Although major pathological response after neoadjuvant cisplatin-based chemotherapy has been shown to predict survival in patients with early-stage NSCLC, this is the first time a similar association has been demonstrated with neoadjuvant immune checkpoint inhibition, Marie Wislez, MD, PhD, a researcher at Hopital Cochin, Paris, reported at the 2021 European Society of Medical Oncology Congress.
Primary outcomes of the multicenter trial showed 12- and 18-month OS of 89.1%, and 12- and 18-month DFS of 78.3% and 73.7%, respectively, in 46 patients treated with preoperative durvalumab. Median OS and DFS were not reached.
Major pathological response was observed in eight patients (18.6%), with three patients experiencing complete pathological response. No deaths or recurrences were observed in patients in this group. A significant association was observed between major pathological response and DFS. However, the study was stopped early because of excessive 90-day postoperative mortality, which the authors said were most likely related to comorbidities.
The current post hoc analysis of data from the study showed poorer overall survival and disease-free survival with increasing percentage of residual viable tumor (RVT) cells on multivariate prognostic analysis (hazard ratio, 1.05 and 1.06; P = .04 and .02, respectively), Dr. Wislez said in her presentation made on Sept. 18 (abstract 1151MO).
“For each 10% increase of RVT, you have an increased risk of death of 64% and increased risk of recurrence of 71%,” she said.
Study subjects, who were enrolled between April 2017 and August 2019, had a median age of 61 years, 67.4% were men, 98% were smokers or former smokes, and all had Eastern Cooperative Oncology Group performance status scores of 0-1. The median percentage of RVT cells was 36.11.
Of the 50 patients enrolled, 46 were eligible for and received durvalumab and 43 underwent surgery. Those with stages IB and 4 cm or greater tumor size to stage IIIA non-N2 NSCLC received three cycles of durvalumab before surgery. Durvalumab was given intravenously at a dose of 750 mg on days 1, 15, and 29, and surgery was performed 2-14 days after the last infusion.
Tissue specimens from patients who underwent neoadjuvant durvalumab and complete surgical resection were retrospectively evaluated by two pathologists blinded to patient outcomes, Dr. Wislez noted.
Session chair Michael Thomas, MD, of Thoraxklinik-Heidelberg at Heidelberg (Germany) University Hospital, described the study as “hypotheses generating,” and noted that it suggests incremental step-wise assessment of pathological response could be an additional tool for subgrouping of patients in upcoming trials.
Indeed, this novel finding suggests that the extent of pathological response could be considered as a surrogate marker for neoadjuvant treatment trials, although the use of a continuous variable would be challenging in the trial setting, Dr. Wislez agreed.
“But it’s a demonstration that [with] immunotherapy monotherapy ... the extent of pathological response is associated with overall survival,” she said.
This study was funded by AstraZeneca. Dr. Wislez reported honoraria from AstraZeneca, Bristol-Myers Squibb, Boehringer Ingelheim, Eli Lilly Oncology, F. Hoffmann–La Roche, Novartis, Merck, and MSD.