On October 19, 2025 Tubulis reported positive early clinical data from its NAPISTAR1-01 Phase I/IIa study (NCT06303505) in a late-breaking oral presentation at the European Society for Medical Oncology (ESMO) (Free ESMO Whitepaper) Congress 2025 in Berlin, Germany. Principal Investigator, Dr. Antonio González-Martín, Director Medical Oncology Department and Cancer Center Director at Clínica Universidad de Navarra, presented the results of Tubulis’ lead antibody-drug conjugate (ADC), TUB-040, in platinum-resistant high-grade serous ovarian cancer (PROC-HGSOC), with a focus on dose levels 1.67 – 3.3 mg/kg. This is the first clinical data to validate Tubulis’ proprietary Tubutecan technology, establishing clear proof of concept for the company’s most advanced ADC targeting NaPi2b.

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"These positive first-in-human data for TUB-040 represent a momentous milestone for Tubulis, validating our unique ADC design strategy, and offering a potential new treatment option for patients with platinum-resistant ovarian cancer," said Dr. Dominik Schumacher, Chief Executive Officer and Co-founder of Tubulis. "Supported by our recent financing, we are poised to rapidly advance TUB-040 towards pivotal trials and expand its clinical development into earlier stages of disease and additional tumor types. The data also provides a foundation to unlock the full potential of ADCs using our Tubutecan platform, expanding its impact to benefit a significant patient population."

Highlights of Tubulis’ clinical data presented at ESMO (Free ESMO Whitepaper) 2025:

Patient population and baseline characteristics
As of the data cut-off on September 1, 2025, 67 patients (46 patients treated at dose levels of 1.67 – 3.3 mg/kg) with PROC were treated with TUB-040 for a median of 161 days (range 21–462) with 21-day treatment cycles
Median age: 62 years (range 34-81); no patient selection for biomarkers
All patients received a median of 4 prior lines of therapy (range 1-7) including bevacizumab (83.6%), PARP inhibitors (76.1%) and mirvetuximab soravtansine (13.4%)
Efficacy
In the 66 efficacy-evaluable patients who had at least one RECIST response assessment, onset of activity was observed at low doses with efficacy across a wide therapeutic range
Responses occurred early (starting at treatment cycle 2) and deepened over time and were also seen in patients who received prior mirvetuximab soravtansine treatment including when mirvetuximab soravtansine was the most recent line of therapy
Within the 1.67-3.3 mg/kg dose cohorts, an ORR of 59% (range of 50-67%), was achieved with a confirmed ORR of 50%; one complete response (CR) was observed at 2.5 mg/kg.
Treatment is ongoing in 80% of patients within the 1.67 – 3.3 mg/kg cohorts and in 93% of all responding patients from this focus group
The confirmed disease control rate (DCR) at 1.67 – 3.3 mg/kg was 96% and a confirmed DCR of 91% was reached across all cohorts at the data-cut-off with efficacy data in the 3.3 mg/kg group still continuing to mature
81% of patients within the 1.67 – 3.3 mg/kg cohorts exhibited a CA-125 response under treatment determined per GCIG standards. CA-125 is an established, prognostic and predictive tumor marker in ovarian carcinoma
Safety and tolerability
TUB-040 was generally well tolerated across all dose levels with the majority of treatment-emergent adverse events (TEAEs) at Grade 1 or 2
There were no fatal TEAE’s across all cohorts and no discontinuations due to adverse events across the 1.67 – 3.3 mg/kg cohorts
No clinically relevant bleeding, pneumonitis, ocular toxicity, stomatitis, or neuropathy were reported, distinguishing TUB-040 from other topoisomerase-I ADCs
Hematologic toxicity was predominately low-grade and manageable at doses of 1.67 – 3.3 mg/kg
Most common ≥Grade 3 TEAEs across 1.67 – 3.3 mg/kg cohorts included: neutropenia (22% ≥G3), anemia (9% ≥G3), thrombocytopenia (4% ≥G3), and nausea (4% ≥G3)
The maximum tolerated dose (MTD) was determined at 4.4 mg/kg
"The interim results demonstrated a highly differentiated clinical profile for TUB-040 in the ADC field, with anti-tumor activity beginning at low doses with a broad therapeutic window that could provide treating physicians with flexibility in dosing. They further validate NaPi2b as a clinically valuable ADC target and confirm that our Tubutecan technology can deliver exatecan for effective tumor targeting with reduced systemic toxicity," said Günter Fingerle-Rowson, MD PhD, Chief Medical Officer of Tubulis. "Our goal now is to accelerate TUB-040’s clinical development to bring this valuable drug to patients as soon as possible."

"Current treatment options for platinum-resistant ovarian cancer are constrained by low response rates, short progression-free survival, and tolerability challenges, underscoring the need for better therapies. The TUB-040 data suggest a significant advance for ADCs, since we are seeing clinical activity without the need for biomarker selection across a range of doses that were well tolerated," added Principal Investigator, Antonio González-Martín, MD PhD.

The ongoing NAPISTAR 1-01 study (NCT06303505) is evaluating TUB-040 in PROC-HGSOC and in adenocarcinoma non-small cell lung cancer (NSCLC). Based on these encouraging results, the company plans to initiate pivotal trials with TUB-040, explore earlier lines of treatment in ovarian cancer, and expand into combination regimens and new solid tumor indications. The first data from the NSCLC cohort will be presented at a future medical conference.

The full abstract will be published in the ESMO (Free ESMO Whitepaper) Congress 2025 Abstract Book, a supplement to the official ESMO (Free ESMO Whitepaper) journal, Annals of Oncology.

About TUB-040 and the Tubutecan Technology

Tubulis’ lead antibody-drug conjugate (ADC) TUB-040 is directed against NaPi2b, an antigen highly overexpressed in ovarian cancer and lung adenocarcinoma. It consists of an IgG1 antibody targeting NaPi2b equipped with Tubulis’ proprietary Tubutecan technology, connecting the Topoisomerase I inhibitor, exatecan, through a cleavable linker system based on the company’s proprietary P5 conjugation technology with a homogeneous DAR of 8. Based on novel chemistry for cysteine-selective conjugation, the technology enables the development of stable, highly targeted ADCs optimized for the on-target delivery of the topoisomerase-1 inhibitor while minimizing systemic toxicity. The candidate is currently being investigated in a multicenter Phase I/IIa study (NAPISTAR1-01, NCT06303505) that aims to evaluate the safety, tolerability, pharmacokinetics, and efficacy of TUB-040 as a monotherapy in patients with platinum-resistant high-grade ovarian cancer (PROC) or relapsed/refractory adenocarcinoma non-small cell lung cancer (NSCLC).

(Press release, Tubulis, OCT 19, 2025, View Source [SID1234656807])

On October 19, 2025 Pfizer Inc. (NYSE: PFE) and Astellas Pharma U.S. Inc. (Head of Commercial: Mike Petroutsas, "Astellas") reported final overall survival (OS) results from the Phase 3 EMBARK study evaluating XTANDI (enzalutamide), in combination with leuprolide and as monotherapy, in men with non-metastatic hormone-sensitive prostate cancer (nmHSPC; also known as nonmetastatic castration-sensitive prostate cancer or nmCSPC) with biochemical recurrence (BCR) at high risk for metastasis. For the key secondary endpoint of OS, XTANDI plus leuprolide reduced the risk of death by 40.3% compared to leuprolide alone (Hazard Ratio [HR]: 0.597; 95% Confidence Interval [CI], 0.444-0.804; p=0.0006), making this the first and only androgen receptor inhibitor-based regimen to demonstrate an OS benefit in nmHSPC with high-risk BCR.1 The 8-year overall survival was 78.9% (95% CI, 73.9% to 83.1%) among patients receiving XTANDI plus leuprolide and 69.5% (95% CI, 64.0% to 74.3%) among patients taking leuprolide alone.1 A numerical improvement in OS with XTANDI as monotherapy compared to leuprolide alone (HR: 0.83 [95% CI, 0.63-1.095; p=0.1867) did not reach statistical significance.1 These data are being presented today in an oral presentation at the European Society for Medical Oncology (ESMO) (Free ESMO Whitepaper) Congress in Berlin, Germany and have been simultaneously published in The New England Journal of Medicine.

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"These results highlight the central role of enzalutamide in extending survival for men with conventional imaging negative HSPC with high-risk BCR," said Stephen J. Freedland, M.D., Director of the Center for Integrated Research in Cancer and Lifestyle at Cedars-Sinai and Associate Director for Training and Education at the Samuel Oschin Comprehensive Cancer Institute. "These data reinforce the benefits of earlier treatment initiation with enzalutamide."

The median follow up time was 94.2 months for XTANDI in combination with leuprolide, 94 months for leuprolide only, and 93.8 months in the monotherapy XTANDI group.1

The safety profile of XTANDI was consistent with that observed at the primary EMBARK analysis, and no new safety signals were identified. The most common adverse events (occurring in ≥10% of patients) in the XTANDI combination group were hot flashes and fatigue. The most common adverse events in the XTANDI monotherapy group were gynecomastia, hot flashes, and fatigue.1,2

"With up to 90 percent of men with high-risk BCR developing metastatic disease, early intervention with effective therapy is critical,"3 said Johanna Bendell, M.D., Chief Development Officer, Oncology, Pfizer. "The final analysis from EMBARK shows that XTANDI plus leuprolide improved outcomes and extended lives for men facing high-risk BCR after local therapy with curative intent."

Among men who have undergone definitive prostate cancer treatment, including radical prostatectomy, radiotherapy or both, an estimated 20-40% will experience BCR within 10 years.4 About nine out of 10 men with high-risk BCR will develop metastatic disease, and one in three will die as a result of their metastatic prostate cancer.3

"This marks the eighth publication of XTANDI data in The New England Journal of Medicine, further demonstrating XTANDI’s profound impact on clinical outcomes in men with certain types of advanced prostate cancer," said Shontelle Dodson, Executive Vice President, Head of Medical Affairs, Astellas. "These findings reinforce XTANDI’s position as a cornerstone therapy in the proactive management of these patients."

The EMBARK trial primary analysis was previously reported in The New England Journal of Medicine in 2023, demonstrating that the study met its primary endpoint with a statistically significant and clinically meaningful improvement in metastasis-free survival (MFS) for patients treated with XTANDI plus leuprolide versus leuprolide alone (HR: 0.42 [95% CI, 0.30-0.61]; p<0.001). Additionally, MFS for XTANDI monotherapy was superior to treatment with leuprolide alone (HR: 0.63 [95% CI, 0.46-0.87]; p=0.005). Of note, the MFS for XTANDI single agent was a secondary endpoint.2

XTANDI is approved for one or more indications in more than 80 countries, including the United States, European Union, and Japan. Earlier approvals were for castration-resistant prostate cancer and metastatic castration-sensitive (hormone-sensitive) prostate cancer. It was then approved for patients with nmCSPC with BCR at high risk for metastasis in 2023 based on improved metastasis-free survival comparing the combination of enzalutamide with leuprolide vs leuprolide alone, as well as enzalutamide monotherapy vs leuprolide alone.

Descriptive updates of multiple secondary and exploratory endpoints (time to new antineoplastic therapy, time to first symptomatic skeletal events, and time to progression on subsequent therapy) were consistent with the primary analyses announced based on the MFS data cutoff in 2023.1

About EMBARK2

This Phase 3, randomized, double-blind, placebo-controlled, multi-national trial enrolled 1,068 patients with non-metastatic hormone-sensitive prostate cancer (nmHSPC; also known as non-metastatic castration-sensitive prostate cancer or nmCSPC) with high-risk biochemical recurrence (BCR) at sites in the United States, Canada, Europe, South America, and the Asia-Pacific region. Patients considered to have high-risk BCR disease had a prostate-specific antigen (PSA) doubling time ≤ 9 months, serum testosterone ≥ 150 ng/dL (5.2 nmol/L), and screening PSA by the central laboratory ≥ 1 ng/mL if they had had a radical prostatectomy (with or without radiotherapy) as primary treatment for prostate cancer or at least 2 ng/mL above the nadir if they had radiotherapy only as primary treatment for prostate cancer. Patients in the EMBARK trial were randomized to receive enzalutamide 160 mg daily plus leuprolide, enzalutamide 160 mg as monotherapy, or leuprolide alone.

The primary results from the EMBARK trial were published in the New England Journal of Medicine in 2023. The primary endpoint of the trial was metastasis-free survival (MFS) for enzalutamide plus leuprolide versus leuprolide alone. MFS is defined as the duration of time between randomization and the earliest objective evidence of radiographic progression by central imaging or death.

For more information on the EMBARK (NCT02319837) trial go to www.clinicaltrials.gov.

About Non-Metastatic Hormone-Sensitive Prostate Cancer with High-Risk Biochemical Recurrence

Non-metastatic hormone- (or castration-) sensitive prostate cancer (nmHSPC or nmCSPC) means there is no detectable evidence of the cancer spreading to distant parts of the body (metastases) with conventional radiological methods (CT/MRI) and the cancer still responds to medical or surgical treatment to lower testosterone levels.5,6 Of men who have undergone definitive prostate cancer treatment, including radical prostatectomy, radiotherapy, or both, an estimated 20-40% will experience a biochemical recurrence (BCR) within 10 years.4 About nine out of 10 men with high-risk BCR will develop metastatic disease, and one in three will die as a result of the recurrence.3 The EMBARK trial focused on men with high-risk BCR. Per the EMBARK protocol, patients with nmHSPC with high-risk BCR are those initially treated by radical prostatectomy or radiotherapy, or both, with a PSA doubling time ≤ 9 months. Patients with nmCSPC who experience BCR after local therapy may be at a higher risk of metastases and death if their PSA doubling time is ≤ 9 months.7

About XTANDI (enzalutamide)

XTANDI (enzalutamide) is an androgen receptor signaling inhibitor. XTANDI is a standard of care and has received regulatory approvals in one or more countries around the world for use in men with metastatic hormone-sensitive prostate cancer (mHSPC), metastatic castration-resistant prostate cancer (mCRPC), non-metastatic castration-resistant prostate cancer (nmCRPC) and non-metastatic hormone-sensitive prostate cancer (nmHSPC) with high-risk biochemical recurrence (BCR). XTANDI is currently approved for one or more of these indications in more than 80 countries, including in the United States, European Union and Japan. Over 1.5 million patients have been treated with XTANDI globally.8

About XTANDI (enzalutamide) and U.S. Important Safety Information

XTANDI (enzalutamide) is indicated for the treatment of patients with:

castration-resistant prostate cancer (CRPC)
metastatic castration-sensitive prostate cancer (mCSPC)
nonmetastatic castration sensitive prostate cancer (nmCSPC) with biochemical recurrence at high risk for metastasis (high-risk BCR)
Important Safety Information

Warnings and Precautions

Seizure occurred in 0.6% of patients receiving XTANDI in eight randomized clinical trials. In a study of patients with predisposing factors for seizure, 2.2% of XTANDI-treated patients experienced a seizure. It is unknown whether anti-epileptic medications will prevent seizures with XTANDI. Patients in the study had one or more of the following predisposing factors: use of medications that may lower the seizure threshold, history of traumatic brain or head injury, history of cerebrovascular accident or transient ischemic attack, and Alzheimer’s disease, meningioma, or leptomeningeal disease from prostate cancer, unexplained loss of consciousness within the last 12 months, history of seizure, presence of a space occupying lesion of the brain, history of arteriovenous malformation, or history of brain infection. Advise patients of the risk of developing a seizure while taking XTANDI and of engaging in any activity where sudden loss of consciousness could cause serious harm to themselves or others. Permanently discontinue XTANDI in patients who develop a seizure during treatment.

Posterior Reversible Encephalopathy Syndrome (PRES) There have been reports of PRES in patients receiving XTANDI. PRES is a neurological disorder that can present with rapidly evolving symptoms including seizure, headache, lethargy, confusion, blindness, and other visual and neurological disturbances, with or without associated hypertension. A diagnosis of PRES requires confirmation by brain imaging, preferably MRI. Discontinue XTANDI in patients who develop PRES.

Hypersensitivity reactions, including edema of the face (0.5%), tongue (0.1%), or lip (0.1%) have been observed with XTANDI in eight randomized clinical trials. Pharyngeal edema has been reported in post-marketing cases. Advise patients who experience any symptoms of hypersensitivity to temporarily discontinue XTANDI and promptly seek medical care. Permanently discontinue XTANDI for serious hypersensitivity reactions.

Ischemic Heart Disease In the combined data of five randomized, placebo-controlled clinical studies, ischemic heart disease occurred more commonly in patients on the XTANDI arm compared to patients on the placebo arm (3.5% vs 2%). Grade 3-4 ischemic events occurred in 1.8% of patients on XTANDI versus 1.1% on placebo. Ischemic events led to death in 0.4% of patients on XTANDI compared to 0.1% on placebo. Monitor for signs and symptoms of ischemic heart disease. Optimize management of cardiovascular risk factors, such as hypertension, diabetes, or dyslipidemia. Discontinue XTANDI for Grade 3-4 ischemic heart disease.

Falls and Fractures occurred in patients receiving XTANDI. Evaluate patients for fracture and fall risk. Monitor and manage patients at risk for fractures according to established treatment guidelines and consider use of bone-targeted agents. In the combined data of five randomized, placebo-controlled clinical studies, falls occurred in 12% of patients treated with XTANDI compared to 6% of patients treated with placebo. Fractures occurred in 13% of patients treated with XTANDI and in 6% of patients treated with placebo.

Embryo-Fetal Toxicity The safety and efficacy of XTANDI have not been established in females. XTANDI can cause fetal harm and loss of pregnancy when administered to a pregnant female. Advise males with female partners of reproductive potential to use effective contraception during treatment with XTANDI and for 3 months after the last dose of XTANDI.

Dysphagia or Choking Severe dysphagia or choking, including events that could be life-threatening requiring medical intervention or fatal, can occur due to XTANDI product size. Advise patients to take each capsule or tablet whole with a sufficient amount of water to ensure that all medication is successfully swallowed. Consider use of a smaller tablet size of XTANDI in patients who have difficulty swallowing. Discontinue XTANDI for patients who cannot swallow capsules or tablets.

Adverse Reactions (ARs)

In the data from the five randomized placebo-controlled trials, the most common ARs (≥ 10%) that occurred more frequently (≥ 2% over placebo) in XTANDI-treated patients were musculoskeletal pain, fatigue, hot flush, constipation, decreased appetite, diarrhea, hypertension, hemorrhage, fall, fracture, and headache. In the bicalutamide-controlled study, the most common ARs (≥ 10%) reported in XTANDI-treated patients were asthenia/fatigue, back pain, musculoskeletal pain, hot flush, hypertension, nausea, constipation, diarrhea, upper respiratory tract infection, and weight loss.

In EMBARK, the placebo-controlled study of nonmetastatic CSPC (nmCSPC) with high-risk biochemical recurrence (BCR) patients, Grade 3 or higher adverse reactions during the total duration of treatment were reported in 46% of patients treated with XTANDI plus leuprolide, 50% of patients receiving XTANDI as a single agent, and 43% of patients receiving placebo plus leuprolide. Permanent treatment discontinuation due to adverse reactions during the total duration of treatment as the primary reason was reported in 21% of patients treated with XTANDI plus leuprolide, 18% of patients receiving XTANDI as a single agent, and 10% of patients receiving placebo plus leuprolide.

Lab Abnormalities: Lab abnormalities that occurred in ≥ 5% of patients, and more frequently (> 2%) in the XTANDI arm compared to placebo in the pooled, randomized, placebo-controlled studies are hemoglobin decrease, neutrophil count decreased, white blood cell decreased, hyperglycemia, hypermagnesemia, hyponatremia, hypophosphatemia, and hypercalcemia.

Hypertension: In the combined data from five randomized placebo-controlled clinical trials, hypertension was reported in 14.2% of XTANDI patients and 7.4% of placebo patients. Hypertension led to study discontinuation in < 1% of patients in each arm.

Drug Interactions

Effect of Other Drugs on XTANDI Avoid coadministration with strong CYP2C8 inhibitors. If coadministration cannot be avoided, reduce the dosage of XTANDI. Avoid coadministration with strong CYP3A4 inducers. If coadministration cannot be avoided, increase the dosage of XTANDI.

Effect of XTANDI on Other Drugs Avoid coadministration with certain CYP3A4, CYP2C9, and CYP2C19 substrates for which minimal decrease in concentration may lead to therapeutic failure of the substrate. If coadministration cannot be avoided, increase the dosage of these substrates in accordance with their Prescribing Information. In cases where active metabolites are formed, there may be increased exposure to the active metabolites.

(Press release, Pfizer, OCT 19, 2025, View Source [SID1234656806])

On October 19, 2025 Faeth Therapeutics reported results from the international DICE trial, a randomized phase 2 study of sapanisertib (TAK228) plus weekly paclitaxel versus paclitaxel alone in women with platinum-resistant or recurrent epithelial ovarian or fallopian tube cancer. The trial was selected for a Late-Breaking Oral Presentation at the European Society for Medical Oncology (ESMO) (Free ESMO Whitepaper) Congress 2025 and met its pre-ordained statistical design and there is sufficient evidence of a positive signal to justify a larger phase 3 design.

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134 patients were enrolled across sites in the UK and Germany. Median age was 62 years and nearly half had received three or more prior therapies. The combination achieved mean progression-free survival (PFS) of 5.8 months compared to 4.0 months with paclitaxel alone, extending time to disease progress by approximately 45 percent. The addition of sapanisertib was associated with a 34% reduction in risk of progression compared to paclitaxel alone (HR=0.66; 90% CI: 0.45–0.96; p=0.07), meeting the trial’s prespecified hazard ratio target of 0.66.

Grade 3/4 adverse events occurred in 7% of patients receiving the combination versus 6.6% for paclitaxel alone. Gastrointestinal toxicities (11.4% vs. 0%) and rash (2.9% vs. 0%) were more common with the combination but were manageable.

"Platinum-resistant ovarian cancer remains one of the toughest conditions we face, with women often cycling through treatments that only briefly hold the disease at bay temporarily," said Jonathan Krell, MD, Ovarian Cancer Action Research Centre, Imperial College London, the study’s lead investigator. "The DICE trial shows that adding an oral targeted agent to weekly paclitaxel can slow progression without added high-grade toxicity, a finding that clearly warrants a phase 3 trial."

"These results reinforce our belief that targeting the metabolism of cancer cells can improve the impact of existing therapies," said Anand Parikh, JD, CEO and co-founder of Faeth Therapeutics. "On the strength of DICE, we see sapanisertib plus paclitaxel as phase 3-ready in ovarian cancer, alongside our ongoing phase 2 in endometrial cancer and planned phase 1b/2 in breast cancer."

Response rate and overall survival analyses are ongoing. The trial is also evaluating biomarkers, including PTEN expression, metabolic signatures, and genomic correlates, to identify patients most likely to benefit from the combination.

About the DICE Trial

DICE (NCT03648489) is a multi-centre randomized phase 2 study comparing weekly paclitaxel alone versus paclitaxel plus sapanisertib in women with platinum-resistant or recurrent ovarian or fallopian tube cancer. The primary endpoint is progression-free survival; secondary endpoints include response rate and overall survival. Translational endpoints include PTEN correlation and exploratory biomarker analyses.

(Press release, Faeth Therapeutics, OCT 19, 2025, View Source [SID1234656805])

On October 19, 2025 Merck and Daiichi Sankyo reported results from the phase 2 (dose optimization) part of the REJOICE-Ovarian01 phase 2/3 trial showed that raludotatug deruxtecan (R-DXd) demonstrated clinically meaningful response rates in patients with recurrent platinum-resistant ovarian, primary peritoneal or fallopian tube cancer. These data were presented today during a late-breaking proffered paper session (LBA42) at the 2025 European Society for Medical Oncology (#ESMO25) Congress.

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Raludotatug deruxtecan is a specifically engineered, potential first-in-class CDH6 directed DXd antibody drug conjugate (ADC) discovered by Daiichi Sankyo (TSE: 4568) and being jointly developed by Daiichi Sankyo and Merck (NYSE: MRK), known as MSD outside of the United States and Canada.

The median overall survival for advanced ovarian cancer following recurrence can be as little as two years, with a five-year survival rate of 31.8% for those with distant stage disease.1,2 Between 70% and 80% of patients diagnosed with advanced ovarian cancer will experience disease progression following standard treatment with platinum-based chemotherapy regimens, highlighting the need for new treatment options.3

A confirmed objective response rate (ORR) of 50.5% (95% confidence interval [CI]: 40.6-60.3) was observed in patients (n=107) with platinum-resistant ovarian cancer receiving raludotatug deruxtecan across three doses (4.8 mg/kg, 5.6 mg/kg and 6.4 mg/kg) as assessed by blinded independent central review (BICR). There were 3 complete responses (CRs) and 51 partial responses (PRs) seen, and a disease control rate (DCR) of 77.6% (95% CI: 68.5–85.1) was observed.

In patients receiving the 5.6 mg/kg dose (n=36), a confirmed ORR of 50.0% (95% CI: 32.9–67.1) was observed as assessed by BICR with two CRs (5.6%), 16 PRs (44.4%) and a DCR of 80.6% (95% CI: 64.0–91.8). Clinically meaningful tumor responses were seen irrespective of dose and across a range of CDH6 expression levels.

The safety profile of raludotatug deruxtecan observed in REJOICE-Ovarian01 is consistent with safety findings from the phase 1 trial with no new safety signals identified. Nausea, anemia, asthenia and neutropenia were the most common treatment-emergent adverse events (TEAEs) across all doses. Treatment discontinuations due to treatment-related TEAEs occurred in 8.3% (n=3), 0.0% (n=0) and 8.6% (n=3) in the 4.8 mg/kg, 5.6mg/kg and 6.4 mg/kg groups, respectively. Grade 3 or higher treatment-related TEAEs occurred in 27.8% (n=10), 30.6% (n=11), and 48.6% (n=17) of patients in the 4.8 mg/kg (n=36), 5.6 mg/kg (n=36), and 6.4 mg/kg (n=35) groups, respectively.

The most common TEAEs (≥10% of total population) in the 5.6 mg/kg cohort included nausea (69.4%), anemia (58.3%), asthenia (50.0%), neutropenia (44.4%), vomiting (33.3%), constipation (27.8%), decreased appetite (25.0%), thrombocytopenia (19.4%), AST increase (16.7%), diarrhea (16.7%) and leukopenia (13.9%). Four (3.7%) interstitial lung disease (ILD)/pneumonitis events were confirmed as treatment-related across all doses as determined by an independent adjudication committee. The majority of ILD events (one with 5.6 mg/kg, two with 6.4 mg/kg) were low grade (grade 1 or 2). One grade ≥3 (4.8 mg/kg) ILD event was reported. Based on these efficacy and safety results, the 5.6 mg/kg dose has been selected for the phase 3 part of the trial.

"When ovarian cancer becomes resistant to platinum-based chemotherapy, treatment options for patients become limited," said Isabelle Ray-Coquard, MD, PhD, President, ENGOT (European Network of Gynecological Oncology Trial) Group, Trial Leader, National Group of Investigators on the Studies of Ovarian and Breast Cancer (GINECO), and Medical Oncologist, Centre Léon Bérard, Lyon, France. "These promising results from the first part of REJOICE-Ovarian01 suggest that raludotatug deruxtecan may have an important role in treating patients with platinum-resistant ovarian cancer and support further evaluation in the phase 3 portion of this trial."

"In this dose optimization analysis, rapid responses with impressive disease control have been observed with raludotatug deruxtecan across a range of CDH6 expression levels," said Ken Takeshita, MD, Global Head, R&D, Daiichi Sankyo. "These results, which contributed to the recent Breakthrough Therapy Designation in the U.S., reinforce the potential for raludotatug deruxtecan to become a new treatment option for certain types of patients with platinum-resistant ovarian cancer."

"While we have seen targeted treatment advancements and improved outcomes in ovarian cancer in recent years, there is still a high unmet need for additional options for patients," said Eliav Barr, MD, Senior Vice President, Head of Global Clinical Development and Chief Medical Officer, Merck Research Laboratories. "CDH6 is highly expressed in ovarian cancer, which underscores the potential of raludotatug deruxtecan to make an impact."

In September 2025, raludotatug deruxtecan was granted Breakthrough Therapy Designation by the U.S. Food and Drug Administration for the treatment of adult patients with platinum-resistant epithelial ovarian, primary peritoneal or fallopian tube cancers expressing CDH6 who have received prior treatment with bevacizumab.

Median follow-up for the 4.8-mg/kg, 5.6-mg/kg and 6.4-mg/kg cohorts was 5.6 months (95% CI: 4.7–6.3), 5.6 months (95% CI: 4.6–5.8), and 5.2 months (95% CI: 4.9–5.8), respectively. A majority of patients (51.4%) in REJOICE-Ovarian01 received three prior lines of treatment, including bevacizumab (n=89; 83.2%), PARP inhibitor (n=75; 70.1%) and mirvetuximab soravtansine (n=3; 2.8%). As of the data cut-off of February 26, 2025, 66 patients (61.7%) remain on treatment with raludotatug deruxtecan.

Summary of REJOICE-Ovarian01 Results

Efficacy Measure

Raludotatug
Deruxtecan
Across 4.8, 5.6 and 6.4
mg/kg (n=107)

Raludotatug
Deruxtecan
6.4 mg/kg
(n=35)

Raludotatug
Deruxtecan
5.6 mg/kg
(n=36)

Raludotatug
Deruxtecan
4.8 mg/kg
(n=36)

Confirmed ORR, % (95% CI)1

50.5%

(40.6–60.3)

57.1%

(39.4–73.7)

50.0%

(32.9–67.1)

44.4%

(27.9–61.9)

CR, n (%)

3 (2.8%)

0

2 (5.6%)

1 (2.8%)

PR, n (%)

51 (47.7%)

20 (57.1%)

16 (44.4%)

15 (41.7%)

SD, n (%)

42 (39.3%)

10 (28.6%)

15 (41.7%)

17 (47.2%)

PD, n (%)

8 (7.5%)

4 (11.4%)

2 (5.6%)

2 (5.6%)

NE, n (%)

3 (2.8%)

1 (2.9%)2

1 (2.8%)3

1 (2.8%)2

DCR, %

(95% CI)

77.6%

(68.5–85.1)

77.1%

(59.9–89.6)

80.6%

(64.0–91.8)

75.0%

(57.8–87.9)

TTR, weeks, median (range)

7.1 weeks

(5.1–19.1)

7.2 weeks

(5.3–19.1)

6.6 weeks

(5.1–18.3)

7.1 weeks

(5.4–18.7)

Data cutoff: February 26, 2025.

1As accessed by BICR per RECIST 1.1. 2Patient had no baseline tumor assessment by BICR. 3Patient had no adequate post-baseline tumor assessment by BICR.

BICR, blinded independent central review; CR, complete response; DCR, disease control rate; ORR, objective response rate; PD, progressive disease; PR, partial response; RECIST 1.1, Response Evaluation Criteria in Solid Tumors version 1.1; SD, stable disease; TTR, time to response.

About REJOICE-Ovarian01
REJOICE-Ovarian01 is a global, multicenter, randomized, open-label phase 2/3 trial evaluating the efficacy and safety of investigational raludotatug deruxtecan in patients with platinum-resistant, high-grade ovarian, primary peritoneal or fallopian tube cancer, with disease progression following at least one but no more than three prior lines of systemic therapy, including prior treatment with mirvetuximab soravtansine for those with documented high-folate receptor alpha expression. Maintenance therapy (e.g., bevacizumab, poly ADP-ribose polymerase [PARP] inhibitors) is considered part of the preceding line of therapy.

The phase 2 part of REJOICE-Ovarian01 is assessing the safety and tolerability of three doses of raludotatug deruxtecan (4.8 mg/kg, 5.6 mg/kg, or 6.4 mg/kg) to identify the recommended dose for the phase 3 part of the trial. The primary endpoint of the phase 2 part of the trial is ORR as assessed by BICR. Key secondary endpoints include ORR as assessed by investigator, DoR, PFS and DCR – all assessed by both BICR and investigator.

The phase 3 part of REJOICE-Ovarian01 is assessing the efficacy and safety of raludotatug deruxtecan at the selected dose (5.6 mg/kg) compared to investigator’s choice of chemotherapy (paclitaxel, pegylated liposomal doxorubicin, gemcitabine or topotecan). The dual primary endpoints of the phase 3 part of the trial are ORR and PFS as assessed by BICR. Secondary endpoints include PFS and ORR as assessed by investigator, DoR and DCR as assessed by both BICR and investigator, and OS. Pharmacokinetic and biomarker endpoints also will be assessed in both parts of the trial.

REJOICE-Ovarian01 is expected to enroll approximately 710 patients across Asia, Europe, North America, and Oceania. For more information, please visit ClinicalTrials.gov.

About Ovarian Cancer
More than 324,000 women were diagnosed with ovarian cancer worldwide in 2022.4 The median overall survival for advanced ovarian cancer following recurrence can be as little as two years, with a five-year survival rate of 31.8% for those with distant stage disease.1,2

The introduction of targeted therapies has expanded treatment options and improved survival outcomes for some patients with ovarian cancer, but additional options are needed for patients with tumors that progress on available medicines.5 Between 70% and 80% of patients diagnosed with advanced ovarian cancer will experience disease progression following standard treatment with platinum-based chemotherapy regimens.3 For patients who develop platinum-resistant ovarian cancer, defined as disease progression less than six months after completion of last platinum-based chemotherapy, prognosis is particularly poor and treatment options are limited.6,7

About CDH6
CDH6 (human cadherin-6) is a cadherin family protein overexpressed in several cancers, including ovarian tumors.8 An estimated 65% to 94% of patients with ovarian cancer have tumors that express CDH6.9,10,11 In addition, CDH6 expression is observed more frequently in high-grade serous carcinomas.9, 10,11 There is currently no CDH6 directed medicine approved for treatment of any cancer.

About Raludotatug Deruxtecan
Raludotatug deruxtecan is an investigational, potential first-in-class CDH6 directed ADC. Designed using Daiichi Sankyo’s proprietary DXd ADC Technology, raludotatug deruxtecan is comprised of a humanized anti-CDH6 IgG1 monoclonal antibody attached to a number of topoisomerase I inhibitor payloads (an exatecan derivative, DXd) via tetrapeptide-based cleavable linkers.

(Press release, Merck & Co, OCT 19, 2025, View Source [SID1234656804])

On October 19, 2025 Daiichi Sankyo reported initial results from the dose escalation part of the first-in-human phase 1/2 trial of DS-3939 demonstrated promising clinical activity in patients with previously treated advanced solid tumors refractory to standard treatment. These data were presented today during a proffered paper session (917O) at the 2025 European Society for Medical Oncology (#ESMO25).

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DS-3939 is a specifically engineered, potential first-in-class tumor-associated mucin-1 (TA-MUC1) directed DXd antibody drug conjugate (ADC) discovered and being developed by Daiichi Sankyo (TSE: 4568).

TA-MUC1 is a tumor-specific transmembrane glycoprotein that is overexpressed in most human epithelial cancers, making it a promising target for cancer therapy.1,2 Currently, there are no TA-MUC1 directed medicines approved for any type of cancer.

Preliminary safety and efficacy results of DS-3939 were reported from the dose escalation part of the phase 1/2 trial in 64 patients with advanced solid tumors, including 16 with non-small cell lung cancer (NSCLC), 12 with pancreatic ductal adenocarcinoma, nine with urothelial carcinoma, eight with ovarian cancer, seven with biliary tract cancer, seven with colorectal cancer and five with breast cancer.

Patients in the dose escalation phase of the study (n=64) received a median of three prior therapies (range, 1-17) for locally advanced/metastatic disease, including more than one-third receiving prior topoisomerase I inhibitor treatment (n=24; 37.5%). As of the data cut-off on August 1, 2025, 15 patients (23.4%) were still being treated with DS-3939.

The safety and tolerability of DS-3939 was evaluated at increasing dose levels from 1.0 mg/kg to 10.0 mg/kg. The most common treatment-emergent adverse events (TEAEs) of any grade in >20% of patients were nausea (60.9%), vomiting (35.9%), fatigue (28.1%), anemia (26.6%), constipation (26.6%), decreased appetite (23.4%), diarrhea (23.4%) and decreased neutrophil count (23.4%). Grade 3 or higher TEAEs occurred in 46.9% of patients (n=30) and the most common (>2%) included decreased neutrophil count (15.6%), anemia (10.9%), pneumonitis (4.7%) and decreased platelet count (3.1%). There were three dose-limited toxicities observed, including one grade 3 anemia needing transfusion (4.0 mg/kg dose), one grade 3 abdominal pain (6.0 mg/kg dose) and one grade 4 decreased platelet count (8.0 mg/kg dose). All grade adjudicated as treatment-related interstitial lung disease (ILD)/pneumonitis occurred in 10.9% (n=7) of patients. The majority of ILD events were low grade (grade 2 [n=6 or 9.4%]) with one grade 3 (n=1 or 1.6%) event as determined by an independent adjudication committee. Following the data cut-off of August 1, 2025, two ILD events were adjudicated as grade 5 and two additional ILD events are pending adjudication.

Preliminary efficacy results were reported across dose levels from 1.0 mg/kg to 10.0 mg/kg of DS-3939. One confirmed complete response was observed in a patient with ovarian cancer and 10 confirmed partial responses were seen in patients with ovarian cancer (n=5), NSCLC (n=4) and breast cancer (n=1). Thirty-nine cases of stable disease were observed in patients with NSCLC (n=11), urothelial carcinoma (n=8), pancreatic ductal adenocarcinoma (n=6), colorectal cancer (n=5), biliary tract cancer (n=4), breast cancer (n=3) and ovarian cancer (n=2) after a median follow-up of 8.8 months (range, 0.6-22.9).

"These initial results are encouraging for patients with advanced solid tumors where treatment options remain limited once standard therapies are no longer effective," said Manish R. Patel, MD, Director of Drug Development, Florida Cancer Specialists and Sarah Cannon Research Institute. "Enrollment continues into the dose expansion part of the trial to help us better understand the potential role DS-3939 may play in treating numerous types of advanced solid tumors."

"These first-in-human results offer preliminary evidence that targeting the novel tumor antigen TA-MUC1 may be a promising treatment approach for multiple types of cancer," said Ken Takeshita, MD, Global Head, R&D, Daiichi Sankyo. "Additionally, these results represent the sixth antibody drug conjugate from the pipeline of Daiichi Sankyo with encouraging early phase data further demonstrating the portability of our DXd antibody drug conjugate technology to new tumor targets."

About the Phase 1/2 Trial
The two-part, multicenter, open-label, first-in-human phase 1/2 trial is assessing the safety and efficacy of DS-3939 in patients with locally advanced, metastatic or unresectable solid tumors not amenable to standard of care treatment for each tumor type.

The first part of the trial (dose escalation) assessed the safety and tolerability of increasing doses of DS-3939 to determine the maximum tolerated dose and/or the recommended doses for expansion (RDEs) in patients with locally advanced, metastatic or unresectable solid tumors.

The second part of the trial (dose expansion) consists of multiple expansion cohorts to assess the safety and efficacy of DS-3939. The trial will evaluate safety endpoints, including dose-limiting toxicities and adverse events, and efficacy endpoints, including objective response rate, disease control rate, duration of response, time to response, progression-free survival and overall survival. Pharmacokinetic and biomarker endpoints also will be assessed.

The trial is ongoing and enrolling patients across multiple tumor types at sites globally, including Asia, Europe and North America. For more information, please visit ClinicalTrials.gov.

About TA-MUC1
TA-MUC1, a tumor-specific transmembrane glycoprotein, is a molecular target that is expressed across a broad range of solid tumors, but has limited expression in normal human tissues.1 Based on the overexpression of TA-MUC1 in solid tumors, it is an attractive target for cancer therapy.2 Currently, there are no TA-MUC1 directed therapies approved for any type of cancer.

About DS-3939
DS-3939 is an investigational, potential first-in-class TA-MUC1 directed ADC. Designed using Daiichi Sankyo’s proprietary DXd ADC Technology, DS-3939 is one of six DXd ADCs in the oncology pipeline of Daiichi Sankyo. DS-3939 is comprised of a humanized anti-TA-MUC1 antibody, attached to a number of topoisomerase I inhibitor payloads (an exatecan derivative, DXd) via tetrapeptide-based cleavable linkers.

(Press release, Daiichi Sankyo, OCT 19, 2025, View Source [SID1234656803])