Purpose
Subjects with long-standing low vision due to retinal or optic nerve pathology and subjects with acute NAION were studied in a 1 year, 2-stratum, Phase I, multi-center, open-label, dose escalation study to determine safety, tolerability and the structural and functional changes after a single IVT injection of QPI-1007, a synthetic, chemically modified siRNA that inhibits expression of caspase 2.
Methods
Low vision subjects with visual acuity (VA) ≤20/200 (Stratum I) and NAION subjects with ≤20/40 and symptom onset within 28 days prior to the study drug injection (Stratum II-S2) were enrolled in 6 cohorts (0.2-6 mg) and 3 cohorts (1.2, 2.4 & 6 mg), respectively. After receiving a single IVT injection, subjects were evaluated for VA, visual field (VF) and retinal nerve fiber layer(RNFL) thickness at days 1, 7, 14, 28, and months 2, 3, 6, 12.
Results
48 subjects (18 low vision, 30 NAION) were enrolled. All expected study visits are complete for all subjects, except the final follow-up visit (Month 12) for the last enrolled cohort (S2, 6 mg). Available data from both strata through Month 3 (n=48), Month 6 (n=48) and Month 12 (n=38) were analyzed. 261 of 273 adverse events (AEs) were of mild-to-moderate severity. There were no serious AEs. The most common AEs were conjunctival hemorrhage (n=29), conjunctival chemosis (n=11), and eye pain (n=11). Among 28 NAION subjects in S2 with on-chart VA, maximum VA gain was at Month 2 (mean± SD: 16.4 ±10.4 letters). The proportion of subjects in S2 (Figure 1) improving by ≥3 lines at Months 3 and 6 were 53.6% (n=15), and 50.0% (n=14) compared with 39.7% (n=48), and 42.6% (n=52) of IONDT historical controls (p = 0.2 and 0.5, respectively; Fisher exact test) [IONDT, 2000]. Of all the S2 subjects with available follow-up data, no subject lost ≥3 lines of VA compared with 9.1% (n=11), 14.8% (n=18), and 15.8% (n=18) at Months 3, 6 and 12, respectively, in the IONDT historical controls. VF mean defect was comparable to baseline. Decrease in RNFL thickness was similar to historical controls [Contreras et al., 2007].
Conclusions
A single IVT injection of QPI-1007 was well tolerated in subjects with long-standing low vision or acute NAION. Further studies are needed to determine QPI-1007’s effect on visual function and RNFL thickness.