Phase 1B study to improve immune responses in head and neck cancer patients using escalating doses of...

Patients with head and neck squamous cell carcinoma (HNSCC) have profound immune defects. These defects are associated with a poor prognosis and are mediated, in part, by immune inhibitory CD34(+) progenitor cells, whose numbers are increased in the peripheral blood of HNSCC patients. Immune inhibitory CD34(+) cells are also present within HNSCC tumors. A phase IB clinical trial was conducted with HNSCC patients to determine if treatment with the differentiation-inducer 25-hydroxyvitamin D(3) could diminish CD34(+) cell levels and improve a panel of immune parameters. Here we present the results of treatment with orally administered escalating doses (20, 40, 60 microg) of 25-hydroxyvitamin D(3), with an emphasis on the six patients who received the maximum dosage of 60 microg per day. Peripheral blood was collected at 0, 1, 2, 4, and 6 weeks, and assessed for markers of immune activity. Although no clinical responses were observed, results of this pilot study demonstrated that treatment of HNSCC patients with 25-hydroxyvitamin D(3 )reduces the number of immune suppressive CD34(+) cells, increases HLA-DR expression, increases plasma IL-12 and IFN-gamma levels, and improves T-cell blastogenesis. In contrast, 25-hydroxyvitamin D(3) treatment did not modulate plasma IL-1beta, IL-2, IL-4, IL-6, IL-10, GM-CSF, or TGF-beta levels.