Cell and gene therapies were set to take the market by storm and transform the treatment landscape. But more than five years out from the first approval in 2017, fewer cell and gene therapies have been approved in the US than expected. The cost of developing and manufacturing these transformative therapies remains astronomical and has brought into question their commercial viability. Why have advances in science and technology not translated into efficiencies in this area? What are the opportunities and challenges to lowering the costs to develop cell and gene therapies, and how low can it really go?