A Study of DB-1303/BNT323 vs Investigator's Choice Chemotherapy in HER2-Low, Hormone Receptor Positive Metastatic Breast Cancer (DYNASTY-Breast02)

PHASE3ACTIVE_NOT_RECRUITING

The goal of this clinical trial is to assess the efficacy of DB-1303/BNT323 compared with investigator's choice chemotherapy in terms of progression-free survival (PFS) by blinded independent central review (BICR) in the HR+, HER2-low (immunohistochemistry \[IHC\]2+/in situ hybridization \[ISH\]- and IHC 1+) population.

Study details:

The study is a Phase III, Randomized, Multi-center, Open-label study in HER2-low, HR+ metastatic breast cancer subjects whose disease has progressed on at least 2 lines of prior ET or within 6 months of first line ET + Cyclin-dependent kinase (CDK) 4/6 inhibitor in the metastatic setting. The primary purpose of the study is to determine the efficacy and safety of DB-1303/BNT323 compared with investigator's choice single agent chemotherapy in the target population. Approximately 532 subjects with HER2 IHC 2+/ISH- and IHC 1+ (HER2-low\] expression will be randomized 1:1 across approximately 255 centers globally to receive either DB-1303 or investigator's choice single agent chemotherapy (capecitabine, paclitaxel or nab-paclitaxel) until Response Evaluation Criteria in Solid Tumors (RECIST) 1.

1 defined disease progression (PD), unless there is unacceptable toxicity, withdrawal of consent, or another criterion for discontinuation is met.

Eligibility criteria

Researchers look for people who fit a certain description, called eligibility criteria. See if you qualify.

Inclusion criteria

  1. Male or female adults (defined as ≥ 18 years of age or acceptable age according to local regulations at the time of voluntarily signing of informed consent).
  2. Pathologically documented breast cancer that has advanced or metastatic.
  3. Has HER2-low expression (IHC 1+ or IHC 2+/ISH-) as determined by the central laboratory result.
  4. Was never previously reported as HER2-positive (IHC 3+ or ISH+) as per American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines.
  5. Is documented as HR+ (either estrogen receptor [ER] and/or progesterone receptor [PgR] positive [ER or PgR ≥1%]) per ASCO/CAP guidelines (Allison et al 2020).
  6. Must have an adequate tumor tissue sample available for assessment of HER2 by central laboratory, in formalin fixation and paraffin embedding (FFPE) blocks based on a mandatory FFPE tumor sample preferably obtained at the time of metastatic disease or later;
  7. Eastern Cooperative Oncology Group performance status of 0 or 1.
  8. Must have had either: Disease progression on endocrine therapy + CDK4/6 inhibitor within 6 months of starting first line treatment for metastatic disease and considered appropriate for chemotherapy as the next treatment by the investigator, OR Disease progression on at least 2 previous lines of ET with or without a targeted therapy (such as CDK4/6, mammalian target of rapamycin [mTOR] or phosphoinositide 3-kinase [PI3-K] inhibitors) administered for the treatment of metastatic disease.
  9. No prior chemotherapy for advanced or metastatic breast cancer. Subjects who have received chemotherapy in the neo-adjuvant or adjuvant setting are eligible, as long as they have had a disease-free interval (defined as completion of systemic chemotherapy to diagnosis of advanced or metastatic disease) of >12 months.
  10. Life expectancy ≥12 weeks at screening.
  11. Subjects must have at least one measurable lesion as defined per RECIST v1.1 (For bone only disease, subjects with lytic or mixed lytic bone lesions that can be measured by CT or MRI are eligible; subjects with sclerotic/osteoblastic bone lesions are not eligible).
  12. Has LVEF ≥ 50% by either echocardiography (ECHO) or multiple-gated acquisition (MUGA) within 28 days before randomization.
  13. Adequate organ and bone marrow function within 14 days before randomization.
  14. Has adequate treatment washout period before randomization.
  15. Evidence of post-menopausal status or negative serum pregnancy test for females of childbearing potential who are sexually active with a non-sterilized male partner. For women of childbearing potential, a negative result for serum pregnancy test (test must have a sensitivity of at least 25 mIU/mL) must be available at the screening visit and urine beta-human chorionic gonadotropin (β-HCG) pregnancy test prior to each administration of study treatment.
  16. Female subjects of childbearing potential who are sexually active with a non-sterilized male partner must use at least one highly effective method of contraception from the time of screening and must agree to continue using such precautions for 7 months after the last dose of study treatment.
  17. Non-sterilized male subjects who are sexually active with a female partner of childbearing potential must use a condom with spermicide from screening and throughout the duration of the study treatment and the washout period (4 months after the last dose of DB-1303, 6 months after the last dose of paclitaxel or nab-paclitaxel, and 3 months after the last dose of capecitabine).
  18. Must be able and willing to comply with the protocol requirements and must sign and date the informed consent form prior to any screening evaluations.

Exclusion criteria

  1. Ineligible for all options in the investigator's choice chemotherapy arm.
  2. Uncontrolled intercurrent illness, including but not limited to, ongoing or active infection, uncontrolled or significant cardiovascular disease, serious chronic gastrointestinal conditions associated with diarrhea, or psychiatric illness/social situations that would limit compliance with study requirement, substantially increase risk of incurring adverse events or compromise the ability of the subject to give written informed consent.
  3. Clinically uncontrolled pleural effusion, ascites or pericardial effusion requiring repeated drainage, peritoneal shunt or cell-free concentrated ascites reinfusion therapy within 2 weeks prior to the randomization.
  4. Uncontrolled or significant cardiovascular disease
  5. Has a medical history of interstitial lung diseases (e.g., non-infectious interstitial pneumonia, pneumonitis, pulmonary fibrosis, and radiation pneumonitis which needs glucocorticoids and antibiotics) or current interstitial lung diseases or who are suspected to have these diseases by imaging at screening.
  6. Has unresolved toxicities from previous anticancer therapy, defined as toxicities (other than alopecia) not yet resolved to Grade ≤ 1 or baseline or Grade ≤ 2 anemia.
  7. Previous treatment with anti-HER2 therapy.
  8. Prior treatment with antibody-drug conjugate that comprised an exatecan derivative that is a topoisomerase I inhibitor.
  9. Prior randomization or treatment in a previous DB-1303/BNT323 study regardless of treatment assignment.
  10. Has substance abuse or any other medical conditions such as psychological conditions, that may, in the opinion of the Investigator, interfere with the subject's participation in the clinical study or evaluation of the clinical study results.
  11. Individuals who are dependent on the Sponsor, clinical site, or Investigator (e.g., is an employee of the Sponsor or the clinical trial site, a dependent of the Investigator, or any site staff member otherwise supervised by the Investigator).
  12. Individuals who are committed to an institution by virtue of an order issued either by the judicial or the administrative authorities, in accordance with local regulations.

Eligibility

Age eligible for study : NA

Healthy volunteers accepted : No

Gender eligible for study: ALL

Things to know

Study dates

Study start:

Primary completion:

Study completion finish:

study type

Study type

TREATMENT

phase

Phase

    PHASE3

trial

Study ID

NCT06018337

Intervention or treatment

DRUG: DB-1303/BNT323

DRUG: Capecitabine

DRUG: Paclitaxel

DRUG: Nab-paclitaxel

Conditions

  • Metastatic Breast Cancer
  • Condition: Metastatic Breast Cancer

  • DRUG: DB-1303/BNT323 and other drugs

  • Camperdown, New South Wales, Australia and more

  • Sponsor: DualityBio Inc.

You may be eligible to participate in this trial based on your search. Check eligibility by answering some questions.

Are you running this trial?

If you're a clinic or sponsor, you can claim this study

Research sites nearby

Closest Location:

Research Site 6108-0

Select from list below to view details:

  • Research Site 6108-0

    Camperdown, New South Wales, Australia

  • Research Site 6116-0

    Kingswood, New South Wales, Australia

  • Research Site 6109-0

    Liverpool, New South Wales, Australia

  • Research Site 6102-0

    Sydney, New South Wales, Australia

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Who is running the clinical trial?

DI

DualityBio Inc.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Participant Group/ArmIntervention/Treatment
EXPERIMENTAL: DB-1303/BNT323
  • Enrolled Subjects will be randomized to receive a 8 mg/kg IV dose of DB-1303/BNT323 on Day 1 of each cycle Q3W
Drug: DB-1303/BNT323
    ACTIVE_COMPARATOR: investigator's choice single agent chemotherapy
    • Enrolled Subjects will be randomized to receive investigator's choice single agent chemotherapy (capecitabine:1000 or 1250 mg/m2, Oral, Twice daily orally for 2 weeks followed by a 1-week rest period in 3-week cycles; paclitaxel:80 mg/m2, IV, Every week (QW) in 3-week cycles; or nab-paclitaxel: 100 mg/m2, IV, Every week (QW) for 3 weeks followed by a one-week rest period in 4-week cycles) until RECIST 1.1 defined disease progression (PD), unless there is unacceptable toxicity, withdrawal of consent, or another criterion for discontinuation is met.
    Drug: Capecitabine, Drug: Paclitaxel, Drug: Nab-paclitaxel

      What is the study measuring?

      Primary Outcome

      MeasureDescriptionTime Frame
      Progression-free survival (PFS) in the HR+, HER2-low populationPFS by BICR according to RECIST 1.1 in the HR+, HER2-low populationUp to approximately 51 months

      Secondary Outcome

      MeasureDescriptionTime Frame
      Overall survival (OS) in the HR+, HER2-low populationOS in the HR+, HER2-low populationUp to approximately 51 months
      Objective response rate (ORR) in the HR+, HER2-low populationORR by BICR and Investigator assessment according to RECIST 1.1 in the HR+, HER2-low populationUp to approximately 51 months
      PFS by Investigator assessmentPFS by Investigator assessment according to RECIST 1.1 in the HR+, HER2-low populationUp to approximately 51 months
      Duration of response (DoR) in the HR+, HER2-low populationDoR by BICR and Investigator assessment according to RECIST 1.1 in the HR+, HER2-low populationUp to approximately 51 months
      Treatment-emergent adverse events (TEAEs)TEAEs per National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) v5.0from the time of the subject signing the informed consent form (ICF) until the follow-up period is completed (35 days after the last dose of study treatment
      Serious adverse events (SAEs)SAEs per NCI CTCAE v5.0from the time of the subject signing the ICF until the follow-up period is completed (35 days after the last dose of study treatment
      Patient reported outcomes (PROs): European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ) - C30Change from baseline in the functioning/symptom/global quality of life (QoL) subscales of EORTC QLQ-C30. Scale scores range from 0-100. For functioning and global QoL scales, higher scores indicate better functioning or global health status. For symptom scales, higher scores indicate greater symptom burden.Up to approximately 51 months
      Patient reported outcomes (PROs): EORTC QLQ-BR45Change from baseline in the functioning/symptom subscales of EORTC QLQ-BR45. Scale scores range from 0-100. For functioning scales, higher scores indicate better functioning. For symptom scales, higher scores indicate greater symptom burden.Up to approximately 51 months
      Patient reported outcomes (PROs): European Quality of Life Five Dimension Five Level Scale (EQ-5D-5L)Change from baseline in EQ-5D-5L health state utility index score and Visual Analogue Scale (VAS) score. VAS score range from 0-100, higher scores indicate better health status.Up to approximately 51 months
      European Quality of Life Five Dimension Five Level Scale (EQ-5D-5L)EQ-5D-5L health state utility index score and Visual Analogue Scale (VAS) score. The change from baseline value will be reported.Up to approximately 51 months
      Are you running this trial?If you're a clinic or sponsor, you can claim this study.

      References

      Clinical Trials Gov: A Study of DB-1303/BNT323 vs Investigator's Choice Chemotherapy in HER2-Low, Hormone Receptor Positive Metastatic Breast Cancer (DYNASTY-Breast02)

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