Immunogenicity of cipaglucosidase alfa/miglustat versus alglucosidase alfa/placebo in late-onset Pompe disease: a Phase III, randomized study (PROPEL)

Topic:

Clinical Trials

Poster Number: 65

Author(s):

Tahseen Mozaffar, MD, University of California, Irvine, CA, USA, Elfrida Benjamin, Amicus Therapeutics, Inc., Philadelphia, PA, USA, Benedikt Schoser, Ludwig-Maximilians-Universität München, Munich, Germany, Priya Kishnani, MD, Duke University Medical Center, Durham, NC, USA, Jordi Díaz-Manera, MD, PhD, John Walton Muscular Dystrophy Research Centre and Newcastle Hospitals NHS Foundation Trust, UK, Yin-Hsiu Chien, MD, Department of Medical Genetics and Pediatrics, National Taiwan University Hospital, Taipei, Taiwan, Sheela Sitaraman, PhD, Amicus Therapeutics, Inc., Philadelphia, PA, USA, Franklin Johnson, Amicus Therapeutics, Inc., Philadelphia, PA, USA, Hadis Williams, Amicus Therapeutics, Inc., Philadelphia, PA, USA, Eric Anderson, Metrum Research Group, Tariffville, CT, USA, John Mondick, Metrum Research Group, Tariffville, CT, USA, Anthony Sileno, MS, Amicus Therapeutics, Inc., Philadelphia, PA, USA

Protein therapeutics may induce unwanted immune responses, including IgG anti-drug antibodies (ADAs), and uncertainty remains regarding the impact of immunogenicity on late-onset Pompe disease (LOPD) treatments. We assessed the immunogenicity of cipaglucosidase alfa (recombinant human acid ?-glucosidase [rhGAA]/miglustat) and alglucosidase alfa/placebo in the PROPEL study (NCT03729362) in 123 adults (n=95 enzyme replacement therapy [ERT]-experienced; n=28 ERT-naïve) with LOPD. Total anti-rhGAA antibodies (measured using a novel, highly sensitive electrochemiluminescence-based immunoassay), neutralizing antibodies (assays measuring inhibition of rhGAA activity using artificial substrate and glycogen, validated for both enzymes; one assay measuring inhibition of rhGAA–CiMPR binding, validated for cipaglucosidase alfa, only), anti-rhGAA immunoglobulin E and antibody cross-reactivity to alglucosidase alfa were assessed. Immunogenicity assessments were evaluated from baseline to study end. Data were stratified by ERT history (experienced or naïve). Effects of immunogenicity markers on efficacy (6-minute walk test [6MWT], forced vital capacity [FVC]), safety, and pharmacokinetics (PK) were evaluated with graphical and tabular investigation and via estimation of covariate effects of immunogenicity using modeling-based analyses. Proportions of ERT-experienced patients with anti-rhGAA antibodies at baseline versus last study visit were similar and stable across both arms (cipaglucosidase alfa/miglustat 83.1% [54/65] vs 74.1% [43/58]; alglucosidase alfa/placebo 73.3% [22/30] vs 70.4% [19/27]). Proportions of ERT-naïve patients with anti-rhGAA antibodies increased from 0% at baseline to 87.5% (14/16) and 100% (6/6) in the cipaglucosidase alfa/miglustat and alglucosidase alfa/placebo arms by study-end. Tabular, graphical and modeling-based analyses of these data showed no clear trends of an effect of immunogenicity on cipaglucosidase alfa/miglustat or alglucosidase alfa/placebo PK, safety, or efficacy in these patients. Using highly sensitive assays, findings showed that treatment effects (efficacy as measured by 6MWT and FVC, safety, and PK) of cipaglucosidase alfa/miglustat or alglucosidase alfa/placebo were not influenced by the presence of ADAs in this cohort of patients with LOPD. Supported by Amicus Therapeutics.