Pembrolizumab

iStock, rudall30 The tragic tale of TIGIT is well known. However, RIPK1, myc, STING and alpha-synuclein have also left a trail of failed clinical trials, canceled partnerships and sunk investments in their wake. For a while, Gilead Sciences and Arcus Biosciences seemed like they could defy the TIGIT odds. In November 2023, their monoclonal antibody domvanalimab achieved a 59% overall response rate when used alongside anti-PD-1 treatment and chemotherapy in a Phase 2 stomach cancer trial. Domvanalimab maintained this efficacy beyond two years, the partners reported in 2024, while also demonstrating progression-free survival. Encouraged by these findings, Gilead and Arcus pushed the asset into Phase 3. But in December last year, the duo announced they were dropping development of domvanalimab in gastric and esophageal malignancies after an underwhelming performance—adding another chapter to the long and troubled tale of anti-TIGIT therapies. TIGIT, short for T cell immunoreceptor with immunoglobulin and tyrosine-based inhibitory motif domain, is a receptor that, when activated, exerts immunosuppressive effects. TIGIT is overexpressed in many malignancies, with cancer cells exploiting its natural function to weaken the body’s anti-cancer response. Many companies have sought to treat cancer by disrupting the TIGIT pathway, but to date, none have succeeded. GSK, for instance, teamed up with Belgian biotech iTeos Therapeutics in 2021 to advance its TIGIT therapy belrestotug. Disappointing mid-stage lung cancer data for the drug eventually forced GSK to pull the plug on the program and the partnership in May 2025. Not long after, iTeos shuttered its operations. Merck and Roche have also been thrown by TIGIT. The former was stymied by safety concerns while the latter failed to see a survival advantage in lung cancer. This dilemma stretches across biopharma: Promising disease targets attract a rush of investments from major drugmakers—only to leave behind a trail of disappointing readouts, discontinued studies and doomed partnerships. BioSpace takes a look at four of those targets, digging into the science behind their therapeutic potential and taking stock of the sponsors that have failed to bear these mechanisms out in the clinic. Immuno-oncology Four Therapies Hanging On in Troubled TIGIT Space TIGIT-targeting therapies have largely disappointed in recent months, with failed studies, terminated partnerships and shuttered businesses. Here are five biopharma players staying alive with differentiated candidates against the once promising immuno-oncology target. July 7, 2025 · 9 min read · Tristan Manalac Read more Big Pharma runs into RIPK1 rough patch Last month, Eli Lilly abandoned Rigel Pharmaceuticals after struggling failing to crack another difficult drug target: RIPK1. RIPK1 —short for receptor-interacting serine/threonine-protein kinase 1—is “a central signaling node,” Stuti Mahajan, consulting manager at DelveInsight, told BioSpace in an email. “The target gained major attention after preclinical studies showed that RIPK1 inhibition could suppress inflammatory cell death and reduce tissue damage across conditions such as ALS [amyotrophic lateral sclerosis], multiple sclerosis, rheumatoid arthritis, psoriasis, and inflammatory bowel disease,” she said. GSK led the industry’s charge, winning the FDA’s first go-ahead in 2014 to conduct clinical trials on a RIPK1 candidate. Sanofi and Denali Therapeutics followed soon after with 2018 agreement to go after the target in neurological and inflammatory diseases. By 2021, Eli Lilly was playing catch-up to its Big Pharma peers, fronting $125 million and promising up to $835 million in milestones to collaborate with Rigel. But the modality’s initial promise soon gave out under the weight of clinical reality, Mahajan told BioSpace . “Clinical translation has been more difficult than initially expected,” she said, with RIPK1-targeting molecules showing “modest or inconsistent” therapeutic benefits. GSK’s candidate, dubbed GSK2982772, failed to significantly improve disease severity in a Phase 2 ulcerative colitis study , according to an August 2021 paper in BMJ Open Gastroenterology . The asset is no longer listed on the pharma’s pipeline page . Sanofi and Denali were also foiled by RIPK1 and were forced in October 2024 to abandon a mid-stage multiple sclerosis study after a disappointing performance from their candidate oditrasertib. Sanofi earlier that year also pulled the plug on a Phase 2 trial of oditrasertib in ALS, similarly due to underwhelming efficacy. Roche added to RIPK1’s losing streak in March of this year, electing to end a Phase 2 study for its asset flizasertib for acute kidney injury in patients undergoing cardiac surgery. The drug was “unable to demonstrate a statistically significant clinical benefit,” according to a federal trials database . Business Sanofi and AstraZeneca Scrap Several Early-Stage Programs in Q1 Sanofi is dropping its Sjögren’s syndrome candidate due to disappointing Phase II efficacy data, while AstraZeneca is stopping work on some early-stage assets amid a portfolio reprioritization. April 25, 2024 · 2 min read · Tyler Patchen Read more Myc, crucial cancer driver, remains undruggable Like TIGIT, myc has long been an attractive but elusive cancer target. Myc refers to a broad family of transcription factors that regulate several key cellular processes, such as growth, division and metabolism. Under healthy conditions, the myc gene is tightly regulated. But in most—if not all—malignancies, it is highly expressed, leading to deregulated pathways that drive cancer. In fact, myc “holds the distinction of being the first oncogene to be found amplified in tumor cells,” according to a 2024 review article published in the journal Signal Transduction and Targeted Therapy . “MYC is over expressed in 70% of malignancies where it drives cell division at an accelerated pace; promotes a hostile tumor microenvironment; and is responsible for resistance against multiple drug classes,” Peter Smith, executive chairman of Racura Oncology, told BioSpace in an email. Despite its prevalence, however, myc remains a largely undruggable target in cancer, owing largely to its structure—"or lack thereof,” Smith said, pointing to the oncogene’s “basic helix-loop-helix transcription factor.” This overall simple structure makes it nearly impossible for drugs to stick to it, he explained. “Using the classic lock and key analogy for a drug interacting with its target, MYC simply has no lock, no well-defined tertiary structure for a drug to bind with high affinity,” Smith added. Currently, there are no small molecule myc inhibitors in development, according to Smith, but that’s not for want of trying. Many drugmakers over the years have tried and failed to advance a myc-directed drug. Aptose Biosciences, for instance, was banking on an asset called APTO-253, which it had been testing in an early study of relapsed or refractory acute myeloid leukemia or myelodysplastic syndrome. APTO-253 was designed to suppress the expression of myc but was discontinued in 2021 after “an internal review of the product pro performance” and prioritization of other more advanced assets. Dicerna Pharmaceuticals also took a crack at myc with its RNA interference therapy DCR-MYC, which was supposed to drive down expression of the problematic gene. The company shelved the asset in 2016 when preliminary results failed to meet the company’s expectations for further development. Faced with a string of failures, “it appears that the majority of major pharmaceutical companies, after decades of research, have simply given up trying,” Smith concluded. STING stymies immunology, oncology advancements Another target that has tripped up the industry is STING (stimulator of interferon genes), a protein involved in various immune cascades. “Activation of the STING pathway induces type I interferon production, dendritic cell activation, and downstream T-cell priming,” Arunima Dabral, assistant project manager, Clinical & Pipeline Analysis at DelveInsight, told BioSpace in an email. Preclinical data supported this mechanism, she said, not only showing potential for immune-mediated diseases but also for cancer. This promise attracted “substantial industry investment,” Dabral said, including from GSK, which in 2022 put $1.4 billion on the line to partner with Mersana Therapeutics. At the heart of this deal was the biotech’s lead asset XMT-2056, an antibody-drug conjugate (ADC) that activates the STING pathway. The partners were supposed to develop the molecule for HER2-positive cancers. GSK and Mersana had a hard time with XMT-2056, however, running into a clinical hold in March 2023 linked to a death in a Phase 1 study that was deemed related to the asset. That pause was lifted in November that year, but that wasn’t enough to make GSK stick around. The pharma ultimately axed XMT-2056 in the first quarter of this year. Policy FDA Lifts Hold on Mersana’s Antibody-Drug Conjugate Following Patient Death The regulator has released Mersana Therapeutics’ antibody-drug conjugate XMT-2056 from its clinical hold, allowing the biotech to proceed with Phase I studies of the candidate with a lower starting dose. November 1, 2023 · 2 min read · Tristan Manalac Read more Merck has also been stymied by STING. The pharma was working on an oral STING agonist ulevostinag, also called MK-1454, which it was studying as a monotherapy or as part of a combo regimen with Keytruda, for solid tumors or lymphomas. Phase 1 data in 2018 showed no partial or complete responses in patients given the STING agonist alone. Merck has since discontinued the asset. Several challenges prevent STING-targeted drugs from succeeding in the clinic, Dabral explained. “Managing the toxicity associated with systemic immune activation, ensuring effective delivery to tumor sites, and overcoming tumor heterogeneity and resistance mechanisms are critical hurdles,” she said. Nevertheless, “the STING field remains active,” Dabral continued, with newer players incorporating novel technologies such as nanoparticle delivery and more selective pathway targeting. Daiichi Sankyo, for instance, is leveraging its ADC platform to advance the STING-targeting DS3610, which in November last year entered Phase 1 testing . The asset seeks to achieve more “precise tumor targeting,” Ken Takeshita, global head of R&D, said in a statement at the time. Alpha-synuclein aggravates in neuro Outside of cancer and immunology, there’s alpha-synuclein, which, owing to its central role in the pathology, is “one of the leading targets” in Parkinson’s disease, DelveInsight’s Mahajan said. Alpha-synuclein (α-syn) is a protein found in neurons that, under healthy conditions, plays a critical role in regulating the secretion of neurotransmitters. In certain neurodegenerative diseases, however, α-syn is wrongly folded, forming toxic clumps that ultimately trigger the destruction of neurons. “Aggregated alpha-synuclein is a defining pathological hallmark of Parkinson’s disease” and related conditions, such as dementia with Lewy bodies and multiple system atrophy, Mahajan explained. Because of its central role in neurodegenerative diseases, many of the industry’s biggest players have invested heavily α-syn-targeting approaches, but results have been mixed. Biogen, for instance, shelled out $32.5 million —and promised $395 million in contingent payments—in December 2010 to acquire a Neurimmune subsidiary, gaining an α-syn-targeting antibody that would later be named cinpanemab. But more than a decade later, in February 2021, Biogen scrapped cinpanemab following a disappointing mid-stage performance. The asset, the company said at the time, failed to show significant benefit in patients with Parkinson’s and “did not achieve proof-of-concept.” Before being discontinued, Biogen was setting cinpanemab up to compete with Roche and Prothena Biosciences’ prasinezumab, another antibody designed to target α-syn. This latter asset, however, did not fare much better. In December 2024, the partners announced that prasinezumab failed the Phase 2b PADOVA study, showing no significant benefit on motor progression. Still, Roche and Prothena are pushing the asset forward to Phase 3 , buoyed by signals of efficacy in the mid-stage study, such as positive trends in biomarker outcomes. Parkinson’s disease Roche, Prothena Push Parkinson’s Drug to Phase III Despite Mid-Stage Fail Analysts at Jefferies give Roche and Prothena’s Phase III study just a 25% to 40% probability of success. June 16, 2025 · 2 min read · Tristan Manalac Read more A major stumbling block for drugmakers, Mahajan explained, is the “difficulty of targeting intracellular pathogenic aggregates using extracellular antibodies”—the modality of choice for both Biogen and Roche/Prothena. The result, she continued, is that most therapies target α-syn found outside the cells, whereas it’s the intracellular aggregates that drive disease. The good news is that α-syn development “remains highly active,” Mahajan said, as the industry continues to refine its strategies toward earlier-stage intervention and better targeting mechanisms.

New analyses from five landmark trials of Enhertu® and Datroway® in breast and gastric cancer alongside pipeline data across other tumor types demonstrate continued oncology leadership Early phase trials-in-progress featuring potential medicines with novel mechanisms highlight the company’s commitment to identifying new breakthrough generating technologies for patients with cancer TOKYO--(BUSINESS WIRE)--Daiichi Sankyo (TSE: 4568) will present new clinical research across its oncology portfolio with more than 25 abstracts in multiple cancers at the 2026 American Society of Clinical Oncology Annual Meeting (#ASCO26). Data at ASCO will highlight the company’s progress toward advancing new standards of care for patients with cancer, including new analyses from five landmark trials in breast and gastric cancer, including the DESTINY-Breast05 (# 516 ), DESTINY-Breast06 (# 1063 ), DESTINY-Breast09 (# 1021 ) and DESTINY-Gastric04 (# 4111 ) phase 3 trials of Enhertu ® (trastuzumab deruxtecan), and the TROPION-Breast02 (# 1002 ) phase 3 trial of Datroway ® (datopotamab deruxtecan). Additional results from earlier phase trials as well as trials-in-progress across new medicines being developed through the company’s breakthrough generating technology (BGT), a platform-based drug discovery model designed to deliver innovative medicines to patients faster, will be highlighted. Data from DESTINY-Breast05 formed the basis of one of two new Enhertu indications recently approved in the U.S. for certain patients with early-stage HER2 positive breast cancer and data from DESTINY-Gastric04 was included as part of a label update to expand the use of Enhertu in Japan and China to include the second-line treatment of patients with HER2 positive metastatic gastric cancer. Additionally, results from TROPION-Breast02 formed the basis of the recent U.S. approval of Datroway in patients with metastatic triple negative breast cancer (TNBC) who are not candidates for PD-1/PD-L1 inhibitor therapy, the first antibody drug conjugate (ADC) to be approved in this setting of TNBC. “The approvals received just prior to ASCO for Enhertu and Datroway, two of our leading DXd antibody drug conjugates, together with the strong science being showcased across our pipeline, highlight the momentum of our oncology portfolio,” said John Tsai, MD, Global Head, R&D, Daiichi Sankyo. “Daiichi Sankyo is committed to creating new standards of care for patients with cancer and continues to leverage its scientific and technological expertise to advance innovation.” Additional Enhertu Data Spans Broad Range of HER2 Expressing Cancers Additional research updates across several additional HER2 expressing cancers include oral and poster sessions highlighting the preliminary safety run-in results from the DESTINY-Ovarian01 (# 5554 ) phase 3 trial evaluating Enhertu in combination with bevacizumab compared to bevacizumab monotherapy as a first-line maintenance therapy in patients with HER2 expressing ovarian cancer; the primary analysis from part 1 of the DESTINY-PanTumor03 (# 3026 ) phase 2 trial evaluating Enhertu in pretreated patients in China with HER2 positive (IHC 3+) solid tumors (excluding breast and gastric cancer); and, findings from the MYTHOS (# 6011 ) phase 2 trial evaluating Enhertu in patients with HER2-low recurrent or metastatic salivary gland cancer. Additional breast and gastric cancer data for Enhertu include an oral presentation from one arm of the DESTINY-Breast07 (# 1012 ) phase 1b/2 trial evaluating Enhertu in combination with durvalumab as a first-line treatment in patients with HER2 positive metastatic breast cancer and a poster presentation highlighting a safety analysis from the DESTINY-Gastric03 (# 4022 ) phase 1b/2 trial evaluating Enhertu in combination with chemotherapy and immunotherapy as a first-line treatment in patients with HER2 expressing metastatic gastric cancer, gastroesophageal junction (GEJ) adenocarcinoma or esophageal adenocarcinoma. Results from cohort two of the EPOC2203 (# 4024 ) phase 1b/2 trial evaluating Enhertu in combination with nivolumab and capecitabine and oxaliplatin in patients with HER2 low gastroesophageal adenocarcinoma and an exploratory analysis of translational data from the EPOC2003 (# 3129 ) phase 2 trial evaluating neoadjuvant chemotherapy in combination with Enhertu in patients with HER2 positive gastric cancer will be highlighted as poster presentations. New Data and Trials-in-Progress Presentations Across Oncology Portfolio Poster presentations will include a trial-in-progress update of REJOICE-Ovarian01 ( TPS5637 ) for the phase 3 part of a phase 2/3 trial evaluating raludotatug deruxtecan (R-DXd) compared to treatment of physician’s choice in patients with platinum-resistant ovarian cancer. Two additional poster presentations will highlight an exposure-response analysis (# 5570 ) and a population pharmacokinetic analysis (# 5571 ) of data from both the REJOICE-Ovarian01 phase 2/3 trial and the phase 1 trial evaluating raludotatug deruxtecan in patients with advanced ovarian cancer or renal cell carcinoma. An oral presentation will highlight results from a phase 1/2 trial (# 6504 ) of Vanflyta® (quizartinib) plus decitabine and venetoclax in patients with newly diagnosed or relapsed/refractory FLT3 -ITD acute myeloid leukemia. Trials-in-progress poster presentations across the DXd ADC portfolio include the TROPION-Urothelial03 ( TPS4642 ) phase 2/3 trial evaluating Datroway and platinum chemotherapy compared to gemcitabine plus platinum chemotherapy in patients with locally advanced or metastatic urothelial carcinoma; the HERTHENA-Breast04 ( TPS1149 ) phase 3 trial evaluating patritumab deruxtecan (HER3-DXd) compared to treatment of physician’s choice in patients with HR positive, HER2 negative unresectable locally advanced or metastatic breast cancer; and the DESTINY-PanTumor04 ( TPS11202 ) hybrid observational trial evaluating Enhertu in patients with HER2 positive (IHC 3+) solid tumors. Trials-in-Progress Presentations Highlight Breakthrough Generating Technology Focus Daiichi Sankyo is leveraging its strength in science and technology to create new medicines for patients with cancer through its BGT approach which is designed to deliver innovative medicines to patients faster and with a higher probability of success. Trials-in-progress poster presentations featuring three potential new medicines include DS3610 ( TPS3159 ), a STING (stimulator of interferon genes) ADC, in patients with advanced or metastatic solid tumors; DS5361 ( TPS2680 ), a small-molecule, nonsense-mediated mRNA decay inhibitor, in patients with advanced or metastatic solid tumors; and, DS9051 ( TPS3179 ), a novel targeted protein degradation molecule, in patients with advanced or metastatic adrenocortical carcinoma or metastatic castration-resistant prostate cancer. Overview of clinical data and trials-in-progress from oncology pipeline of Daiichi Sankyo include: Presentation Title Author Abstract Presentation (CDT) Breast A DESTINY-Breast09 analysis of treatment duration and clinical outcomes by best response to trastuzumab deruxtecan (T-DXd) + pertuzumab Y. Park 1021 Rapid Oral Presentation Sunday, May 31 11:30 am – 1:00 pm Secondary safety analysis of trastuzumab deruxtecan (T-DXd) vs trastuzumab emtansine (T-DM1) in DESTINY-Breast05: clinical and demographic risk factors of interstitial lung disease and radiation pneumonitis M. Untch 516 Rapid Oral Presentation Monday, June 1 9:45 – 11:15 am Neoadjuvant rilvegostomig (R) + trastuzumab deruxtecan (T-DXd) in high-risk HER2-negative breast cancer: Results from the I-SPY 2.2 trial C. O’Sullivan LBA514 Rapid Oral Presentation Monday, June 1 9:45 – 11:15 am Trastuzumab deruxtecan (T-DXd) + durvalumab in patients with previously untreated HER2 positive unresectable/metastatic breast cancer (mBC): final analysis from DESTINY-Breast07 S. Loi 1012 Oral Presentation Sunday, May 31 8:30 – 10:00 am First-line datopotamab deruxtecan (Dato-DXd) vs chemotherapy in patients with locally recurrent inoperable or metastatic triple negative breast cancer for whom immunotherapy was not an option: additional efficacy endpoints from the TROPION-Breast02 study D. Cescon 1002 Oral Presentation Tuesday, June 2 9:45 am – 12:45 pm Impact of adherence to interstitial lung disease (ILD)/pneumonitis toxicity management guidelines on ILD/pneumonitis outcomes: a retrospective analysis of patients treated with trastuzumab deruxtecan (T-DXd) in DESTINY-Breast06 C. Mateo 1063 Poster Session Monday, June 1 1:30 – 4:30 pm HERTHENA-Breast04: a phase 3, randomized, open-label study evaluating the efficacy and safety of patritumab deruxtecan (HER3-DXd) versus treatment of physician’s choice in hormone receptor positive (HR +)/HER2-) unresectable locally advanced or metastatic breast cancer B. Pistilli TPS1149 Poster Session Monday, June 1 1:30 – 4:30 pm Identifying patients with human epidermal growth factor receptor 2 (HER2) low and ultralow breast cancer: use of digital, artificial intelligence-based computational algorithms to assist HER2 scoring by pathologists S. Krishnamurthy 1022 Poster Session Monday, June 1 1:30 – 4:30 pm Gastric Additional health-related quality of life analysis from DESTINY-Gastric04, a randomized phase 3 study of trastuzumab deruxtecan (T-DXd) vs ramucirumab + paclitaxel in patients with HER2 positive unresectable/metastatic gastric cancer/gastroesophageal junction adenocarcinoma K. Shitara 4111 Poster Session Saturday, May 30 9:00 am – 12:00 pm First-line trastuzumab deruxtecan (T-DXd)-based regimens in advanced HER2 expressing gastric cancer, gastroesophageal junction adenocarcinoma, or esophageal adenocarcinoma: safety results from DESTINY-Gastric03 Part 2 arms D and F, and Part 4 Y. Janjigian 4022 Poster Session Saturday, May 30 9:00 am – 12:00 pm An open-label phase 1b/2 study of trastuzumab deruxtecan combined with nivolumab and CAPOX in patients with HER2 low gastroesophageal adenocarcinoma (EPOC2203) Y. Aoki 4024 Poster Session Saturday, May 30 9:00 am – 12:00 pm Tumor and immune microenvironment remodeling with neoadjuvant trastuzumab deruxtecan in HER2 positive gastric cancer: exploratory analyses from the phase 2 EPOC2003 study A. Kawazoe 3129 Poster Session Saturday, May 30 1:30 – 4:30 pm Ovarian Trastuzumab deruxtecan (T-DXd) + bevacizumab (BEV) as first-line (1L) maintenance therapy in patients with HER2 expressing ovarian cancer: results from the DESTINY-Ovarian01 safety run-in A. Gonzalez Martin 5554 Poster Session Monday, June 1 9:00 am – 12:00 pm REJOICE-Ovarian01: phase 3 part of a phase 2/3 study evaluating raludotatug deruxtecan (R-DXd) versus treatment of physician’s choice in patients with platinum-resistant ovarian cancer D. Richardson TPS5637 Poster Session Monday, June 1 9:00 am – 12:00 pm Exposure-response analyses of efficacy and safety with raludotatug deruxtecan (R-DXd), a CDH6-directed ADC, to inform dose selection for phase 3 development in platinum-resistant ovarian cancer F. Hurtado 5570 Poster Session Monday, June 1 9:00 am – 12:00 pm Population pharmacokinetic analysis of raludotatug deruxtecan (R-DXd), a CDH6-directed ADC, in patients with advanced ovarian cancer or renal cell carcinoma F. Hurtado 5571 Poster Session Monday, June 1 9:00 am – 12:00 pm Urothelial TROPION-Urothelial03: a phase 2/3 study of datopotamab deruxtecan (Dato-DXd) + platinum chemotherapy vs gemcitabine + platinum chemotherapy in participants with locally advanced or metastatic urothelial carcinoma with progression on or after enfortumab vedotin + pembrolizumab M. Galsky TPS4642 Poster Session Sunday, May 31 9:00 am – 12:00 pm Salivary Trastuzumab deruxtecan in patients with HER2 low recurrent/metastatic salivary gland carcinoma: results from the phase 2 MYTHOS trial I. Kinoshita 6011 Oral Presentation Monday, June 1 8:00 – 9:30 am AML Quizartinib in combination with decitabine and venetoclax for newly diagnosed and relapsed/refractory FLT3 mutated acute myeloid leukemia M. Yilmaz 6504 Oral Presentation Tuesday, June 2 9:45 am – 12:45 pm Pan Tumor Trastuzumab deruxtecan (T-DXd) for pretreated patients in China with HER2 IHC 3+ solid tumors: DESTINY-PanTumor03 Part 1 primary analysis Y. Zhang 3026 Poster Session Saturday, May 30 1:30 – 4:30 pm A pragmatic, hybrid observational study evaluating the effectiveness of trastuzumab deruxtecan (T-DXd) in patients with HER2 IHC3+ solid tumors: DESTINY-PanTumor04 B. Monk TPS11202 Poster Session Monday, June 1 9:00 am – 12:00 pm HER2 independent antitumor and pharmacodynamic responses to trastuzumab deruxtecan in patients with advanced solid tumors S. Shin 3031 Poster Session Saturday, May 30 1:30 – 4:30 pm Topoisomerase 1 and DNA damage: pharmacodynamic responses and mechanism of trastuzumab deruxtecan in HER2-expressing advanced solid tumors D. Wilsker 3092 Poster Session Saturday, May 30 1:30 – 4:30 pm BGT A phase 1, first-in-human study of DS3610, a stimulator of interferon genes (STING) agonist ADC, in patients with advanced/metastatic solid tumors S. Koganemaru TPS3159 Poster Session Saturday, May 30 1:30 – 4:30 pm A phase 1, first-in-human study of DS5361, a small-molecule, nonsense-mediated mRNA decay inhibitor, in patients with advanced/metastatic solid tumors (Parts 1 and 2) S. Sen TPS2680 Poster Session Saturday, May 30 1:30 – 4:30 pm A phase 1, first-in-human study of DS9051, a novel targeted protein degradation molecule, in patients with advanced/metastatic adrenocortical carcinoma or metastatic castration-resistant prostate cancer M. Patel TPS3179 Poster Session Saturday, May 30 1:30 – 4:30 pm About the ADC Portfolio of Daiichi Sankyo The Daiichi Sankyo ADC portfolio consists of eight ADCs in clinical development crafted from ADC technology discovered in-house by Daiichi Sankyo. The DXd ADC Technology platform of Daiichi Sankyo consists of seven ADCs in clinical development where each ADC is comprised of a monoclonal antibody attached to a number of topoisomerase I inhibitor payloads (an exatecan derivative, DXd) via tetrapeptide-based cleavable linkers. The DXd ADCs include Enhertu and Datroway, which are being jointly developed and commercialized globally with AstraZeneca, and ifinatamab deruxtecan (I-DXd), raludotatug deruxtecan (R-DXd) and patritumab deruxtecan (HER3-DXd), which are being jointly developed and commercialized globally with Merck & Co., Inc, Rahway, NJ, USA. DS-3939 and DS3790 are being developed by Daiichi Sankyo. An additional ADC being developed by Daiichi Sankyo is DS3610, which consists of an antibody attached to a novel payload that acts as an agonist of STING. Ifinatamab deruxtecan, raludotatug deruxtecan, patritumab deruxtecan, DS-3939, DS3610 and DS3790 are investigational medicines that have not been approved for any indication in any country. Safety and efficacy have not been established. About Daiichi Sankyo Daiichi Sankyo (TSE: 4568) is a global healthcare company committed to becoming a trusted healthcare innovator, transforming the lives of people through its strength in science and technology. The company discovers and develops new standards of care to address diverse medical needs to fulfill its purpose of contributing to the enrichment of quality of life around the world. With a strategic focus on oncology, Daiichi Sankyo is advancing an industry-leading antibody drug conjugate portfolio along with identifying new breakthrough generating technologies to deliver practice-changing medicines to patients, healthcare professionals and society. For more information, please visit . Contacts MEDIA CONTACTS: Global: Jennifer Brennan jennifer.brennan@daiichisankyo.com +1 908 900 3183 (mobile) Japan: DS-PR_jp@daiichisankyo.com INVESTOR RELATIONS CONTACT: DaiichiSankyoIR_jp@daiichisankyo.com