Dexamethasone/Povidone-Iodine Effective for Conjunctivitis

Caroline Helwick

October 11, 2017

CHICAGO — Dexamethasone/povidone-iodine ophthalmic suspension (SHP640) effectively treated viral conjunctivitis in a randomized controlled phase 2 trial, researchers reported at Academy 2017, the American Academy of Optometry (AAOpt) Annual Conference.

Acute conjunctivitis, or "pink eye," is a highly contagious disease of the ocular surface. It is characterized by redness, discharge, and pain, and is associated with significant patient discomfort and lost productivity. In adults, the cause is usually adenovirus, while in children it is usually bacterial.

"No medications are currently approved in the U.S for adenoviral conjunctivitis. Infected patients can easily transmit the disease to others," said lead investigator Abhijit Narvekar, MBBS, DPM, MS, director of Global Clinical Development at Shire in Lexington, Massachusetts, who presented the findings at a press briefing today.

Combination Drug

SHP640 is being evaluated for the treatment of infectious (adenoviral and bacterial) conjunctivitis in adults and children. Shire obtained SHP640 (formerly known as FST-100) through the acquisition of Foresight Biotherapeutics, Inc, in August 2015. It combines a broad-spectrum antiseptic (povidone-iodine, 0.6%) and an anti-inflammatory steroid (dexamethasone, 0.1%).

"If approved, SHP640 could be a single treatment option for both adenoviral and bacterial conjunctivitis, which are challenging to differentiate clinically," Dr Narvekar said.

Phase 2 Study

The company conducted a multicenter, double-masked phase 2 trial to test SHP640 in 176 Asian adults with a positive Rapid Pathogen Screening Adeno Detector Plus TM test. Participants were randomized to SHP640, to povidone-iodine (PVP-I), or to vehicle. Mean age was 34.5 years, and 66% were males. One drop of study was instilled in both eyes four times daily for 5 days.

The primary efficacy endpoints were clinical resolution and adenoviral eradication (negative cell culture-immunofluorescence assay). Safety measures included slit-lamp biomicroscopy with nondilated fundus exam, best clinical visual acuity, and adverse events. 

Efficacy and Safety Demonstrated

Patients treated with SHP640 were significantly more likely to have clinical resolution of conjunctivitis as determined by the absence of conjunctival discharge and bulbar redness at Day 6. The separate components of conjunctival discharge and bulbar redness were also significantly improved (Table), Dr Narvekar reported.

Table. Efficacy Outcomes for SHP640, PVP-I and Vehicle

Endpoint

SHP640

(N=48)

PVP-I

(N=50)

Vehicle

(N=46)

P Value,

SHP640 vs Vehicle

Clinical resolution (%) 31.3 18.0 10.9 .0158
Watery conjunctival discharge (%) 54.2 32.0 26.1 .0056
Bulbar conjunctival redness (%) 33.3 18.0 13.0 .0202
Adenovirus eradication, Day 6 (%) 79.2 62.0 56.5 .0186

The proportion of patients demonstrating eradication of virus at the Day 6 visit was also significantly higher with SHP640 versus vehicle and numerically higher versus PVP-I (Table).

At the Day 12 visit, 95.8% were free of virus after SHP640 treatment, compared with 84.0% of the PVP-I group and 76.1% of the vehicle arm (P = .0056 vs vehicle).  Eradication was observed as early as Day 3 with both SHP640 and PVP-I (35.4% and 32.0%, respectively), which were both significantly higher than the 8.7% rate achieved with vehicle.

No serious adverse events were reported. The majority of treatment-emergent adverse events were mild and none were considered related to study treatment. The three most common were corneal infiltrates, punctate keratitis, and eyelid edema, all of which were more common in the comparison arms than in the SHP640 arm.

"Results of this phase 2 study showed that SHP640 had significantly better outcomes, in terms of clinical resolution and adenoviral eradication, than with vehicle. They support its continued investigation for the treatment of acute adenoviral conjunctivitis and the continued evaluation of the results on duration of illness," Dr Narvekar said.

Phase 3 studies are currently under way in both adenoviral and bacterial conjunctivitis.

Potentially Practice-changing

Press briefing moderator Edward Chu, OD, from the Long Beach VA Medical Center in California, said that SHP640 could make a difference in how conjunctivitis is managed in the clinic.

"Currently, conjunctivitis is essentially treated like the common cold. You can use lubricants, but that's not exactly treating the underlying condition. Optometrists usually just tell patients, 'This will go away on its own,' and it is self-resolving. But this study, along with some smaller studies and anecdotal reports, suggests that this treatment can speed the resolution of conjunctivitis faster," Dr Chu said. 

"Now, we may have something that could reduce the time that the eye is red, and that could definitely change practice," he commented.

Dr Narvekar is employed by Shire, who is developing SHP640. Dr Chu has disclosed no relevant financial relationships.

American Academy of Optometry (AAOpt) 2017 Conference. Presented October 11, 2017.

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