Biosion Inc. is getting more than $40 million in cash up front from Aclaris Therapeutics Inc. for the rights to develop two antibodies. The regulatory and sales milestones could also bring Biosion another $900 million. The two assets are BSI-045B, a high affinity and high potency anti-TSLP monoclonal antibody, and BSI-502, a bispecific antibody directed against TSLP and IL4R.