Author of

• 18502

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  P3.02c - Poster Session with Presenters Present (ID 472)

  • Event: WCLC 2016
  • Type: Poster Presenters Present
  • Track: Advanced NSCLC
  • Presentations: 1
  • Moderators:
  • Coordinates: 12/07/2016, 14:30 - 15:45, Hall B (Poster Area)

  • 18550

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    P3.02c-048 - A Phase I/II Trial Evaluating the Combination of Stereotactic Body Radiotherapy and Pembrolizumab in Metastatic NSCLC (ID 5249)

    14:30 - 14:30  |  Author(s): S. Nath
    • Abstract

    Background:
    Immune checkpoint inhibitors are taking on a growing role in the treatment of patients with metastatic NSCLC. Pre-clinical evidence suggests that radiotherapy may increase the frequency, or enhance the strength of the host anti-cancer immune response. We report the preliminary results of an ongoing phase I/II trial combining stereotactic body radiotherapy (SBRT) and the anti-PD-1 antibody pembrolizumab in patients with metastatic NSCLC.
    
    Methods:
    Eligible patients are those with metastatic NSCLC who have received no prior immune-directed therapy, and have at least 2 sites of measurable disease as per RECIST 1.1. PD-L1 expression is not required for study entry. All patients are treated with pembrolizumab at 200 mg every 3 weeks until development of progressive disease by immune-related RECIST criteria (irPD). After irPD, patients receive SBRT to a single site of disease and continue pembrolizumab. The primary endpoint is safety and tolerability. Secondary endpoints include the pre- and post-SBRT overall response rate.
    
    Results:
    27 patients with advanced NSCLC have enrolled and started trial therapy. The overall response rate (irPR and irCR) to the initial course of pembrolizumab is 35%. To date, 13 patients have had irPD: 5 were not eligible for SBRT and stopped study treatment (2 developed new brain metastases, 3 had decline in PS), and 8 patients received SBRT to a single site of disease (6 thoracic, 1 adrenal, 1 vertebral) and continued pembrolizumab. 5 of these patients are evaluable for post-SBRT response: 1 patient had confirmed irPD, 4 have irSD and continue pembrolizumab post-SBRT at a median duration of 3 months (range 1 to 5 months). 2 of the 4 patients with irSD have had > 20% decrease in the sum of diameters of their unirradiated targets, since SBRT. Regarding adverse events, in the pre-SBRT phase 6 of 27 patients (22%) developed grade 3 treatment-related toxicity (2 colitis, hepatitis, pneumonitis, hypothyroidism, conjunctivitis). In the SBRT and post-SBRT phases, there have been no grade 2 or greater treatment-related events.
    
    Conclusion:
    The addition of SBRT to pembrolizumab has not resulted in an increase in treatment-related toxicity. Several patients who had serially confirmed irPD to pembrolizumab monotherapy underwent SBRT and now have irSD, with some evidence of tumor regression. Updated results will be presented.