Efficacy and safety of hexaminolevulinate photodynamic therapy in patients with low-grade cervical intraepithelial neoplasia

Objective: Non-surgical therapies are needed to reduce the rate of progression of low-grade cervical intraepithelial neoplasia (CIN 1) to high grade CIN (CIN 2/3). The aim of this study was to assess the efficacy and safety of hexaminolevulinate (HAL) photodynamic therapy (PDT) in the treatment of patients with CIN 1.

Study design: This phase IIa prospective double-blind study randomized patients with CIN 1 into three groups: HAL vaginal suppository, placebo vaginal suppository or follow-up only. Patients in the first two groups received HAL or placebo suppositories 5 hours before illumination with 50 J/cm(2) red coherent light (633 nm) using a special light catheter. All patients had a follow up including colposcopy, cytology and human papilloma virus (HPV) testing 3 and 6 months and additional biopsy 6 months after PDT. The main outcome measure was efficacy, defined as complete histologic remission 6 months after PDT. Secondary outcomes were histologic remission 3 months and HPV eradication 6 months after first PDT.

Results: Seventy patients were randomized: 47 to HAL, 12 to placebo, 11 to follow up only. After 6 months CIN lesions had cleared in 57% of patients in the HAL-PDT group compared to 25% in the combined control group (per protocol population, P = 0.04). Twenty-six patients (37%) reported 44 adverse events (AEs), of which 40 were mild or moderate. Nineteen treatment-related AEs were reported by 15 patients (32%) in the HAL PDT group, one in the placebo PDT group (8%), and none in the follow-up group. The most common adverse events were local discomfort including mild pain/cramping (11) and leucorrhoea (2).

Conclusion: HAL PDT shows a favorable efficacy and safety profile and represents a promising alternative to observation and surgical procedures in patients with CIN 1.