Expertise and know-how in many therapeutic modalities doesn't offer extensive intellectual property protection in unique domains. Do you have a kick ass technology platform for developing small molecule tyrosine kinase inhibitors or monoclonal antibodies? Sweet, but so do dozens of other companies.

This forces drug developers to go deep in a single focus area (Revolution Medicines is all-in on pan-RAS inhibitors) or broad in a single therapeutic area (AbCellera generates hundreds of monoclonal antibodies for partners but retains little economics for individual assets).

Depth or breadth can each be valuable, but RNAi platforms don't have to choose. They're not limited by intellectual property. Alnylam Pharmaceuticals, Novo Nordisk, Arrowhead Pharmaceuticals, Wave Life Sciences, and one or two others own substantially all the proprietary ways to design clinically-meaningful siRNA molecules. They invented the ways to modify siRNA structures regardless of therapeutic area, which is unique to this therapeutic modality.

In other words, any drug developer can develop a monoclonal antibody to treat a brain disease. But if you want to treat a brain disease by silencing gene expression using RNAi, then you have to partner with one of a handful of companies. That allows RNAi specialists to extract significant economics for relatively immature assets.