How to improve peptide purification for affordable insulin
September 27, 2023
/ The Bio-Works Team
The global diabetes pandemic has created a massive demand for insulin, especially in China, which is expected to have half the world’s diabetes patients soon. Meeting this demand means developing extremely efficient production methods that can supply affordable insulin with high purity. A promising approach is adding an orthogonal step upstream during the main reverse-phase chromatography (RPC) peptide purification process to increase purity and guard the expensive high-performance RPC columns from bioburden and stringent cleaning-in-place procedures.
Diabetes – the growing pandemic puts insulin supply to the test
The aging population and dramatic changes in the lifestyle of many countries have meant that diabetes has become a pandemic in the past decade, with one in eleven adults having diabetes. This represents 425 million patients globally and an incidence rate as high as 8.8%. It has been estimated that 629 million people worldwide will have diabetes by 2045.
Diabetes is a lifelong illness that means the body is unable to regulate blood sugar and requires complex and delicate management to minimize long-term complications. Type 1 diabetes is not preventable and requires insulin injections. Type 2 diabetes can be prevented and reversed through lifestyle changes, although insulin injection may be necessary for some Type 2 diabetes that cannot be controlled by oral medicine only. Type 2 diabetes accounts for 90–95% of cases worldwide, and rates have risen rapidly, primarily driven by lifestyle factors, which include growing obesity rates.
Poorly managed diabetes can lead to severe complications; only about 6% of patients will live free of diabetes-related complications. One key factor in the management of diabetes is access to insulin, and only one in two people with Type 2 diabetes have access to the insulin they need.
China is the #1 market for insulin
It has been estimated that 141 million Chinese had diabetes in 2021, which ranks China as the number 1 country in need of insulin globally. The country’s diabetes market is increasing rapidly and is predicted to be over $6 billion in 2022. The aging population and hastened medical reforms aimed to expand treatment to a huge patient population with unmet needs means that China will, therefore, become a major arena in the fight to supply insulin to treat diabetes.
Availability and affordability: breaking the market domination
So, why is insulin, one of the first ‘wonder drugs’ of the 20th Century, still prohibitively one of the most expensive drugs 100 years after its introduction as a life-saving drug? One reason is that three multinational companies – Novo Nordisk, Eli Lilly and Company, and Sanofi- dominate the global insulin market, which is estimated to reach $90 billion by 2029. Also, falling API prices and increased demand for insulin are powering a significant increase in efforts to produce highly competitive insulin in China.
The effort to break the domination of the big three global players will demand a deep understanding of the market and the manufacturing of high-quality products with built-in process efficiency and economy.
Purity is key for insulin biosimilars
Purified animal-sourced insulin was initially the only type of insulin available to diabetic patients. In 1982, recombinant DNA technology enabled the production of human insulin (Humulin R) for the first time, but this product still did not mirror the normal release of insulin. This has been followed by the development of insulin analogs, such as long-acting insulin glargine in 2000, that are aimed to replicate normal insulin patterns - although human insulin products are more affordable than insulin analogs, which may not have cost-effective benefits.
At the molecular level, insulin analogs are different from human insulin only in a few amino acids, and the manufacturing process is very similar for both regular human insulin (RHI) and insulin analogs. Recombinant insulin is produced either in yeast (usually Saccharomyces cerevisiae) or Escherichia coli. In yeast, insulin may be engineered as a single-chain protein with a protease cleavage site that separates the insulin A chain from a C-terminally truncated insulin B chain to which a synthetic C-terminal tail is grafted onto insulin by reverse proteolysis.
The production method, including purification and refolding, is common to RHI and insulin analogs, and biosimilar manufacturers have confirmed that for recombinant molecules that have a high level of similarity, it is likely that the inherent cost of upstream processing is very similar. It has been estimated that most of the manufacturing cost (94%) is associated with the recovery and purification of insulin, while the remainder (6%) is the fermentation process. This means that being competitive focuses on maximizing the yield of high purity insulin. High purity is essential in biosimilars, where new manufacturers must show that there are no new or other impurities in the product that they market at a much lower price than the original.
A peptide purification approach to boost quality and yield and beat resin fouling
The standard peptide purification techniques for recombinant human insulin precursors involve reverse phase chromatography (RPC), often including different steps using different buffer systems pH to give complementary selectivity. The purification of recombinant insulin means handling an initial extract with a high bioburden that consists of host-cell proteins, nucleic acids, lipids, etc. This can cause fouling of the expensive RPC columns that are difficult to remove since the option of cleaning-in-place (CIP) using sodium hydroxide is limited for these silica resins.
A cost-effective solution to this problem is adding an orthogonal upstream separation step, for example, ion exchange chromatography (IEX), using a column resistant to CIP procedures.
The benefits of adding such a step have been highlighted by a global insulin manufacturer that added peptide purification by IEX using WorkBeads 40S from Bio-Works as an upstream process step, which increased the purity of the final product by 3% and boosted production efficiency by 7%. The higher purity meant a higher yield of the active substance in every production cycle and a much-improved final product that would increase profits by millions of dollars. This became a strong motivator for the customer to incorporate WorkBeads 40S into their regular production. It is improvements to process efficiency and economy like this that will be critical to meeting the escalating need for affordable insulin.
Download our application note that discusses how cation exchange chromatography is an efficient technique for the purification of peptides.
1. 50 Years of Global Health Progress. International Federation of Pharmaceutical Manufacturers & Associations. https://50years.ifpma.org/
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