IRX-2 has been evaluated in 2 previous clinical studies:

  • Phase 1 study in 13 patients with recurrent head and neck squamous cell carcinoma (HNSCC)1
  • Phase 2a study in 27 newly diagnosed patients with HNSCC, which was conducted at top US academic centers2


IRX-2 has been adequately tolerated to date with good treatment compliance throughout its clinical program.

  • The most common drug-related adverse events (AEs) were mild nausea and injection site reaction (grade 2 or less); other AEs were generally mild
  • There have been no delays in surgery due to AEs
  • No significant drug-related AE occurred in any laboratory parameter

In the most recent Phase 2 study, 8 serious adverse events (SAEs) were reported in 7 patients.

  • 5 SAEs (aspiration pneumonia in 3 patients, abscess of the neck in 1 patient, and alcohol withdrawal in 1 patient) were considered by the investigator to be unrelated to the study drug
  • 2 SAEs (upper respiratory tract infection and asthma exacerbation) were considered to be unlikely related to the study drug
  • 1 SAE (postoperative neck wound infection) was reported as possibly related to the study drug

Overall, the pattern of SAEs is consistent with that expected in this patient population and does not suggest that the IRX-2 regimen is associated with the occurrence of any unique SAEs.1,2


During clinical studies, changes that may suggest efficacy have been observed in the key cell counts, lymph node changes, infiltration of lymphocytes into the tumor, some regression, delayed recurrence, and improved survival.1,2 In the Phase 2a study, the occurrence of an immunologically mediated antitumor effect was suggested by2,3

  • Pronounced lymphocytic infiltration in some tumors
  • Modest tumor shrinkage at the end of a 21-day regimen in 11 patients
  • Reduction of glycolytic activity in the tumor and lymph nodes on posttreatment PET scan in 1 patient
  • Correlation of improved overall survival at 5 years with high overall lymphocytic infiltration


Increased lymphocyte infiltration in patients with head and neck cancer treated with the IRX-2 immunotherapy regimen. Cancer Immunol Immunother. 2012;61:771-782.

A phase 1 safety study of an IRX-2 regimen in patients with squamous cell carcinoma of the head and neck. Am J Clin Oncol. 2011;34:173-178.

A short course of neoadjuvant
IRX-2 induces changes in peripheral blood lymphocyte subsets of patients with head and neck squamous cell carcinoma. Cancer Immunol Immunother. 2012;61:783-788.

Novel neoadjuvant immunotherapy regimen safety and survival in head and neck squamous cell cancer. Head Neck.