Clinical outcomes of concomitant anti-PD-1 therapy and denosumab treatment in non-small cell lung cancer patients with bone metastasis: a single-center retrospective study

INTRODUCTION: Concomitant anti-programmed cell death protein 1 (anti-PD-1) therapy and denosumab treatment can improve clinical outcomes of non-small cell lung cancer (NSCLC) patients with bone metastasis. However, limited data are available among Chinese patients in real-world clinical practice, and the effect of this treatment combination on bone metastases has not been adequately studied. METHODS: This single-centre, retrospective study analysed NSCLC patients with bone metastases who received first-line anti-PD1-therapy and concomitant denosumab treatment between March 2021 and June 2022. Clinical outcomes were described and bone lesion response was evaluated using a novel, exploratory quantitative method based on single photon emission computed tomography/computed tomography scans. RESULTS: Among 66 included patients, the median overall survival was 21.5 months (95% CI: 17.0-NR). The overall survival rate (95% CI) was 96.9% (92.9%-100.0%) at 6 months and 79.7% (70.4%-90.2%) at 12 months. The median progression-free survival was 7.7 months (95% CI: 6.2-12.8). The overall response rate was 36.4% (95% CI: 24.9%-49.1%), with 24 (36.4%) patients having partial response. An exploratory subgroup analysis showed that patients who received ≥ 6 doses of denosumab may have longer median overall survival compared to the < 6 doses subgroup (23.3 vs. 15.3 months, P = 0.023), though immortal time bias and confounding limit interpretation. Out of 33 bone lesions identified, 28 had decreased uptake values between consecutive bone scans (mean change in region-of-interest ratio: -32.7%±19.2%). CONCLUSION: This study described real-world clinical NSCLC patients with bone metastases receiving concomitant anti-PD-1 therapy and denosumab. The findings should be interpreted as exploratory and hypothesis-generating given the retrospective, single-arm design. The novel, quantitative assessment method may provide an exploratory approach to monitoring changes in bone lesions, and further validation in larger, prospective cohorts is required.