- Part 1: Histological or cytological diagnosis of a solid tumor that is
advanced/metastatic, patients intolerant to standard treatment, resistant to standard
therapy or for which no standard therapy is available.
- Part 2: Arm A: Patients with histological or cytological proven diagnosis of
adenocarcinoma of the breast (HR+ HER2 ) with evidence of either locally advanced
disease not amenable to resection or radiation therapy with curative intent or
metastatic disease not amenable to curative therapy.
- Documentation of HR positive (ie, ER positive and/or progesterone receptor positive
tumor, (>1% positive stained cells) and HER2 negative tumor (described above);
- Have progressed on prior CDK4/6 inhibitor therapy;
- Received greater than or equal to 2 prior lines of therapy in the metastatic setting;
- Must have evaluable disease by RECIST v 1.1.
- Arm B: Histological or cytological diagnosis of castration resistant prostate cancer
(serum testosterone of less than 50 ng/dL). Received either abiraterone and/or
enzalutamide treatment and has evidence of prostate cancer progression (per Prostate
Cancer Working Group 3 Criteria for progression at trial entry): Elevated prostate
specific antigen (PSA) only; Bone only metastasis and nodal disease (Escalation only);
Nodal disease (no bone disease present);Visceral (lung, liver, adrenal, CNS) disease
(other sites) (For Expansion measurable by RECIST 1.1 only).
- Age greater than or equal to 18 years.
- Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) 0 or 1.
- Adequate bone marrow function, including: Absolute Neutrophil Count (ANC) greater than
or equal to 1,500/mm3 or 1.5 x 109/L; Platelets greater than or equal to 100,000/mm3
or 100 x 109/L; Hemoglobin greater than or equal to 9 g/dL.
- Adequate renal function, including serum creatinine less than or equal to1.5 x upper
limit of normal (ULN) or estimated creatinine clearance greater than or equal to 60
mL/min as calculated using the method standard for the institution. In equivocal
cases, a 24 hour urine collection test can be used to estimate the creatinine
clearance more accurately. In Part 2: Serum creatinine of less than or equal to 3.0 x
upper limit of normal.
- Adequate liver function, including: Total serum bilirubin less than or equal to 1.5 x
ULN unless the patient has documented Gilbert syndrome; Aspartate and alanine
aminotransferase (AST and ALT) less than or equal to 2.5 x ULN, 5.0 x ULN if there is
liver involvement by the tumor; Alkaline phosphatase less than or equal to 2.5 x ULN
(less than or equal to 5 x ULN in case of bone metastasis).
- Serum phosphate within normal range (if abnormal, must be not clinically significant
per the Investigator and approval for patient inclusion after agreement from sponsor.
- Resolved acute effects of any prior therapy to baseline severity or CTCAE less than or
equal to Grade 1 except for adverse events not constituting a safety risk by
- Serum pregnancy test (for females of childbearing potential) negative at screening.
- Female patients of non-childbearing potential must meet at least 1 of the following
criteria: Achieved postmenopausal status, defined as follows: cessation of regular
menses for at least 12 consecutive months with no alternative pathological or
physiological cause; and must have a serum follicle stimulating hormone (FSH) level
confirming the postmenopausal state; Have undergone a documented hysterectomy and/or
bilateral oophorectomy; Have medically confirmed ovarian failure. All other female
patients (including female patients with tubal ligations) are considered to be of
- Evidence of a personally signed and dated informed consent document indicating that
the patient has been informed of all pertinent aspects of the study.
- Willing and able to comply with scheduled visits, treatment plan, laboratory tests,
and other procedures.
- Central Nervous System (CNS) metastases, carcinomatous meningitis, or leptomeningeal
disease as indicated by baseline brain MRI (or CT with contrast if MRI is medically
contraindicated), clinical symptoms, cerebral edema, and/or progressive growth. If
contrast is medically contraindicated, a non-contrast CT scan may be performed.
- Patients with a history of CNS metastases or cord compression.
- Liver metastases at baseline as evidenced by CT scan or MRI that may be at risk for
bleeding, such as those that are greater than 1cm.
- Patients with advanced/metastatic, symptomatic, visceral spread, that are at risk of
life threatening complications in the short term (including patients with massive
uncontrolled effusions [pleural, pericardial, peritoneal], pulmonary lymphangitis, and
over 50% liver involvement). Note: Patients with indwelling catheter for drainage, or
requirement for drainage no more frequently than monthly will be allowed.
- Any other active malignancy within 3 years prior to randomization, except for
adequately treated basal cell or squamous cell skin cancer, or carcinoma in situ.
- History of clinically significant tumor bleeding (except for bleeding in a post
operative setting), coagulopathy or arterio-venous malformations, or aneurysms in the
CNS, liver, lung, or other major organ of the study. Patients with known
Osler-Weber-Rendu disease, Hemophilia A, Hemophilia B (Christmas Disease), Von
Willibrand's Disease, Factor 13 deficiency and Factor 7 deficiency, antibodies to
Factors 8 and 7, history of other bleeding diatheses and abnormal INR values.
- Evidence of a tumor that compresses or invades major blood vessels or tumor cavitation
that in the opinion of the investigator is likely to bleed.
- Major surgery within 4 weeks prior to first dose.
- Prior organ transplantation including heart and allogeneic stem cell transplantation.
- Radiation therapy within 4 weeks prior to study entry. Note: Patients who have
received radiotherapy must have recovered from any reversible side effects, such as
nausea and vomiting.
- Last anti cancer therapy including investigational drug(s) within 28 days (or 5 half
lives, whichever is shorter) prior to study entry excluding hormonal therapy which
requires no treatment free interval.
- Active and clinically significant bacterial, fungal, or viral infection, including
known hepatitis B virus (HBV), known hepatitis C virus (HCV), known human
immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS) related
illness. In equivocal cases, with positive serology, those patients with a negative
viral load are potentially eligible provided the other entry criteria are met. Note:
Inclusion of patients with well controlled HIV, HBV or HCV can be discussed with
sponsor on a case by case basis.
- Any of the following in the previous 6 months: myocardial infarction, congenital long
QT syndrome, Torsades de pointes, arrhythmias (including sustained ventricular
tachyarrhythmia and ventricular fibrillation), right bundle branch block and left
anterior hemiblock (bifascicular block), unstable angina, coronary/peripheral artery
bypass graft, symptomatic congestive heart failure (New York Heart Association class
III or IV), cerebrovascular accident, transient ischemic attack, or symptomatic
pulmonary embolism; deep venous thrombosis; arterial occlusive disease; ongoing
cardiac dysrhythmias of National Cancer Institute (NCI) CTCAE Grade greater than or
equal to 2, atrial fibrillation of any grade that is uncontrolled, or QTcF interval
>470 msec at screening. Note: There is an exception where a cardiac rhythm
device/pacemaker is fitted and results in QTcF >470 msec. -Anticoagulation therapy
with heparin, low molecular weight heparin, vitamin K antagonists anti platelet
agents, or factor Xa inhibitors throughout the study and for at least 28 days post the
last dose of study treatment. (If anticoagulation therapy is medically indicated on
trial, patients should stop treatment with PF-06952229. For those requiring temporary
anticoagulant therapy, resumption of PF-06952229 treatment may be permitted after
discussion with the Sponsor. In any other case, study treatment should be permanently
discontinued, and the patient should enter the follow-up portion of the trial.)
- Moderate or severe heart valve function defect including moderate or severe valve
stenosis or regurgitation.
- Evidence or history of septal aneurysm, other heart aneurysm, or any aneurysm of the
- Grade 3 or greater cardiac troponin I at baseline.
- Left ventricular ejection fraction (LVEF) of less than or equal to 50% or significant
- Hypertension that cannot be controlled by medications (>150/90 mmHg despite optimal
medical therapy) or requiring more than 2 medications for adequate control.
- Clinically significant non healing or healing wounds.
- For patients entering the combination with enzalutamide arm, history of seizures other
than isolated febrile seizure in childhood;
- Has a history of a cerebrovascular accident or transient ischemic attack less than 6
- Known or suspected hypersensitivity to active ingredient/excipients of PF-06952229,
letrozole, palbociclib, or enzalutamide.
- Other acute or chronic medical or psychiatric condition, including recent (within the
past year) or active suicidal ideation or behavior or laboratory abnormality that may
increase the risk associated with study participation or investigational product
administration or may interfere with the interpretation of study results and, in the
judgment of the investigator, would make the patient inappropriate for entry into this
- Investigator site staff members directly involved in the conduct of the study and
their family members, site staff members otherwise supervised by the investigator, or
patients who are Pfizer employees, including their family members, directly involved
in the conduct of the study.
- Pregnant female patients; breastfeeding female patients; fertile male patients and
female patients of childbearing potential who are unwilling or unable to use 2 highly
effective methods of contraception as outlined in this protocol for the duration of
the study and for at least 28 days after the last dose of investigational product.
- Inability to consume or absorb study drug, including but not limited to: Active
inflammatory gastrointestinal (GI) disease, known diverticular disease or previous
gastric resection or lap band surgery. Impairment of gastro intestinal function or GI
disease that may significantly alter the absorption of PF 06952229, such as history of
GI surgery with may result in intestinal blind loops and patients with clinically
significant gastroparesis, short bowel syndrome, unresolved nausea, vomiting, active
inflammatory bowel disease or diarrhea of CTCAE Grade >1.
- Current use or anticipated need for food or drugs that are known strong CYP3A4/5
inhibitors, including their administration within 5 half lives of the CYP3A4/5
inhibitor, prior to first dose of investigational product. Current or anticipated use
of moderate CYP3A4/5 inhibitors (including their administration within 5 half lives of
the CYP3A4/5 inhibitor, prior to first dose of investigational product) should be
avoided if possible, and any use will need to be reviewed and approved by the sponsor.
- Strong CYP3A4/5 inhibitors: eg, grapefruit juice or grapefruit/grapefruit related
citrus fruits (eg, Seville oranges, pomelos), ketoconazole, miconazole, itraconazole,
voriconazole, posaconazole, clarithromycin, telithromycin, indinavir, saquinavir,
ritonavir, nelfinavir, amprenavir, fosamprenavir nefazodone, lopinavir,
troleandomycin, mibefradil, and conivaptan. Current list can be found at Indiana
University Purdue University Indianapolis.
- Moderate CYP3A4/5 inhibitors: eg, erythromycin, verapamil, atazanavir, delavirdine,
fluconazole, darunavir, diltiazem, aprepitant, imatinib, tofisopam, ciprofloxacin, and
cimetidine. Current list can be found at Indiana University Purdue University
- Current use or anticipated need for drugs that are known strong CYP3A4/5 inducers,
with the exception of enzalutamide in Part 2, including their administration within 4
weeks or 5 half lives of the CYP3A4/5 inducer, whichever is longer, prior to the first
dose of investigational product. Strong CYP3A4/5 inducers: eg, phenobarbital,
rifampin, phenytoin, carbamazepine, rifabutin, rifapentine, clevidipine, St. John's
- Have initiated bisphosphonates or approved receptor activator of nuclear factor kappa
B ligand (RANK L) targeted agents (for example, denosumab) randomization.
- Active, known or suspected autoimmune diseases including inflammatory bowel disease
(including ulcerative colitis and Crohn's disease), rheumatoid arthritis, systemic
progressive sclerosis, systemic lupus erythematosus (SLE), autoimmune vasculitis (eg,
Wegener's Granulomatosis), CNS or motor neuropathy considered to be of autoimmune
origin (eg, Guillain-Barre Syndrome, Myasthenia Gravis, Multiple Sclerosis).