Imfinzi (durvalumab) combined with radiotherapy suggests promising results for certain patients with non-small cell lung cancer (NSCLC), according to preliminary findings from a phase 2 trail.
Current results from the phase 2 trial, DOLPHIN, determined that the treatment combination of Imfinzi and radiotherapy offered sufficient benefits regarding efficacy and safety for patients with PD-L1 positive (a protein found in abnormally high amounts on certain cancer cells) and unresectable (cannot be surgically removed) locally advanced NSCLC, according to a study published by JAMA Network.
Imfinzi is a type of immunotherapy that is considered both a monoclonal antibody and a checkpoint inhibitor. Imfinzi binds to the PD-L1 protein, which helps immune cells effectively destroy cancer cells. The drug can either be used alone or in combination with another type of cancer drug. Imfinzi was approved by the Food and Drug Administration in 2018 for patients with locally advanced NSCLC.
In the study, the authors reported that there was a total of 35 participants, the majority of whom identified as men and were current or former smokers. The median age of patients was 72 years and more than half of the patients had adenocarcinoma, which is known to be the most common type of NSCLC, according to National Cancer Institute.
Efficacy and safety were two focuses in the study, in which the authors identified 12-month progression-free survival (PFS, period during and after treatment when the disease does not worsen) as their primary endpoint, or the main result at the end of a study to demonstrate the efficacy of a treatment.
Regarding efficacy, the study authors found that the median PFS was 25.6 months with the treatment combination of Imfinzi and radiotherapy. They also established that among 33 patients, 11 had a complete response and 19 had a partial response to treatment. However, it was reported in the study that five patients who had a complete response had postoperative recurrences, meaning their cancer came back after surgery.
“In the preplanned exploratory subgroup analyses for PFS, patients with a complete response or a partial response had better PFS,” wrote the study authors. “Younger patients (aged 75 or younger) and patients with postoperative (after surgery) recurrence had better PFS.”
According to the study authors, the safety profile of Imfinzi with radiotherapy was considered tolerable, although 100% of patients experienced side effects of any grade, meaning side effects that were from mild to severe. In 18 patients, there were grade 3 or 4 side effects, including lower lymphocyte (type of white blood cell) count, pneumonia, lung infection, hyperglycemia (high levels of glucose in blood) and increased levels of aspartate aminotransferase (an enzyme mostly found in the liver).
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“With regard to safety, (side effects) of grade 3 or 4 were more common in the present study (52.9%) than in the PACIFIC trial,” the study authors wrote. “The most common (side effect) in the present study was decreased lymphocyte count (14.7%). Decreased lymphocyte count also occurs with (radiotherapy).”
The PACIFIC trial was a phase 3 trial that evaluated the results of patients with unresectable, locally advanced NSCLC who received Imfinzi with platinum-based, concurrent chemoradiation therapy, according to clinicaltrials.gov.
Based on the preliminary findings of the DOLPHIN trial, the study authors have determined that the treatment strategy of Imfinzi combined with radiotherapy is “promising with tolerable (side effects) and warrants further investigation.”
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