A research team used directed evolution to develop a bespoke aminotransferase, a type of enzyme, to significantly accelerate the manufacturing process and reduce production costs. This new biocatalytic route has the potential to improve global access to Lenacapavir.
The study containing the finding, “Biocatalytic Production of a Key Chiral Intermediate of the HIV Capsid Inhibitor Lenacapavir”, was published in the Journal of the American Chemical Society.
Lenacapavir, approved by the FDA and MHRA, is a twice‑yearly injectable drug that has shown extremely high levels of protection in pre‑exposure prophylaxis (PrEP) trials. Royalty‑free license agreements are already in place to enable generic manufacturers to supply Lenacapavir to 120 lower‑income countries, yet the high cost of producing its active pharmaceutical ingredient remains a major barrier to widespread availability.
A sustainable route to a complex molecule
Made up of four distinct building blocks, Lenacapavir’s highly functionalized central core is a very challenging building block to synthesize. This core is constructed from a chiral amine that can exist in two mirror-image forms (like a left and a right hand). The handedness – or chirality – is important in pharmaceuticals as only one form of the molecule will work as intended.
Currently, Lenacapavir is made via traditional multi-step chemical synthesis, but due to the central core’s chirality and challenging molecular structure it is a costly and time-consuming process. Biocatalysis offers significant potential for faster and cheaper production.
To achieve this, the Manchester Institute of Biotechnology (MIB) team focused on using directed evolution – a method that speeds up nature’s trial-and-error evolution process – to develop an enzyme that could catalyze the target reaction to produce the chiral amine core. Using an approach known as substrate walking, the researchers began with an aminotransferase that showed no detectable activity on the desired substrate. Over eight rounds of directed evolution, involving screening more than 12,000 enzyme variants, they installed 10 mutations that progressively unlocked activity, improved stability and reshaped the active site of the enzyme so that it could accept the central amine core’s bulky ketone precursor.
The final enzyme performed exceptionally well, converting 98% of the starting substrate, producing a yield of more than 90% with a purity of over 99% enantiomeric excess (e.e.) meaning that the correct chiral form was produced. The researchers also tested the enzyme under industrially relevant conditions showing its potential to work at scale.
The team also used X-ray crystallography to create a detailed 3D picture of the improved enzyme showing how the molecular changes arising from evolution allowed the enzyme to accept the substrate and transform it into the target product. Understanding the enzyme’s structure helps scientists unpick its mechanism of action which allows them to improve future enzyme design campaigns.
Towards large‑scale implementation
The team is now collaborating with industrial partners to translate the methodology from laboratory scale to industrial biomanufacturing. The details of this new manufacturing route are also freely available for companies to use. Any company interested in producing Lenacapavir via this new process can contact Prozomix to request free samples of the enzyme.
If implemented at scale, the process could enable a shorter, cleaner and more economical production route for Lenacapavir, supporting ambitions to make long‑acting HIV prevention accessible worldwide.
