Manufacturing an siRNA involves a lengthy 150-step chemical synthesis and a great industry challenge is finding a way to manufacture large quantities of GMP quality RNA at a commercially viable cost.
>Sirna's newly-patented process promises to overcome this challenge, achieving chemical yields in excess of 60 per cent while still maintaining high purity.
"This chemical yield is unparalleled in the area of oligonucleotide synthesis," said Chandra Vargeese, Sirna's vice president of chemistry.
The new patent broadly covers a process for the synthesis, deprotection and purification of nucleic acids with one or more ribonucleotides.
This process is critical for the efficient synthesis of RNA at high yields and high purity and is applicable to both small- and large-scale production of oligonucleotides such as siRNAs and aptamers.
Sirna is the only RNAi therapeutics company with its own cGMP manufacturing capacity and the new patent will expand Sirna's leadership position in the area.
"This new patent adds to our 48 issued and over 240 pending patent applications covering all aspects of siRNA technology," said Bharat Chowrira, Sirna's vice president.
The company can currently produce approximately 25 kilograms per year of oligonucleotide-based compounds and has produced all material for human testing of Sirna-027, its siRNA-based drug for age-related macular degeneration, set to enter Phase II human trials in the second quarter of 2006.
Sirna will also be producing clinical material for Sirna-AV34, its clinical candidate for the treatment of hepatitis C, which is expected to enter the clinic this year.