Clearside Biomedical has reported negative results from the Phase III SAPPHIRE clinical trial after it failed to meet the primary endpoint.

The trial investigated the superiority of xipere (formerly suprachoroidal CLS-TA) plus intravitreal anti-VEGF agent eylea (aflibercept) over intravitreal eylea monotherapy for the treatment of retinal vein occlusion (RVO).

A total of 460 patients with treatment naïve RVO were enrolled in the multicentre, masked, controlled trial.

It featured two treatment arms of xipere, plus intravitreal eylea combination and intravitreal eylea-alone.

The randomised trial’s primary endpoint was the proportion of patients in the combination treatment arm, as against the intravitreal eylea-alone control arm, with improvements in best corrected visual acuity (BCVA) from baseline of at least 15 letters on the Early Treatment Diabetic Retinopathy Study (ETDRS) scale at eight weeks following initial treatment.

Patients in both arms received at least 15 ETDRS letters in best corrected visual acuity (BCVA) at eight weeks.

“In the SAPPHIRE trial, approximately 50% of patients in both arms showed at least a 15 letter improvement in vision.”

Results showed that the patients in the xipere plus intravitreal eylea combination arm did not achieve any additional visual outcome benefit over the patients in the intravitreal eylea-alone control arm.

However, the safety profile was reported to be similar with previous studies of xipere after eight weeks.

Clearside Biomedical CEO and president Daniel White said: “In the SAPPHIRE trial, approximately 50% of patients in both arms showed at least a 15 letter improvement in vision. Unfortunately, there was no additional benefit for patients receiving xipere together with intravitreal Eylea.

“In light of these eight-week topline data, we plan to discontinue clinical development of combination therapy for RVO, which includes SAPPHIRE and its companion Phase III clinical trial, TOPAZ.”

Clearside’s first investigational treatment xipere is a proprietary suspension of the corticosteroid triamcinolone acetonide that is developed to be administered to the back of the eye through suprachoroidal space (SCS).