Identification and Optimization of RNA-Splicing Modulators as Huntingtin Protein-Lowering Agents for the Treatment of Huntington's Disease

  • J Med Chem. 2023 Sep 28;66(18):13205-13246. doi: 10.1021/acs.jmedchem.3c01173.
Longbin Liu  1 Karine Malagu  2 Alan F Haughan  2 Vinod Khetarpal  1 Andrew J Stott  2 William Esmieu  2 Huw D Vater  2 Stephen J Webster  2 Amanda J Van de Poël  2 Cole Clissold  2 Brett Cosgrove  2 Benjamin Sutton  2 Jonathan A Spencer  2 Perla Breccia  2 Emanuela Gancia  2 Silvia Bonomo  2 Tammy Ladduwahetty  2 Ovadia Lazari  2 Hiral Patel  2 Helen C Atton  2 Steve Clifton  2 Daniel M Mota  2 Dario Magnani  2 Amy O'Neill  2 Marta Stebbeds  2 Natsuko Macabuag  2 Daniel Todd  2 Maria E Herva  2 Philip Mitchell  2 Mijke Visser  3 Sara Compte Sancerni  3 Laure Grand Moursel  3 Marta da Silva  3 Eva Kritikou  3 Taneli T Heikkinen  4 Tamuna Bolkvadze  4 Valentina Fodale  5 Debora Spadafora  5 Manuel Daldin  5 Alberto Bresciani  5 John E Mangette  6 Elizabeth M Doherty  1 Matthew R Lee  1 Todd Herbst  1 Edith Monteagudo  1 Douglas Macdonald  1 Nikolay V Plotnikov  1 Mark Chambers  2 George McAllister  1 Ignacio Muňoz-Sanjuan  1 Celia Dominguez  1
Affiliations
  • 1. CHDI Management/CHDI Foundation, 6080 Center Drive, Los Angeles, California 90045, United States.
  • 2. Discovery from Charles River, Charles River, Chesterford Research Park, Saffron Walden CB10 1XL, U.K.
  • 3. Charles River, Darwinweg 24, 2333 CR Leiden, The Netherlands.
  • 4. Charles River, Microkatu 1, Kuopio 70210 Finland.
  • 5. IRBM S.p.A., Pomezia, Roma 00071, Italy.
  • 6. Curia Global, Inc., Buffalo, New York 14203, United States.
Abstract

Huntington's disease (HD) is caused by an expanded CAG trinucleotide repeat in exon 1 of the Huntingtin (HTT) gene. We report the design of a series of HTT pre-mRNA splicing modulators that lower Huntingtin (HTT) protein, including the toxic mutant Huntingtin (mHTT), by promoting insertion of a pseudoexon containing a premature termination codon at the exon 49-50 junction. The resulting transcript undergoes nonsense-mediated decay, leading to a reduction of HTT mRNA transcripts and protein levels. The starting benzamide core was modified to pyrazine amide and further optimized to give a potent, CNS-penetrant, and orally bioavailable HTT-splicing modulator 27. This compound reduced canonical splicing of the HTT RNA exon 49-50 and demonstrated significant HTT-lowering in both human HD stem cells and mouse BACHD models. Compound 27 is a structurally diverse HTT-splicing modulator that may help understand the mechanism of adverse effects such as peripheral neuropathy associated with branaplam.

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