RESUMEN
BACKGROUND: The sap from Euphorbia peplus, commonly known as petty spurge in the U.K. or radium weed in Australia, has been used as a traditional treatment for a number of cancers. OBJECTIVE: To determine the effectiveness of E. peplus sap in a phase I/II clinical study for the topical treatment of basal cell carcinomas (BCC), squamous cell carcinomas (SCC) and intraepidermal carcinomas (IEC). METHODS: Thirty-six patients, who had refused, failed or were unsuitable for conventional treatment, were enrolled in a phase I/II clinical study. A total of 48 skin cancer lesions were treated topically with 100-300 µL of E. peplus sap once daily for 3 days. RESULTS: The complete clinical response rates at 1 month were 82% (n = 28) for BCC, 94% (n = 16) for IEC and 75% (n = 4) for SCC. After a mean follow-up of 15 months these rates were 57%, 75% and 50%, respectively. For superficial lesions < 16 mm, the response rates after follow-up were 100% for IEC (n = 10) and 78% for BCC (n = 9). CONCLUSIONS: The clinical responses for these relatively unfavourable lesions (43% had failed previous treatments, 35% were situated in the head and neck region and 30% were > 2 cm in diameter), are comparable with existing nonsurgical treatments. An active ingredient of E. peplus sap has been identified as ingenol mebutate (PEP005). This clinical study affirms community experience with E. peplus sap, and supports further clinical development of PEP005 for the treatment of BCC, SCC and IEC.