HPN536

P1/2, N=95, Completed, Harpoon Therapeutics | Active, not recruiting --> Completed | N=200 --> 95 | Trial completion date: May 2023 --> Jan 2023

P1/2, N=180, Recruiting, Harpoon Therapeutics | N=87 --> 180 | Trial completion date: May 2021 --> May 2022 | Trial primary completion date: May 2021 --> Apr 2022

TriTAC molecules are currently being investigated in multiple phase 1/2 clinical trials in solid tumors, including HPN424 targeting prostate-specific membrane antigen (PSMA) in prostate cancer (NCT03577028), HPN536 targeting mesothelin (MSLN) in multiple malignancies (NCT03872206) and HPN328 targeting Delta Like Canonical Notch Ligand 3 (DLL3) in small cell lung cancer (SCLC) (NCT04471727). In addition, in the MSLN-expressing NCI-H292 lung cancer model that co-expresses constitutive, high levels of PD-L1, both anti-PD1 and anti-PDL1 antibodies significantly enhanced the antitumor effects of the MSLN-targeting TriTAC HPN536 in vivo. Together these results demonstrate the potential utility of PD1/PDL1 blockade to enhance the potency of TriTAC-mediated tumor cell killing, supporting further investigation of these combinatorial approaches in patients.

HPN536 is potent, well tolerated and exhibits extended half-life in non-human primates. It is current in phase 1 clinical testing in patients with MSLN-expressing malignancies (NCT03872206).