Imdelltra can be prescribed at general hospitals in Korea

Secures access at Big 5 hospitals, including Samsung Medical Center, Asan Medical Center, and Severance Hospital

Phase 2 data confirm objective response rate… NCCN recommends its use as monotherapy

The bispecific antibody anticancer drug Imdelltra is entering major hospital prescription lists in Korea.

According to industry sources, Amgen Korea's Imdelltra (talatamab), a treatment for relapsed or refractory extensive-stage small cell lung cancer (SCLC), has passed the Drug Committee (DC) reviews at leading general hospitals, including Samsung Medical Center, Asan Medical Center, and Severance Hospital.

However, Imdelltra has not yet been listed for reimbursement. In January, during the Health Insurance Review and Assessment Service’s first Cancer Drug Review Committee meeting of the year, the drug received a decision of “reimbursement criteria not established.”

Therefore, it remains to be seen whether Imdelltra will secure reimbursement status and emerge as a treatment option in the underserved small-cell lung cancer field.

Approved in Korea in May last year, Imdelltra is a bispecific antibody targeting delta-like ligand 3 (DLL3), which is expressed in approximately 85–96% of patients with small cell lung cancer. DLL3 is typically localized intracellularly in normal cells but is aberrantly expressed on the surface of tumor cells in SCLC and other neuroendocrine cancers.

Imdelltra binds to both the DLL3 antigen on cancer cells and the CD3 antigen on T cells, redirecting T cells to induce tumor cell death. Crucially, it acts directly on the antigens of T cells and cancer cells, independent of Major Histocompatibility Complex Class I (MHC-1) expression, one of the key pathways cancer cells use to evade the immune system, making it effective even against immune-evading cancer cells.

The efficacy of Imdelltra was demonstrated in the DeLLphi-301 clinical trial, a phase 2 study conducted in adult patients with extensive-stage SCLC whose disease had progressed after at least two prior lines of therapy, including platinum-based chemotherapy.

In the study, Imdelltra showed a clinically meaningful objective response rate (ORR). Among 100 patients treated with Imdelltra 10 mg, the ORR was 40%, and 58% of responders (n=23/40) maintained their response for six months or longer.

Furthermore, the median overall survival (OS) in the Imdelltra 10mg group was 14.3 months, and the median progression-free survival (PFS) was 4.9 months. Treatment-related adverse events in the Imdelltra 10mg group were mostly low grade, with grade 3 or higher adverse events occurring in 29% of patients in the clinical Parts 1-2 and 15% of patients in Part 3.

Based on these results, the National Comprehensive Cancer Network (NCCN) recommends Imdelltra monotherapy as a preferred regimen for platinum-resistant patients and as another recommended regimen for platinum-sensitive patients. In addition, the American Society of Clinical Oncology (ASCO) has issued a strong recommendation for Imdelltra monotherapy in patients with recurrent disease after chemotherapy.

Small cell lung cancer (SCLC) accounts for approximately 10-15% of all lung cancer patients and is characterized by rapid cancer cell proliferation, leading to widespread metastasis within a short period. It is known that 6 to 7 out of 10 patients are diagnosed at the extensive stage, where cancer cells have metastasized to the contralateral lung or distant organs.

Current treatment options for extensive-stage SCLC are limited, primarily consisting of chemotherapy and immunotherapy. Therapeutic choices become even more restricted beyond third-line treatment. Although initial response rates to chemotherapy are relatively high, responses are often short-lived, with rapid disease progression. Particularly in refractory or resistant patients whose disease progressed within 6 months after the last chemotherapy treatment, the response rate to conventional chemotherapy drops below 10%, underscoring the substantial unmet need for new treatment options.