The first patient has been successfully dosed in a phase 2 clinical study evaluating Opamtistomig (LBL-024), an investigational PD-L1/4-1BB bispecific antibody, for the first-line treatment of locally advanced or metastatic oesophageal squamous cell carcinoma (ESCC).
ESCC ranks as the seventh most common cancer in China, characterised by insidious onset and poor prognosis.
Although immune checkpoint inhibitors combined with chemotherapy have improved objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) compared to chemotherapy alone, median OS remains only 12-17 months.
This underscores the limitations of current treatment approaches and the urgent need for improved outcomes, highlighting the necessity to explore more effective innovative strategies to address this significant clinical challenge.
Opamtistomig is a uniquely engineered bispecific antibody designed to simultaneously block PD-1/L1-mediated immune suppression and selectively activate the 4-1BB co-stimulatory pathway.
By restoring T-cell functionality and expanding effector T-cell populations within the tumour microenvironment, Opamtistomig has the potential to deliver more potent and durable anti-tumour activity than PD-1/PD-L1 blockade alone, particularly in difficult-to-treat and immunotherapy-resistant tumours.
To date, Opamtistomig has demonstrated first- or best-in-class potential in phase 2 or registrational clinical trials across three indications: non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC), and extrapulmonary neuroendocrine carcinoma (EP-NEC).
The open-label, multi-centre phase 2 clinical study is led by Professor Shen Lin of Beijing Cancer Hospital and is being conducted across multiple hospitals in China. The trial aims to evaluate the efficacy and safety of Opamtistomig administered in patients with ESCC.
About ESCC
China is a region with a high incidence of oesophageal cancer, accounting for approximately 50% of the newly diagnosed and fatal cases of oesophageal cancer worldwide. Oesophageal cancer is broadly classified into ESCC and oesophageal adenocarcinoma, of which squamous cell carcinoma represents the predominant subtype in China.
According to 2022 data published by the International Agency for Research on Cancer (IARC) of the World Health Organization, ESCC ranked seventh among all cancers in China in terms of incidence, with an estimated 224,000 new cases and approximately 187,000 deaths recorded annually.
Early-stage oesophageal cancer typically presents with no obvious clinical symptoms, and most patients are diagnosed at a locally advanced stage or with distant metastases. As a result, prognosis remains poor, with a five-year survival rate of only 10.0% to 30.0%.
In two ongoing clinical studies in China, Opamtistomig has demonstrated promising efficacy and a favourable safety profile in patients with advanced EP-NEC, both as monotherapy and in combination with chemotherapy. Given the absence of a globally accepted standard of care for EP-NEC, these results support the advancement of a single-arm pivotal study toward potential accelerated approval.
