The largest marijuana business association in Massachusetts has dropped a lawsuit against the state after more than a dozen key members of the group quit or renounced the litigation in the face of a fierce backlash from advocates.

The Commonwealth Dispensary Association, which represents dozens of established brick-and-mortar marijuana companies, sued the state Cannabis Control Commission earlier this month to overturn recently implemented regulations that created a new, competing class of online pot-delivery retailers — and that reserve the licenses exclusively for disenfranchised entrepreneurs for three years.