Intralesional SD-101 in Combination with Pembrolizumab in Anti-PD-1 Treatment-Naïve Head and Neck Squamous Cell Carcinoma: Results from a Multicenter, Phase II Trial

Academic Article


  • Purpose: To determine whether SD-101, a Toll-like receptor 9 agonist, potentiates the antitumor activity of anti-PD-1 antibodies in patients with anti-PD-1/PD-L1 naïve, recurrent/metastatic head and neck squamous cell carcinoma (HNSCC). Patients and Methods: Patients with PD-1 Ab-naïve HNSCC received either 2 mg SD-101 injected in one to four lesions or 8 mg SD-101 injected into a single lesion weekly X 4 doses then every 3 weeks X 7 doses. Pembrolizumab was administered at 200 mg every 3 weeks. Results: A total of 28 patients received 2 mg and 23 received 8 mg per injection, respectively. A total of 76% of patients had received prior systemic therapy. Combined positive score was ≥1 to < 20 in 35 patients (70%) and ≥ 20 in 15 patients (30%) of 50 patients with available data. There were 12 patients with grade ≥3 treatment-related adverse events (24%), and no treatment-related deaths. The objective response rate was 24% including 2 complete and 10 partial responses. The median duration of response was 7.0 [95% confidence interval (CI): 2.1–11.1] months. The response rate was higher in human papillomavirus–positive (HPVþ) patients (44%, N = 16). Responses were not associated with PD-L1 expression levels or IFNg-related gene expression at baseline. Responses were observed both in injected (32%) and in noninjected lesions (29%). Progression-free and overall survival at 9 months were 19.0% (95% CI: 9.1–31.7) and 64.7% (95% CI: 45.3–78.7), respectively. Conclusions: SD-101 combined with pembrolizumab induced objective responses, especially in HPVþ tumors, which were frequently associated with increased intratumoral inflammation and effector immune cell activity.
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    Digital Object Identifier (doi)

    Author List

  • Cohen EEW; Nabell L; Wong DJ; Day T; Daniels GA; Milhem M; Deva S; Jameson M; Guntinas-Lichius O; Almubarak M
  • Start Page

  • 1157
  • End Page

  • 1166
  • Volume

  • 28
  • Issue

  • 6