Behind this massive transaction lies the accelerating rise of domestic enterprises in the small cell lung cancer field. On August 25, BeiGene announced the signing of a royalty purchase agreement with Royalty Pharma. The latter paid an upfront payment of $885 million to acquire royalty rights from sales of BeiGene's tarlatamab (Imdelltra) outside China. According to the agreement terms, BeiGene has the right to sell remaining royalty collection rights within 12 months, potentially receiving up to $65 million in additional payments. BeiGene will also share in revenue portions when the product's annual sales exceed $1.5 billion, proportional to its royalty stake.

Additionally, under existing collaboration agreements with Amgen, BeiGene will retain royalty rights and all other rights for other products, including the first-in-class STEAP1 and CD3-targeting XmAb bispecific antibody xaluritamig, currently being studied in metastatic castration-resistant prostate cancer patients.

Industry experts widely believe that BeiGene's transaction for tarlatamab differs from traditional License-out deals, representing another important evolution in Chinese innovative drug overseas expansion models. By retaining complete rights in the Chinese market and partial overseas royalty interests, BeiGene has secured substantial financial returns while maintaining linkage to the product's future performance. This provides domestic innovative pharmaceutical companies with another internationalization approach.

**Tarlatamab Enters "Harvest Period"**

BeiGene/Amgen's initial BD transaction with Royalty achieved three major benefits: ① $885 million upfront payment for acquiring majority royalty rights from annual sales of Imdelltra (including any dosage, form, formulation, administration method or route) outside China. ② Up to $65 million additional payment: From closing date to August 25, 2026, BeiGene has the discretionary right to sell additional royalty collection rights to Royalty Pharma, potentially receiving up to $65 million in additional payments, with amounts adjusted proportionally to additional royalty value. ③ Additional profit sharing: If Imdelltra's annual net revenue outside China exceeds $1.5 billion, BeiGene can share in a portion of excess royalties while retaining other economic benefits under the Amgen collaboration agreement.

This transaction differs from traditional BD models, with upfront payments representing 93% of the total transaction ceiling, payable upon closing. This means substantial capital can be quickly recovered without waiting for Imdelltra's long-term sales validation or relying on single milestone payments.

Industry insiders note that for BeiGene, this essentially exchanges Imdelltra's future "cash flow expectations" for current "development capital," retaining global commercialization leadership while creating funding space for subsequent pipeline development. The up to $65 million "sell option" and additional profit sharing above $1.5 billion also leave growth potential for exceeding Imdelltra commercialization progress expectations.

The ability to achieve these unprecedented transaction conditions fundamentally stems from Royalty's recognition of Imdelltra's inherent product value and predictable market competitiveness.

Tarlatamab is a first-in-class immunotherapy that simultaneously binds DLL3 protein on tumor cells and CD3 protein on T cells, thereby activating T cells to kill DLL3-expressing tumor cells by forming cytolytic synapses that induce tumor cell lysis. The drug is jointly developed by Amgen and BeiGene. In May 2024, tarlatamab received FDA accelerated approval for treating extensive-stage small cell lung cancer (ES-SCLC) after platinum chemotherapy progression, becoming the world's first DLL3-targeting bispecific antibody drug.

Domestically, marketing applications for second-line and third-line ES-SCLC treatment were both accepted in July. In April 2025, Amgen announced that tarlatamab met the primary endpoint in the Phase III DeLLphi-304 study. This study enrolled ES-SCLC patients with progression after first-line platinum chemotherapy, showing that compared to standard of care (SOC) chemotherapy, tarlatamab significantly extended overall survival (OS), with median OS of 13.6 months versus 8.3 months, demonstrating statistical and clinical significance.

This Phase III data may provide a more solid foundation for future market prospects. Additionally, tarlatamab is being evaluated in multiple studies with encouraging progress, indicating broader future market potential, including: DeLLphi-303, evaluating tarlatamab combined with standard treatment for first-line ES-SCLC patients in a Phase Ib study; DeLLphi-304, a randomized Phase III trial comparing tarlatamab monotherapy with standard chemotherapy for second-line ES-SCLC treatment; DeLLphi-306, evaluating tarlatamab for treating limited-stage SCLC patients after concurrent chemoradiotherapy in a randomized, placebo-controlled Phase III trial; DeLLphi-308, a Phase Ib study evaluating subcutaneous tarlatamab for second-line and beyond ES-SCLC treatment; and DeLLphi-309, a Phase II study evaluating alternative intravenous dosing regimens of tarlatamab for second-line ES-SCLC treatment.

**Domestic SCLC R&D Acceleration**

SCLC is a highly aggressive and destructive malignant tumor characterized by rapid growth and easy metastasis, accounting for approximately 15% of all lung cancer cases globally, with about 70% of SCLC patients further diagnosed with ES-SCLC. Current first-line treatment for SCLC patients remains primarily platinum-based chemotherapy, but most patients experience disease progression within 6 months, with very limited treatment options after recurrence and median survival time of only 8-10 months.

Given its treatment challenges and market potential, multiple domestic enterprises are actively positioning in the small cell lung cancer field, with CSPC, Qilu Pharma, Promis and others all showing strong development momentum.

In May 2024, CSPC's benmelstoximab injection combined with anlotinib, etoposide and carboplatin received approval for first-line ES-SCLC treatment. In the ETER701 Phase III study, patients receiving this four-drug combination therapy achieved a median overall survival (OS) of 19.3 months, extending survival by 7.4 months compared to chemotherapy alone, showing impressive efficacy data. This represents China's first PD-L1 antibody combined with anlotinib for first-line ES-SCLC therapy, providing new treatment options for these patients.

In new drug research, investigational drugs entering pivotal clinical trials mainly fall into three major areas: ADC drugs, DLL3 TCE, and IO bispecific/multispecific antibodies. For instance, Promis's PD-L1/VEGF bispecific antibody PM8002 is currently conducting Phase III studies treating extensive-stage small cell lung cancer in China (second-line treatment) and the United States (first-line treatment).

Recently, the 2025 European Lung Cancer Conference (ELCC) reported updated data from a Phase II study of PM8002 plus etoposide plus platinum chemotherapy for first-line treatment of extensive-stage small cell lung cancer. Data showed that as of December 20, 2024, 48 patients had completed at least one tumor assessment, with 5 patients still receiving treatment. Among 48 patients, 42 achieved partial response, with an overall objective response rate (ORR) of 87.5%; confirmed objective response rate was 85.4%, and disease control rate was 100%.

Additionally, Qilu Pharma's PD-1/CTLA-4 combination antibody made progress in February this year when Qilu Pharma registered a Phase III clinical study (CTR20250450) of QL1706 injection (Eparolizumab/Tovorelimab) monotherapy consolidation treatment for limited-stage small cell lung cancer on the drug clinical trial registration platform.

Capital operations and innovative R&D in the biopharmaceutical field are reshaping the small cell lung cancer treatment landscape. However, industry voices also express caution that while domestic enterprises have globally leading competitive advantages and excellent early-stage R&D data in the SCLC field, development failures and safety risks still exist.