Bassetti MF, Morris BA, Sethakorn N, Lang JM, Schehr JL, Zhao SG, Morris ZS, Buehler D, Eickhoff JC, Harari PM, Traynor AM, Campbell TC, Baschnagel AM, Leal TA. Combining Dual Checkpoint Immunotherapy with Ablative Radiation to All Sites of Oligometastatic Non-Small Cell Lung Cancer: Toxicity and Efficacy Results of a Phase 1b Trial.
Int J Radiat Oncol Biol Phys 2024;
118:1481-1489. [PMID:
38072321 PMCID:
PMC10947887 DOI:
10.1016/j.ijrobp.2023.11.040]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 11/02/2023] [Accepted: 11/17/2023] [Indexed: 12/21/2023]
Abstract
PURPOSE
Ablative local treatment of all radiographically detected metastatic sites in patients with oligometastatic non-small cell lung cancer (NSCLC) increases progression-free survival (PFS) and overall survival (OS). Prior studies demonstrated the safety of combining stereotactic body radiation therapy (SBRT) with single-agent immunotherapy. We investigated the safety of combining SBRT to all metastatic tumor sites with dual checkpoint, anticytotoxic T-lymphocyte-associated protein 4 (anti-CTLA-4), and anti-programmed cell death ligand 1 (anti-PD-L1) immunotherapy for patients with oligometastatic NSCLC.
METHODS AND MATERIALS
We conducted a phase 1b clinical trial in patients with oligometastatic NSCLC with up to 6 sites of extracranial metastatic disease. All sites of disease were treated with SBRT to a dose of 30 to 50 Gy in 5 fractions. Dual checkpoint immunotherapy was started 7 days after completion of radiation using anti-CTLA-4 (tremelimumab) and anti-PD-L1 (durvalumab) immunotherapy for a total of 4 cycles followed by durvalumab alone until progression or toxicity.
RESULTS
Of the 17 patients enrolled in this study, 15 patients received at least 1 dose of combination immunotherapy per protocol. The study was closed early (17 of planned 21 patients) due to slow accrual during the COVID-19 pandemic. Grade 3+ treatment-related adverse events were observed in 6 patients (40%), of which only one was possibly related to the addition of SBRT to immunotherapy. Median PFS was 42 months and median OS has not yet been reached.
CONCLUSIONS
Delivering ablative SBRT to all sites of metastatic disease in combination with dual checkpoint immunotherapy did not result in excessive rates of toxicity compared with historical studies of dual checkpoint immunotherapy alone. Although the study was not powered for treatment efficacy results, durable PFS and OS results suggest potential therapeutic benefit compared with immunotherapy or radiation alone in this patient population.
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