step forward and really improves the outlook for these patients,” Rimner added. “The addition of this immunotherapy drug following concurrent chemoradiation really needs to be implemented as the standard of care for these patients.”