TRPH-222 is a novel, site-specific antibody-drug conjugate (ADC) targeting CD22, a B-cell-restricted sialo-glycoprotein that is an important modulator of B-cell signaling and survival, which is expressed on nearly all B-cell malignancies. CD22 is a clinically validated ADC target with potential in Non-Hodgkin lymphoma (NHL) and acute lymphoblastic leukemia (ALL). The compound itself combines a site-specific modified humanized antibody conjugated to a cytotoxic payload using SMARTag conjugation technology with Hydrazino-Pictet-Spengler (HIPS) chemistry and a proprietary 4AP linker.
Pre-clinical data have shown that this optimization of payload placement and linker composition, combined with the stability afforded by HIPS chemistry, leads to better tolerability and expanded therapeutic index. Our TRPH-222 Phase 1 clinical study for patients with relapsed and/or refractory B-cell lymphoma (NCT03682796) demonstrated robust single agent activity in heavily pre-treated R/R FL patients. We are planning a Phase 2 study start in the second half of 2022.