Intratumoral PEG-interleukin-2 therapy in patients with locoregionally recurrent head and neck squamous-cell carcinoma

BACKGROUND: An enhanced efficacy of local as compared to systemic administration of interleukin-2 (IL-2) has been demonstrated in several experimental tumors. We previously reported that guinea pigs with palpable tumors and regional micrometastases could be cured by intratumoral injections of polyethylene glycol-modified IL-2 (PEG-IL-2). In the present study this treatment schedule was applied in a clinical situation.

PATIENTS AND METHODS: Nineteen patients with 11 local and 11 regional recurrences of head and neck squamous cell carcinoma (HNSCC) were treated with intratumoral injections of 200,000 U of PEG-IL-2 3 times weekly in courses of 4 weeks.

RESULTS: Treatment was given on an out-patient basis, and was well tolerated. Temporary regional swelling and redness developed in 10 patients, and in 9 of them systemic eosinophilia was documented. Median duration of treatment was 4 weeks (range 2-14 weeks). Seventeen patients were evaluable for response. One complete response (CR; 6%; duration 91 weeks), and 6 stable diseases (SDs; duration 8-57+ weeks) were recorded. The CR and the 3 best SDs (23, 40, 57+ weeks) occurred in patients with a single regional tumor recurrence of relatively small size. During treatment, all 4 developed locoregional edema and redness, and high levels of circulating eosinophils. Median survival was 23 weeks for all patients, and 45+ weeks for the patients with SD.

CONCLUSION: Intratumoral injection of PEG-IL-2 in patients with HNSCC is feasible. This treatment appears beneficial for highly selected patients. The objective response rate is insufficient to justify wide clinical application.