Abstract 37: Anti-OX40 (MEDI6469) prior to definitive surgical resection in patients with head and neck squamous cell carcinoma

• Published in: Clinical cancer research 2017-12, Vol.23 (23_Supplement), p.37-37
• Main Authors: Bell, R. Bryan, Leidner, Rom S., Duhen, Rebekka A., Ballesteros-Merino, Carmen, Feng, Zipei, Koguchi, Yoshinobu, Bifulco, Carlo B., Curti, Brendan D., Urba, Walter J., Fox, Bernard A., Weinberg, Andrew D.
• Format: Article
• Language: English
• ISSN: 1078-0432; 1557-3265
• DOI: 10.1158/1557-3265.AACRAHNS17-37

Background: Head and neck squamous cell carcinomas (HNSCC) produce suppressive factors that impair the immune system, thus limiting effective antitumor immunity. OX40 is a member of the tumor necrosis factor (TNF) receptor family and its biologic activity leads to potent co-stimulation, which can enhance T-cell memory, proliferation and antitumor activity in patients with metastatic cancer. However, its effect on wound healing and the optimal timing of administration in relation to surgery to induce immune changes within the tumor microenvironment (TME) is not known. Objectives: To determine the safety and peak immunologic activity of neoadjuvant anti-OX40 treatment administered prior to definitive surgical resection in patients with locoregionally advanced HNSCC. Methods: Between January 2016 and July 2016, 10 patients with locoregionally advanced HNSCC were enrolled into this phase Ib neoadjuvant time course trial testing a murine antibody to OX40 (MEDI6469) administered 2 days, 1 week and 2 weeks prior to definitive surgical resection. In order to assess changes in the tumor microenvironment (TME), a tissue biopsy and peripheral blood samples were obtained prior to MEDI6469 infusion and tissue was also harvested at the time of surgical resection from the primary tumor site, metastatic and draining lymph nodes along with peripheral blood. Assessments of tumor infiltrating lymphocyte (TIL) populations were performed based on flow cytometry and fluorescent multiplex immunohistochemistry (mIHC); other circulating immunologic parameters that correlate with changes induced by MEDI6469 administration were also measured. These immune changes were assessed and compiled in a “cumulative suppression index,” which incorporates immunosuppressive elements within the tumor, such as FoxP3+ and PD-L1+ cells, to be correlated with clinical variables and outcome. Surgical complications were described using the Clavien-Dindo grading scale. Clinical trial information: NCT02274155. Results: MEDI6469 administration was well tolerated and there were no grade 3 or 4 adverse events (AEs) attributable to anti-OX40 treatment. The toxicity profile was mild, most commonly consisting of low-grade fever prior to surgery, which was performed in all patients without delay. Postoperative grade 3 and 4 complications per Clavien-Dindo scale were observed in two patients. Immunologic changes were observed at all time courses with significant activation and proliferation of CD4+ and CD8+ cen