Vascular-Targeted Photodynamic Therapy Shows Promise in Low-Risk Prostate Cancer
In a European phase III trial reported in The Lancet Oncology, Azzouzi et al found that padeliporfin vascular-targeted photodynamic therapy was associated with a reduced rate of disease progression vs active surveillance in men with low-risk prostate cancer.
Study Details
In the open-label trial, 413 patients with Gleason pattern 3 disease and no previous treatment from 47 sites in Europe were randomized between March 2011 and April 2013 to receive vascular-targeted photodynamic therapy (n = 206) or active surveillance (n = 207). Photodynamic therapy consisted of 4 mg/kg of intravenous padeliporfin over 10 minutes with optical fibers inserted into the prostate to cover the treatment zone and subsequent activation by laser light at 753 nm with a fixed power of 150 mW/cm for 22 minutes and 15 seconds. Active surveillance consisted of biopsy at 12-month intervals and prostate-specific antigen measurement and digital rectal examination at 3-month intervals.
The co-primary endpoints were treatment failure (histologic progression of cancer from low to moderate or high risk or death at 24 months) and absence of definite cancer (absence of any histology result positive for cancer at month 24) in the intent-to-treat population.
Reduced Disease Progression
Median follow-up was 24 months. Disease progression at 24 months was found in 28% of the photodynamic therapy group vs 58% of the active surveillance group (adjusted hazard ratio = 0.34, P < .0001). Negative prostate biopsy at 24 months was found in 49% vs 14% (adjusted risk ratio = 3.67, P < .0001).
Adverse Events
The most common grade 3 or 4 adverse events were prostatitis (2% in the photodynamic therapy group vs < 1% in the active surveillance group), acute urinary retention (2% vs < 1%), and erectile dysfunction (1% vs 1%). The most common serious adverse event in the photodynamic therapy group was urinary retention, which occurred in 15 patients (7%); urinary retention resolved in all patients within 2 months. The most common serious adverse event in the active surveillance group was myocardial infarction (3 patients, 1%).
The investigators concluded: “Padeliporfin vascular-targeted photodynamic therapy is a safe, effective treatment for low-risk, localized prostate cancer. This treatment might allow more men to consider a tissue-preserving approach and defer or avoid radical therapy.”
The study was funded by Steba Biotech.
Mark Emberton, FMedSci, of University College London, is the corresponding author of The Lancet Oncology article.
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