The timing of durvalumab administration affects the risk of pneumonitis in patients with locally advanced non-small cell lung cancer: a systematic review and meta-analysis.

Purpose: The PACIFIC study has demonstrated that the administration of durvalumab following concurrent chemoradiotherapy can significantly improve both overall survival and progression-free survival rates in patients with locally advanced unresectable non-small cell lung cancer. While the latest NCCN guidelines recommend this combination regimen, they do not specify the optimal timing for administering durvalumab after completing radiotherapy. The PACIFIC study suggested initiating durvalumab within 42 days of completing radiotherapy, but early administration of the drug may increase the incidence of pneumonitis. Therefore, we conducted this study to investigate whether the time interval between completion of radiotherapy and initiation of durvalumab treatment is associated with the risk of pneumonitis (Grade ≥ 3), which is the primary endpoint, as well as progression-free survival, which is the secondary endpoint.

Methods: A comprehensive search of clinical trials in PubMed and EMBASE was conducted up to March 2023 to identify clinical trials involving locally advanced unresectable non-small cell lung cancer patients who were treated with durvalumab following chemoradiotherapy. Meta-analysis was performed on single-arm studies to estimate the incidence of pneumonitis (Grade ≥ 3) and progression-free survival in all studies, as well as in studies that administered durvalumab within 42 days after completion of radiotherapy.

Results: This meta-analysis consisted of nine studies with a total of 2560 patients. The analysis showed that the incidence of pneumonitis (Grade ≥ 3) was 5.36% [95%CI (0.03, 0.08), I = 18.41%, p = 0.29], while the 1-year progression-free survival rate was 57.91% [95%CI (0.53, 0.63), I = 10.57%, p = 0.35]. Furthermore, when the duration between completion of radiotherapy and initiation of durvalumab treatment was shorter than 42 days, the incidence of pneumonitis (Grade ≥ 3) was 4.12% [95%CI (0.02, 0.06), I = 0.00%, p = 0.56], with a 1-year progression-free survival rate of 61.03% [95%CI (0.51, 0.71), I = 59.06%, p = 0.09].

Conclusion: Overall, based on the available evidence, it appears that there is no significant increase in pneumonitis or decrease in progression-free survival (PFS) when the time interval is less than 42 days and a shorter interval between treatment sessions does not necessarily have a detrimental effect on the rate of pneumonitis. We recommend that clinicians carefully evaluate the specific circumstances of each patient to determine the optimal timing for initiating immunotherapy.