Avrobio Inc., a clinical stage gene therapy company, and Tectonic Therapeutic Inc., a privately-held biotechnology company developing GPCR (G-protein coupled receptor)-targeted therapeutic proteins, co-founded by Timothy A. Springer and Andrew C. Kruse of Harvard Medical School, have entered into a definitive merger agreement to combine in an all-stock transaction.   This news comes months after Avrobio completed a review of its business and decided to halt further development of its programs ...