China’s NMPA Approves IND for SKB107 for Solid Tumor Bone Metastases

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China’s Center for Drug Evaluation of the National Medical Products Administration has approved the investigational new drug application for the radionucleotide-drug conjugate (RDC) SKB107 (formerly TBM-001) for the management of bone metastases in patients with solid tumors.1

SKB107 is the first RDC drug clinical project from Sichuan Kelun-Biotech Biopharmaceutical Company, and is the company’s first nuclear drug project to enter clinical studies.1,2 The RDC has finished preclinical evaluation and is planned to undergo clinical investigation in the phase 1a setting.2 The RDC was developed through collaboration between Sichuan Kelun-Biotech Biopharmaceutical Company and a team led by Chen Yue, MD, at the Affiliated Hospital of Southwest Medical University in Sichuan, China.

This RDC uses a small molecule as a targeting ligand that is conjugated with a chelator and a therapeutic radionucleotide. In contrast with external radiation therapy, treatment with SKB107 is highly targeted, reducing damage to healthy tissues.1 Additionally, compared with other bone-modifying drugs, SKB107 can kill tumor cells with bone metastases. The RDC also has a favorable safety profile, according to the news release.

Bone is the most common site of metastasis in patients with advanced malignant tumors; approximately 70% to 80% of patients with advanced malignant tumors will develop metastases in the bone, which are associated with quality of life (QOL) declines and shortened survival times. Across all patients with common tumors, patients with breast cancer, lung cancer, kidney cancer prostate cancer, and thyroid cancer comprise the highest incidence of bone metastases; approximately 80% all of metastases in the bone arise in patients with these cancers.

In patients with lung cancer specifically, bone is among the most common sites of hematogenous metastasis, which has an incidence of approximately 30% to 40%.3 The most common site of bone metastasis in patients with lung cancer is the spine (> 50%), followed by the rib (~50%), pelvis (20%), sternum (~15%), and femur (~15%). Among patients with lung adenocarcinoma, the incidence of spinal metastases is approximately 79%. Moreover, approximately 50% of patients with lung cancer bone metastases will have skeletal-related events (SREs), which decrease survival time, negatively affect QOL, and increase the overall treatment burden.

Bone metastases are associated with serious complications, including severe bone pain, as well as bone-related events like spinal cord compression and pathologic fracture. These complications can increase the risk of death and decrease patients’ QOL.

Beyond primary disease management, the optimal management of bone metastases includes multidisciplinary collaboration and comprehensive treatment plans that are individualized to each patient. The most commonly used treatment strategies for patients with bone metastases arising from malignant tumors currently include comprehensive approaches like chemotherapy, molecular targeted therapy, and immunotherapy for patients with multiple bone metastases; radiation therapy for patients with isolated or multiple bone metastases, as well as those with extraspinal compression or peripheral nerve tumor compression; analgesic therapy for patients with bone pain; surgery for patients with pathological fracture or spinal cord compression; interventional therapy, such as ablation therapy; bone-modifying drug therapies for patients with confirmed bone metastases; and psychological supportive treatment for patients with depression or anxiety.

However, the news release noted that these treatments provide limited benefits to patients regarding QOL improvements, delays in the occurrence of SREs, avoiding the development of SREs, and prolonged survival.1 Therefore, the development of safer and more effective treatments with novel mechanisms of action is crucial.

References

1. Kelun-Biotech's radionuclide-drug conjugate (RDC) SKB107 receives NMPA approval for the treatment of bone metastases in solid tumors. News release. Sichaun Kelun-Biotech Biopharmaceutical Co., Ltd. March 25, 2025. Accessed March 26, 2025. https://www.prnewswire.com/news-releases/kelun-biotechs-radionuclide-drug-conjugate-rdc-skb107-receives-nmpa-approval-for-the-treatment-of-bone-metastases-in-solid-tumors-302411462.html
2. Science and product pipeline. Kelun-Biotech Colenbotai. Accessed March 26, 2025. https://www.kelun-biotech.com/product.aspx?mid=165#165
3. Duan J, Fang W, Xu H, et al. Chinese expert consensus on the diagnosis and treatment of bone metastasis in lung cancer (2022 edition). J Natl Cancer Cent. 2023;3(4):256-265. doi:10.1016/j.jncc.2023.08.004