A phase 1 safety study of an IRX-2 regimen in patients with squamous cell carcinoma of the head and neck.

Objectives: Head and neck squamous cell carcinoma (HNSCC) is associated with profound defects in cellular immunity. IRX-2, a primary cell-derived biologic containing multiple cytokines, has enhanced immune responses and induced tumor rejection in preclinical studies. This phase 1 open label study aimed to determine the clinical and laboratory safety of an IRX-2 regimen in patients with HNSCC.

Methods: Patients with HNSCC who had failed surgery and/or radiation therapy were enrolled. IRX-2 was injected subcutaneously at 115 units per dose, 2 doses/d over 10 days, starting on day 4. Patients received low-dose cyclophosphamide infusion on day 1 and took oral indomethacin and zinc daily from day 1 through day 21. Safety and laboratory assessments were undertaken throughout the treatment and 4 weeks after completion of the regimen.

Results: A total of 13 patients with advanced disease were enrolled in the safety/intent-to-treat population; all experienced treatment-emergent adverse events (AEs). The most frequent AEs were blood and lymphatic disorders, followed by gastrointestinal disorders. Most AEs were mild to moderate in severity. Three patients discontinued the study due to an AE, including 2 deaths. Two patients died after the study period due to tumor progression. No death or discontinuation was considered related to the study drugs. Antitumor responses were noted by radiographic assessment. In the 8 patients who had antitumor data at day 21, 1 patient had complete response, 5 had stable disease, and 2 had progressive disease.

Conclusions: The IRX-2 regimen was tolerated in patients with advanced HNSCC who failed surgery and/or radiation therapy. The safety and antitumor activity observed warrants further studies.