Welcome to the CRISPR Powerhouse

It’s incredible how far the mAb industry has come. The first therapeutic mAb was approved in 1986. Now, the global market for mAbs is anticipated to grow to $451.89 billion by 2028 from an already-impressive $178.50 billion in 2021 (1). We are also seeing the emergence of increasingly complex antibody therapeutics, including bi-and multi-specific antibodies, as well as small-format single domain VHH antibodies originally derived from camelids.

But while the pace of innovation in antibody therapeutics is accelerating, the challenges of manufacturing them at the scale required to meet demand remains a bottleneck. For a start, antibody bioproduction is a relatively low yield process, with each liter of bioreactor volume typically producing around 10 doses of a mAb compared with 1,400-2,000 doses of a viral vaccine (2). Furthermore, antibody production can affect cell growth and viability, even triggering apoptosis. There can also be issues with expression, post-translational modification, folding and purification, adding further layers of complexity to the manufacturing process.

Antibody manufacturers are continually looking for ways to improve and optimize production. So at this point I’d like to turn everyone’s attention to CRISPR/Cas9 – the gene editing technology invented by Nobel prizewinners Emmanuelle Charpentier and Jennifer Doudna. As many of you may know, CRISPR/Cas9 (often just referred to as CRISPR) is a standalone genetic modification tool used to delete, add, or alter specific regions of the genome with high precision. It can be used in a wide range of cell types and species, including the commonly-used bioproduction workhorses of HEK293 (derived from human embryonic kidney) and CHO cells.

Unsurprisingly for such a flexible and useful technology, CRISPR gene editing could improve antibody manufacturing processes in a number of areas, including regulating apoptosis and cell cycle progression to enhance growth, engineering cells to grow at lower temperatures or in cheaper media to reduce manufacturing costs, and modifying the biological pathways within cells to ensure correct expression, post-translational modification, and folding of the resulting products (3).

At a broad level, CRISPR can be used for genome engineering of host cells to create lines that are optimized for large-scale cell antibody production. Industry leader Lonza is among a group of companies that have taken a license from ERS Genomics to use CRISPR for just this purpose. 

Zooming in on the antibody production process, CRISPR can also be used to precisely control the insertion of an antibody cassette into a specific location or multiple locations within the genome of the cell. This approach reduces the likelihood of epigenetic silencing effects and helps guarantee high levels of stable gene expression. It also facilitates the rapid development of new antibody producing lines by cutting down the time required to clonally isolate high-producing cells.

CRISPR can be used to engineer the molecular chaperones that are responsible for ensuring correct protein folding, which is particularly useful for increasing the yield of antibodies that are more difficult to express (4). Similarly, genome engineering can be used to modify the enzymes involved in post-translational modification, such as the addition of N-glycan sugars, which have an important role in antibody activity, efficacy, and safety.

Unwanted binding of endogenous proteins is another problem in bioproduction. These proteins can affect antibody secretion or co-purify with the antibody being produced, causing problems during purification or downstream processing, adding time and cost to manufacturing. CRISPR can remove or alter these problematic proteins.

Another potential application of CRISPR exists in the area of antibody-drug conjugate (ADC) development. With a global market expected to reach $13.8 billion by 2028 (5),ADCs offer a more precise way of treating cancer, improving efficacy and reducing side effects. However, the addition of therapeutic payloads can disrupt antibody stability and affinity, and it can also be difficult to control the number of drug molecules that are added to each antibody. Precision engineering of modification sites using CRISPR can result in more efficient and reliable drug conjugation – and far faster and more accurately than conventional antibody engineering techniques (6).

That’s just a snapshot of the possibilities. The past decade has seen exceptional growth in the market for antibody therapeutics, and this trend is only set to continue. As the demand for these next-generation biotherapeutics continues to grow at pace, manufacturers should start embracing the great potential of CRISPR.