WI231696: Bosutinib, Palbocicilib and Fulvestrant for HR+HER2- Advanced Breast Cancer Refractory to a CDK4/6 Inhibitor
![]() |
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. |
ClinicalTrials.gov Identifier: NCT03854903 |
Recruitment Status :
Recruiting
First Posted : February 26, 2019
Last Update Posted : April 2, 2020
|
- Study Details
- Tabular View
- No Results Posted
- Disclaimer
- How to Read a Study Record
This is an open-label, single-arm, phase I trial. It is designed with a conservative dose escalation plan to ensure patient's safety and with a strong translational component to inform if target inhibition is achieved. With concerns regarding safety, based on extensive available pharmacokinetic data and clinical efficacy experience, bosutinib will be given 5-days in a row followed by 2 days rest in a weekly basis, instead of daily.
The protocol will enroll patients per 3+3 escalation design. The Dose Limiting Toxicity (DLT) observation period is 28 days. At the end of DLT observation period of each cohort of 3 patients, decision will be made regarding further escalation or de-escalation according to this plan. Once the MTD of the combination is reached, the safety data will be analyzed. There will be no dose reductions during DLT observation period. Dose reduction within patients (individually) is allowed after the 4-week DLT observation period. Treatment in this phase I trial will be administered until there is disease progression or unacceptable toxicity.
Condition or disease | Intervention/treatment | Phase |
---|---|---|
Metastatic Breast Cancer Human Epidermal Growth Factor 2 Negative Carcinoma of Breast Hormone Receptor Positive Breast Cancer | Drug: Palbociclib Drug: Bosutinib Drug: Fulvestrant | Phase 1 |
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 18 participants |
Allocation: | Non-Randomized |
Intervention Model: | Sequential Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Treatment |
Official Title: | A Phase I Trial of Palbociclib and Bosutinib With Fulvestrant in Patients With Metastatic Hormone Receptor Positive and HER2 Negative (HR+ HER2-) Breast Cancer Refractory to an Aromatase Inhibitor and a CDK4/6 Inhibitor (ASPIRE - WI231696) |
Actual Study Start Date : | April 1, 2019 |
Estimated Primary Completion Date : | December 2021 |
Estimated Study Completion Date : | December 2022 |

Arm | Intervention/treatment |
---|---|
Experimental: Dose Level A1
|
Drug: Palbociclib
Palbociclib is taken orally.
Other Name: Ibrance Drug: Bosutinib Bosutinib is taken orally.
Other Name: Bosulif Drug: Fulvestrant Fulvestrant is given as an intramuscular injection.
Other Name: Faslodex |
Experimental: Dose Level A2
|
Drug: Palbociclib
Palbociclib is taken orally.
Other Name: Ibrance Drug: Bosutinib Bosutinib is taken orally.
Other Name: Bosulif |
Experimental: Dose Level B1
|
Drug: Palbociclib
Palbociclib is taken orally.
Other Name: Ibrance Drug: Bosutinib Bosutinib is taken orally.
Other Name: Bosulif Drug: Fulvestrant Fulvestrant is given as an intramuscular injection.
Other Name: Faslodex |
Experimental: Dose Level B2
|
Drug: Palbociclib
Palbociclib is taken orally.
Other Name: Ibrance Drug: Bosutinib Bosutinib is taken orally.
Other Name: Bosulif Drug: Fulvestrant Fulvestrant is given as an intramuscular injection.
Other Name: Faslodex |
- Toxicity of bosutinib when used in combination with palbociclib and fulvestrant in patients with advanced HR+MBC who are refractory to AI and CDK4/6 inhibitors [ Time Frame: 1 year ]Toxicity of adverse events will be measured via the Common Toxicity Criteria for Adverse Events (CTCAE 4.03)
- Incidence of adverse events of bosutinib when used in combination with palbociclib and fulvestrant in patients with advanced HR+MBC who are refractory to AI and CDK4/6 inhibitors [ Time Frame: 1 year ]Incidence of adverse events will be measured via the Common Toxicity Criteria for Adverse Events (CTCAE 4.03)
- Grade of adverse events of bosutinib when used in combination with palbociclib and fulvestrant in patients with advanced HR+MBC who are refractory to AI and CDK4/6 inhibitors [ Time Frame: 1 year ]Grade of adverse events will be measured via the Common Toxicity Criteria for Adverse Events (CTCAE 4.03)
- Maximum Tolerated Doses (MTD) of palbociclib and bosutinib when used in combination with fulvestrant in patients with advanced HR+MBC who are refractory to AI and CDK4/6 inhibitors [ Time Frame: 28 days of therapy ]This is a 3+3 escalation phase I study. Three patients will be enrolled at each dose cohort and an evaluation of dose escalation will take place after 3 patients have completed 28 days of therapy. If none of the 3 patients has a dose-limiting toxicity, the next cohort will be treated at the next dose level as per the dose escalation schema. At each dose level, if one patient experiences a dose-limiting toxicity, an additional 3 patients will be enrolled. If 2 or more patients experience dose-limiting toxicity in a single cohort (either 2/3 patients, or 2/6 patients in an expanded cohort), the MTD will have been exceeded and dose escalation will stop.
- Recommended Phase II Dose (RP2D) of palbociclib and bosutinib when used in combination with fulvestrant in patients with advanced HR+MBC who are refractory to AI and CDK4/6 inhibitors [ Time Frame: 1 year ]Once the MTD of the combination is reached, the safety data will be analyzed. Dose reduction within patients (individually) is allowed after the 4-week DLT observation period. This phase I trial will inform the RP2D (recommended phase 2 doses of the drugs on the combination).

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: | Female |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Signed informed consent obtained prior to any study specific assessments and procedures.
- Age ≥18 years
- Premenopausal and postmenopausal women
-
Biopsy proven diagnosis of ER and/or PR positive, HER2 negative, advanced breast cancer (locoregionally recurrent or metastatic disease), either from the primary or a metastatic site.
ER, PR and HER2 measurements should be performed according to institutional guidelines, in a CLIA-approved setting.
Breast cancer is ER-positive and/or PR-positive tumor (≥1% positive stained cells) based on local CLIA-certified laboratory results
HER2-negative breast cancer:
Cut-off values for positive/negative staining should be in accordance
- A formalin-fixed paraffin-embedded (FFPE) tumor tissue block from diagnostic biopsy must be transmitted to MedStar Georgetown University Hospital Pathology Department repository and confirmation of receipt must be available prior to initiation of treatment on study.
- ECOG performance status 0-1
- Must have received no more than 3 lines of chemotherapy for the treatment of breast cancer and be progressive on at least one aromatase inhibitor and one CDK 4/6 inhibitor.
-
Pregnancy must be ruled out Serum or urine pregnancy test must be negative within 14 days of treatment start in women of childbearing potential.
Pregnancy testing does not need to be pursued in patients who are judged as postmenopausal before enrollment, or who have undergone bilateral oophorectomy, total hysterectomy, or bilateral tubal ligation.
Patients may be considered postmenopausal in case that one of the following criteria applies (Section 5.4.1.2):
Prior bilateral oophorectomy, OR Age ≥ 60 years, OR Age < 60 years with intact uterus and amenorrhoeic for ≥ 12 consecutive months prior to chemotherapy and/or endocrine therapy exposure, OR Age < 60 years hysterectomized and FSH and plasma estradiol levels in the post-menopausal range according to local policies prior to chemotherapy and/or endocrine therapy exposure
-
Willingness to undergo adequate contraception if childbearing potential Women of childbearing potential must use adequate contraception for the duration of protocol treatment and for 3 months after the last treatment with palbociclib/bosutinib.
Adequate contraception is defined as one highly effective form (i.e. abstinence, (fe)male sterilization) OR two effective forms (e.g. non-hormonal IUD and condom / occlusive cap with spermicidal foam / gel / film / cream / suppository).
- Patients must be able and willing to swallow and retain oral medication
- Absolute neutrophil count (ANC) ≥ 1,500/mm^3
- Platelets ≥ 100,000/mm^3
- Hemoglobin ≥ 9 g/dL
- AST and/or ALT ≤3 x ULN
- Alkaline phosphatase ≤2.5 x ULN (≤5.0 x ULN if bone metastases present)
- Total serum bilirubin ≤1.5 x ULN
- Serum creatinine within normal institutional limits or creatinine clearance ≥ 50 mL/min/1.73 m^2 for patients with serum creatinine levels above institutional ULN.
- Resolution of all acute toxic effects of prior therapy, including radiotherapy to grade ≤1 (except toxicities not considered a safety risk for the patient) and recovery from surgical procedures.
- Patients who are willing and able to comply with scheduled visits, treatment plan, laboratory tests, and other study procedures.
Exclusion Criteria:
- Concurrent therapy with other Investigational Products.
- Current use of food or drugs known to be potent inhibitors or inducers of CYP3A4
- Known hypersensitivity to fulvestrant, palbociclib or bosutinib, or to any of their excipients.
- Uncontrolled intercurrent illness including (active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, diabetes, pulmonary embolism in the past 6 months, or psychiatric illness/social situations that would limit compliance with study requirements).
- Active uncontrolled or symptomatic brain metastases. Previously treated and clinically stable, as per Investigator's judgment, brain metastases are permitted.
- Unable to comply with study requirements
- Presence of a condition that would interfere with enteric absorption of palbociclib/bosutinib.
- Pregnant women, or women of childbearing potential without a negative pregnancy test (serum or urine) within 14 days prior to starting treatment on study Breastfeeding must be discontinued prior to study entry.
- Patients on combination antiretroviral therapy, i.e. those who are HIV-positive (potential for pharmacokinetic interactions or increased immunosuppression with palbociclib).
- Patients with clinically significant history of liver disease, including viral or other known hepatitis, current alcohol abuse, or cirrhosis, etc.
- Patients on chronic anticoagulation (fulvestrant is IM injection)

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): NCT03854903
United States, District of Columbia | |
Lombardi Comprehensive Cancer Center | Recruiting |
Washington, District of Columbia, United States, 20007 | |
Contact: Nellie Novielli, RN 202-687-3923 noviella@georgetown.edu | |
Contact: Julie Castle, RN 202-687-2209 bickmorj@georgetown.edu | |
Principal Investigator: Paula Pohlmann, MD, MSc, PhD | |
Sub-Investigator: Claudine Isaacs, MD | |
Sub-Investigator: Asma Dilawari, MD | |
Sub-Investigator: Filipa Lynce, MD | |
Sub-Investigator: Robert Warren, MD |
Study Chair: | Paula R Pohlmann, MD, MSc, PhD | Georgetown University |
Responsible Party: | Georgetown University |
ClinicalTrials.gov Identifier: | NCT03854903 |
Other Study ID Numbers: |
STUDY00000057 |
First Posted: | February 26, 2019 Key Record Dates |
Last Update Posted: | April 2, 2020 |
Last Verified: | April 2020 |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
breast cancer HR+ HER2- HR positive HER2 negative metastatic |
aromatase inhibitor CDK4/6 inhibitor palbociclib bosutinib fulvestrant Faslodex |
Breast Neoplasms Neoplasms by Site Neoplasms Breast Diseases Skin Diseases Fulvestrant Palbociclib Antineoplastic Agents, Hormonal Antineoplastic Agents |
Estrogen Receptor Antagonists Estrogen Antagonists Hormone Antagonists Hormones, Hormone Substitutes, and Hormone Antagonists Physiological Effects of Drugs Protein Kinase Inhibitors Enzyme Inhibitors Molecular Mechanisms of Pharmacological Action |