Dose limiting toxicities (DLTs) of IMGN151 when given as monotherapy and in combination with other anti-cancer therapies DLT events are defined as clinically significant adverse events or abnormal laboratory values assessed as unrelated to disease progression, underlying disease, intercurrent illness, or concomitant medications.

An adverse event (AE) is defined as any untoward medical occurrence in a participant or clinical investigation participant administered a pharmaceutical product which does not necessarily have a causal relationship with the treatment. The investigator assesses the relationship of each event to the use of study drug.