Metz reports that beginning in late 2009 and continuing into this year, Agilent has seen a growing number of late-stage programs for oligo APIs. These include scale up and supply of Phase III trial materials through to full process validation and commercial launch. The company’s new large-scale, multipurpose GMP facility in Boulder, Colorado, was designed to accommodate kilogram-scale oligo production. The plant has capacity in the low hundreds of kilograms per year and is on-stream and fully qualified. Agilent anticipates several projects moving forward into large-scale production in the 2011–2013 timeframe.
Exemplifying some of the challenging aspects of producing larger quantities of atypical oligonucleotides is the experience of Noxxon Pharma, which has taken its Spiegelmer® oligos into clinical development. NOX-E36 is completing a Phase I trial in inflammation and will enter a Phase II study in 2010. NOX-A12, designed to stimulate autologous stem cell recruitment, is also finishing up a Phase I trial and will begin a proof-of-concept Phase II study this year.
In December, the company announced the identification of a Spiegelmer with picomolar affinity and high selectivity for a target being pursued in collaboration with Eli Lilly for the treatment of migraine headache.
Spiegelmers are mirror-image, L-configured oligos composed of the L-isomer of ribonucleic acid. They bind to a biological target in a manner similar to antibody-antigen recognition, explains Stefan Vonhoff, Ph.D., vp of chemistry, manufacturing and control at Noxxon. Because they are not degraded by naturally occurring nucleases, Spiegelmers offer an attractive in vivo stability profile. They are unmodified L-RNA oligonucleotides that are synthesized using standard production processes established for natural D-configured oligos.
Initially, “the development of a scalable and cost-efficient manufacturing process for the L-RNA monomers” was a challenge, says Dr. Vonhoff. Today, the monomers are synthesized at multikilogram scale and the key raw material, L-ribose, has turned into a chemical commodity produced at ton scale for the manufacturing of antiviral drugs such as clevudine, which is used to treat hepatitis B.
Now, notes Dr. Vonhoff, Noxxon’s main process-development focus is on GMP manufacturing of Spiegelmers, in which efficient purification strategies are key to producing the drug substance at a consistently high quality. Noxxon has initiated a program with a CMO partner “to improve loading efficiency while maintaining the quality of the product,” says Dr. Vonhoff. The main impurities produced during the manufacture of Spiegelmers are “failure sequences,” he adds. “Due to their unnatural L-configuration, those N(+)-mers and N(-)-mers” are unlikely to exert off-target effects.
As therapeutic oligos move through preclinical testing into human studies and on to commercialization there is an increasing need for higher throughput analytical methods and strategies for assessing the composition and purity of larger amounts of compound isolated from biological samples such as blood and tissue. Analytical processes focus on identifying potentially active metabolites, quantifying and identifying impurities, and characterizing the pharmacokinetic properties of the drug as part of required ADME studies.