Cloudbreak Pharma has reported statistically significant improvements in both primary endpoints of its Phase 3 trial evaluating CBT-001, an investigational eye drop for pterygium. The treatment demonstrated improvements in conjunctival hyperemia and the prevention of progression in pterygium lesion length compared with a vehicle control, with benefits observed at the three-month and 12-month assessments, respectively.
The clinical findings come as the Hong Kong-based biotech faces an investigation into concerns surrounding its initial public offering (IPO). Trading in Cloudbreak shares was suspended in September amid concerns that the company’s IPO may have been manipulated to create an artificial impression of demand for its stock.
CBT-001 Demonstrates Improvements Across Both Endpoints
The Phase 3 study, identified as CS-301 (NCT05456425), evaluated two concentrations of CBT-001, 0.1% and 0.2%, administered twice daily. Both doses were compared with a vehicle control. The primary endpoints assessed changes in conjunctival hyperemia at three months and the prevention of pterygium progression at 12 months.
For the first endpoint, both concentrations demonstrated statistically significant improvements in conjunctival hyperemia at Month 3, with a p-value below 0.001. Improvements were observed as early as Week 2 and remained evident at every subsequent assessment through Month 12.
The second endpoint also favoured CBT-001. Both doses demonstrated statistically significant improvements compared with the vehicle control in preventing progression of pterygium lesion length at Month 12, also achieving a p-value below 0.001. The treatment-versus-vehicle benefit represented approximately 10% of the baseline measurement. Cloudbreak reported that the observed treatment effect had not reached a plateau by the 12-month assessment.
The trial enrolled 659 participants, with 164 assigned to the 0.1% concentration, 329 receiving the 0.2% dose and 166 assigned to the vehicle group. The multinational study was conducted in the United States, China, New Zealand, Australia and India. Participants were followed for up to 24 months under the study protocol, which also included an additional 12-month double-masked extension to collect safety data.
Eye-Related Adverse Events Reported
Superficial punctate keratitis was the most frequently reported adverse event among patients receiving the lower CBT-001 concentration, affecting 20% of participants compared with 8% in the vehicle group. Most cases resolved following treatment with artificial tears. Other individual adverse events occurred in 2% or fewer participants in the 0.1% group.
The higher concentration showed a similar adverse event profile, although the incidence was greater.
Commenting on the findings, Cloudbreak Chief Medical Officer Abu Abraham said, “We are encouraged by the performance of CBT-001 in this Phase 3 trial, which demonstrated consistent, statistically significant improvements in both conjunctival hyperemia and pterygium lesion length.”
FDA Discussions and Development Plans
Cloudbreak plans to conduct additional analyses of the trial results before meeting with the US Food and Drug Administration (FDA) to review the findings and discuss the clinical and regulatory implications for CBT-001.
In March 2026, the company said it planned to begin a second Phase 3 trial during the third quarter of the year, with completion anticipated in late 2028. In September, it estimated that commercialisation of CBT-001 in the United States could take place between 2030 and 2032.
Cloudbreak has commercialisation partnerships covering Greater China and other Asian markets, including Japan and South Korea. As of March, the company was also exploring self-commercialisation and outlicensing options for the United States and other regions.
Separate IPO Investigation Continues
Alongside its clinical development activities, Cloudbreak is addressing concerns surrounding its Hong Kong IPO. Following the suspension of its shares in September, the company’s board decided to establish an independent special committee to investigate the issues raised.
The company also delayed publication of its 2026 interim report in response to the internal investigation. Cloudbreak published an update on the investigation and trading suspension in late September.
Cloudbreak Reports Positive Phase 3 Progress for CBT-001
Cloudbreak Pharma has announced encouraging Phase 3 results for CBT-001 in the treatment of pterygium, a condition that affects the surface of the eye. The trial met its key endpoints, marking an important development for the company and for patients who may need new treatment options.
CBT-001 Reaches Important Clinical Milestones
The successful trial results represent a significant milestone for Cloudbreak and its ophthalmology development program. Meeting Phase 3 endpoints can provide important evidence about a therapy’s potential effectiveness and safety, supporting the next stages of clinical and regulatory development.
CBT-001 is being studied as a potential treatment designed to address pterygium, a condition involving abnormal tissue growth on the eye. Cloudbreak is focused on developing an innovative approach that could help address an area where treatment options have historically been limited.
