Skip to main content

PI3K-beta Inhibitor GSK2636771 and Pembrolizumab in Treating Patients with Stage III-IV Cancer and PTEN Loss

Trial Status: Temporarily Closed to Accrual

This phase I / II trial studies the side effects and best dose of PI3K-beta inhibitor GSK2636771 when given together with pembrolizumab and to see how well they work in treating patients with stage III-IV cancer and PTEN loss. PI3K-beta inhibitor GSK2636771 may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Giving PI3K-beta inhibitor GSK2636771 and pembrolizumab may work better in treating patients with metastatic cancer.

Inclusion Criteria

  • Be willing and able to provide written informed consent for the trial
  • Evidence of PTEN loss in tumors by immunohistochemistry (IHC) or molecular analysis
  • Have measurable disease based on RECIST 1.1
  • Have a performance status of 0 or 1 on the Eastern Cooperative Oncology Group (ECOG) performance scale
  • Patients who have unresectable stage III through stage IV metastatic prostate, triple negative breast, or endometrial carcinoma. Patients with metastatic melanoma must have progressed on PD-L1 or PD-1 directed therapy or must have not achieved complete or partial response after 6 months of therapy, including combinations
  • Patients with prostate, triple negative breast, and endometrial malignancy must have either progressed or refused approved treatments for their respective malignancies
  • Have a life expectancy of at least 12 weeks
  • Patients who have not had chemotherapy or radiotherapy within 2 weeks (6 weeks for nitrosoureas or mitomycin C) prior to starting protocol treatment or those who have not recovered from adverse events due to agents administered more than 4 weeks earlier
  • Able to swallow and retain orally administered medication
  • On the dose expansion and phase II portions of the study, patients must be willing to provide tissue from a newly obtained core or excisional biopsy of a tumor lesion before and at least one time point while on therapy. Correlative biopsies will be optional in the phase I portion of the study. Newly-obtained is defined as a specimen obtained up to 6 weeks (42 days) prior to initiation of treatment on day 1 without intervening systemic therapy
  • Absolute neutrophil count >= 1500 per microliter (uL) (within 14 days of treatment initiation)
  • Platelets >= 100,000 per uL (within 14 days of treatment initiation)
  • Hemoglobin >= 9 grams per deciliter or >= 5.6 millimoles per liter without transfusion or erythropoietin (EPO) dependency (within 7 days of assessment) (within 14 days of treatment initiation)
  • Serum creatinine =< 1.0 x the upper limit of normal (ULN) OR measured or calculated creatinine clearance per institutional standard (glomerular filtration rate [GFR] can also be used in place of creatinine or creatinine clearance [CrCl]) must be >= 60 milliliters per minute OR proteinuria by urine dipstick =< 1+ (within 14 days of treatment initiation)
  • Aspartate aminotransferase (AST) AND alanine aminotransferase (ALT) =< 2.5 times the ULN OR =< 5 times the ULN for subjects with liver metastases (within 14 days of treatment initiation)
  • Alkaline phosphatase (Alk phos) =< 2 times the ULN (within 14 days of treatment initiation)
  • Serum total bilirubin =< 2.0 mg/dL except in patients with Gilbert’s disease. Direct bilirubin =< ULN for subjects with total bilirubin levels > 1.5 ULN (within 14 days of treatment initiation)
  • Albumin >= 2.5 g/dL (within 14 days of treatment initiation)
  • Left ventricular ejection fraction (LVEF) >= 50% by echocardiogram (ECHO) or multigated acquisition (MUGA) (within 14 days of treatment initiation)
  • International normalized ratio (INR) or prothrombin time (PT)=< 1.5 x ULN unless the subject is receiving anticoagulant therapy as long as PT or partial thromboplastin time (PTT) is within therapeutic range of intended use of anticoagulants (within 14 days of treatment initiation)
  • Activated partial thromboplastin time (aPTT) =< 1.5 x ULN unless the subject is receiving anticoagulant therapy as long as PT or PTT is within therapeutic range of intended use of anticoagulants (within 14 days of treatment initiation)
  • Serum phosphate within normal limit (within 14 days of treatment initiation)
  • Serum calcium within normal limit (within 14 days of treatment initiation)
  • Female subject of childbearing potential should have a negative urine or serum pregnancy within 72 hours prior to receiving the first dose of study medication. If the urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required
  • Female subjects of childbearing potential must be willing to use an adequate method of contraception for the course of the study through 4 months after the last dose of study medication * Note: Abstinence is acceptable if this is the usual lifestyle and preferred contraception for the subject
  • Male subjects with a female partner of childbearing potential must agree to use acceptable methods of contraception from the time of screening until 3 months after the last dose of study treatments

Exclusion Criteria

  • Patients are excluded if they have a history of or active autoimmune disease, as follows: patients with a history of inflammatory bowel disease are excluded from this study as are patients with a history of symptomatic disease (e.g., rheumatoid arthritis, systemic progressive sclerosis [scleroderma], systemic lupus erythematosus, autoimmune vasculitis [e.g., Wegener’s granulomatosis]). Patients with motor neuropathy considered of autoimmune origin (e.g., Guillain-Barre syndrome and myasthenia gravis) are excluded. Patients with a history of autoimmune thyroiditis are eligible if their current thyroid disorder is treated and stable with replacement or other medical therapy
  • Has active infections or serious general medical conditions (such as active myocardial infarction [MI], cerebrovascular accident [CVA], or respiratory failure)
  • Any unresolved > grade 1 toxicity (per Common Terminology Criteria for Adverse Events [CTCAE] 4.0) from previous anti-cancer therapy or previously administered agent at the time of enrollment, except for alopecia, grade 2 anemia (if hemoglobin is > 9 g/dL) * Note: If the subject received major surgery, they must have recovered adequately from the toxicity and/or complications from the intervention prior to starting therapy
  • Presence of any clinically significant gastrointestinal (GI) abnormality or other condition(s) that may alter absorption such as malabsorption syndrome or major resection of the stomach or substantial portion of the small intestine
  • Active peptic ulcer disease or history of abdominal fistula, GI perforation, or intra abdominal abscess within 28 days prior to enrollment
  • Previous major surgery within 28 days prior to enrollment
  • Evidence of severe or uncontrolled systemic diseases (e.g., unstable or uncompensated respiratory, hepatic, renal or cardiac disease)
  • Has a corrected QT (QTc) > 450 milliseconds (msec) or QTc > 480 msec for subjects with bundle branch block (BBB) * NOTES: The QTc is the QT interval corrected for heart rate by Bazett’s formula (QTcB), Fridericia’s formula (QTcF), and/or another method, machine-read or manually over-read. The specific formula that will be used to determine eligibility and discontinuation for an individual subject should be determined prior to initiation of the study. In other words, several different formulae cannot be used to calculate the QTc for an individual subject and then the lowest QTc value used to include or discontinue the subject from the trial. For purposes of data analysis QTcF will be used
  • History or evidence of cardiovascular risk including any of the following: * Clinically significant electrocardiogram (ECG) abnormalities including second degree (type II) or third degree atrioventricular block * History of myocardial infarction, acute coronary syndromes (including unstable angina), coronary angioplasty, stenting, or bypass grafting within the past 6 months prior to enrollment * Class III or IV heart failure as defined by the New York Heart Association (NYHA) functional classification system * Left ventricular ejection fraction (LVEF) below 50% * Known cardiac metastases
  • Poorly controlled hypertension (defined as systolic blood pressure [SBP] of >= 150 mmHg or diastolic blood pressure [DBP] of > 100 mmHg based on a mean of three measurements at approximately 2-minute intervals) * NOTE: Initiation or adjustment of antihypertensive medication(s) is permitted if done thirty or more days prior to enrollment
  • History of congenital platelet function defect (e.g., Bernard-Soulier syndrome, Chediak-Higashi syndrome, Glanzmann thrombasthenia, storage pool defect)
  • Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of trial treatment * NOTE: Replacement dose steroids (equivalent to 10 mg prednisone) are allowed
  • Has a known history of active TB (Bacillus tuberculosis)
  • Hypersensitivity to pembrolizumab or GSK2636771 or excipients
  • Has a known prior or additional malignancy that is progressing or requires active treatment. Exceptions include basal cell carcinoma of the skin or squamous cell carcinoma of the skin that has undergone potentially curative therapy or in situ cervical cancer
  • Has known active central nervous system (CNS) metastases and/or carcinomatous meningitis. Subjects with previously treated brain metastases may participate provided they are stable (without evidence of progression by imaging for at least two weeks prior to the first dose of trial treatment and any neurologic symptoms have returned to baseline), have no evidence of new or enlarging brain metastases, and are not using steroids for at least 7 days prior to trial treatment. This exception does not include carcinomatous meningitis which is excluded regardless of clinical stability
  • Has a history of (non-infectious) pneumonitis that required steroids or current pneumonitis
  • Has a history or current evidence of any condition, therapy, or laboratory abnormality that might confound the results of the trial, interfere with the subject’s participation for the full duration of the trial, or is not in the best interest of the subject to participate, in the opinion of the treating investigator
  • Has known psychiatric or substance abuse disorders that in the opinion of the registering physician or principal investigator (PI) would interfere with cooperation with the requirements of the trial
  • Has a known history or positive test for human immunodeficiency virus (HIV) (HIV 1/2 antibodies). Testing at the time of screening is not required
  • Presence of hepatitis B surface antigen (HBsAg), positive hepatitis C antibody test result at time of screening or any history of hepatitis. Patients with hepatitis C treated curatively and who have completed therapy successfully will be considered eligible
  • Has received a live vaccine within 30 days of planned start of study therapy
  • Current use of or anticipated requirement during the study of any prohibited medication(s) * Note: Seasonal influenza vaccines for injection are generally inactivated flu vaccines and are allowed; however intranasal influenza vaccines (e.g., Flu-Mist) are live attenuated vaccines, and are not allowed


M D Anderson Cancer Center
Contact: Hussein Abdul-Hassan Tawbi
Phone: 713-792-6111


I. To determine the safety, maximum-tolerated dose (MTD), and/or recommended phase II dose (RP2D) of the combination of PI3K-beta inhibitor GSK2636771 (GSK2636771) and pembrolizumab in metastatic cancer (melanoma, triple negative breast cancer [TNBC], prostate, and endometrial). (Phase I)

II. To determine the efficacy of the combination of GSK2636771 and pembrolizumab as defined by objective response rate (ORR) by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 in metastatic cancer (melanoma, TNBC, prostate, and endometrial). (Phase II)


I. To determine the safety and tolerability of the combination of GSK2636771 and pembrolizumab when administered at the MTD/RP2D in patients with metastatic cancer.

II. To determine the pharmacokinetics of GSK2636771 in combination with pembrolizumab and correlate with response and pathway inhibition.

III. To compare the objective response rate of the combination as determined by RECIST 1.1 and the immune related Response Criteria (ir-RC).

IV. To determine the progression-free and overall survival.

V. To determine the incidence of grade 3 and 4 immune-related adverse events.

VI. To identify biomarkers predictive of response and/or resistance to the combination therapy through the analysis of tissue samples.

VII. To determine the pharmacodynamic effects of the combination on phosphatidylinositol 3-kinase (PI3K) pathway inhibition in tumor cells, T cell trafficking into tumor and tumor microenvironment, circulating chemokines and T cell populations.

OUTLINE: This is a phase I, dose-escalation study of PI3K-beta inhibitor GSK2636771 followed by a phase II study.

Patients receive PI3K-beta inhibitor GSK2636771 orally (PO) daily on days 1-21 and pembrolizumab intravenously (IV) over 30 minutes on day 1. Cycles repeat every 21 days for up to 2 years in the absence of disease progression or unacceptable toxicity.

After completion of study treatment, patients are followed up for 30 days and then every 6 weeks.

Trial Phase Phase I/II

Trial Type Treatment

Lead Organization
M D Anderson Cancer Center

Principal Investigator
Hussein Abdul-Hassan Tawbi

  • Primary ID 2016-0774
  • Secondary IDs NCI-2018-01609
  • ID NCT03131908