Phase I-II study of intratumor immunotherapy with BCG cell wall skeleton plus P₃

A vaccine composed of BCG cell wall skeleton (CWS) and a trehalose dimycolate called P₃, attached to microdroplets of mineral oil, was evaluated for activity and toxicity when injected into tumor nodules. A total of 99 nodules in 23 patients with metastatic melanoma and carcinoma of the breast were treated overa dose range of 150 μg, 300 μg, and 600 μg cell wall skeleton plus P₃ per cm of nodule diameter. At least one injected nodule resolved in 11 of the 23 patients (48%), and 34% of all injected nodules resolved. Response correlated with nodule size of 1 cm or less, cutaneous location, and immunocompetence measured by PPD and recall skin testing. Toxicity became manifest in ulceration (61% of patients), fever (52%), and pain (26%).