Phase III BRIGHT trial of PRX 102 shows drug well tolerated in Fabry Disease.

The results indicate that treatment with 2 mg/kg of PRX 102 administered by intravenous (IV) infusion every four weeks was well tolerated, and Fabry disease assessed by estimated glomerular filtration rate (eGFR) slope and plasma lyso-Gb3 concentration was stable. Overall, 33 of 182 total treatment-emergent adverse events (TEAEs) reported in nine (30.0%) patients were considered treatment-related; all were mild or moderate in severity and the majority were resolved at the end of the study. There were no serious or severe treatment-related TEAEs and no TEAEs led to death or study withdrawal.

Of the treatment-related TEAEs, 27 were infusion-related reactions (IRRs) and the remainder were single events of diarrhea, erythema, fatigue, influenza-like illness, increased urine protein/creatinine ratio, and urine positive for white blood cells. The 27 IRRs were reported in five (16.7%) patients, all male. All IRRs occurred during the infusion or within two hours post-infusion; no events were recorded between two and 24 hours post-infusion. None of the patients without anti-drug antibodies (ADAs) at screening developed treatment-induced ADAs following the switch to PRX 102 treatment.

Study outcome measures show that plasma lyso-Gb3 concentrations remained stable during the study with a mean change (±SE) of 3.01 nM (0.94) from baseline (19.36 nM ±3.35) to Week 52 (22.23 ±3.60 nM). Mean absolute eGFR values were stable during the 52-week treatment period, with a mean change from baseline of -1.27 mL/min/1.73 m2(1.39). Mean (SE) eGFR slope, at the end of the study, for the overall population, was -2.92 (1.05) mL/min/1.73m2/year indicating stability.