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• After a median follow-up of 18.9 months, the median PFS was 8.3 months in the sac-TMT group and 4.3 months in the chemotherapy group (hazard ratio (HR), 0.49; 95% confidence interval (CI), 0.39 to 0.62; two-sided P<0.0001).

• OS was significantly longer with sac-TMT than with chemotherapy (HR, 0.60; 95% CI, 0.44 to 0.82; two-sided P=0.001); 18-month OS rate was 65.8% and 48.0%, respectively. In the supplementary analysis, in which data were censored at the start date of subsequent ADC, the HR was 0.56 (95% CI, 0.41 to 0.77).

• Sac-TMT was associated with a higher incidence of stomatitis with most cases being mild and with grade 3 or higher cases reported in very few patients (4.8%; all were grade 3). Low incidence of ocular-surface toxic effects, no ILD or pneumonitis, and one infusion-related reaction (grade 2) was reported in the sac-TMT group.

On October 20, results from the Phase III registrational clinical study OptiTROP-Lung04—led by Professor Zhang Li's team from Sun Yat-sen University Cancer Center—were published in the New England Journal of Medicine (Impact Factor = 78.5). The study evaluated the efficacy and safety of the TROP2 antibody-drug conjugate (ADC) sacituzumab tirumotecan (sac-TMT) monotherapy versus pemetrexed plus platinum chemotherapy for the treatment of patients with epidermal growth factor receptor (EGFR)-mutant locally advanced or metastatic non-squamous non-small cell lung cancer (NSCLC) who have progressed failed after treatment with EGFR-tyrosine kinase inhibitor (TKI) therapy. The study was also selected as a Late-Breaking Abstract (LBA) at the 2025 European Society for Medical Oncology (ESMO) Congress and was presented as an oral report in the Presidential Symposium (Presentation # LBA5).  

OptiTROP-Lung04 is a randomized, open-label, multicenter Phase III study designed to evaluate the efficacy and safety of sac-TMT monotherapy versus pemetrexed plus platinum in patients with EGFR-mutated locally advanced or metastatic NSCLC who had progressed on prior EGFR-TKI therapy. Eligible patients were those with histologically and/or cytologically confirmed disease. The primary endpoint was Progression-Free Survival (PFS) assessed by a Blinded Independent Review Committee (BIRC) per RECIST v1.1, and the key secondary endpoint was overall survival (OS). Results showed that compared with platinum-based doublet chemotherapy, sac-TMT monotherapy demonstrated a statistically significant and clinically meaningful improvement in both PFS and OS. Consistent PFS and OS benefits were observed across all prespecified subgroups, including prior EGFR-TKI therapy, presence of liver or brain metastases, and EGFR mutation subtype.

Based on the positive results of the OptiTROP-Lung04 study, sac-TMT has been approved by the National Medical Products Administration (NMPA) in China for the treatment of adult patients with EGFR mutation-positive locally advanced or metastatic non-squamous NSCLC who have progressed after EGFR-TKI therapy. To date, sac-TMT monotherapy remains the only approved treatment option for advanced EGFR-mutant NSCLC patients who have progressed after prior TKI therapy, as well as those who have progressed after prior TKI and platinum-based chemotherapy (either concurrently or sequentially). This achievement provides comprehensive coverage for the entire population of TKI-resistant patients.

Dr. Michael Ge, Chief Ｅxecutive Officer of Kelun-Biotech, commented: “OptiTROP-Lung04 is a key study that propels sac-TMT from late-line to an earlier-line treatment-setting in lung cancer, achieving a significant improvement in overall survival. We are thrilled that the results have been published in The New England Journal of Medicine, allowing this important finding to be shared widely among medical professionals and providing a reference for future lung cancer research. Together with our partner MSD, we will continue to advance sac-TMT’s clinical development and regulatory approvals, covering broader lung cancer and other indications, with the goal of making sac-TMT a cornerstone therapy for the benefit of patients.”

Professor Shengxiang Ren from the Department of Oncology at Shanghai Pulmonary Hospital, Tongji University, stated: “The application of third-generation EGFR-TKIs has significantly improved the overall prognosis for patients with advanced EGFR-mutant NSCLC. However, drug resistance is almost inevitable. Traditional treatment after resistance involves platinum-based doublet chemotherapy, which offers limited overall benefit. In recent years, regimens of chemotherapy plus immune checkpoint inhibitors+anti-angiogenic agents, or EGFR/c-Met bsAb, or PD-1/VEGF bsAb, have been successively approved for this indication. However, all these approaches are chemotherapy-based, highlighting an urgent need to explore novel treatment regimens. The OptiTROP-Lung04 study confirms sac-TMT as the first treatment option as a monotherapy to deliver clear dual benefits in both PFS and OS following EGFR-TKI progression. The sequential application of sac-TMT prior to chemotherapy demonstrates strong competence, establishing itself as a new standard of care for patients with advanced EGFR-mutant lung cancer after TKI resistance.”

About Sac-TMT

Sac-TMT, a core product of the Company, is a novel human TROP2 ADC in which the Company has proprietary intellectual property rights, targeting advanced solid tumors such as NSCLC, breast cancer (BC), gastric cancer (GC), gynecological tumors, among others. Sac-TMT is developed with a novel linker to conjugate the payload, a belotecan-derivative topoisomerase I inhibitor with a drug-to-antibody-ratio (DAR) of 7.4. Sac-TMT specifically recognizes TROP2 on the surface of tumor cells by recombinant anti-TROP2 humanized monoclonal antibodies, which is then endocytosed by tumor cells and releases the payload KL610023 intracellularly. KL610023, as a topoisomerase I inhibitor, induces DNA damage to tumor cells, which in turn leads to cell-cycle arrest and apoptosis. In addition, it also releases KL610023 in the tumor microenvironment. Given that KL610023 is membrane permeable, it can enable a bystander effect, or in other words kill adjacent tumor cells.

In May 2022, the Company licensed the exclusive rights to MSD (the tradename of Merck & Co., Inc., Rahway, NJ, USA) to develop, use, manufacture and commercialize sac-TMT in all territories outside of Greater China (includes Mainland China, Hong Kong, Macau, and Taiwan).

To date, three indications for sac-TMT have been approved and marketed in China for the treatment of adult patients with unresectable locally advanced or metastatic triple negative breast cancer (TNBC) who have received at least two prior systemic therapies (at least one of them for advanced or metastatic setting), EGFR mutation-positive locally advanced or metastatic non-squamous NSCLC following progression on EGFR-TKI therapy and platinum-based chemotherapy and EGFR mutant-positive locally advanced or metastatic non-squamous NSCLC who progressed after treatment with EGFR-TKI therapy. Sac-TMT is the first TROP2 ADC drug approved for marketing in lung cancer globally. In addition, the new indication application for sac-TMT for the treatment of adult patients with unresectable locally advanced, metastatic hormone receptor positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) BC who have received prior endocrine therapy and other systemic treatments in the advanced or metastatic setting was accepted by the Center for Drug Evaluation of the NMPA, and was included in the priority review and approval process.

As of today, the Company has initiated 9 registrational clinical studies in China. MSD has initiated 15 ongoing Phase Ⅲ global clinical studies of sac-TMT as a monotherapy or with pembrolizumab1 or other anti-cancer agents for several types of cancer. These studies are sponsored and led by MSD.

About Kelun-Biotech

Kelun-Biotech (6990.HK) is a holding subsidiary of Kelun Pharmaceutical (002422.SZ), which focuses on the R&D, manufacturing, commercialization and global collaboration of innovative biological drugs and small molecule drugs. The company focuses on major disease areas such as solid tumors, autoimmune, inflammatory, and metabolic diseases, and in establishing a globalized drug development and industrialization platform to address the unmet medical needs in China and the rest of world. The Company is committed to becoming a leading global enterprise in the field of innovative drugs. At present, the Company has more than 30 ongoing key innovative drug projects, of which 4 projects have been approved for marketing, 1 project is in the NDA stage and more than 10 projects are in the clinical stage. The company has established one of the world's leading proprietary ADC and novel DC platforms, OptiDC™, and has 2 ADC projects approved for marketing, and multiple ADC and novel DC assets in clinical or preclinical research stage. For more information, please visit https://kelun-biotech.com/.

References:

1. Pembrolizumab (KEYTRUDA®) is a registered trademark of Merck Sharp & Dohme LLC (MSD), a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.

CHENGDU, China, Oct, 18 , 2025——Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. (the “Company”) announced that at the 2025 European Society for Medical Oncology (ESMO) Congress held in Berlin, Germany, Results from a Phase 3 study of the Company’s human epidermal growth factor receptor 2 (HER2)-directed ADC trastuzumab botidotin (also known as A166) trastuzumab botidotin versus trastuzumab emtansine (T-DM1) in HER2-positive unresectable or metastatic BC was presented as an oral report by Professor Xichun Hu from Fudan University Shanghai Cancer Center (Presentation # LBA24, Proffered paper session 1: Breast cancer, metastatic).

Trastuzumab botidotin is a HER2-targeted ADC composed of a cytotoxic drug (Duostatin-5, anti-microtubule agent) with site-specific conjugation to trastuzumab via a stable protease-cleavable valine-citrulline linker. The unique linker is stable in plasma and selectively cleaved by lysosomal cathepsin B that is up-regulated in cancer cells.

In this study, a total of 365 patients with HER2+ unresectable or metastatic BC who had received at least one prior anti-HER2 therapy were randomized (1:1) to receive trastuzumab botidotin or T-DM1. 53% of patients had received ≥2 lines of anti-HER2 therapy, 61% of patients had HER2 Immunohistochemistry (IHC) 3+, and 60% of patients had been treated with TKIs, particularly pyrotinib (56%). As of April 26, 2025, median follow-up was 14.9 months.

Median PFS was significantly longer in trastuzumab botidotin than in T-DM1 (11.1 months vs 4.4 months; HR: 0.39, 95% CI, 0.30-0.51, p<0.0001). PFS benefit with trastuzumab botidotin was consistently observed regardless of prior lines of anti-HER2 therapy (HR 0.36, 95% CI, 0.25-0.53, for 1 prior line; HR 0.39, 95% CI, 0.28-0.56, for ≥2 prior lines).

ORR by blinded independent central review (BICR) was 76.9% vs 53.0%.

A trend toward benefit in OS was observed in trastuzumab botidotin (HR 0.62; 95% CI, 0.38-1.03).

Grade ≥3 treatment emergent adverse events (TEAEs) occurred in 69.8% of patients in trastuzumab botidotin and 63.7% in T-DM1. The most common TEAEs associated with dose reduction were ocular AEs for trastuzumab botidotin, and were platelet count decreased for trastuzumab emtansine. Only two patients permanently discontinued trastuzumab botidotin due to TEAE. No on-treatment deaths were observed in trastuzumab botidotin, compared with 1.6% in T-DM1, all of which were considered unrelated to treatment.

As a conclusion, this second head-to-head trial comparing T-DM1 with other anti-HER2 regimens demonstrated that trastuzumab botidotin statistically improved PFS with an ORR of 76.9% vs 53.0%. PFS benefit with trastuzumab botidotin was consistently observed regardless of prior lines of anti-HER2 therapy. Ocular AEs were also manageable.

"Professor Xichun Hu, National Lead Principal Investigator from Fudan University Shanghai Cancer Center:“Trastuzumab botidotin effectively balances safety and efficacy through its unique molecular design, reducing the incidence of interstitial lung disease and hematologic toxicity. According to research data, trastuzumab botidotin demonstrated significant survival benefits in the pivotal Phase III trial, with an overall manageable safety profile, providing a new important treatment option for pretreated HER2+ BC patients. These positive results also offer robust evidence-based support for personalized treatment and updates to clinical practice guidelines.”

About Trastuzumab botidotin

Trastuzumab botidotin is a differentiated HER2 ADC to treat advanced HER2+ solid tumors. As an innovative HER2 ADC developed by the Company, it conjugates a novel, monomethyl auristatin F (MMAF) derivative (a highly cytotoxic tubulin inhibitor, Duo-5) via a stable, enzyme-cleavable linker to a HER2 monoclonal antibody with a DAR of 2. Trastuzumab botidotin specifically binds to HER2 on the surface of tumor cells and is internalized by tumor cells, releasing the toxin molecule Duo-5 inside the cell. Duo-5 induces tumor cell cycle arrest in the G2/M phase, leading to tumor cell apoptosis. After targeting HER2, trastuzumab botidotin can also inhibit the HER2 signaling pathway; it has antibody-dependent cell-mediated cytotoxicity (ADCC) activity.

Based on the results of a multi-center, randomized, open-label, controlled, Phase 3 KL166-III-06 study, trastuzumab botidotin was approved for marketing by the NMPA in for adult patients with unresectable or metastatic HER2 positive BC who have received one or more prior anti-HER2 therapy. At a pre-specified interim analysis, trastuzumab botidotin demonstrated a statistically significant and clinically meaningful improvement in the primary endpoint of PFS as assessed by the BICR compared with T-DM1[; the beneficial trend for OS of trastuzumab botidotin was also observed.

Currently, the Company has initiated an open, multi-center Phase 2 clinical study of trastuzumab botidotin in the treatment of HER2+ unresectable or metastatic BC that previously received a topoisomerase inhibitor ADC.

About Kelun-Biotech

Kelun-Biotech (6990.HK) is a holding subsidiary of Kelun Pharmaceutical (002422.SZ), which focuses on the R&D, manufacturing, commercialization and global collaboration of innovative biological drugs and small molecule drugs. The company focuses on major disease areas such as solid tumors, autoimmune, inflammatory, and metabolic diseases, and in establishing a globalized drug development and industrialization platform to address the unmet medical needs in China and the rest of world. The Company is committed to becoming a leading global enterprise in the field of innovative drugs. At present, the Company has more than 30 ongoing key innovative drug projects, of which 4 projects have been approved for marketing, 1 projects are in the NDA stage and more than 10 projects are in the clinical stage. The company has established one of the world's leading proprietary ADC and novel DC platforms, OptiDC™, and has 1 ADC project approved for marketing and multiple ADC and novel DC assets in clinical or preclinical research stage. For more information, please visit https://kelun-biotech.com/.

CHENGDU, China, Oct, 19, 2025——Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. (the “Company”) announced that at the 2025 European Society for Medical Oncology (ESMO) Congress held in Berlin, Germany, results from a Phase 3 OptiTROP-Lung04 trial of the Company’s trophoblast cell-surface antigen 2 (TROP2)-directed antibody-drug conjugate (ADC) sacituzumab tirumotecan (sac-TMT)  in EGFR-mutated non-small cell lung cancer (NSCLC) following progression on epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) was presented as an oral report by Professor Li Zhang from Sun Yat-sen University Cancer Center (Presentation # LBA5, Presidential Symposium II) and were simultaneously published in the New England Journal of Medicine (Impact Factor = 78.5).

In the OptiTROP-Lung04 trial, a total of 376 patients were randomized (1:1) to receive sac-TMT monotherapy or chemotherapy.

As at the data cut-off date July 06, 2025, the median follow-up is 18.9 months. the median Progression-Free Survival (PFS) was 8.3 months in the sac-TMT group and 4.3 months in the chemotherapy group. Sac-TMT significantly improved PFS over chemotherapy with 51% lower risk of disease progression or death (hazard ratio (HR) 0.49; 95% confidence interval (CI), 0.39-0.62; P<0.0001).

At the preplanned interim analysis of overall survival (OS), the OS was not reached (NR) in the sac-TMT group and 17.4 months in the chemotherapy group. sac-TMT significantly improved OS over chemotherapy with 40% lower risk of death (hazard ratio (HR) 0.6; 95% CI: 0.44-0.82; two-sided P=0.001). In the supplemental analysis, when censoring patients at the date of initiation of subsequent ADCs, sac-TMT significantly improved OS over chemotherapy with 44% lower risk of death (HR, 0.56; 95% CI, 0.41 - 0.77).

Sac-TMT significantly improved ORR as compared to chemotherapy (60.6% vs 43.1%)

A consistent PFS and OS benefit of sac-TMT over chemotherapy was observed across all predefined subgroups, including prior EGFR-TKI therapy, presence of liver or brain metastases, and EGFR mutation subtype.

The incidence of any grade treatment-related adverse events (TRAEs) and grade ≥3 TRAEs was similar between the two groups. The most common TRAEs for both sac-TMT and chemotherapy were hematologic toxicities. No TRAEs led to discontinuation or death, and no cases of interstitial lung disease/pneumonitis were reported in the sac-TMT group. Ocular surface toxicity: occurred in 9.6% of patients in the sac-TMT group, all of which were grade 1 - 2.

As a conclusion, sac-TMT demonstrates highly statistically significant and clinically meaningful improvements in PFS and OS compared to platinum-based chemotherapy and showed a manageable safety profile, with no unexpected safety signals identified. Several global phase 3 studies of sac-TMT monotherapy (NCT06305754, NCT06074588) and combination study with osimertinib in China (NCT06670196) in EGFR-mutant NSCLC are ongoing.

Professor Zhang Li, National Lead Principal Investigator from Sun Yat-sen University Cancer Center, commented: "Compared to platinum-based doublet chemotherapy, sac-TMT not only significantly prolonged PFS but also demonstrated a statistically significant and clinically meaningful improvement in OS within this patient population. This achievement marks a major breakthrough in global lung cancer treatment—sac-TMT, as a monotherapy, demonstrated statistically significant and clinically meaningful improvements in both PFS and OS in the Phase III trial for patients with EGFR-TKI-resistant NSCLC. This study provides highly valuable, new evidence-based guidance for lung cancer management worldwide and has the potential to reshape the therapeutic landscape for EGFR-TKI-resistant NSCLC "

 About sac-TMT

Sac-TMT, a core product of the Company, is a novel human TROP2 ADC in which the Company has proprietary intellectual property rights, targeting advanced solid tumors such as NSCLC, BC, GC, gynecological tumors, among others. Sac-TMT is developed with a novel linker to conjugate the payload, a belotecan-derivative topoisomerase I inhibitor with a drug-to-antibody-ratio (DAR) of 7.4. Sac-TMT specifically recognizes TROP2 on the surface of tumor cells by recombinant anti-TROP2 humanized monoclonal antibodies, which is then endocytosed by tumor cells and releases the payload KL610023 intracellularly. KL610023, as a topoisomerase I inhibitor, induces DNA damage to tumor cells, which in turn leads to cell-cycle arrest and apoptosis. In addition, it also releases KL610023 in the tumor microenvironment. Given that KL610023 is membrane permeable, it can enable a bystander effect, or in other words kill adjacent tumor cells.

In May 2022, the Company licensed the exclusive rights to MSD (the tradename of Merck & Co., Inc, Rahway, NJ, USA) to develop, use, manufacture and commercialize sac-TMT in all territories outside of Greater China (which includes Mainland China, Hong Kong, Macao and Taiwan).

To date, three indications for sac-TMT have been approved and marketed in China for the treatment of adult patients with unresectable locally advanced or metastatic triple negative breast cancer (TNBC) who have received at least two prior systemic therapies (at least one of them for advanced or metastatic setting), EGFR mutation-positive locally advanced or metastatic non-squamous NSCLC following progression on EGFR-TKI therapy and platinum-based chemotherapy and EGFR mutant-positive locally advanced or metastatic non-squamous NSCLC who progressed after treatment with EGFR-TKI therapy. Sac-TMT is the first TROP2 ADC drug approved for marketing in lung cancer globally. In addition, the new indication applications for sac-TMT for the treatment of adult patients with unresectable locally advanced, metastatic HR+/HER2- BC who have received prior endocrine therapy and other systemic treatments in the advanced or metastatic setting was accepted by the Center for Drug Evaluation (CDE) of the National Medical Products Administration (NMPA), and was included in the priority review and approval process.

As of today, the Company has initiated 9 registrational clinical studies in China. MSD has initiated 15 ongoing Phase 3 global clinical studies of sac-TMT as a monotherapy or with pembrolizumab or other anti-cancer agents for several types of cancer. These studies are sponsored and led by MSD.

About Kelun-Biotech

Kelun-Biotech (6990.HK) is a holding subsidiary of Kelun Pharmaceutical (002422.SZ), which focuses on the R&D, manufacturing, commercialization and global collaboration of innovative biological drugs and small molecule drugs. The company focuses on major disease areas such as solid tumors, autoimmune, inflammatory, and metabolic diseases, and in establishing a globalized drug development and industrialization platform to address the unmet medical needs in China and the rest of world. The Company is committed to becoming a leading global enterprise in the field of innovative drugs. At present, the Company has more than 30 ongoing key innovative drug projects, of which 4 projects have been approved for marketing, 1 project is in the NDA stage and more than 10 projects are in the clinical stage. The company has established one of the world's leading proprietary ADC and novel DC platforms, OptiDC™, and has 2 ADC project approved for marketing and multiple ADC and novel DC assets in clinical or preclinical research stage. For more information, please visit https://kelun-biotech.com/.

 (May 24th, Chengdu and New Jersey) The 2024 American Society of Clinical Oncology (ASCO) Annual Meeting to be held in Chicago, Illinois, the United States of America from May 31 to June 4, 2024, Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. (the “Company”) will present two clinical stage study results at ASCO.

1.The Phase 3 OptiTROP-Breast01 study of its anti-TROP2 ADC sacituzumab tirumotecan (sac-TMT) (formerly SKB264/MK-2870) in patients with previously treated locally recurrent or metastatic triple-negative breast cancer (TNBC).

?   Session: Special clinical science symposium (Abstract #104; Next-Generation Antibody–Drug Conjugates: The Revolution Continues),

?   Time:  June 2, 2024, 9:45 AM to 11:15 AM local time

2.  The Phase 2 OptiTROP-Lung01 study of sac-TMT in combination with KL-A167 (an anti-PD-L1 mAb) as 1L treatment for patients with advanced non-small cell lung cancer (NSCLC)

?   Session: oral (Abstract #8502; Lung Cancer—Non-Small Cell Metastatic Oral)

?   Time: May 31, 2024, 2:45 PM to 5:45 PM local time.

Sac-TMT is jointly developed by Kelun-Biotech and MSD (the tradename of Merck & Co., Inc., Rahway, NJ, USA) at clinical stage.

The abstracts for the above studies were published on ASCO’s official website on [May 23, 2024], local time. The study results are summarized as follows:

TNBC

Patients were randomly assigned (1:1) to receive sac-TMT (n = 130) or chemotherapy (n = 133). The median age was 51 years; 87% had visceral metastases; 26% received prior PD-1/PD-L1 inhibitors; 48% received three or more prior lines of chemotherapy for advanced disease. The primary endpoint of progression free survival (PFS) was met based on interim analysis (data cut-off: Jun 21, 2023) with a 69% reduction in risk of progression or death (HR 0.31; 95% CI, 0.22 to 0.45; P <0.00001).

The median PFS, as assessed by BICR, was 5.7 months (95% CI, 4.3 to 7.2) with sac-TMT and 2.3 months (95% CI, 1.6 to 2.7) with chemotherapy; PFS rate at 6 months was 43.4% vs 11.1%. In the subset of patients with trophoblast cell-surface antigen 2 (TROP2) H-score > 200, the median PFS was 5.8 months with sac-TMT and 1.9 months with chemotherapy (HR 0.28; 95% CI, 0.17 to 0.48). At the first planned interim analysis for overall survival (OS) (data cut-off: Nov 30, 2023) with median follow-up of 10.4 months, OS was statistically significant in favor of sac-TMT (HR 0.53; 95% CI, 0.36 to 0.78; P =0.0005); the median OS was not reached (95% CI, 11.2 to NE) with sac-TMT and 9.4 months (95% CI, 8.5 to 11.7) with chemotherapy. The objective response rate (ORR) assessed by BICR was 43.8% with sac-TMT and 12.8% with chemotherapy.

Most common grade ≥ 3 treatment-related adverse events (TRAEs) (sac-TMT vs. chemotherapy) were neutrophil count decreased (32.3% vs. 47.0%), anemia (27.7% vs. 6.1%) and white blood cell count (WBC) decreased (25.4% vs. 36.4%).

A Phase 3 global study led by MSD of sac-TMT plus pembrolizumab versus treatment of physician's choice (TPC) in TNBC who received neoadjuvant therapy and did not achieve a pathological complete response (pCR) at surgery (NCT06393374) and a Phase 3 study led by the Company of sac-TMT in China for 1L treatment of unresectable locally advanced, recurrent or metastatic PD-L1 negative TNBC (NCT06279364) are ongoing.

NSCLC

Patients with treatment naive advanced NSCLC without actionable genomic alterations were enrolled to receive sac-TMT 5 mg/kg Q3W plus KL-A167 1200 mg Q3W (cohort 1A) or sac-TMT 5 mg/kg Q2W plus KL-A167 900 mg Q2W (cohort 1B) in a non-randomized manner until disease progression or unacceptable toxicity. As of January 02, 2024, 40 and 63 patients have been enrolled in cohort 1A and 1B, respectively. Median ages were 63/63 years (cohort 1A/1B); 97.5%/85.7% had Eastern Cooperative Oncology Group (ECOG) Performance status (PS) of 1; 30.0%/33.3%, 32.5%/30.2% and 37.5%/36.5% of patients had programmed death ligand 1 (PD-L1) expression < 1%, 1%-49% and ≥ 50% of tumor cells by IHC 22C3 pharmDx assay, respectively.

After median follow up of 14.0 months for cohort 1A, the ORR was 48.6% (18/37, 2 pending confirmation), disease control rate (DCR) was 94.6% and median PFS was 15.4 months (95% CI: 6.7, NE) with a 6-month PFS rate of 69.2%. After median follow-up of 6.9 months for cohort 1B, the ORR was 77.6% (45/58, 5 pending confirmation), DCR was 100% and median PFS was not reached with a 6-month PFS rate of 84.6%. Additional subgroup analyses of cohort 1B are shown in the following table:

*Including confirmed or unconfirmed response. ORR was calculated based on response evaluable population defined as patients with ≥ 1 on-study scans.

In cohorts 1A and 1B, the most common Grade ≥ 3 TRAEs were neutrophil count decreased (30.0%/30.2%), WBC decreased (5.0%/17.5%), anemia (5.0%/15.9%), rash (5.0%/6.3%) and drug eruption (7.5%/0). Treatment-related adverse events leading to discontinuation of sac-TMT occurred in 1 patient of cohort 1B due to drug hypersensitivity, and there were no treatment-related deaths.

Two Phase 3 global studies led by MSD of sac-TMT in patients with 3L+ EGFR mutant NSCLC (NCT06074588), and 2L EGFR mutant NSCLC (NCT06305754) and a Phase 3 study led by the Company of sac-TMT in China in patients with 2L EGFR mutant NSCLC (NCT05870319) are ongoing. Additionally, Three Phase 3 global studies led by MSD of sac-TMT plus pembrolizumab are ongoing: One in patients with 1L Metastatic Squamous NSCLC (NCT06422143) , a second  in patients with metastatic NSCLC expressing PD-L1 ≥ 50% (NCT06170788), and the third in patients with resectable NSCLC not achieving a pathological complete response (NCT06312137) .

2024 American Association for Cancer Research (AACR) Annual Meeting is being held in San Diego, California, the United States of America from April 5^th to 10^th, 2024, local time.

Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. (6990.HK, the “Company”) will present two study results of anti-TROP2 ADC sacituzumab tirumotecan (sac-TMT, formerly SKB264/MK-2870) during the AACR meeting scheduled below. The abstracts for the studies have been published on the official website of the AACR on April 5^th, 2024, local time (See link below).

1. The updated efficacy and safety results for its anti-TROP2 ADCSKB264/sac-TMT in patients with previously treated advanced non-small cell lung cancer (NSCLC) from a phase 2 study in a poster session scheduled on April 9 2024, 1:30 PM - 5:00 PM local time (Abstract Presentation Number: CT247).

2.The preliminary efficacy and safety results for its anti-TROP2 ADC SKB264/sac-TMT in patients with previously treated advanced gastric or gastroesophageal junction (GEJ) cancer from a phase 2 study as an oral presentation, which is scheduled in a session on April 9 2024, 2:30 PM - 4:30 PM local time (Abstract Presentation Number: CT038).

The study results are summarized as follows:

NSCLC

Patients with previously treated advanced NSCLC were enrolled to receive SKB264/sac-TMT at 5 mg/kg Q2W until disease progression or unacceptable toxicity (KL264-01, NCT04152499). The data cut-off date was November 22, 2023.

Five Phase 3 global studies of SKB264/sac-TMT in patients with NSCLC are ongoing. Including two Phase 3 global studies of SKB264/sac-TMT in patients with 3L+ EGFR mutant NSCLC (NCT06074588), and 2L EGFR mutant NSCLC (NCT06305754) and a Phase 3 study ofSKB264/sac-TMT in China in patients with 2L EGFR mutant NSCLC (NCT05870319). Additionally two Phase 3 global studies of SKB264/sac-TMT plus pembrolizumab in patients with metastatic NSCLC expressing programmed death ligand 1 (PD-L1)≥ 50% (NCT06170788) and resectable NSCLC not achieving pathological complete response (NCT06312137) are ongoing.

As of the Data Cut-off date, 43 NSCLC patients had been enrolled and the median follow-up was 17.2 months. 21 patients with EGFR wild type had received a median of 3 prior regimens of therapy including anti-PD-1/L1 inhibitors. 22 patients with EGFR mutant had progressed on or after TKI therapy, 50% of whom also failed at least one line of chemotherapy. Updated efficacy results are shown in the following:

*Including confirmed or unconfirmed response. Based on response evaluable patients (≥1 on-study scans) with 4 patients (2 EGFR mutant patients with non-squamous histology and 2 EGFR wild type patients with squamous histology) excluded.

The most common Grade ≥3 treatment-related adverse events (TRAEs) were neutrophil count decreased (34.9%), anemia (30.2%), white blood cell (WBC) count decreased (25.6%), stomatitis (9.3%), and rash (7.0%). No TRAEs leading to treatment discontinuation or deaths occurred. No drug-related interstitial lung disease (ILD)/pneumonitis was reported.

Gastric/GEJ cancer

Patients with previously treated inoperable advanced gastric/GEJ adenocarcinoma were enrolled to receive SKB264/sac-TMT monotherapy at 5 mg/kg Q2W until disease progression or unacceptable toxicity in Phase 2 expansion cohort of KL264-01 study (NCT04152499). Patients with heavily pre-treated gastric/GEJ cancer were enrolled first, and then the cohort was amended to enroll patients with only one prior therapy of chemotherapy and anti-PD-1/L1 therapy. The data cut-off date was Nov 22, 2023.

As of the data cut-off date, a total of 48 patients were enrolled and followed up for at least 9 weeks. 24 patients (50.0%) had received one prior line of therapy (2L), while 24 patients (50.0%) had received ≥ 2 prior lines of therapy (3L+). 40 patients (83.3%) had received prior anti-PD-1/L1 inhibitors. Of 41 response-evaluable patients (defined as ≥ 1 on-study scans), the objective response rate (ORR) was 22.0% (9 partial responses, 2 pending confirmation) and disease control rate (DCR) was 80.5%. The ORRs in the 2L and 3L+ setting were 27.3% (including 2 pending confirmation) and 15.8%, respectively. Median duration of response (DoR) was 7.5 months. In the subset of 3L+ patients (n=24 including 54.2% of patients with ≥ 4 prior lines of therapy) with more mature follow-up (median follow up of 14.6 months), the median progression free survival (mPFS) was 3.7 months (95% CI: 2.6, 5.4) and median overall survival (mOS) was 7.6 months (95% CI: 5.3, 15.5).

The most common ≥ Grade 3 TRAEs were anemia (20.8%), neutrophil count decreased (18.8%), WBC decreased (12.5%) and neutropenia (6.3%). No TRAEs leading to treatment discontinuation or deaths occurred. No neuropathy or drug-related ILD/pneumonitis was reported.

A Phase 3 global study of SKB264/sac-TMT monotherapy versus standard of care (SOC) chemotherapy in 3L+ gastric/GEJ adenocarcinoma is being planned.

Press Contact: Xinwei Li, klbio_pr@kelun.com

On 8^th March 2024, Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. (6990.HK, Kelun-Biotech)’s innovative core product TROP2-ADC SKB264 (also known as MK-2870) was granted Breakthrough Therapy Designation（BTD） by the Center for Drug Evaluation（ CDE） of the National Medical Products Administration (NMPA) of China for first-line treatment of unresectable locally advanced, recurrent or metastatic PD-L1 negative  triple negative breast cancer (TNBC). SKB264 (MK-2870) is jointly developed by Kelun-Biotech and MSD (the tradename of Merck & Co., Inc., Rahway, NJ, USA).

This is the fourth Breakthrough Therapy Designation for SKB264 (MK-2870) granted by the NMPA. Previously, SKB264 (MK-2870) was granted BTD for:

• July 2022, locally advanced or metastatic TNBC.

• January 2023, EGFR-mutant locally advanced or metastatic non-small cell lung cancer (NSCLC) after progression on EGFR tyrosine kinase inhibitor (TKI) therapy.

• June 2023, locally advanced or metastatic hormone receptor-positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) breast cancer in patients who have previously received at least two lines of systematic chemotherapy.

Breast cancer is one of the most common malignant tumors in women, with its incidence showing an increasing trend year by year. The International Agency for Research on Cancer (IARC) and the World Health Organization (WHO) estimated that in 2020, there were over 2.26 million new cases of breast cancer globally, accounting for 11.7% of all tumors, making it the most prevalent cancer [1]. Triple-negative breast cancer (TNBC) is a clinical subtype that is negative for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), comprising 10.0% to 20.8% of all breast cancer types. Triple-negative breast cancer is characterized by high heterogeneity, a high rate of recurrence and metastasis, and a poorer prognosis compared to other types of breast cancer. It lacks effective and specific treatment methods [2]. Currently, the primary treatment for PD-L1 negative TNBC is chemotherapy, which offers limited survival benefits, highlighting the urgent need for new treatment plans. For patients with inoperable locally advanced, recurrent, or metastatic PD-L1 negative triple-negative breast cancer, the first-line standard treatment in China still involves chemotherapy, including single-agent or combination chemotherapy [3]. Compared to single-agent chemotherapy, combination chemotherapy has greater toxicity and offers limited survival benefits.

BTD is designed to expedite the development of new drugs for serious diseases that have shown significant efficacy or safety over existing therapies in preliminary clinical trials. For new drugs included in the Breakthrough Therapy List, CDE will prioritize the allocation of resources for communication, enhanced guidance, and promotion of drug development. If the relevant conditions have been assessed to be met, an application for conditional approval and an application for priority review and approval may also be submitted at the time of the application for drug marketing authorization. This will help accelerate the SKB264 (MK-2870) development process and address the unmet clinical needs of Chinese patients as soon as possible.

参考文献：
[1] Cancer statistics in China and United States, 2022: profiles, trends, and determinants. Chin Med J(Engl).2022 Feb 9; 135(5):584-590.
[2] 三阴性乳腺癌含铂方案临床应用专家共识（2021版）.中华肿瘤防治杂志2021年6月第28卷第12期.
[3] 《中国临床肿瘤学会（CSCO）乳腺癌诊疗指南2023版》.

Our key product A400(EP0031), a small molecule rearranged during transfection (RET) kinase inhibitor program, has been granted Fast Track designation by the United States Food and Drug Administration (FDA) for the treatment of RET fusion-positive non-small cell lung cancer (NSCLC).

A400 (EP0031) is a second-generation selective RET inhibitor (SRI) with broad activity against common RET fusions and mutations.

• In March 2021, the Company granted Ellipses Pharma Limited, a U.K.-based international drug development company, an exclusive, royalty-bearing, sub licensable license to develop, manufacture and commercialize A400 (EP0031) in all countries excluding Greater China, North Korea, South Korea, Singapore, Malaysia and Thailand. 

• In June 2022, the FDA approved an investigational new drug application for A400 (EP0031), and a phase 1/2 trial is ongoing in patients with malignant tumors with RET gene alteration. 

• In November 2023, A400 was granted Orphan Drug Designation by the FDA for the treatment of RET fusion-positive solid tumors.

In preclinical studies, A400 (EP0031) demonstrated favourable inhibitory activity against key RET kinases in-vitro and in-vivo. A400 (EP0031) also demonstrated good penetration of the blood brain barrier in animal models. Data shared at the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting on A400 (EP0031) showed promising anti-tumor efficacy in patients with advanced RET+ solid tumors, highlighted by ORR of 80.8% and 69.7% for 1L and 2L+ advanced RET+ NSCLC, respectively, based on results from its ongoing phase 1/2 trial. In both cases, DCR of over 96% were reported.

At present, the Company is conducting A400 (EP0031) pivotal clinical study in China for RET- positive NSCLC.

About Ellipses Pharma Limited

Ellipses Pharma is a global drug development company based in London, focused on accelerating the development of cancer treatments through an innovative drug development model that combines unbiased vetting to de-risk initial asset selection with an uninterrupted funding flow to minimise the time it takes to advance lead products through clinical trials and reach patients.

About Kelun-Biotech

Kelun-Biotech（6990.HK）is a holding subsidiary of Kelun Pharmaceutical (002422.SZ), which focuses on the R&D, manufacturing, commercialization and global collaboration of innovative biological drugs and small molecule drugs. The company focuses on major disease areas such as solid tumors, autoimmune, inflammatory, and metabolic diseases, and in establishing a globalized drug development and industrialization platform to address the unmet medical needs in China and the rest of world. The Company is committed to becoming a leading global enterprise in the field of innovative drugs. At present, the Company has 33 ongoing innovative projects in major disease areas such as solid tumors, autoimmune, inflammatory, and metabolic diseases, including 14 projects in the clinical stage with several global trials being conducted simultaneously in multiple countries, including China, Europe, and the United States. The company has established one of the world’s leading proprietary ADC platforms, OptiDC, and has four ADC projects in the clinical stage (two of which are in the NDA stage) and several projects in the preclinical stage. For more information, please visit https://kelun-biotech.com/.

pursuant to the Notice of Adjustment of Stock List of Southbound Trading Link of the Shanghai-Hong Kong Stock Connect ( 关于沪港通下港股通目标调整的通知) made by the Shanghai StockExchange on March 1, 2024, the Company will be included in the list of eligible shares of the Southbound Trading Link of the Shanghai-Hong Kong Stock Connect with effect from March 4, 2024.

On February 21, 2024, the prestigious international finance magazine, FinanceAsia, held its 2023 annual achievement awards ceremony in Hong Kong. Kelun-Biotech (6990.HK) was invited to attend the celebration dinner and was awarded the "Best IPO in Asia and Hong Kong for 2023" honor.

FinanceAsia is regarded as one of the most representative professional monthly magazine in Asia's capital market and has significant influence in the investment industry. Founded in 1996, its sponsored "FinanceAsia Achievement Awards" is one of the most influential and credible industry award selections in the Asia-Pacific region, the award ceremony is an significant annual gathering in the investment industry.

About Kelun-Biotech

Kelun-Biotech（6990.HK）is a holding subsidiary of Kelun Pharmaceutical (002422.SZ), which focuses on the R&D, manufacturing, commercialization and global collaboration of innovative biological drugs and small molecule drugs. The company focuses on major disease areas such as solid tumors, autoimmune, inflammatory, and metabolic diseases, and in establishing a globalized drug development and industrialization platform to address the unmet medical needs in China and the rest of world. The Company is committed to becoming a leading global enterprise in the field of innovative drugs. At present, the Company has 33 ongoing innovative projects in major disease areas such as solid tumors, autoimmune, inflammatory, and metabolic diseases, including 14 projects in the clinical stage with several global trials being conducted simultaneously in multiple countries, including China, Europe, and the United States. The company has established one of the world’s leading proprietary ADC platforms, OptiDC, and has four ADC projects in the clinical stage (two of which are in the NDA stage) and several projects in the preclinical stage. For more information, please visit https://kelun-biotech.com/.