DUBLIN – Roche Holding AG has joined Jnana Therapeutics Inc. in its quest to drug the human repertoire of solute carrier (SLC) metabolite transporters as a means of tackling a swath of immune-mediated and neurological diseases. The Basel, Switzerland-based pharma is paying Boston-based Jnana $40 million up front and could pay over $1 billion more in research funding, preclinical, development and commercial milestones, as well as sales royalties, in a multitarget deal.