Nanjing Leads Biolabs Co., announced the first patient has been successfully dosed in a Phase 1b/II clinical trial (NCT07099430) evaluating Opamtistomig (LBL-024, PD-L1/4-1BB bispecific antibody) as monotherapy or in combination with other agents for the ‌first-line treatment of advanced melanoma‌‌.

Opamtistomig‌, a uniquely designed PD-L1/4-1BB bispecific antibody that simultaneously blocks PD-1/L1-mediated immune suppression and enhances 4-1BB-regulated T-cell activation. This dual mechanism has the potential to convert "cold tumors" into "hot tumors", overcoming resistance to immunotherapy and improving response rates in hard-to-treat cancers.

In two prior clinical trials, Opamtistomig demonstrated promising efficacy and a favorable safety profile in patients with highly malignant, immune-cold extrapulmonary neuroendocrine carcinoma (EP-NEC), both as monotherapy and in combination with chemotherapy. Notably, patient enrollment was completed in August 2025 for a pivotal single-arm registration trial evaluating Opamtistomig monotherapy in EP-NEC.

In addition, multiple Phase 1b/II studies are ongoing to assess Opamtistomig combined with chemotherapy for:

• First-line small cell lung cancer (SCLC)‌
• ‌First-and second-line non-small cell lung cancer (NSCLC)

This newly initiated Phase 1b/II multicenter trial, led by Professor Chen Yu from Fujian Cancer Hospital, with participation from multiple hospitals, aims to evaluate Opamtistomig's efficacy and safety in advanced melanoma as monotherapy or in combination regimens.

Dr. Charles Cai, Chief Medical Officer of Leads Biolabs, stated:

"The continued clinical advancement of Opamtistomig in EP-NEC and other tumor types highlights its unique ability to activate T cells while releasing immune suppression, offering hope to patients with immune-cold tumors who have limited treatment options. With more than 10 indications currently targeted across nine clinical trials, we are committed to accelerating development and delivering breakthrough therapies that expand the benefits of immunotherapy to more patients worldwide."