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Device inadequacy seen as factor in failure of encapsulated cell therapy to meet goal
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SAN FRANCISCO — Device inadequacy and wrong patient population were postulated as contributing factors in the failure of NT-503-3, an encapsulated cell therapy, to meet its primary goal of fewer than 20% of patients requiring rescue therapy following implant placement.
“The encapsulated cell technology [Neurotech] did what it was supposed to; however, a high rate of rescue events resulted in early study termination,” Szilárd Kiss, MD, said at the American Society of Retina Specialists annual meeting.
Szilárd Kiss
At the time of study termination, 26 devices had been implanted and 40% of participants had been enrolled in the phase 2 study comparing the third generation of the VEGF receptor encapsulated technology with every other month dosing with Eylea (aflibercept, Regeneron) in patients with neovascular age-related macular degeneration. The primary endpoint was noninferiority with regard to visual acuity.
Among reasons for the failure, Kiss suggested that even though the device did produce anti-VEGF, “The encapsulated device technology did not produce enough anti-VEGF in these elderly patients to stop the act of [choroidal neovascularization]. And, perhaps it was the wrong patient population. They needed too much anti-VEGF. Hardship environment for cells in terms of nutrients and oxygen may also have been a contributing factor.”
Patients received at least three previous injections of aflibercept, with the last injection being no more than 4 months earlier, they had good responses to injections, best corrected visual acuity was between 20/25 and 20/200 at screening and baseline, and patients had limited pathology that would impair any visual gains.
“Importantly, the drug levels were inadequate,” Kiss said, even though theoretical modeling and animal studies suggested higher anti-VEGF levels would be produced.
“This phase 2 trial really presents to us the challenges ... to decreasing that real-world injection burden,” Kiss said. – by Patricia Nale, ELS
Reference:
Kiss S. Key learnings from a phase 2 study of encapsulated cell therapy for the treatment of neovascular AMD. Presented at: American Society of Retina Specialists annual meeting; Aug. 9-14, 2016; San Francisco.
Disclosure: Kiss reports he is a consultant for Neurotech.