CFI-402257, a Potent and Selective TTK Inhibitor, in Solid Tumors and With Fulvestrant in Breast Cancer
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ClinicalTrials.gov Identifier: NCT05251714 |
Recruitment Status :
Recruiting
First Posted : February 23, 2022
Last Update Posted : February 6, 2023
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Condition or disease | Intervention/treatment | Phase |
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Advanced Solid Tumor Breast Cancer | Drug: CFI-402257 Drug: Fulvestrant | Phase 1 Phase 2 |
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 44 participants |
Allocation: | Non-Randomized |
Intervention Model: | Sequential Assignment |
Intervention Model Description: | Dose escalation and expansion for monotherapy and combination arms with fulvestrant |
Masking: | None (Open Label) |
Primary Purpose: | Treatment |
Official Title: | A Dose-confirming Study of CFI-402257 as a Single Agent in Advanced Solid Tumors and in Combination With Fulvestrant in Patients With ER+/HER2- Advanced Breast Cancer After Disease Progression on Prior CDK4/6 and Endocrine Therapy |
Actual Study Start Date : | May 27, 2022 |
Estimated Primary Completion Date : | August 2025 |
Estimated Study Completion Date : | August 2025 |

Arm | Intervention/treatment |
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Experimental: Part A: Monotherapy Escalation and Expansion
Dose selection and expansion of CFI-402257
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Drug: CFI-402257
Oral once daily in 28 day cycles
Other Names:
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Experimental: Part B: Combination Escalation and Expansion
Dose selection and expansion of CFI-402257 with Fulvestrant
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Drug: CFI-402257
Oral once daily in 28 day cycles
Other Names:
Drug: Fulvestrant 500 mg given by IM injection on Day 1 and Day 15 of Cycle 1 and Day 1 of each subsequent cycle
Other Name: Faslodex |
- To assess the incidence of adverse events of CFI-402257 as a single agent and at the recommended phase 2 dose (RP2D) [ Time Frame: 48 months ]The number of subjects who experience an adverse event that was possibly related to study drug as assessed by CTCAE v 5.0.
- To assess the incidence of adverse events of CFI-402257 in combination with fulvestrant and at the recommended phase 2 dose (RP2D) [ Time Frame: 48 months ]The number of subjects who experience an adverse event that was possibly related to study drug as assessed by CTCAE v 5.0.
- Assessment of objective response rates [ Time Frame: 48 months ]Objective response rate will be summarized by dose cohort and overall using the percent of patients in each tumor response category.
- Assessment of objective response rates of the combination [ Time Frame: 48 months ]Objective response rate will be summarized overall for advanced breast cancer patients
- Assessment of the pharmacokinetic profile of CFI-402257 through AUC [ Time Frame: 48 months ]Area under the plasma concentration (AUC) versus time curve from time 0 to time of least measurable concentration tabulated by dose group.
- Assessment of the pharmacokinetic profile of CFI-402257 in combination with fulvestrant through AUC [ Time Frame: 48 months ]Area under the plasma concentration (AUC) versus time curve from time 0 to time of least measurable concentration tabulated by dose group.
- To evaluate the effect of CFI-402257 treatment on changes in variant allele function [ Time Frame: 48 months ]Changes in variant allele function will be measured by looking at circulating tumor deoxyribonucleic acid compared to baseline

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 18 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria: Part A
- Have histological or cytological proof of advanced cancer that has progressed on at least 1 prior line of systemic therapy.
- Have measurable or nonmeasurable disease as per RECIST 1.1 guidelines or other appropriate disease assessment guidelines.
- Are ≥18 years of age.
- Have clinically acceptable laboratory screening results (i.e., clinical chemistry, hematology, and urinalysis) within certain limits specified.
- Have an ECOG performance status of 0 or 1.
- Be able to swallow oral medications.
- Have a life expectancy of greater than 3 months.
- Women and men of childbearing potential must agree to use highly effective means of contraception.
- A negative serum pregnancy test within 72 hours prior to the initiation of protocol therapy..
- Can understand the requirements of the study, provide written informed consent.
Inclusion Criteria: Part B
- Have histologically and/or cytologically confirmed diagnosis of breast cancer positive for estrogen receptor (ER) and/or progesterone receptor (PR) and negative for HER2 for which no curative therapy exists.
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Prior therapy:
- Must have previously received at least 1 and no more than 3 lines of endocrine therapy (ET), either as monotherapy or as a combination therapy with CDK4/6 inhibitor for breast cancer.
- Must have progressed during or within 28 days of completion of prior treatment with a CDK4/6 inhibitor in combination an AI or tamoxifen.
- Must have received no more than 1 line of cytotoxic chemotherapy in the advanced/metastatic setting.
- Have measurable or nonmeasurable disease as per RECIST 1.1 guidelines.
- Are female or male
- Are ≥18 years of age
- Are postmenopausal. Premenopausal or perimenopausal patients are required to receive goserelin for at least 4 weeks before the start of study drug.
- Have clinically acceptable laboratory screening results (i.e., clinical chemistry, hematology, and urinalysis) within certain limits.
- Have an ECOG performance status of 0 or 1.
- Be able to swallow oral medications.
- Have a life expectancy greater than 3 months.
- Women of childbearing potential must agree to use highly effective means of contraception.
- A negative serum pregnancy test within 72 hours prior to the initiation of protocol therapy will be required for women of childbearing potential.
- Can understand the requirements of the study, provide written informed consent.
Exclusion Criteria: All Parts
- Are pregnant or nursing.
- Have received chemotherapy, biological therapy, or investigational treatment less than 4 weeks (6 weeks for nitrosoureas or mitomycin C) prior to first dose of study drug. Have received radiotherapy less than 2 weeks prior to first dose of study drug.
- Received growth factors within 14 days prior to initiation of dosing of CFI-402257 or who will require ongoing treatment with growth factors
- Have active, acute, or clinically significant chronic infections.
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Have the following cardiovascular conditions
- Have uncontrolled severe hypertension
- Have symptomatic congestive heart failure
- Have active angina pectoris or recent myocardial infarction
- Have chronic atrial fibrillation or QTc of greater than 470 msec.
- Have had major surgery within 21 days of starting therapy.
- Primary central nervous system malignancies or known central nervous system metastasis.
- Being treated with full dose warfarin.
- Coagulopathy or any history of coagulopathy within the past 6 months, including history of deep vein thrombosis or pulmonary embolism.
- Patients must avoid the use of CYP3A sensitive substrates, PgP, BCRP inhibitors prior to the first dose of CFI-402257.
- Have had prior treatment with a TTK/MPS1 inhibitor.
- Part B only: Known bleeding disorder which would prohibit administration of fulvestrant.
- Part B only: Concomitant active malignancy other than ER+/HER2- advanced breast cancer.
- Part A only: Concomitant active malignancy other than primary malignancy

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): NCT05251714
Contact: Treadwell Therapeutics Clinical Trials | +1-416-455-7510 | clinicaltrials@treadwelltx.com |
United States, Ohio | |
The Ohio State University Comprehensive Cancer Center | Not yet recruiting |
Columbus, Ohio, United States, 43210 | |
Contact: R Wesolowski | |
United States, Texas | |
START San Antonio | Recruiting |
San Antonio, Texas, United States, 78229 | |
Contact: Muralidhar Beeram | |
United States, Utah | |
START - Mountain Region | Recruiting |
West Valley City, Utah, United States, 84119 | |
Contact: Justin Call | |
Contact: Casey Larsen casey.larsen@startthecure.com | |
United States, Virginia | |
Virginia Cancer Specialist | Recruiting |
Fairfax, Virginia, United States, 22031 | |
Contact: Melissa Hackmaster melissa.hackmaster@usoncology.com |
Principal Investigator: | R Wesolowski | The Ohio State University Comprehensive Cancer Center |
Responsible Party: | Treadwell Therapeutics, Inc |
ClinicalTrials.gov Identifier: | NCT05251714 |
Other Study ID Numbers: |
TWT-203 |
First Posted: | February 23, 2022 Key Record Dates |
Last Update Posted: | February 6, 2023 |
Last Verified: | July 2022 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | No |
Plan Description: | It is too early to determine whether we will make IPD available - we do not yet have a process written on this. Field will be updated once our policy / process is written. |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
Treadwell Therapeutics advanced solid tumors advanced breast cancer CFI-402257 2257 fulvestrant TWT-203 |
TWT203 UHN University Health Network Treadwell endocrine therapy TTK TTK inhibitor |
Breast Neoplasms Neoplasms by Site Neoplasms Breast Diseases Skin Diseases Fulvestrant Antineoplastic Agents, Hormonal |
Antineoplastic Agents Estrogen Receptor Antagonists Estrogen Antagonists Hormone Antagonists Hormones, Hormone Substitutes, and Hormone Antagonists Physiological Effects of Drugs |