Results, Setbacks

Clearside Bio loses nearly half its value pre-market as lead eye drug fails pivotal test

Eye drug developer Clearside Biomedical $CSLD said late-stage data showed its experimental treatment, Xipere, did not induce an additional benefit when used in tandem with Regeneron’s $REGN flagship Eylea in patients with retinal vein occlusion (RVO), a common cause of sudden, painless, loss of vision in one eye.

This Phase III failure has prompted the company to abandon the development of a Xipere (formerly suprachoroidal CLS-TA) combination therapy for RVO, and sent its shares plummeting 46% in pre-market trading.

Boris Peaker

In the SAPPHIRE trial, 460 patients with treatment-naïve RVO were either given Eylea monotherapy or Eylea+Xipere. Topline data after eight weeks showed that in each arm, about half the patients experienced at least a 15-letter improvement in vision, indicating that Xipere did not confer any additional benefit in the trial. Clearside was also testing Xipere in combination with Eylea’s anti-VEGF rivals — Lucentis and Avastin — in the TOPAZ trial. Both trials are being terminated.

In a note published late last month, Cowen’s Boris Peaker had modeled $400 million in peak US sales for Xipere in RVO.

On Monday, the Alpharetta, Georgia-based company said its application to market Xipere, its lead investigational drug, as a monotherapy for uveitis — an inflammation of the middle layer of the eye — remains on track to be filed by the end of the year. Data have shown that Xipere confers significant benefit irrespective of the anatomical location of the uveitis (anterior, intermediate, posterior, or panuveitis), making it a strong competitor to Allergan’s $AGN Ozurdex, which is approved only for posterior uveitis, according to Peaker, who has modelled $100 million in peak US sales for the uveitis indication.

The drug is also being tested as a monotherapy or in combination with Eylea for diabetic macular edema. Clearside’s pipeline of ophthalmic treatments is based on the theory that drugs will be most effective if they can be delivered to the part of the eye that requires treatment, such as the choroid and retina.


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