Merrimack has won four its last five. The Bulldogs have dropped three straight and have lost four of five following a four-game winning streak.
Derring's 3-pointer with 4:07 to go made it 61-59 and Merrimack led the rest of the way. Bryant led 36-30 at intermission.
Juan Cardenas led Bryant (9-8, 1-3) with a career-high 26 points and Ben Lin tied a career-high 19 points. Ikenna Ndugba collared 11 rebounds.