June 2015
Volume 56, Issue 7
ARVO Annual Meeting Abstract  |   June 2015
Interim Results of a Dose Escalation Study of NT-503 Encapsulated Cell Therapy for the Treatment of Choroidal Neovascularization in AMD
Author Affiliations & Notes
  • Anat Loewenstein
    Ophthalmology, Tel Aviv Medical Center, Tel Aviv, Israel
  • Hugo Quiroz-Mercado
    Denver Health Medical Center, Denver, CO
  • Jose Luis Guerrero-Naranjo
    Asociacion para evitar la ceguera en Mexico, Coyoacan, Mexico
  • Sergio Rojas
    Hospital de la Luz, IAP Mexico City, Cuernavaca, Mexico
  • Arturo Santos
    Centro de Retina Medica y Quirurgica, Zapopan, Mexico
  • Juan Carlos Altamirano
    Centro de Retina Medica y Quirurgica, Zapopan, Mexico
  • Yael Morales
    Instituto de Ojos Vidaurri, Monterrey, Mexico
  • Rhett Schiffman
    Neurotech, Cumberland, RI
  • Footnotes
    Commercial Relationships Anat Loewenstein, Allergan (C), Bayer (C), NotalVision (C), Novartis (C), Teva (C); Hugo Quiroz-Mercado, None; Jose Luis Guerrero-Naranjo, None; Sergio Rojas, Alcon (R), Allergan (C), Bayer (C), Iridex (I), Neurotech (I), Novartis (C); Arturo Santos, None; Juan Carlos Altamirano, None; Yael Morales, None; Rhett Schiffman, Neurotech (E)
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science June 2015, Vol.56, 2277. doi:
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      Anat Loewenstein, Hugo Quiroz-Mercado, Jose Luis Guerrero-Naranjo, Sergio Rojas, Arturo Santos, Juan Carlos Altamirano, Yael Morales, Rhett Schiffman; Interim Results of a Dose Escalation Study of NT-503 Encapsulated Cell Therapy for the Treatment of Choroidal Neovascularization in AMD. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):2277.

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      © ARVO (1962-2015); The Authors (2016-present)

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Purpose: To evaluate the safety and clinical response to two doses of NT-503 Encapsulated Cell Therapy (ECT) for the treatment of choroidal neovascularization in AMD over a 24 month period. The NT-503 ECT implant continuously releases a soluble vascular endothelial growth factor receptor (VEGFR) protein into the vitreous cavity for at least 2 years.

Methods: This is an on-going, open-label, dose-escalation study. Twenty-six patients in the per-protocol population received a single, ECT implant (releasing 2.0-2.5 μg/d of VEGFR) and 21 patients received two ECT implants (releasing 4.0-5.0 μg/d of VEGFR). Safety and clinical response measures collected during the study include best-corrected ETDRS visual acuity and retinal thickness from registered sd-OCT images read by masked graders at the Duke Reading Center. The need for rescue therapy with ranibizumab, based upon predefined OCT or vision criteria, is also being evaluated.

Results: There was a clear dose response with two implants, achieving greater numerical improvements in visual acuity and reductions in macular thickening. With two implants, there was an improvement in median BCVA of ≥ ~10.0 ETDRS letters from month 12 out to 20 months, the last visit with available data. Median macular thickening improved >~170 microns from month 12 to month 20. To date, 11 of 26 (42.3%) with a single implant and 4 of 21 (19.0%) with double implants required rescue therapy after implantation. Most adverse events were related to the surgical procedure, concurrent ocular conditions, or unrelated conditions. There were no cases of treatment-related cataract or infectious endophthalmitis, or treatment discontinuations.

Conclusions: NT-503 ECT was well tolerated and a dose response was observed. Clinically meaningful improvements in visual acuity and reductions in macular thickening were observed in patients receiving two NT-503 ECT implants out to at least 20 months, thereby establishing a proof of concept for the long-term therapeutic potential of NT-503 in AMD and for the ECT platform. A next-generation single, multi-chamber device, which achieves a 2-3 fold increase in VEGFR production over that achieved with the two implants tested in this study, and which can support combination therapy, is being evaluated in a randomized, masked clinical trial versus aflibercept (Eylea®) dosed on label every 8 weeks.


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