CD56

BPDCN is an aggressive hematologic malignancy with a historically poor prognosisVisualDx is a clinical decision support system used by more than 2,300 hospitals, clinics, and medical schools around the world VisualDx’s system seeks to enhance identification of people who may have BPDCN, leveraging actual images of BPDCN skin lesions and artificial intelligence/machine learning (AI/ML) technologies incorporated into the VisualDx platform FLORENCE, Italy and NEW YORK, March 20, 2025 (GLOBE NEWSWIRE) -- The Menarini Group ("Menarini"), a leading international pharmaceutical and diagnostics company, and Stemline Therapeutics, Inc. ("Stemline"), a wholly-owned subsidiary of the Menarini Group focused on bringing transformational oncology treatments to cancer patients, today announced that they are collaborating with VisualDx to enhance identification of people who may have BPDCN. This is an example of innovative companies working together to bring artificial intelligence/machine learning (AI/ML) tools to help identify BPDCN as a possible early differential diagnosis. The project includes leveraging actual images of BPDCN skin lesions and AI/ML technologies incorporated into the VisualDx platform. The AI model is now live within VisualDx. VisualDx is a physician-led company committed to improving medical decision-making, medical education and research. The VisualDx tool is a clinical decision support system used by more than 2,300 hospitals, clinics, and medical schools around the world. The software includes a comprehensive database of clinical images, submitted through partnerships with learning institutions and others, and vetted by clinicians, to assist healthcare professionals to identify skin concerns across all skin types. Through the AI image search, clinicians can better understand different skin conditions with the goal of supporting patients to get more accurate diagnoses throughout their care journeys. BPDCN is an aggressive orphan hematologic malignancy with a historically poor prognosis (approximately 8.7 to 14 months post diagnosis1) that typically presents skin lesions and can also involve the bone marrow, blood, central nervous system, lymph nodes and viscera. Dermatologists may be the first to recognize the signs of BPDCN and biopsy suspicious lesions. Pathologists can then test for BPDCN by testing for certain biomarkers which are highly expressed on BPDCN cells. Tagraxofusp-erzs is the only approved treatment for patients with BPDCN, and the first and only approved CD123-targeted therapy, in the United States, Europe and other global regions. "BPDCN is a rare and clinically aggressive hematologic malignancy, often presenting with cutaneous lesions. Due to its aggressive nature and the immature cell involvement, the prognosis can be poor if not treated promptly,” said Marina Konopleva, MD, Phd, Professor, Molecular Pharmacology, Director, Leukemia Program and Co-Director, Blood Cancer Institute, at Montefiore Einstein. “Early diagnosis plays a critical role in improving patient outcomes, and emerging AI/ML technologies may offer valuable support in the differential diagnosis and early identification of BPDCN." “BPDCN often first presents as a skin lesion and usually has a poor prognosis. There is a dire need for early diagnosis so that patients may access appropriate treatment options,” said Elcin Barker Ergun, CEO of the Menarini Group. “We are delighted to collaborate with VisualDx to provide healthcare teams with a tool using the latest artificial intelligence/machine learning (AI/ML) technology to help interpret challenging skin lesions.” VisualDx does not store any images uploaded by clinicians taking a picture of their patients’ skin exams. This helps maintain the patient’s privacy. About BPDCNBPDCN, formerly blastic NK-cell lymphoma, is an aggressive, orphan hematologic malignancy, often with cutaneous manifestations, with historically poor outcomes. BPDCN typically presents skin lesions and may also involve bone marrow, blood, central nervous system, lymph nodes and viscera. The BPDCN cell of origin is the plasmacytoid dendritic cell (pDC) precursor. The diagnosis of BPDCN is based on the immunophenotypic diagnostic triad of CD123, CD4, and CD56, as well as other markers. The World Health Organization (WHO) termed this disease “BPDCN” in 2008; previous names included blastic NK cell lymphoma and CD4+/CD56+ hematodermic neoplasm. About ELZONRIS® (Tagraxofusp-erzs)U.S. Indication: ELZONRIS is a prescription medicine used to treat blastic plasmacytoid dendritic cell neoplasm (BPDCN) in adults and pediatric patients 2 years and older. Full prescribing information for the U.S. can be found at www.elzonris.com IMPORTANT SAFETY INFORMATION, ELZONRIS®Boxed WARNING: CAPILLARY LEAK SYNDROME Capillary Leak Syndrome (CLS) which may be life-threatening or fatal, can occur in patients receiving ELZONRIS. Monitor for signs and symptoms of CLS and take actions as recommended. Warnings and Precautions Capillary Leak Syndrome Capillary leak syndrome (CLS), including life-threatening and fatal cases, has been reported among patients treated with ELZONRIS. In patients receiving ELZONRIS in clinical trials, the overall incidence of CLS was 53% (65/122), including Grade 1 or 2 in 43% (52/122) of patients, Grade 3 in 7% (8/122) of patients, Grade 4 in 1% (1/122) of patients, and four fatalities (3%). The median time to onset was 4 days (range - 1 to 46 days), and all but 5 patients experienced an event in Cycle 1. Before initiating therapy with ELZONRIS, ensure that the patient has adequate cardiac function and serum albumin is greater than or equal to 3.2 g/dL. During treatment with ELZONRIS, monitor serum albumin levels prior to the initiation of each dose of ELZONRIS and as indicated clinically thereafter, and assess patients for other signs or symptoms of CLS, including weight gain, new onset or worsening edema, including pulmonary edema, hypotension or hemodynamic instability. Hypersensitivity Reactions ELZONRIS can cause severe hypersensitivity reactions. In patients receiving ELZONRIS in clinical trials, hypersensitivity reactions were reported in 43% (53/122) of patients treated with ELZONRIS and were Grade ≥ 3 in 7% (9/122). Manifestations of hypersensitivity reported in ≥ 5% of patients include rash, pruritus, and stomatitis. Monitor patients for hypersensitivity reactions during treatment with ELZONRIS. Interrupt ELZONRIS infusion and provide supportive care as needed if a hypersensitivity reaction should occur. Hepatotoxicity Treatment with ELZONRIS was associated with elevations in liver enzymes. In patients receiving ELZONRIS in clinical trials, elevations in ALT occurred in 79% (96/122) and elevations in AST occurred in 76% (93/122). Grade 3 ALT elevations were reported in 26% (32/122) of patients. Grade 3 AST elevations were reported in 30% (36/122) and Grade 4 AST elevations were reported in 3% (4/122) of patients. Elevated liver enzymes occurred in the majority of patients in Cycle 1 and were reversible following dose interruption. Monitor alanine aminotransferase (ALT) and aspartate aminotransferase (AST) prior to each infusion with ELZONRIS. Withhold ELZONRIS temporarily if the transaminases rise to greater than 5 times the upper limit of normal and resume treatment upon normalization or when resolved. Adverse Reactions Most common adverse reactions (incidence ≥ 30%) are capillary leak syndrome, nausea, fatigue, pyrexia, peripheral edema, and weight increase. Most common laboratory abnormalities (incidence ≥ 50%) are decreases in albumin, platelets, hemoglobin, calcium, and sodium, and increases in glucose, ALT and AST. Please see full Prescribing Information, including Boxed WARNING.To report SUSPECTED ADVERSE REACTIONS, contact Stemline Therapeutics, Inc. at 1-877-332-7961 or contact the FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. About The Menarini GroupThe Menarini Group is a leading international pharmaceutical and diagnostics company, with a turnover of over $4.7 billion and over 17,000 employees. Menarini is focused on therapeutic areas with high unmet needs with products for cardiology, oncology, pneumology, gastroenterology, infectious diseases, diabetology, inflammation, and analgesia. With 18 production sites and 9 Research and Development centers, Menarini's products are available in 140 countries worldwide. For further information, please visit menarini.com. About Stemline Therapeutics Inc.Stemline Therapeutics, Inc. (“Stemline”), a wholly-owned subsidiary of the Menarini Group, is a commercial-stage biopharmaceutical company focused on bringing transformational oncology treatments to patients. Stemline commercializes elacestrant, an oral endocrine therapy indicated for the treatment of postmenopausal women or adult men with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative, ESR1-mutated advanced or metastatic breast cancer with disease progression following at least one line of endocrine therapy, in the U.S., Europe, and other global regions. Stemline also commercializes tagraxofusp-erzs, a novel targeted therapy directed to CD123, for patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN), an aggressive hematologic cancer, in the United States, Europe, and other global regions. In addition, Stemline commercializes selinexor, an XPO1 inhibitor for multiple myeloma, in Europe. The company is also conducting multiple label-expansion studies with elacestrant and tagraxofusp in breast and hematologic cancer indications, respectively, and has an extensive clinical pipeline of additional drug candidates in various stages of development for a host of solid and hematologic cancers. About VisualDxVisualDx is a company dedicated to improving medical decisions through augmented thinking and timely visualization. It is committed to reducing disparities in medicine and believes technology can bridge gaps in knowledge to bring about more equitable care. VisualDx has become the standard professional resource at more than 2,300 hospitals, clinics and medical schools worldwide by combining problem oriented clinical search with the world's best curated medical image library, plus medical knowledge from experts and sophisticated machine learning algorithms to help with differential diagnosis, variation, treatment, and patient communication. Learn more at www.visualdx.com Media ContactsThe Menarini GroupValeria Speroni CardiEmail: pressoffice@menarini.com Stemline Therapeutics, Inc.Cheya PopeEmail: media@menarinistemline.com 1 Pagano L, et al Haematological. 2013;98 (2): 239-246 and Pemmaraju N Curr Hematol Malig Rep. 2017; 12(6): 510-512

Fully enrolled the Phase 2/3 trial of lead asset CTX-009 (DLL4 and VEGF-A bispecific antibody) in patients with biliary tract cancers (BTC); top-line data readout is on track for the end of the first quarter of 2025.Designing a Phase 2 trial of CTX-009 in combination with chemotherapy in patients with DLL4-positive colorectal cancer (CRC) treated in the second-line setting; trial initiation expected in mid-2025.Identified neural cell adhesion molecule (NCAM or CD56) as a potential biomarker of response to CTX-471 based on data from the Phase 1 trial; planning a Phase 2 trial in patients with tumors expressing NCAM for mid-2025.Fully enrolled the second dosing cohort of the Phase 1 dose-escalation study of CTX-8371 (PD-1 x PD-L1 bispecific antibody); enrollment into the third dosing cohort is expected to begin in the coming month.Cash balance of $135 million in cash and marketable securities as of September 30, 2024, which is expected to provide cash runway into the first quarter of 2027. BOSTON, Nov. 12, 2024 (GLOBE NEWSWIRE) -- Compass Therapeutics, Inc. (Nasdaq: CMPX), a clinical-stage, oncology-focused biopharmaceutical company developing proprietary antibody-based therapeutics to treat multiple human diseases, today reported third quarter 2024 financial results and provided a business update. “We continue to be extremely encouraged with the progress across our clinical-stage programs, with three drugs already in the clinic and our deepening understanding of the potential clinical and regulatory pathways for each,” said Thomas Schuetz, MD, PhD, CEO of Compass and Vice Chairman of the Board of Directors. “In particular, we recently presented data showing a correlation between NCAM (CD56) expression and disease control with CTX-471 monotherapy. Given the high prevalence of NCAM expression across multiple tumor types, we are planning a Phase 2 monotherapy trial evaluating CTX-471 in patients whose tumors express this biomarker. With respect to our lead asset, CTX-009, we are on track for a top-line data readout in the U.S. at the end of the first quarter of 2025 for COMPANION-002, our Phase 2/3 combination study in patients with advanced BTC. Regarding CTX-009 in CRC, we are designing a Phase 2 study in the second-line setting in patients with metastatic CRC utilizing the DLL4 biomarker based on our observations from COMPANION-003.” DEVELOPMENT PIPELINE UPDATES: CTX-009 (DLL4 and VEGF-A bispecific antibody) Top-line data readout in the U.S. on track for the end of Q1 2025 for COMPANION-002, the Company’s Phase 2/3 randomized trial of CTX-009 in combination with paclitaxel in patients with advanced BTC (see press release). Stage 1 of COMPANION-003, a Phase 2 trial in the U.S. of CTX-009 as a monotherapy in patients with advanced metastatic CRC was completed and, although it is not advancing to Stage 2, showed encouraging preliminary efficacy and safety results. The data from this study has informed the design of a Phase 2 study in the second-line setting in combination with chemotherapy in patients with DLL4-positive CRC. An investigator sponsored study of CTX-009 in patients with BTC in the first-line setting at The University of Texas MD Anderson Cancer Center is being initiated. CTX-009 will be added to the standard first-line regimen of gemcitabine, cisplatin, and durvalumab. CTX-471 (CD137 agonist antibody) CTX-471, a novel anti-CD137 agonist antibody, demonstrated durable clinical responses in Phase 1, which were presented at the American Society of Clinical Oncology (ASCO) Annual Meeting earlier this year.An analysis of biopsy specimens from patients treated with CTX-471 monotherapy in the Phase 1b study identified pharmacodynamic and response biomarkers. These data were presented at the 39th Society for Immunotherapy of Cancer 2024 Annual Meeting. Specifically, data showed a correlation between the levels of NCAM (CD56) expression and disease control in patients treated with CTX-471 monotherapy. CTX-8371 (PD-1 x PD-L1 bispecific antibody) CTX-8371 is a next generation bispecific checkpoint inhibitor that simultaneously targets PD-1 and PD-L1 and exhibits a unique mechanism-of-action that involves cleavage of cell surface PD-1.The second dosing cohort in the Phase 1 dose-escalation study of CTX-8371 is fully enrolled; no dose limiting toxicities (DLTs) have been observed to date. Enrollment into the third dosing cohort is expected to begin in the coming month. Pre-clinical Research Continuing exploration of the synergies observed in pre-clinical and discovery work between VEGF blockade, CD137 agonism, checkpoint inhibition, and other cell engagement to identify novel bispecific antibody drug candidates with complementary anti-tumor activity. FINANCIAL RESULTS: Net loss for the quarter ended September 30, 2024, was $10.5 million or $0.08 per share of common stock, compared to $10.0 million or $0.08 per share of common stock for the same period in 2023. Net loss for the nine months ended September 30, 2024, was $34.3 million or $0.25 per share of common stock, compared to $29.1 million or $0.23 per share of common stock for the same period in 2023. Research and Development (R&D) Expenses R&D expenses were $8.6 million for the quarter ended September 30, 2024, as compared to $8.8 million for the same period in 2023, a decrease of $0.2 million. R&D expenses were $29.3 million for the nine months ended September 30, 2024, as compared to $25.7 million for the same period in 2023, an increase of $3.6 million. This increase was primarily attributable to a $5.2 million increase in clinical costs related to the COMPANION-002 trial, partially offset by $3.2 million less in manufacturing expense for CTX-009. General and Administrative (G&A) Expenses G&A expenses were $3.6 million for the quarter ended September 30, 2024, as compared to $3.1 million for the same period in 2023, an increase of $0.5 million. The increase was due to $0.5 million more stock compensation expense than prior year. G&A expenses were $11.6 million for the nine months ended September 30, 2024, as compared to $9.3 million for the same period in 2023, an increase of $2.3 million. The increase was due to expenses related to the departure of the CEO in the second quarter and more stock compensation expense than prior year. CASH POSITION: As of September 30, 2024, cash and marketable securities were $135 million as compared to $152 million as of December 31, 2023, which gives a cash runway into the first quarter of 2027. During the first nine months of 2024, Compass decreased its cash position by $17 million, primarily by cash used in operating activities partially offset by $18 million cash received from issuance of stock through its at-the-market offering program. About CTX-009 CTX-009 is a bispecific antibody that simultaneously blocks Delta-like ligand 4 (DLL4) and vascular endothelial growth factor A (VEGF-A) signaling pathways, which are critical to angiogenesis and tumor vascularization. Preclinical and early clinical data of CTX-009 suggest that blockade of both pathways provides robust anti-tumor activity across several solid tumors, including colorectal, gastric, cholangiocarcinoma, pancreatic and non-small cell lung cancer. Partial responses to CTX-009 as a monotherapy have been observed in heavily pre-treated patients with cancer who were resistant to approved anti-VEGF therapies. COMPANION-002, a Phase 2/3 trial of CTX-009 (DLL4 and VEGF-A bispecific antibody) plus paclitaxel versus paclitaxel monotherapy in patients with previously treated, unresectable advanced metastatic or recurrent biliary tract cancers (BTC) is ongoing. Clinical Trial information: NCT05506943. About CTX-471 CTX-471 is a fully human monoclonal antibody that binds and activates a novel epitope of the co-stimulatory receptor CD137, also known as 4-1BB, a member of the tumor necrosis factor receptor superfamily. The antibody is currently being evaluated in a Phase 1b clinical trial in patients with solid tumors that have progressed after at least three months on an approved PD-1 or PD-L1 inhibitor. Initial results reported from a monotherapy cohort of the study included five clinical responses, all in patients who previously received checkpoint inhibitors, including a durable partial response (PR) in a patient with small-cell lung cancer that converted to a complete response (as confirmed by PET scan) and four additional PRs (one unconfirmed) in patients with melanoma and mesothelioma. CTX-471 has been generally well tolerated. In preclinical studies, CTX-471 has demonstrated potent monotherapy activity against multiple syngeneic tumor models, including the generation of long-term functional immunological memory. Clinical Trial information: NCT03881488. About CTX-8371 CTX-8371 is a next generation bispecific checkpoint inhibitor that simultaneously targets PD-1 and PD-L1 and exhibits a unique mechanism-of-action that involves cleavage of cell surface PD-1. CTX-8371 received FDA clearance of the IND in October 2023. The Phase 1 CTX-8371 study design includes five ascending doses (0.1, 0.3, 1.0, 3.0, and 10 mg/kg) and the study is enrolling patients with melanoma, non-small cell lung cancer (NSCLC), head and neck squamous cell carcinoma (HNSCC), Hodgkin Lymphoma, and triple negative breast cancer (TNBC) who have progressed on at least one prior regimen containing checkpoint blocker. No DLTs observed in the first dosing cohort and the second dosing cohort has been initiated. Clinical Trial information: NCT06150664. About Compass TherapeuticsCompass Therapeutics, Inc. is a clinical-stage oncology-focused biopharmaceutical company developing proprietary antibody-based therapeutics to treat multiple human diseases. Compass’s scientific focus is on the relationship between angiogenesis, the immune system, and tumor growth. The company pipeline of novel product candidates is designed to target multiple critical biological pathways required for an effective anti-tumor response. These include modulation of the microvasculature via angiogenesis-targeted agents, induction of a potent immune response via activators on effector cells in the tumor microenvironment, and alleviation of immunosuppressive mechanisms used by tumors to evade immune surveillance. Compass plans to advance its product candidates through clinical development as both standalone therapies and in combination with proprietary pipeline antibodies based on supportive clinical and nonclinical data. The company was founded in 2014 and is headquartered in Boston, Massachusetts. For more information, visit the Compass Therapeutics website at https://www.compasstherapeutics.com. Forward-Looking StatementsThis press release contains forward-looking statements. Statements in this press release that are not purely historical are forward-looking statements. Such forward-looking statements include, among other things, references to Compass’s financial position to continue advancing its product candidates, expectations about cash runway, business and development plans, and statements regarding Compass’s product candidates, including their development and clinical trial milestones such as the expected trial design, timing of enrollment, patient dosing and data readouts, regulatory plans with respect to Compass’s product candidates and the therapeutic potential thereof. Actual results could differ from those projected in any forward-looking statements due to numerous factors. Such factors include, among others, Compass’s ability to raise the additional funding it will need to continue to pursue its business and product development plans, the inherent uncertainties associated with developing product candidates and operating as a development stage company, Compass’s ability to identify additional product candidates for development, Compass’s ability to develop, complete clinical trials for, obtain approvals for and commercialize any of its product candidates, competition in the industry in which Compass operates and market conditions. These forward-looking statements are made as of the date of this press release, and Compass assumes no obligation to update the forward-looking statements, or to update the reasons why actual results could differ from those projected in the forward-looking statements, except as required by law. Investors should consult all of the information set forth herein and should also refer to the risk factor disclosure set forth in the reports and other documents Compass files with the U.S. Securities and Exchange Commission (SEC) available at www.sec.gov, including without limitation Compass’s latest Annual Report on Form 10-K, Quarterly Report on Form 10-Q and subsequent filings with the SEC. Investor Contactir@compasstherapeutics.com Media Contact Anna Gifford, Senior Manager of Communications media@compasstherapeutics.com 617-500-8099 Compass Therapeutics, Inc. and SubsidiariesConsolidated Statement of Operations (unaudited)(In thousands, except per share data) Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 License revenue $— $— $850 $— Operating expenses: Research and development 8,612 8,831 29,304 25,694 General and administrative 3,627 3,095 11,597 9,276 Loss from operations (12,239) (11,926) (40,051) (34,970)Other income 1,758 1,962 5,709 5,891 Net loss $(10,481) $(9,964) $(34,342) $(29,079)Net loss per share - basic and diluted $(0.08) $(0.08) $(0.25) $(0.23) Compass Therapeutics, Inc. and SubsidiariesCondensed Consolidated Balance Sheets(In thousands, except par value) September 30, 2024 December 31,2023 (unaudited) Assets Current assets: Cash and cash equivalents $36,801 $24,228Marketable securities 98,601 128,233Prepaid expenses and other current assets 5,738 1,420Total current assets 141,140 153,881Property and equipment, net 493 898Operating lease, right-of-use ("ROU") asset 6,950 1,776Other assets 568 320Total assets $149,151 $156,875Liabilities and Stockholders' Equity Current liabilities: Accounts payable $960 $4,090Accrued expenses 2,916 2,514Operating lease obligations, current portion 557 1,197Total current liabilities 4,433 7,801Operating lease obligations, long-term portion 6,320 536Total liabilities 10,753 8,337Total stockholders' equity 138,398 148,538Total liabilities and stockholders' equity $149,151 $156,875

New data showed a correlation between the levels of neural cell adhesion molecule (NCAM or CD56) expression and response and disease control in patients treated with CTX-471 monotherapy.Predictive biomarkers correlated with response and changes in pharmacodynamic markers were seen in patients treated with CTX-471, a novel anti-CD137 agonist antibody, in an analysis from the Phase 1 monotherapy study. BOSTON, Nov. 08, 2024 (GLOBE NEWSWIRE) -- Compass Therapeutics, Inc. (Nasdaq: CMPX), a clinical-stage, oncology-focused biopharmaceutical company developing proprietary antibody-based therapeutics, today announced its poster presentation entitled “Pharmacodynamic and Response Biomarkers in the Monotherapy Arm of a Phase 1 Trial of CTX-471, a Novel Anti-CD137 Agonist Antibody” at the 39th Society for Immunotherapy of Cancer (SITC) Annual Meeting, from November 6-10, 2024 in Houston, TX. “This exciting new response biomarker data is extremely important for CTX-471 and our clinical strategy,” said Thomas Schuetz, MD, PhD, CEO of Compass and Vice Chairman of the Board of Directors. “Through a comprehensive analysis of tissue and blood samples, we discovered an unexpected correlation between NCAM (CD56) and patient response to CTX-471, as well as a possible mechanistic connection to Natural Killer (NK) Cell activation. This adds more potential indications to CTX-471’s development pathway and we are now planning a Phase 2 monotherapy basket study of CTX-471 in patients whose tumors express NCAM. This patient population is substantial.” These data arise from Compass’s Phase 1 open-label, first-in-human study that evaluated CTX-471 as a monotherapy in patients with metastatic or locally advanced malignancies that have progressed while receiving an approved PD-1 or PD-L1 inhibitor. Exploratory data reported here complement safety and efficacy data previously published at ASCO 2024. Biopsy specimens and blood samples from patients treated with CTX-471 were analyzed by multi-parameter immunofluorescence, flow cytometry, and a panel of cytokines using the Neogenomics Multi-omyx platform. To measure pharmacodynamic effects, comparisons were made between samples collected before and after CTX-471 treatment. To survey response biomarkers, values from baseline samples obtained from patients with tumors showing complete or partial responses as well as stable disease were compared with tumors showing progressive disease. Further, the authors propose a mechanism by which NCAM facilitates CTX-471 response. Specifically, tumor cell NCAM appears to enrich activated NK cells in the tumor microenvironment that express the CTX-471 target, CD137 (4-1BB). The dataset shows these effects to be specific for NCAM expressing lymphocytes such as NK cells and is not observed in other lymphocyte subsets such as CD8+ T cells. These findings are novel in a clinical setting and support the potential use of NCAM as a selection marker for future clinical trials. Data highlights from the poster presentation include: CTX-471 pharmacodynamic biomarker changes were consistent with immune stimulation.CTX-471 disease control is associated with measurable baseline biomarkers.Baseline tumor cell expression of NCAM/CD56 is associated with response and disease control.A novel baseline circulating cell phenotype is associated with partial responses to CTX-471. A copy of the presentation materials can be accessed on the Compass website at https://www.compasstherapeutics.com/pipeline once the presentation has concluded. About CTX-471CTX-471 is a fully human monoclonal antibody that binds and activates a novel epitope of the co-stimulatory receptor CD137, also known as 4-1BB, a member of the tumor necrosis factor receptor superfamily. In preclinical studies, CTX-471 has demonstrated potent monotherapy activity against multiple syngeneic tumor models, including the generation of long-term functional immunological memory. The antibody is currently being evaluated in a Phase 1b clinical trial in patients with solid tumors that have progressed after at least three months on an approved PD-1 or PD-L1 inhibitor. Initial results reported from a monotherapy cohort of the study included five clinical responses, all in patients who previously received checkpoint inhibitors, including a durable partial response (PR) in a patient with small-cell lung cancer that converted to a complete response (as confirmed by PET scan) and four additional PRs (one unconfirmed) in patients with melanoma and mesothelioma. CTX-471 has been generally well tolerated. Clinical Trial information: NCT03881488. About NCAM (CD56) Neural cell adhesion molecule (NCAM) is a membrane glycoprotein that belongs to the immunoglobulin superfamily mediating homotypic interactions between cells on which it is expressed. It plays a role in neural cell adhesion and central nervous system development. In cancer, NCAM is linked with tumor invasion and metastases, with the most relevant tumor types being neural crest-derived (e.g., metastatic melanoma, SCLC, and glioblastoma) and neuroendocrine tumors (NET). The prevalence of NCAM high tumors ranges from approximately 30% of metastatic melanoma to virtually all of SCLC, glioblastoma and NETs. About Compass Therapeutics Compass Therapeutics, Inc. is a clinical-stage oncology-focused biopharmaceutical company developing proprietary antibody-based therapeutics to treat multiple human diseases. Compass’s scientific focus is on the relationship between angiogenesis, the immune system, and tumor growth. The company pipeline of novel product candidates is designed to target multiple critical biological pathways required for an effective anti-tumor response. These include modulation of the microvasculature via angiogenesis-targeted agents, induction of a potent immune response via activators on effector cells in the tumor microenvironment, and alleviation of immunosuppressive mechanisms used by tumors to evade immune surveillance. Compass plans to advance its product candidates through clinical development as both standalone therapies and in combination with proprietary pipeline antibodies based on supportive clinical and nonclinical data. The company was founded in 2014 and is headquartered in Boston, Massachusetts. For more information, visit the Compass Therapeutics website at https://www.compasstherapeutics.com. Forward-Looking StatementsThis press release contains forward-looking statements. Statements in this press release that are not purely historical are forward-looking statements. Such forward-looking statements include, among other things, statements regarding Compass’s product candidates, such as CTX-471, and the results of scientific and clinical analyses of such product candidates, including their development and clinical trial milestones such as identification of potential biomarkers or other indicators of the therapeutic potential thereof, the expected trial design, timing of enrollment, patient dosing and data readouts, regulatory plans with respect to Compass’s product candidates and the therapeutic potential thereof, and references to Compass’s financial position to continue advancing these product candidates or related business and development plans. Actual results could differ from those projected in any forward-looking statements due to numerous factors. Such factors include, among others, Compass’s ability to raise the additional funding it will need to continue to pursue its business and product development plans, the inherent uncertainties associated with developing product candidates and operating as a development stage company, Compass’s ability to identify additional product candidates for development, Compass’s ability to develop, complete clinical trials for, obtain approvals for and commercialize any of its product candidates, competition in the industry in which Compass operates and market conditions. These forward-looking statements are made as of the date of this press release, and Compass assumes no obligation to update the forward-looking statements, or to update the reasons why actual results could differ from those projected in the forward-looking statements, except as required by law. Investors should consult all of the information set forth herein and should also refer to the risk factor disclosure set forth in the reports and other documents Compass files with the U.S. Securities and Exchange Commission (SEC) available at www.sec.gov, including without limitation Compass’s latest Annual Report on Form 10-K, Quarterly Report on Form 10-Q and subsequent filings with the SEC. Investor Contactir@compasstherapeutics.com Media Contact Anna Gifford, Senior Manager of Communications media@compasstherapeutics.com617-500-8099