The Pivotal Clinical Study1
The randomized clinical trial published in the Journal of Clinical Investigation established the scientific foundation for the 5-FU + calcipotriene combination.
Citation: Cunningham TJ, Tabacchi M, Eliane JP, et al. J Clin Invest. 2017;127(1):106-116.
Study Overview
This investigator-initiated, randomized, double-blind clinical trial enrolled 131 participants with multiple actinic keratoses. Participants received either topical calcipotriene combined with 5-FU or a control regimen of petroleum jelly plus 5-FU, applied twice daily for four consecutive days.
Participants Enrolled
Treatment Duration
Randomized Study
Why This Study Matters
Most published studies evaluating topical therapies for actinic keratosis involve treatment regimens lasting several weeks. This study explored whether combining calcipotriene with 5-FU could produce meaningful clinical responses following just four days of treatment by engaging the body’s adaptive immune response.
In addition to measuring lesion clearance, investigators examined biological markers of immune activation to better understand how the combination produced its clinical effects.
Clinical Results
Treatment with calcipotriene plus 5-FU resulted in significantly greater reductions in actinic keratoses compared with the control regimen
Key Findings
Significant improvement in lesion reduction
Higher complete and partial clearance rates
Consistent benefit across facial, scalp, and upper extremity treatment sites
Statistically significant findings across primary efficacy measures
Efficacy by Treatment Site1
| Treatment Site | Combination Therapy | Control | P-Value | |
|---|---|---|---|---|
| Face | 87.8% | 26.3% | < 0.0001 | |
| Scalp | 82.5% | 31.2% | < 0.0001 | |
| Upper Extremities | 75.4% | 29.8% | < 0.001 |
Immune Mechanism1
Beyond evaluating clinical outcomes, investigators examined changes within treated skin to better understand the mechanism underlying the observed treatment response.
TSLP Expression
Increased thymic stromal lymphopoietin production
CD4+ T Cell Activation
Activation of helper T cells for immune response
Antigen Presentation
Enhanced markers of cellular recognition
Adaptive Immunity
Evidence of immune system learning and memory
Safety & Tolerability1
Localized skin reactions (redness, burning) at treatment site
Reactions peaked approximately 10-11 days post-treatment
Resolved without serious complications
No scarring, infection, or systemic adverse events reported
Peak Reaction Time
Skin reactions typically peaked around days 10-11 before gradually resolving
Three-Year Follow-Up
Participants from the original randomized study were followed for up to three years to evaluate the durability of the immune response.3
Key Findings
During follow-up, fewer participants who received the combination developed squamous cell carcinoma on treated areas of the face and scalp compared with the control group.3
Investigators also observed evidence consistent with persistent tissue-resident memory T cells.3
These findings support the hypothesis that immune activation may extend beyond the initial treatment period, although additional research is needed to further define the long-term clinical implications.3
Clinical Perspective
The published clinical evidence demonstrates that combining topical 5-FU with calcipotriene produced meaningful reductions in actinic keratoses following a four-day treatment regimen while providing mechanistic evidence of adaptive immune activation.1
Together with the subsequent three-year follow-up, these studies contribute to a growing body of research exploring immune-directed approaches to field treatment in actinic keratosis.3