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. 2025 Sep 25.
doi: 10.1111/jdv.70069. Online ahead of print.

KOH 5% solution versus diclofenac 3% for the treatment of actinic keratosis - Results from a three-armed RCT

U Reinhold  1 , N Leitz  2 , R Dominicus  3 , E L Szabó  4 , T Dirschka  5 , G Popp  6 , T C Fischer  7 , N Adamini  8 , R Ostendorf  9 , M Asefi  10 , H Durani  11 , T Hölting  12 , U Amann  13 , F Kreuziger  14 , T Assmann  15 , H Brüning  16 , L Freitag  17 , K Hoffmann  18 , R Gedschold  19
Affiliations

KOH 5% solution versus diclofenac 3% for the treatment of actinic keratosis - Results from a three-armed RCT

U Reinhold et al. J Eur Acad Dermatol Venereol. .

Abstract

Background: Actinic Keratosis (AK) has the potential to progress into malignant cancer, thus necessitating timely and effective treatment. Despite several existing therapies, there is still a need for effective, well-tolerated therapeutic options, especially in the early treatment of patients with few isolated lesions in primary care.

Objectives: To investigate the efficacy and safety of potassium hydroxide (KOH) 5% solution in comparison to diclofenac 3% gel and placebo for the treatment of mild-to-moderate AK.

Methods: In this randomized controlled trial, patients with mild or moderate AK applied KOH or placebo solution double-blinded twice daily for 28 days, followed by a 28-day off-treatment phase (1 treatment cycle) for up to three treatment cycles or until treatment success. In a third arm, diclofenac was applied twice daily for 60 days and evaluated investigator-blinded. The primary endpoint was treatment success, defined as complete clearance (CC) of all initially present AK lesions per patient at the end of treatment (EOT).

Results: In total, 631 patients were enrolled. Treatment success was achieved by 45.2% of patients treated with KOH, compared to 23.8% and 22.9% with diclofenac and placebo, respectively. Similarly, complete remission rates for individual lesions were higher with KOH (65.0%) than with diclofenac (45.9%) or placebo (39.9%). KOH showed a faster onset of action, with higher CC rates already after 1 month compared to diclofenac (16.0% vs. 9.2%) and converging efficacies after 6 months. Most adverse reactions were mild and localized, with comparable tolerability of KOH and diclofenac.

Conclusions: KOH 5% solution proved superior to placebo and, when compared to diclofenac 3% gel, demonstrated significantly higher efficacy at EOT, as well as faster onset of action with comparable long-term efficacy and tolerability. KOH 5% solution is a valuable addition to the available treatment options for lesion-directed therapy in patients with mild-to-moderate AK.

Gov identifier: NCT04552327.

Keywords: actinic keratosis; diclofenac; lesion‐directed therapy; potassium hydroxide.

Plain language summary

Repeatedly sun‐damaged skin can develop rough, scaly patches called actinic keratosis, which may eventually develop into skin cancer. In a trial with 631 adult patients at German medical centers, researchers tested whether a potassium hydroxide (KOH) solution could treat these patches compared to an often‐used standard therapy and to an inactive control (placebo). The results show that KOH solution is effective and safe in the therapy of early‐stage disease and quickly produces noticeable results. This makes KOH a useful option when choosing treatments for patients with early signs of actinic keratosis.

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References

REFERENCES

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