Crizotinib in Combination With Enzalutamide in Metastatic Castration-resistant Prostate Cancer

• A traditional 3+3 dose escalation scheme will be used to identify the recommended phase 2 dose (RP2D) of crizotinib when used in combination with standard fixed dose enzalutamide.
• Patients who fulfill eligibility criteria will be entered into the trial to receive crizotinib and enzalutamide.
• After the screening procedures confirm participation in the research study:

• The participant will be given a study drug-dosing calendar for each treatment cycle. The investigators are looking for the highest dose of the combination of study drugs that can be administered safely without severe or unmanageable side effects in participants that have, not everyone who participates in this research study will receive the same dose of the study drug. The dose given will depend on the number of participants who have been enrolled in the study prior and how well the dose was tolerated.

Inclusion criteria

• Laboratory and diagnostic tests, such as MRIs and CT scans, required for eligibility must be documented from tests performed within 30 days prior to the date of registration.
• The patient has pathologically confirmed adenocarcinoma of the prostate
• The subject must have CRPC with castrate levels of serum testosterone less than 50 ng/dL.

-- NOTE: Subjects must maintain a castrate state. If they have not had an orchiectomy must continue to receive LHRH or GnRH agonists unless intolerant.

• Evidence of metastatic disease by radiographic imaging (bone scan or other nodal or visceral lesions on CT or MRI)
• Prostate cancer progression since last prior therapy documented by PSA according to PCWG2 or radiographic progression according to modified RECIST criteria Version 1.1
• No limit on number or type of prior therapies

• Prior treatment with docetaxel is permitted but not required
• Prior treatment with ketoconazole, estrogens, abiraterone or novel antiandrogens allowed, including past enzalutamide
• Require at least a 6 week withdrawal period from the last dose of bicalutamide, or nilutamide or 4 weeks from last flutamide or enzalutamide dose Must have a documented PSA rise after stopping the antiandrogen --- Will require a 2 week washout period from last dose of ketoconazole, chemotherapy, or radiation
• Prior radiation is allowed
• Age ≥18 years
• ECOG performance status <2 (See Appendix 1)
• Life expectancy of greater than 6 months
• Participants must have normal organ and marrow function as defined below:

• Absolute neutrophil count ≥1,500/mcL
• Hemoglobin ≥8 g/dL

---*Transfusions and erythropoietin supplementation permitted

• Platelets ≥100,000/mcL
• Total bilirubin within normal institutional limits (unless known Gilbert's syndrome)
• AST(SGOT)/ALT(SGPT) ≤2.5 × institutional upper limit of normal or ≤5X if presence of liver metastases

--- *For patients with documented bone metastases, AST can be > 2.5x ULN if the investigator can provide evidence of no underlying liver dysfunction and thus, it is likely that the AST is originating from bone source.

• Creatinine clearance ≥30 mL/min/1.73 m2 for participants with creatinine levels above institutional normal.
• Able to swallow the study drug as a whole tablet
• The effects of crizotinib and enzalutamide on the developing human fetus are unknown. For this reason and because investigational agents as well as other standard antiandrogen agents used in this trial may be teratogenic, men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while her partner is participating in this study, she should inform her treating physician immediately. Men treated or enrolled on this protocol must also agree to use adequate contraception prior to the study, for the duration of study participation, and 4 months after completion of crizotinib administration.
• Ability to understand and the willingness to sign a written informed consent document.

Exclusion criteria

• Pathology consistent with small cell carcinoma of the prostate
• Prior treatment with c-Met inhibitors
• Participants who have received any other investigational systemic agents in the last 2 weeks.
• Persistent grade >1 (NCI CTCAE v4.0) AEs due to investigational drugs that were administered more than 14 days before study enrollment with the exception of alocepia.
• Participants with known brain metastases will be excluded from this clinical trial because of their poor prognosis and because they often develop progressive neurologic dysfunction or seizures that would confound the evaluation of neurologic and other adverse events.
• History of allergic reactions attributed to compounds of similar chemical or biologic composition to crizotinib or enzalutamide.
• History of seizure or any condition that may predispose to seizure (e.g., prior cortical stroke or significant brain trauma, history of loss of consciousness or transient ischemic attack within 12 months of study entry).
• Concomitant medications that would lower seizure threshold
• Concomitant use of medications that may alter pharmacokinetics of crizotinib or enzalutamide. See section 5.5, but would exclude the use of strong CYP3A or CYP2C8 inhibitors, strong or moderate CYP3A inducers, CYP2C8, CYP3A4, CYP2C9 and CYP2C19 substrates with narrow therapeutic indice.

-- Because the lists of these agents are constantly changing, it is important to regularly consult a frequently-updated list such as: http://medicine.iupui.edu/clinpharm/ddis/table.aspx

• Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.

• Clinically significant heart disease defined as:

• Myocardial infarction within 6 months of Screening visit.
• Uncontrolled angina within 3 months of Screening visit.
• Congestive heart failure New York Heart Association (NYHA) class 3 or 4, or subjects with history of congestive heart failure NYHA class 3 or 4 in the past, or history of anthracycline or anthracenedione (mitoxantrone) treatment, unless a screening echocardiogram or multi-gated acquisition scan (MUGA) performed within three months of the Screening visit results in a left ventricular ejection fraction that is ≥45%.
• History of clinically significant ventricular arrhythmias (e.g., ventricular tachycardia, ventricular fibrillation, torsade de pointes).
• Prolonged corrected QT interval by the Fridericia correction formula (QTcF) on the screening electrocardiogram (ECG) > 470 msec.
• History of Mobitz II second degree or third degree heart block without a permanent pacemaker in place.
• Hypotension (systolic blood pressure <86 mmHg) or bradycardia with a heart rate of <50 beats per minute on the Screening ECG, unless pharmaceutically induced and thus reversible (i.e. beta blockers) or known, chronic asymptomatic baseline heart rate.
• Uncontrolled hypertension as indicated by a resting systolic blood pressure >170 mmHg or diastolic blood pressure >105 mmHg at the Screening visit.
• No medications known to prolong the QT interval as crizotinib may increase the risk for QT prolongation
• Thrombosis or vascular ischemic events within the last six months, such as deep venous thrombosis, pulmonary embolism, transient ischemic attack, cerebral infarction, or myocardial infarction
• No medications known to prolong the QT interval as crizotinib may increase the risk for QT prolongation
• Pregnant women are excluded from this study because women do not get prostate cancer, as they have no prostate.
• No defined washout period from major or minor surgery is required but incisions must be fully healed.
• HIV-positive participants on combination antiretroviral therapy are ineligible because of the potential for pharmacokinetic interactions with crizotinib or enzalutamide. In addition, these participants are at increased risk of lethal infections when treated with marrow-suppressive therapy. Appropriate studies will be undertaken in participants receiving combination antiretroviral therapy when indicated.
• Inability to comply with study and/or follow-up procedures