LRP5

Recently, Merus announced that the first patient has been dosed in the phase 3 clinical trial LiGeR-HN2, aimed at evaluating the efficacy of petosemtamab in the second-line and third-line treatment of patients with recurrent or metastatic head and neck squamous cell carcinoma (r/m HNSCC). LiGeR-HN2 is a randomized, open-label phase 3 clinical trial primarily assessing the safety and efficacy of petosemtamab compared to standard therapy in patients with recurrent or metastatic head and neck squamous cell carcinoma. The trial will enroll patients who have previously received first-line treatment and whose disease has progressed. The primary endpoints of the study typically include objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and safety assessments. Petosemtamab is a bispecific antibody developed by Merus that simultaneously targets both the epidermal growth factor receptor (EGFR) and LGR5 (Leucine-rich repeat-containing G protein-coupled receptor 5), receptors which are overexpressed in various types of cancer. By targeting these two receptors, petosemtamab aims to more effectively target and kill cancer cells while reducing the impact on healthy cells. Data presented by Merus at the 2024 American Society of Clinical Oncology (ASCO) showed that in patients with head and neck squamous cell carcinoma (HNSCC), when used in combination with Keytruda, six out of ten evaluable patients demonstrated a tumor response, achieving a response rate of 60%. Furthermore, Merus' latest public materials on their website also released mid-stage clinical updates of petosemtamab as a monotherapy for second-line and beyond HNSCC, which showed a response rate of 37% in 43 evaluable patients (2L+ HNSCC, ORR 37%), and mid-stage clinical updates of its combination with the PD-1 monoclonal antibody Keytruda for first-line HNSCC, which achieved a response rate of 67% in 24 evaluable patients (1L HNSCC, RR 67%). The company projects that by 2028, the global market size for HNSCC will exceed $5 billion, highlighting the substantial commercial potential of petosemtamab for this indication. The FDA has granted petosemtamab Breakthrough Therapy Designation (BTD) for the treatment of patients with recurrent or metastatic HNSCC who have experienced disease progression following platinum-based chemotherapy and anti-programmed cell death receptor-1 (PD-1) or anti-programmed death-ligand 1 (PD-L1) antibody therapy. Partnering with GileadIn early 2024, Gilead Sciences announced that it will pay Merus a $56 million upfront payment and make a $25 million equity investment in the biotech company. Through the partnership with Merus, Gilead Sciences aims to leverage Merus's expertise in the development of bispecific and multispecific antibodies to create innovative antibody therapies. The specific targets of the collaboration have not been disclosed. About LGR5LGR5, also known as GPR49, is a seven-transmembrane protein that belongs to the GPCR superfamily. Within this GPCR superfamily, LGR5, along with LGR4 and LGR6 which are part of the glycoprotein-receptor orphan subgroup, share a distinctive structural feature: a large extracellular domain containing 17 leucine-rich repeat sequences. When LGR5 binds to its ligand R-Spondin (RSPO), it collaborates with the Wnt receptors (Frizzled and LRP5/6) to enhance the Wnt/β-catenin signaling pathway. LGR5 regulates the Wnt/β-catenin signaling pathway in normal intestinal stem cells. For instance, during normal homeostasis of the intestine, the expression of LGR5 is restricted to the stem cell compartments located at the base of the crypts. As the progeny of the stem cells migrate upward through the proliferative zone and undergo differentiation, this expression of LGR5 is lost. Consistently, isolated single LGR5+ cells from the intestine can form self-organizing crypt/villus structures known as organoids, capable of reconstituting all differentiated epithelial lineages present in the intestine. The table below presents the pipeline status of clinical studies related to LGR5, all of which are for cancer-related indications. Merus clearly holds a leading position in this target competition. Next Indication: Colorectal CancerIn an interview with the CEO of Merus, it was also mentioned that the company is looking forward to evaluating petosemtamab in metastatic colorectal cancer (mCRC), which represents another significant potential opportunity. Colorectal cancer (CRC) is the third most commonly diagnosed malignancy worldwide and the fourth leading cause of cancer-related deaths, with its burden expected to increase by 60% by 2030. Despite significant improvements in detection and treatment protocols, most advanced-stage cancer patients will die from recurrence of their disease. A widely recognized reason for CRC recurrence is the failure of existing therapies to eradicate subpopulations of cancer stem cells (CSCs) within the tumor. CSCs express a variety of markers, including CD133, CD44, CD166, ALDH, EphB2, and Leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5). These CSCs are capable of resisting therapeutic assaults and re-establishing tumor growth after treatment interventions, creating an urgent need for innovative, non-toxic targeted cancer therapies to induce sustained clinical remission. A key early event in the progression of colorectal cancer is the dysregulation of the Wnt/β-catenin signaling pathway, which is often constitutively activated by genetic mutations in APC or β-catenin. Under normal conditions, the lack of Wnt ligands leads to the constitutive phosphorylation of β-catenin, followed by proteasomal degradation, keeping Wnt target genes suppressed. When Wnt ligands bind to the Wnt receptors Frizzled and LRP5/6, the accumulation of β-catenin in the cytoplasm leads to its nuclear translocation, where it binds with the TCF/LEF family of transcription factors and activates oncogenic Wnt target genes such as c-myc, cyclinD1, and survivin. How to obtain the latest research advancements in the field of biopharmaceuticals? 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Low density lipoprotein receptor-associated protein 5/6 (LRP5/6) forms a complex with Wnt protein that triggers cytoplasmic tail phosphorylation of LRP5 or LRP6, which in turn causes Axin to bind to it and inhibit the activity of glycogen synthase kinase (GSK-3β). This process leads to increased phosphorylation of β-catenin, promotes its nuclear translocation, forms complexes with DNA-binding proteins, activates target gene promoters, and ultimately promotes differentiation, proliferation, and survival of osteoblasts. Studies have revealed that Sclerostin secreted by Osteocytes (Osteocytes) interferes with Wnt signaling and stabilizes β-catenin by competitively binding LRP5/6, thus reducing osteogenic activity and triggering osteoporosis. Therefore, blocking the interaction between sclerotin and LRP5/6 can enhance Wnt signaling, increase bone formation, and inhibit bone resorption. By specifically binding to osteosin, osteosinomumab reduces its inhibition of Wnt signaling pathway, thereby promoting osteogenesis and inhibiting osteoclast, and realizing dual mechanism therapy for osteoporosis. Currently, only one drug that targets SOST, Romozolzumab, has been approved for marketing. Romosozumab is the first humanized IgG2 monoclonal antibody targeting SOST osteosclerosis protein, but its road to market has been challenging. In 2017, the FDA rejected romosozumab's U.S. marketing application, citing concerns about an increased risk of cardiovascular events in patients. Subsequently, Amgen and UCB provided additional Phase III clinical data at the FDA request, which was not approved until April 2023. However, the EU CHMP rejected romosozumab's marketing application in June of the same year due to cardiovascular risk concerns, which also limited its projected 2024 sales to only $3.2 billion. Setrusumab is the world's second SOST monoclonal antibody for the treatment of osteogenesis imperfecta (OI). OI is a rare genetic bone disorder characterized by low bone mass and fragility fractures. Setrusumab is a fully human IgG2 monoclonal antibody that treats OI by inhibiting the function of sclerosin, a protein that inhibits the activity of osteoblasts. In June, Ultragenyx Pharmaceutical and Mereo BioPharma announced that setrusumab showed significant results in a sustained reduction in fracture rates in Orbit, the Phase 2 portion of a 2/3 clinical trial for OI patients. Blosozumab is a humanized monoclonal antibody against osteosin developed by Eli Lilly for the treatment of osteoporosis. The company is licensed to develop and commercialize Blosozumab in Greater China. Lilly completed Phase II clinical trials in the United States and Japan, showing favorable safety and efficacy. In May 2023, Transom Group announced Phase I data showing that TST002 (Blosozumab) demonstrated a good safety and tolerability profile in all dose groups, and demonstrated a clinically significant increase in lumbar bone density in terms of efficacy. SHR-1222, China's first SOST monoclonal antibody developed by Hengrui Pharmaceutical, is currently in Phase I clinical trials. Osteoporosis is a systemic bone disease characterized by loss of bone mass and destruction of bone microstructure, resulting in increased bone fragility and susceptibility to fracture. With an aging population, China has the largest number of osteoporosis patients, with about 90 million patients, accounting for 7 percent of the total population, and at least 210 million people with lower than normal bone mass. Therefore, the market potential of osteoporosis treatment drugs is huge. The market size of osteoporosis drugs in China is expected to reach 36.8 billion yuan in 2025 and further grow to 51.2 billion yuan in 2030. The sclerotinomumab represented by Romozomumab provides a new strategy for the treatment of osteoporosis, which is expected to overcome the limitations of traditional drugs and become the focus of future research and treatment.

Bispecific antibodies (bsAbs) possess unique advantages due to their ability to simultaneously target two distinct antigens, which helps to enhance the immune system's recognition and killing of tumor cells. As of the end of 2023, 14 bsAbs have been approved: 11 of them for cancer treatment and 3 for non-oncological indications. BsAbs come in various structural formats, target different antigens, and mediate antitumor functions through different molecular mechanisms. The development of antibodies targeting G protein-coupled receptor (GPCR) targets is relatively more challenging compared to traditional drugs such as small molecules, peptides, recombinant hormones, etc., with slower progress in comparison. In contrast, the development of Antibody-Drug Conjugates (ADCs) targeting members of the GPCR family has seen a gradual increase in research momentum over the past decade. Dual-specificity antibodies related to GPCRAccording to statistics from the Synapse database, there are currently 23 bispecific antibody therapeutics worldwide targeting GPCR (G protein-coupled receptor) class targets, including targets such as CXCR4 (+PD-L1) , GPRC5D (+CD3) , GPRC5D (+BCMA+CD30) , SSTR2 (+CD3) , ETA (+CD3) , ETA (+TGF-B) , CCR8 (+TIGIT) , CCR8 (+CTLA4) , CCR2 (+M-CSF) , FZD5 (+LRP6) , FZD4 (+LRP5), GIPR+GLP-1R, FSHR (+albumin) , LGR5 (+EGFR). Johnson & Johnson's Talquetamab became the world's first approved bispecific antibody targeting a GPCR class target to be marketed. Bispecific antibodies that target both GPRC5D and CD3 include Nanjing Leads Biolabs' LBL-034, which is in Phase 1/2 clinical trials, and Roche's Forimtamig, which is in Phase 1 clinical development. Additionally, the GPRC5D+CD3+BCMA trispecific antibody MBS314, co-developed by Kyinno Biotechnology and Beijing Mabworks Biotech, is in Phase 1/2 clinical trials, and the GPRC5D+CD3+BCMA trispecific antibody SIM-0500, co-developed by Simcere Pharmaceutical Group Limited and Shanghai Xianxiang Pharmaceutical Technology, is in the clinical application stage. Translate the following text into English with professional accuracy: The Dutch biotechnology company Merus has developed a bispecific product, Petosemtamab (MCLA-158), currently in Phase 1/2 clinical trials. This is a bispecific Biclonics® fucose-low full human IgG1 antibody that simultaneously targets the epidermal growth factor receptor (EGFR) and leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5). Petosemtamab is designed with three independent mechanisms of action: Inhibition of the EGFR-dependent signaling pathway: By binding with EGFR on the surface of tumor cells, it blocks normal signal transmission, thereby inhibiting processes such as tumor cell proliferation, migration, and angiogenesis.  LGR5-mediated EGFR internalization and degradation: Petosemtamab can bind to LGR5, leading to the internalization and degradation of EGFR within cancer cells, further diminishing EGFR’s pro-carcinogenic activity.  Enhancement of antibody-dependent cellular cytotoxicity and phagocytosis (ADCC/ADCP): With its bispecific structure, Petosemtamab can recruit and activate the immune system's natural killer (NK) cells and macrophages, enhancing their ability to recognize and eliminate cancer cells expressing EGFR and LGR5, thus achieving indirect antitumor effects. At the 2023 Annual Meeting of the American Association for Cancer Research (AACR), Merus presented the results of a Phase 1/2 clinical trial cohort expansion, showing that Petosemtamab demonstrated a manageable safety profile and significant therapeutic effects in patients with advanced head and neck squamous cell carcinoma (HNSCC). Among the 43 patients with advanced HNSCC treated with Petosemtamab, the overall response rate (ORR) reached 37.2%, with tumor reductions observed in 16 patients. The data specifics included: 1 patient achieved a complete response (CR), and 15 patients had partial responses (PR). In addition, 15 patients achieved a stable disease (SD) condition. As a result, the disease control rate (DCR) was 72.1% (n=31/43; 95% CI, 56.3%-84.7%), which means that over seventy percent of the patients experienced no tumor progression or saw reductions in tumor size following treatment. The bi-specific product SZN-1326, originally developed by the American biotechnology company Surrozen, is in Phase 1 clinical research. The product is designed based on Surrozen's proprietary SWAP™ technology, with the goal of modulating the Wnt signaling pathway in intestinal epithelium. The Wnt/β-catenin signaling pathway plays a crucial role in the renewal of intestinal stem cells, the maintenance of intestinal epithelial homeostasis, and the regeneration process. Studies have confirmed that this pathway is dysregulated in inflammatory bowel disease (IBD). Fzd5 is a Wnt receptor with high expression in intestinal epithelial tissues. SZN-1326 is a bi-specific, effectorless IgG1 antibody that targets both FZD5 and 8, as well as the LRP6 receptor. Preclinical research has indicated that SZN-1326 can effectively activate the Wnt signaling pathway. Furthermore, in organoid cultures of the intestine, it can stimulate the growth of the organoids; it increases the expression levels of the Wnt target gene Axin2 in colonic tissue; and in a mouse model, SZN-1326 can also ameliorate colitis symptoms induced by Dextran Sulfate Sodium (DSS). At present, bispecific antibodies targeting GPCR class targets are primarily indicated for cancer-related clinical applications, with popular therapeutic directions including multiple myeloma, plasma cell myeloma, solid tumors, and more. However, there is also a diversity of clinical indications, such as bispecific antibodies targeting GIPR and GLP-1R for the treatment of obesity and diabetes, bispecific antibodies targeting ETA for the treatment of pulmonary fibrosis and pulmonary arterial hypertension, bispecific antibodies targeting FSHR for the treatment of male/female infertility, and bispecific antibodies targeting FZD4 for the treatment of diabetic retinopathy and wet age-related macular degeneration.