17P - Correlation between plasma EBV DNA and clinical response to pembrolizumab in patients with advanced or metastatic nasopharyngeal carcinoma

Date 20 November 2015
Event ESMO Symposium on Immuno-Oncology 2015
Session Welcome reception and general Poster viewing
Topics Immunotherapy
Head and Neck Cancers
Presenter Hsiang-Fong Kao
Citation Annals of Oncology (2015) 26 (suppl_8): 5-14. 10.1093/annonc/mdv514
Authors H. Kao1, C. Hsu1, H. Huang1, J. Cheng2, R. Hong1
  • 1Oncology, National Taiwan University Hospital, 10002 - Taipei/TW
  • 2Oncology Clinical Research, Merck Sharpe and Dohme, 19454 - North Wales/US



KEYNOTE-028 is a phase Ib trial of pembrolizumab for recurrent or metastatic, PD-L1+ solid tumors, including nasopharyngeal carcinoma (NPC). The correlation between plasma Epstein-Barr virus (EBV) DNA level, an established prognostic factor for NPC, and responses to pembrolizumab treatment was explored.


Plasma EBV DNA of NPC patients who were enrolled into KEYNOTE-028 at our center were followed and analyzed by a certificated laboratory using RealStar EBV PCR Kit (Altona Diagnostics) and ABI 7500 (Applied Biosystems). Pembrolizumab 10 mg/kg was administered every 2 week for up to 2 years or until confirmed progression or unacceptable toxicity. Treatment response were evaluated every 8 weeks by computed tomography (RECIST 1.1).


Eight patients were enrolled at our hospital and 4 patients had serial EBV DNA follow-up. At the first response evaluation, two patients had partial response, one had stable disease, and one had progressive disease. Plasma EBV DNA decreased in the patients with partial response or stable disease, but increased in the patient with progressive disease. One partial responder had tumor progression later, and the plasma EBV DNA started to elevate 6 weeks before the documentation of tumor progression by imaging. The other partial responder was still under pembrolizumab treatment and already took 23 cycles of treatment. The plasma EBV DNA was always under 1,000 copies/mL. The patient with stable disease discontinued study treatment after cycle 13 due to toxicity. The plasma EBV DNA elevated at the end of treatment and the last image showed 111% increase in the target lesion.


Our preliminary findings suggest that plasma EBV DNA may correlate with response to pembrolizumab treatment. Elevation of plasma EBV DNA may be an early sign of progressive disease.

Clinical trial identification



J. Cheng: Employee of Merck Sharp and Dohme. All authors have declared no conflicts of interest.