Results of a Phase I Clinical Study Using Dendritic Cell Vaccinations for Thyroid Cancer

Objective: We assessed the feasibility and efficacy of dendritic cell (DC) therapy for advanced thyroid papillary and follicular cancer. Design: Six Japanese patients (2 men and 4 women; aged 46–72 years, mean 60 years), who were diagnosed as advanced thyroid cancer with refractory distant metastases (papillary, n=5; follicular, n=1), were enrolled. Patients were first vaccinated weekly for 4 weeks with 10⁷ autologous tumor lysate-pulsed monocyte-derived mature DCs followed by fortnightly vaccinations for 8 weeks (total=8 vaccinations). Lowdose(350 KIU) interleukin-2 was also administered for 3 days at each vaccination. Clinical response, adverse effects, delayed-type hypersensitivity skin testing (DTH), and IFN- _γ production by peripheral CD3⁺ lymphocytes were evaluated. Main Outcome: Of the 6 patients, disease was assessed as stable in 2 and as progressive in 4. No adverse events were observed. Results of DTH and IFN- _γ production in peripheral lymphocytes did not correlate to the clinical response. Conclusions: DC immunotherapy could be administered to patients with thyroid papillary or follicular cancer without substantial side effects.