MO034A SUBGROUP ANALYSIS OF FEMALE PATIENTS IN A PHASE 3 OPEN-LABEL STUDY TO ASSESS THE SAFETY AND EFFICACY OF PEGUNIGALSIDASE ALFA IN PATIENTS WITH FABRY DISEASE PREVIOUSLY TREATED WITH AGALSIDASE ALFA

Background and Aims Females with Fabry disease (FD) often develop symptoms and disease complications later in life than males. However, they can experience significant health declines, including renal function impairment. Pegunigalsidase alfa is a novel PEGylated alpha-galactosidase A enzyme in development for the treatment of patients with FD with potential pharmacokinetic benefits. We previously reported that males with FD showed improvements in several parameters including median (minimum, maximum) estimated glomerular filtration rate (eGFR) slope from -4.6 (-20.5, 4.8) to -1.1 (-18.6, 14.2) mL/min/1.73m2/year after treatment with pegunigalsidase alfa.(Tondel et al. ASN 2020. PO0562. www.asn.scientificposters.com) Here we report a subgroup analysis of the safety and efficacy of pegunigalsidase alfa treatment in females with FD. Method BRIDGE (PB-102-F30; NCT03018730) is a phase 3, open-label, switch-over study designed to assess the safety and efficacy of pegunigalsidase alfa in adults with FD previously treated with agalsidase alfa for at least 2 years. Patients received intravenous pegunigalsidase alfa at 1 mg/kg every other week for 12 months. Results Twenty-two patients were enrolled in the study; of the 20 patients who completed 12 months of study treatment, 7 were female. Females had a mean age of 46.7 years (range: 26–59 years), and had the following median (minimum, maximum) baseline measurements: residual enzymatic activity in leucocytes of 23.7% (16, 46) of the normal laboratory mean; plasma lyso-Gb3 of 12.9 (7.4, 23.2) nmol/L; eGFR of 87.7 (55.3, 109.2) mL/min/1.73m2; and an annualized eGFR slope of −3.7 (-11.2, 1.5) mL/min/1.73m2/year. After 12 months of pegunigalsidase alfa treatment, the annualized eGFR slope was 1.4 (-6.3, 4.1) mL/min/1.73m2/year, indicating an improvement from baseline of 5.9 mL/min/1.73m2/year. In addition, plasma lyso-Gb3 had a reduction of 23.3% (-45.7, -17.3). Although all females had baseline mean residual enzyme activity > 5% and were previously treated with agalsidase alfa, only 2 had stable kidney disease (eGFR slope ≥ -3 mL/min/1.73m2/year), while 2 had moderately progressing kidney disease (eGFR slope between ≥-5 and < -3 mL/min/1.73m2/year), and 3 had fast progressing kidney disease (eGFR slope < -5 mL/min/1.73 m²/year).( Wanner et al. 2018 Mol Genet Metab 124:189-203) After treatment all but 1 patient experienced categorical improvement or remained stable; this patient had a decline of < 3 mL/min/1.73m2/year and remained in the fast progressing disease category. Mean left ventricular mass index in females increased from 66.9 g/m2 at baseline to 74.1 g/m2 at month 12, but remained within normal ranges(47–77 g/m2).(Kawel-Boehm et al. 2015 J Cardiovasc Magn Reson 17:29) All females had at least 1 treatment-emergent adverse event (TEAE), and all TEAEs were mild or moderate. The most common TEAEs reported in female were nasopharyngitis (n=2), oropharyngeal pain (n=2), and headache (n=2). None of these TEAEs were considered related to treatment. However, 2 females had injection site reactions and 2 developed transient, non-neutralizing anti-drug antibodies to pegunigalsidase alfa treatment. Conclusion The current study included females with symptoms of Fabry disease comparable to the disease presentation of males enrolled in this study. At baseline most females had eGFR decline characterizing progressive or rapidly progressive kidney disease. Most females showed improvements in disease status following 12 months of pegunigalsidase alfa treatment, as previously reported for males enrolled in this study. This long-term, controlled study suggests a potential benefit and a favorable safety profile for pegunigalsidase alfa on renal function in females with FD previously treated with agalsidase alfa. While this subgroup analysis should be interpreted with caution due to the small number of patients, these findings may provide valuable insight for future studies.

Globotriaosylsphingosine (lyso-Gb3) and analogues in plasma and urine of patients with Fabry disease and correlations with long-term treatment and genotypes in a nationwide female Danish cohort

IntroductionRecent studies showed the usefulness of globotriaosylsphingosine (lyso-Gb3) and related analogues, deacylated forms of globotriaosylceramide (Gb3), for high-risk screening, treatment monitoring and follow-up for patients with Fabry disease.MethodsWe evaluated Gb3, lyso-Gb3 and analogues using tandem mass spectrometry in 57 women with Fabry disease followed during a period of 15.4 years. Twenty-one women were never treated and 36 received treatment (agalsidase-beta, n=30; agalsidase-alfa, n=5; or migalastat, n=1). Lyso-Gb3 and analogues at m/z (−28), (−2), (+16), (+34) and (+50) were analysed in plasma and urine. Total Gb3 and lyso-Gb3 analogues at m/z (−12) and (+14) were evaluated in urine while the analogue at m/z (+18) was evaluated in plasma.ResultsA strong correlation between plasma and urine lyso-Gb3 and analogue levels was revealed. Plasma and urine lyso-Gb3 and analogue levels were not statistically different between patients carrying missense (n=49), nonsense (n=6) or deletion mutations (n=2). Never treated patients had lower plasma lyso-Gb3 and analogues at m/z (−28), (−2), (+16), (+34) and the seven urinary lyso-Gb3 analogues compared with pretreatment levels of the treated patients. A significant reduction of plasma lyso-Gb3 and five analogues, as well as urine Gb3 and six lyso-Gb3 analogues, but not lyso-Gb3 and lyso-Gb3 at m/z (+50), was observed post-treatment with agalsidase-beta. The same tendency was observed with agalsidase-alfa.ConclusionWomen with Fabry disease who started treatment based on clinical manifestations had higher lyso-Gb3 and analogue biomarker levels than never treated women. This indicates that a biomarker cut-off could potentially be a decision tool for treatment initiation in women with Fabry disease.

Treatment switch in Fabry disease- a matter of dose?

BackgroundPatients with Fabry disease (FD) on reduced dose of agalsidase-beta or after switch to agalsidase-alfa show a decline in chronic kidney disease epidemiology collaboration-based estimated glomerular filtration rate (eGFR) and a worsened plasma lyso-Gb3 decrease. Hence, the most effective dose is still a matter of debate.MethodsIn this prospective observational study, we assessed end-organ damage and clinical symptoms in 78 patients who had received agalsidase-beta (1.0 mg/kg) for >1 year, which were assigned to continue this treatment (agalsidase-beta, regular-dose group, n=17); received a reduced dose of agalsidase-beta and subsequent switch to agalsidase-alfa (0.2 mg/kg) or a direct switch to 0.2 mg/kg agalsidase-alfa (switch group, n=22); or were re-switched to agalsidase-beta after receiving agalsidase-alfa for 12 months (re-switch group, n=39) with a follow-up of 88±25 months.ResultsNo differences for clinical events were observed for all groups. Patients within the re-switch group started with the worst eGFR values at baseline (p=0.0217). Overall, eGFR values remained stable in the regular-dose group (p=0.1052) and decreased significantly in the re-switch and switch groups (p<0.0001 and p=0.0052, respectively). However, in all groups males presented with an annual loss of eGFR by –2.9, –2.5 and −3.9 mL/min/1.73 m² (regular-dose, re-switch, switch groups, all p<0.05). In females, eGFR decreased significantly only in the re-switch group by −2.9 mL/min/1.73 m² per year (p<0.01). Lyso-Gb3 decreased in the re-switch group after a change back to agalsidase-beta (p<0.05).ConclusionsOur data suggest that a re-switch to high dosage of agalsidase results in a better biochemical response, but not in a significant renal amelioration especially in classical males.