March 2026

OPHTHALMOLOGY

Q&A WITH CHRIS BOWEN, MD: COMPOUNDED IMIQUIMOD FOR OCULAR SURFACE CANCERS

Can You Briefly Explain Ocular Surface Malignancies and How They’re Treated?
Ocular surface malignancies include ocular surface squamous neoplasia (OSSN) and conjunctival melanoma in situ or primary acquired melanosis with atypia. OSSN ranges from precancerous dysplasia to invasive squamous cell carcinoma and is associated with UV exposure, smoking, HPV and immunosuppression.

These conditions are typically treated with surgical excision and, when disease is diffuse or margins are positive, topical chemotherapies such as compounded 5‑fluorouracil (5‑FU) or mitomycin‑C (MMC). While effective, both can be toxic to the ocular surface and affect vision. Our goal was to find a treatment that could control disease while being gentler on the eye.

Why Are Current Topical Treatments Not Ideal?
5‑FU and MMC are off‑label chemotherapies. Although 5‑FU is fairly effective, repeated cycles increase irritation and discomfort. MMC is even more toxic and is commonly associated with limbal stem cell deficiency, which can cause chronic pain, light sensitivity and vision loss. Despite these risks, they’ve been used because there haven’t been better options.

Imiquimod offers an immunotherapy‑based approach, rather than chemotherapy, which may reduce direct toxicity to the eye.

What Led You To Explore Imiquimod?
At multidisciplinary tumor board meetings at Northwestern Medicine, I saw dermatology colleagues successfully using imiquimod 5% cream for melanoma in situ of the skin. While the commercial cream isn’t suitable for the eye due to irritating alcohols, it raised the question of whether we could compound imiquimod into an ophthalmic‑safe formulation.

Working with a compounding pharmacy, we created a petrolatum‑based ointment that was safe for ocular use. We were encouraged by how well patients tolerated it and by the favorable tumor responses we observed. This kind of innovation is a direct result of strong multidisciplinary collaboration.

What Did the Study Show?
In this initial case series of five patients, compounded imiquimod 5% ophthalmic ointment was well tolerated and resulted in complete response in three patients and partial response in two after 12 weeks of treatment. It’s possible that longer treatment courses could lead to even greater efficacy.

Were Any Findings Surprising?
The most common side effect was a mild “pink‑eye–like” reaction. Interestingly, I found that reassuring because it suggested the drug was activating the immune system. Importantly, these reactions resolved after stopping treatment, and no serious ocular complications were observed.

How Significant Were the Adverse Effects?
Overall, side effects were mild and reversible, mainly involving conjunctivitis or eyelid irritation. When commercial imiquimod cream was used on the eyelids, some patients experienced temporary skin erosion or eyelash whitening or loss, all of which resolved with treatment breaks. We did not see vision‑threatening complications.

Should Clinicians Consider This Treatment Off‑Label?
With only five patients, definitive conclusions can’t be made. However, this study suggests that compounded imiquimod 5% ointment may be a safe and effective option for diffuse conjunctival melanoma in situ or OSSN. Many patients are interested in this approach because of its once‑daily dosing and favorable side‑effect profile.
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What Is the Main Takeaway?
This study introduces a new potential treatment option for ocular surface cancers with early promising safety and efficacy. Compounded imiquimod 5% ophthalmic ointment appears to be well tolerated, reasonably cost‑effective and feasible to compound at other institutions, offering another tool in the treatment of these challenging diseases.
R. Chris Bowen, MD, Director of Ocular Oncology Service and Assistant Professor of Ophthalmology at Northwestern Medicine

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