ATMPs 1

• Antisense technology:

  • Target diseases with inappropriate production of gene products
  • Expression of oncogenes
  • Overexpression of cytokines
  • Intracellular viral replication
  • Translation of mRNA with splicing errors (ineffective proteins)
  • Aim: prevent transcription of mutated gene by targeting mRNA transcripts copied from the DNA
• Spiranza (Nusinersen)

  • Spinal muscular atrophy - SMN deficiency
  • Targets SMN2 gene, which can produce some functional SMN.
  • During RNA splicing the 7th exon of SMN2 is lost, resulting in defective SMN protein.
  • Nusinersen is an antisense oligonucleotide that binds near exon 7 and modifies the splicing to include exon 7 in the RNA message
  • Resulting in production of more functional SMN protein
• siRNA Mechanism

  • siRNA is delivered as a double stranded RNA molecule.
  • Once in the body siRNA duplex is cleaved by the Dicer protein.
  • The unwounded siRNA forms the RISC complex with other proteins.
  • The complex bind to the complementary mRNA sequence and cleaves the mRNA resulting in breakdown of the mRNA.
  • This silences the expression of the target protein involved in disease.
• siRNA

  • =Short interfering RNA
  • Double-stranded non coding RNA molecules typically about 20-25 base pairs in length
  • Regulate gene expression (involved in disease) by interfering with mRNA
  • siRNA molecules are designed to be complementary to the mRNA sequence of the target gene so they can specifically bind together.
• Onpattro (patisiran)

  • Used in hereditary transthyretin amyloidosis
  • TTR protein misfolded so it accumulates as fibrils in tissues.
  • Silences the mutated gene coding for transthyretin  (TTR) in liver
  • siRNA mechanism
• Transfection

  • The process of introducing Nucleic acids into cells by non-viral methods
  • Benefits: low immunogenicity; therapeutic gene not integrated into host chromosome (no disruption of host genes)
  • Methods: cationic liposomes ; direct injection of DNA
• Gendicine

  • Treats head and neck squamous cell carcinoma
  • Engineered adenovirus carrying the human p53 gene, which integrates within cells DNA so that p53 protein is produced, leading to tumour regression.
  • Replication-incompetent adenovirus
• Synthetic Oligonucleotides

  Not ATMP

  1. Antisense Oligonucleotides
  2. siRNA
• Zynteglo (Ex vivo gene therapy)

  • Treats Transfusion-dependent β-thalassaemia (TDT)
  • Lentiviruses vector (a sub type of reterovirus)
  • Autologous Hematopoietic stem cells are modified Ex-vivo
  • Contain functional copy of the betaglobin gene
  • HSCs engraft in the patient's bone marrow to produce RBCs with functional Hb
• Kymriah (ex vivo gene therapy)

  • Used in B-cell leukaemia ad lymphoma
  • Consisting of autologous genetically modified white blood cells
  • Introduces a receptor (CAR) on the surface of T cells which allows T cells to specifically target cancerous B cells by binding to CD19 receptor on B-cells.
• Antisense mechanism

  • Oligonucleotide= small number of chains of nucleic acids , complementary to the strand of sense mRNA which is going to get translated.
  • When the antisense oligonucleotide bins to the mRNA it prevents the mRNA being translated into the protein, so the defective protein is not produced.