Ribociclib and Bicalutamide in AR+ TNBC

Individuals from populations who are underrepresented in clinical research (e.g., racial and ethnic minorities, women, individuals from rural/frontier communities, older individuals) will be enrolled with a goal of ensuring that all eligible patients are given the opportunity to participate in novel clinical trials and that research findings can be generalizable to the entire population.

Androgen Receptor (AR) positivity definitions -Phase I: Metastatic or unresectable AR+ triple-negative breast cancer (TNBC); AR positivity defined as IHC staining of >0% of tumor nuclei.

OR

-Phase II: Metastatic or unresectable AR+ triple-negative breast cancer (TNBC); AR positivity defined as IHC staining of ≥10% of tumor nuclei.

Inclusion Criteria for Phase I and II study.

In addition to being AR positive as defined in protocol, subjects must also meet all of the following applicable inclusion criteria.

• Histological or cytological confirmed, metastatic or unresectable triple-negativebreast cancer (TNBC). TNBC will be defined as expression of ER<10%, PR< 10% and HER2negative either by IHC (0, 1+ are negative, 2+ equivocal) or in situ hybridizationmethod (ratio <2.0 is negative).

• Written informed consent and HIPAA authorization for release of personal healthinformation. NOTE: HIPAA authorization may be included in the informed consent orobtained separately.

• Up to 3 prior line of systemic therapy for metastatic disease is allowed.Combination therapy will be considered 1 line.

• Age ≥ 18 years at the time of consent.

• ECOG Performance Status of 0, 1 or 2 within 28 days prior to registration.

• Life expectancy of > 12 weeks as determined by the treating physician.

• Measurable disease according to RECIST 1.1 within 28 days prior to registration.

• No active central nervous system (CNS) metastatic disease. NOTE: Subjects with CNSinvolvement must meet ALL of the following to be eligible:

• At least 28 days from prior definitive treatment of their CNS disease bysurgical resection, stereotactic body radiation therapy (SBRT) or whole brainradiation treatment (WBRT) at the time of registration

• AND asymptomatic and off systemic corticosteroids and/or enzyme-inducinganti-epileptic medications for brain metastases for >14 days prior toregistration.

• Prior cancer treatment must be completed at least 14 days prior to registration andthe subject must have recovered from all reversible acute toxic effects of theregimen (other than alopecia) to ≤grade 1 or to baseline prior to initiation of thattherapy.

• Screening rate-corrected QT interval (QTc) must be <450msec and a resting heart rateof at least 50-90 bpm via a standard 12-lead ECG within 28 days prior toregistration.

• Demonstrate adequate bone marrow and organ function as defined in the protocol; allscreening labs to be obtained within 28 days prior to registration.

• Females of childbearing potential must have a negative serum pregnancy test within 7days prior to registration. NOTE: Females are considered of child bearing potentialunless they are surgically sterile (have undergone a hysterectomy, bilateral tuballigation, or bilateral oophorectomy), or they are naturally postmenopausal for atleast 12 consecutive months, or her male partner has had a vasectomy at least 6months prior to screening (The sterilized male partner must be her only sexualpartner.).

• Females of childbearing potential and males must be willing to abstain fromheterosexual activity or must agree to use adequate contraception (hormonal orbarrier method) for the duration of study participation and for 3 weeks afterdiscontinuation of study treatment.

• As determined by the enrolling physician or protocol designee, ability of thesubject to understand and comply with study procedures for the entire length of thestudy.

• Able to swallow bicalutamide and ribociclib tablets.

Exclusion Criteria:

• Prior therapy with AR antagonists including but not limited to bicalutamide,enzalutamide, abiraterone and orteronel.

• Prior therapy with any CDK 4/6 inhibitors with the exception of participation in awindow or preoperative study for Stage I-III operable breast cancer..

• Active infection requiring systemic therapy.

• Pregnant or breastfeeding (NOTE: breast milk cannot be stored for future use whilethe mother is being treated on study).

• Known additional malignancy that is active and/or progressive requiring treatment;exceptions include basal cell or squamous cell skin cancer, in situ cervical orbladder cancer, or other cancer for which the subject has been disease-free for atleast three years.

• Treatment with any investigational drug within 14 days prior to registration orwithin 5 half-lives of the investigational product, whichever is longer.Immunotherapies such as PD-L1 or PD-1 inhibitors only require a 14 day window,regardless of half-life. Investigational imaging agents are not included in thisdefinition and are allowed.

• Subject who has received radiotherapy <14 days prior to registration, and who hasnot recovered to grade 1 or better from related side effects of such therapy (exceptions include alopecia and any adverse events deemed by the investigator to beunlikely to interfere with the study drug safety).

• Subject has had major surgery within 14 days prior to registration or has notrecovered from major side effects of the surgery (tumor biopsy is not considered asmajor surgery).

• Known hypersensitivity to any of the excipients of ribociclib or bicalutamide.

• Any impairment of gastrointestinal (GI) function or GI disease that maysignificantly alter the absorption of the study drugs (e.g., ulcerative diseases,uncontrolled nausea, vomiting, diarrhea, malabsorption syndrome, or small bowelresection).

• Known history of HIV infection (testing not mandatory).

• Any concurrent severe and/or uncontrolled medical condition that would, in theinvestigator's judgment, cause unacceptable safety risks, contraindicate subjectparticipation in the clinical study or compromise compliance with the protocol (e.g.chronic pancreatitis, chronic active hepatitis, active untreated or uncontrolledfungal, bacterial or viral infections, etc.).

• Subjects with any of the following conditions are excluded:

• Serious or non-healing wound, ulcer, or bone fracture.

• History of abdominal fistula, gastrointestinal perforation, or intra- abdominalabscess within 28 days prior to registration.

• Any history of cerebrovascular accident (CVA) or transient ischemic attackwithin 12 months prior to registration.

• Any history of arterial or venous thrombosis/thromboembolic event, includingpulmonary embolism within the past 12 months prior to registration.

• History of acute coronary syndromes (including myocardial infarction, unstableangina, coronary artery bypass grafting, coronary angioplasty, or stenting) orsymptomatic pericarditis within 6 months prior to registration.

• Symptomatic congestive heart failure (New York Heart Association III-IV) ordocumented current cardiomyopathy with left ventricular ejection fraction (LVEF) <50%

• Clinically significant cardiac arrhythmias (e.g. ventricular tachycardia) orclinically significant, complete left bundle branch block, high-grade AV block (e.g. bifascicular block, Mobitz type II and third-degree AV block).

• Any episode of atrial fibrillation in the prior 12 months.

• Long QT syndrome or family history of idiopathic sudden death or congenitallong QT syndrome.

• Concomitant use of medication(s) with a known risk to prolong the QT intervaland/or known to cause Torsades de Pointe that cannot be discontinued (within 5half-lives or 7 days prior to starting study drug) or replaced by safealternative medication. See ManualDocuments/Info tab of the EDC for list ofmedications.

• Systolic blood pressure (SBP) >160 mmHg or <90 mmHg at screening.

• Currently receiving any known strong inducers or inhibitors of CYP3A4/5 which cannotbe discontinued 7 days prior to starting study drug (see Appendix 1 for details).

• Subject is currently receiving or has received systemic corticosteroids <14 daysprior to starting study drugs. The following uses of corticosteroids are permitted:a short duration (<5 days) of systemic corticosteroidssingle doses, any duration oftopical applications (e.g., for rash), inhaled sprays (e.g., for obstructive airwaysdiseases), eye drops or local injections (e.g., intra-articular).

• Subject is currently receiving warfarin or other coumarin-derived anticoagulant fortreatment, prophylaxis or otherwise. Therapy with heparin, low molecular weightheparin (LMWH), novel oral anticoagulants (NOACs) or fondaparinux is allowed.

• In subjects with a diagnosis of cirrhosis, sSubjects with a Child-Pugh score B or Care excluded. Please see chart in the ManualDocuments/Info tab of the electronicdata capture system (EDC) for Child-Pugh score calculation. If subject does not havediagnosed or suspected cirrhosis, the Child-Pugh score does not need to becalculated.

• Subjects taking herbal supplements (St. John's Wort, gingko balboa, etc.) mustdiscontinue these supplements 14 days prior to study registration.

• Consumption of grapefruit, grapefruit hybrids, pummelos, star-fruit, Seville orangesor products containing the juice of each within 7 days prior to study registration.