Neoadjuvant atezolizumab prior to lung cancer surgery was well tolerated by patients with stage IB-IIIB lung cancer and produced a 21% major pathologic response rate, according to the primary analysis of the Lung Cancer Mutation Consortium (LCMC) 3 study.
Small pilot studies previously suggested that preoperative immune checkpoint inhibitor (ICI) therapy may benefit patients with resectable non-small cell lung cancer (NSCLC).
The LCMC3 study is “unique” because it is the largest monotherapy trial of checkpoint inhibition in resectable NSCLC, and it’s “a landmark study” because it validated results from smaller trials and can serve as a benchmark for future ones, said Jay M. Lee, MD, of the University of California, Los Angeles.
Lee presented results from LCMC3 at the 2020 World Congress on Lung Cancer (Abstract PS01.05), which was rescheduled for January 2021.
The study included 181 patients, median age 65 years, with stage IB-IIIB NSCLC. The vast majority (90%) of patients were current/former smokers, and two-thirds had a nonsquamous histology. Patients were categorized in the following stages: 17 patients were staged at IB, 20 were IIA, 55 were IIB, 72 were IIIA, and 17 were IIIB.
Patients received 1,200 mg of neoadjuvant atezolizumab intravenously every 3 weeks for two cycles followed by resection between 30 and 50 days from the first cycle. Patients who benefited from the therapy continued adjuvant atezolizumab for 12 months.
The primary endpoint was major pathological response, defined as no more than 10% viable tumor cells at surgery, in patients without epidermal growth factor receptor or anaplastic lymphoma kinase mutations.
Following atezolizumab treatment, 43% of patients were down-staged, and 19% were up-staged. Some degree of pathological regression was observed in all but 3 of the 159 patients who underwent resection.
Among the 144 patients included in the efficacy analysis, the major pathological response rate was 21%, with 7% of patients achieving a complete pathological response.
“We demonstrated that more than half of patients resected with a minimally invasive operation. Remarkably, only 15% required thoracotomy. The 92% complete resection rate is comparable, if not superior to, preoperative chemotherapy trials,” Lee said.
The majority (88%) of patients underwent surgical resection within a 20-day protocol window. The median time from end of neoadjuvant therapy to surgery was 22 days.
“Historically, the neoadjuvant chemotherapy window is much later for surgery, 3 weeks from neoadjuvant therapy, and that can be stretched to up to 56 days,” Lee said.
In an exploratory analysis, the 1.5-year overall survival rate was 91% for stage I and II disease and 87% for stage III disease. The survival in both cohorts was superior to that expected historically, Lee noted.
Intraoperative complications were rare (3%). Postoperative adverse reactions correlated with fewer viable tumor cells in the resected specimen.
One patient died following surgery after the first 30 days, which was deemed unrelated to treatment. Another patient died between 30 and 90 days from treatment-related pneumonitis.
“The LCMC3 study successfully met its primary endpoint of achieving major pathological response,” Lee concluded. “Neoadjuvant atezolizumab monotherapy was well tolerated, and resection was performed with low perioperative morbidity and mortality, usually within a narrow protocol window and with a short time frame from completion of atezolizumab and with a correspondingly high complete resection rate.”
The study’s results suggest that “neoadjuvant atezolizumab monotherapy is effective, well tolerated, and surgically acceptable,” said study discussant Shinichi Toyooka, MD, of Okayama (Japan) University Hospital.
“I would consider single-agent ICI neoadjuvant therapy for patients with early-stage disease and poor performance status, and an ICI plus chemotherapy for more advanced resectable cases, like locally advanced disease,” Toyooka said.
The LCMC3 study is sponsored by Genentech. Lee disclosed relationships with Genentech/Roche, AstraZeneca, Bristol-Myers Squibb, Merck, and Novartis. Toyooka disclosed relationships with AstraZeneca, Chugai, Taiho Pharmaceutical Group, and Ono Pharmaceutical.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.