A Study of ZN-c5 and Abemaciclib in Participants With Breast Cancer
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ClinicalTrials.gov Identifier: NCT04514159 |
Recruitment Status :
Completed
First Posted : August 14, 2020
Last Update Posted : February 1, 2023
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Condition or disease | Intervention/treatment | Phase |
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Breast Cancer | Drug: ZN-c5 Drug: Abemaciclib | Phase 1 |
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 14 participants |
Allocation: | N/A |
Intervention Model: | Single Group Assignment |
Intervention Model Description: | All participants will receive the same treatment but ZN-c5 will be given at different doses in this dose escalation study. |
Masking: | None (Open Label) |
Primary Purpose: | Treatment |
Official Title: | A Phase 1b Study of ZN-c5 in Combination With Abemaciclib in Patients With Estrogen-Receptor Positive, Human Epidermal Growth Factor Receptor-2 Negative Advanced Breast Cancer |
Actual Study Start Date : | November 12, 2020 |
Actual Primary Completion Date : | October 24, 2022 |
Actual Study Completion Date : | October 24, 2022 |

Arm | Intervention/treatment |
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Experimental: ZN-c5 + abemaciclib combination therapy
Participants will take abemaciclib (150mg) orally twice a day and ZN-c5 (dose escalation) orally once or twice a day to determine the safety, tolerability, and maximum tolerated dose (MTD) or recommended Phase 2 dose (RP2D).
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Drug: ZN-c5
ZN-c5 is the study drug. Drug: Abemaciclib Abemaciclib (VERZENIO®) is an approved drug.
Other Name: VERZENIO® |
- Incidence and severity of adverse events from ZN-c5 in combination with abemaciclib [ Time Frame: Through study completion, anticipated to be 21 months ]Measured by the number of treatment-emergent adverse events and graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) v5.0
- Determine tumor responses to combination treatment [ Time Frame: Through study completion, anticipated to be 21 months ]Measured by radiographic responses as defined by revised Response Evaluation Criteria in Solid Tumor (RECIST) v1.1.

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Ages Eligible for Study: | 18 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Age ≥ 18 years of age
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Women can be peri- or postmenopausal, as defined by at least one of the following:
- Age ≥ 60 years;
- Age < 60 years and cessation of regular menses for at least 12 consecutive months with no alternative pathological or physiological cause; and serum estradiol and follicle-stimulating hormone (FSH) level within the laboratory's reference range for postmenopausal females;
- Documented bilateral oophorectomy;
- Must receive a gonadotrophin-releasing hormone agonist beginning at least 4 weeks prior to the first dose of study medication
- Histologically or cytologically confirmed diagnosis of advanced adenocarcinoma of the breast
- Estrogen receptor positive disease
- Human Epidermal Growth Factor Receptor 2 negative disease
- Measurable disease per Response Evaluation Criteria in Solid Tumors v1.1
Exclusion Criteria:
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Prior therapy within the following windows:
- Tamoxifen, aromatase inhibitor, fulvestrant, or other anti-cancer endocrine therapy < 14 days;
- Any investigational drug therapy < 28 days or 5 half-lives (whichever is shorter)
- Any prior systemic chemotherapy regardless of the stop date, but the subject must have recovered to eligibility levels from prior toxicity
- Prior treatment with CDK4/6 inhibitors
- Unexplained symptomatic endometrial disorders (including, but not limited to, endometrial hyperplasia, dysfunctional uterine bleeding, or cysts)

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04514159
United States, Arizona | |
Site 2 | |
Gilbert, Arizona, United States, 85234 | |
United States, South Carolina | |
Site 1 | |
Charleston, South Carolina, United States, 29414 | |
Poland | |
Site 6 | |
Grudziądz, Poland, 86-300 | |
Site 4 | |
Kraków, Poland, 30-348 | |
Site 5 | |
Łódź, Poland, 93-513 |
Study Chair: | Carrie Brownstein, MD | Zeno Alpha Inc. |
Responsible Party: | Zeno Alpha Inc. |
ClinicalTrials.gov Identifier: | NCT04514159 |
Other Study ID Numbers: |
ZN-c5-003 |
First Posted: | August 14, 2020 Key Record Dates |
Last Update Posted: | February 1, 2023 |
Last Verified: | January 2023 |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
Dose escalation Phase 1 combination Selective estrogen receptor degrader |
Hormone sensitive Estrogen receptor Hormone receptor |
Breast Neoplasms Neoplasms by Site Neoplasms Breast Diseases Skin Diseases |