Cloudbreak Pharma Inc. announced top-line results from its phase 3 study of CBT-001 as a potential treatment for pterygium. Both doses of CBT-001 demonstrated statistically significant improvements vs vehicle in conjunctival hyperemia at month 3 and prevention of progression of pterygium lesion length at month 12, the company said in a press release.

According to Cloudbreak, the findings mark the first time a drug has demonstrated disease-modifying activity in pterygium through a statistically significant improvement in hyperemia and lesion size. Additional analyses are ongoing.

For conjunctival hyperemia, both CBT-001 0.2% and CBT-001 0.1% administered twice daily demonstrated statistically significant improvement vs vehicle at month 3 (P<.001). This improvement was observed as early as week 2 and maintained through every visit up to month 12.

Both CBT-001 doses demonstrated statistically significant improvement vs vehicle at month 12 (P<.001). In terms of lesion size, the treatment-vs-vehicle benefit was approximately 10% of baseline. As of month 12, the observed treatment effect had not yet reached a plateau.

In addition, the company noted that superficial punctate keratitis was the most commonly reported adverse event in the CBT-001 0.1% group (20% vs 8% in the vehicle group), with most cases resolving following treatment with artificial tears. All other individual adverse events occurred in 2% or fewer patients in the 0.1% group. A similar adverse event profile was observed with the 0.2% dose, although at a higher incidence.

Cloudbreak said it is conducting additional analyses of the phase 3 results and intends to meet with the US Food and Drug Administration (FDA) to review the study findings and discuss potential next steps for the CBT-001 development program, including the clinical and regulatory implications of the results.

CS-301 is a multi-regional, double-masked, randomized, vehicle-controlled phase 3 trial in patients with pterygium comparing 2 doses of CBT-001 ophthalmic emulsion (0.1%, 0.2%) administered twice daily over 24 months vs vehicle. The primary efficacy endpoints include reduction in conjunctival hyperemia related to the vascularized pterygium lesion at 3 months and prevention of pterygium progression at 12 months. The study protocol also includes a 12-month double-masked extension for an additional 12 months of safety data.

Enrollment began in the United States in June 2022 and expanded to China, New Zealand, Australia, and India. The top-line results summary reports 659 patients: 164 assigned to CBT-001 0.1%, 329 to CBT-001 0.2%, and 166 to vehicle. The study included 58% male and 42% female participants.