The field of biosimilars promises some new and exciting opportunities but could potentially be full of mines. Failure to detect and defuse these mines may result in delay or ultimate failure of a biosimilar development program.

The opportunities lie in the fact that there are large market needs both in the industrialized countries — due to the necessity to keep healthcare costs under control — and developing countries, especially in countries such as China, India and Brazil, where there is increasing demand for healthcare coverage. In addition, it is well known that as many as 21 products, some of which represent current top-selling biologics, will be losing patent protection by 2020, creating significant opportunity for developers of biosimilars. It is thus projected that by 2020 the market size for biosimilars will be well in excess of $50 billion.

Of course, along with these opportunities lie many challenges. The challenges in the development of biosimilars are presented by a number of factors, including:

• Significant technical difficulties due to the complex nature of biologics
• Poorly defined (still!) regulatory pathways to get these products to market
• Patent obstructions that may be brought about by the product innovators
• Ever-increasing global competition
• Pricing pressure

Furthermore, the estimated costs of developing a biosimilar is in the range of $30 to 100 million or more and will likely take as long as five to seven years. Thus, the development risks and costs are significant, and far costlier than is the case for small molecule generics.

In developing a biosimilar, one can envision three main potential strategies that a developer can pursue:

1. If available, utilize internal capabilities and capacities; if not available, build necessary capabilities and capacities, but at significant expenditure of capital and time.
2. Outsource the entire development cycle from preclinical to clinical development to a single, large CDMO with diversified and broad capabilities.
3. Outsource different parts of the product development to different service providers such that the program development needs are well matched with the expertise and industry/regulatory track records of the chosen CROs/CMOs.

While developers of biosimilars will likely select one or a combination of these approaches based on their unique circumstances, it is our recommendation that the third of these three strategies is likely to result in greater success in bringing a biosimilar to market.
The successful development of a biosimilar is comprised of a number of discrete steps:

• Correct engineering and optimization of a cell line that is stable and highly productive
• Development of the appropriate analytics to evaluate the characteristics and quality of the product generated with the selected and optimized cell line in comparison to the commercial (originator) / reference product
• Development of a manufacturing process
• Continued development of appropriately sophisticated analytics to be able to effectively compare the biosimilar product in development to the reference product
• Manufacture small-scale GMP lots to support toxicology studies and more comprehensive comparability study between biosimilar and reference product, encompassing physicochemical, biological and biophysical techniques
• Finalize release and stability indicating methods preceded by validation of all supporting analytical methods, manufacturing, and processing activities
• Scale-up manufacturing process and produce lots
• Use large scale production lots to perform:

              — PK/PD study
              — Clinical immunogenicity
              — Clinical trial
              — Continued biochemical/biological comparability

Based on the recently issued FDA guidance on the development of biosimilars, a comprehensive and deep comparative analytical approach will be key to any biosimilar development program. In fact, it is expected that the availability of highly sophisticated physicochemical and biological capabilities will allow for detailed characterization of the desired product, along with the identification and characterization of product-related substances as well as product and process-related impurities.

A well designed analytical program for characterization of a biosimilar molecule in comparison to the reference product will include (minimally) confirmation of the amino acid sequence, determination of post-translational modifications, including both N- and O-linked glycosylation, along with the structural analysis of the glycan moieties, if present, and degree of sialic acid occupancy. In addition, mapping of disulfides, along with quantitation of any free cysteines, should also be performed. Integrity of the N- and C-termini and other modifications, such as deamidation, oxidation, potential glycation, etc. will have to be mapped and quantified. Additional characterization including secondary and tertiary structural characteristics will also have to be assessed by means of various biophysical techniques, including circular dichroism, fourier-transform infrared spectroscopy, intrinsic fluorescence and differential scanning calorimetry to determine melting temperature, an indicator of protein folding.

As all proteins undergo some degree of aggregation, it is important to quantify the type and amount of aggregates by techniques other than size-exclusion chromatography. Analytical ultracentrifugation and field-flow fractionation are but two available techniques.

A potency assay, preferably reflective of the clinical mechanism of action of the drug, will be used to compare the biosimilar molecule in development to the reference product. Such an assay could be simply a binding assay by means of fluorescence
polarization or surface plasmon resonance, or a more complex assay may be needed, requiring the use of living cells.

As stated in the quality guidance issued by the FDA in February 2012, the greater the certainty of the proposed biosimilar, the more selective of an approach may be taken when implementing follow-up animal and/or clinical studies. The bottom line is that the better the comparability package between the biosimilar in development and the reference product showing similarity between the two molecules, the easier will be the regulatory path to market for the biosimilar. Unlike developing a novel product, which involves a sequence of expanding steps, the development of a biosimilar is exactly the opposite; the sequence of events starts very broadly and narrows as the development evolves with the understanding that, at later stages, efforts are aimed at addressing any residual uncertainty with respect to the similarity of the two products.

It is clear that the analytical development of the biosimilar should be entrusted to a contract service provider with strong expertise in protein-based characterization. It is important that such a provider be able to not only perform the standard method development and validation to support product release and stability but also possess strong mass spectroscopy along with biophysical capabilities to ensure a robust and detailed comparison between the proposed biosimilar and the reference product. Indeed it is recommended that a specialized provider with strong molecular and cell biology expertise rather than a conventional CMO be utilized for the development and optimization of the expression system. It should be recognized that while a CMO may often provide the full spectrum of services from an expression system to standard analytics and, of course, process development and manufacturing, these services are typically off-the-shelf approaches that may serve to be inadequate if complex issues arise.

In summary, it is our recommendation that if the development of a biosimilar is going to be mostly or fully outsourced, it is best to utilize a combination of contract service providers with tailored expertise. To maximize your chance of success, choose the following:

• A CRO/CDMO with true expertise in molecular and cellular biology to develop and optimize the expression system
• An expert analytical provider to conduct the analytical development, product characterization and comparison analysis, along with lot release, and stability testing
• A strong process-minded CMO to perform process development and manufacturing
• A clinically focused CRO for preclinical and clinical work

Entrusting the entire biosimilar development to a “One-Stop Shop” CRO, while logistically very palatable and (possibly, at first pass) less expensive, can be quite risky and possibly more costly in the long run. Outsourcing the development program to multiple service providers — each with focused and tailored expertise — will reduce the risk. This will require aggressive program management, with tight control of timelines and cross-communication among the various service providers. The sponsor, essentially, must direct the flow of information and keep oversight of the entire program.

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Mario DiPaola is chief scientific officer and chief operating office at Blue Stream Laboratories, Inc. He can be reached at [xxxx].