Long-term Responders to Nanoparticle Albumin-bound Paclitaxel Following Immune Checkpoint Inhibitor in Non-small Cell Lung Cancer.

Background/aim: The efficacy of cytotoxic chemo-therapy has been reported to improve after immune checkpoint inhibitor (ICI) administration. We previously conducted a multicenter prospective clinical study to evaluate the efficacy and safety of nanoparticle albumin-bound paclitaxel (nab-PTX) after ICI treatment. In that study, some patients showed a long-term response to nab-PTX, which is not usually observed with single-agent chemotherapy. The present study aimed to evaluate the clinical characteristics of these patients.

Patients and methods: We retrospectively analyzed updated data from 29 patients enrolled in our clinical study who received nab-PTX monotherapy after ICI treatment. We defined a "long-term responder" as a patient who achieved a 1-year progression-free survival (PFS).

Results: Among the 29 patients, 10 (34.5%) were long-term responders, two of whom achieved a 5-year PFS. A key difference between long-term and non-long-term responders was that the long-term responders had a significantly higher number of patients with Eastern Cooperative Oncology Group-performance status of 0 (70.0% versus 10.5%; p=0.002). Furthermore, median cycles of previous ICIs and median treatment cycles were significantly higher in long-term responders than in non-long-term responders (8 cycles versus 3 cycles; p=0.03) (5.9 months versus 2.0 months; p=0.02). In the 10 long-term responders, six patients required at least a one-stage dose reduction owing to adverse events, and four patients required a two-stage dose reduction.

Conclusion: Nab-PTX administration after ICI treatment may elicit a long-term response. A long-term response can be achieved even with a dose reduction due to adverse events.