Protein Phosphatase 2A Inhibitor, in Recurrent Glioblastoma

Background:

• Primary gliomas are an incurable disease in spite of aggressive multimodality therapy consisting of craniotomy, irradiation, and chemotherapy. Therapeutic options for patients with recurrent glioma are limited, and there is an unmet need to identify more effective agents.
• LB100, a water-soluble small molecule novel protein phosphatase 2A (PP2A) inhibitor, was commercially developed through a Cooperative Research and Development Agreement (CRADA) based on our previous intramural research. This compound has shown to be effective in a variety of cancer types in both in vitro and in vivo models. Preclinical studies indicate LB100 has in vitro and in vivo activity as a single agent as well as potentiating the effect of cytotoxic agents including temozolomide, docetaxel, doxorubicin, and ionizing radiation. LB100 is active in combination with temozolomide or doxorubicin against xenografts of glioblastoma, neuroblastoma, pheochromocytoma, breast cancer, fibrosarcoma, and melanoma.
• A complete phase I study of LB100 has established its safety and the recommended phase II dose (2.33 mg/m^2, daily for three days every 3 weeks).
• Although it is a polar compound, rodent studies suggest LB100 has activity in the brain.
• Whether LB100 can across the human blood brain barrier (BBB), and at what concentration relative to the plasma level is not known. Characterizing these parameters is important because:

• 1) Our ongoing in vitro studies indicate that LB100 has distinct mechanisms of action at different drug concentrations (e.g., nM versus uM);
• 2) There are other brain tumors lacking effective medical therapies but without a BBB. Characterizing the LB100 BBB penetration profile will assist in defining its optimal clinical indication.

Objective:

-To determine the pharmacokinetic (PK) properties of LB100 in glioma tumor tissues.

Eligibility:

• Patients with histologically proven glioblastoma and grades II-III astrocytomas and oligodendrogliomas.
• A clear clinical indication for another surgical resection must be present.
• Subjects must be greater than or equal to 18 years old.
• Karnofsky performance status of greater than or equal to 60%.
• Patients must have adequate organ function.

Design:

• This is a two stage Phase II, open label, single institution study to determine the PK and pharmacodynamic (PD) profile of LB100.
• The dose (established from a Phase I study) will be 2.33 mg/m^2 delivered intravenously over 2 hours.
• PK and PD effect of LB100 treated tissues will only be evaluated with pathologic confirmation of recurrent tumor. Resected material demonstrating chemoradiation treatment effect or inflammatory response will not be included in the analysis.
• PK will be determined by quantitating LB100 in tumor tissues removed at various time points.
• The primary endpoint is PK response, defined as a binary variable indicating the presence/absence of LB100 in tumor tissues.
• PD effect is defined as statistically significant elevation of phospho-proteins in treated tumor tissues compared to untreated glioma specimens. Untreated inter-patient baseline variance and standard deviation (SD) will be calculated. Post-treatment PD effect difference greater than 2.5 times the baseline SD is statistically significant at the .05 significance level. Due to relatively small sample size, t-distribution is to be used to calculate the cutoff defining the PD response.
• Up to 25 patients may be enrolled to obtain 8 evaluable subjects. A two-stage design will be used. Five patients will be initially treated. If at least one of five demonstrates PK activity, 3 additional subjects will be enrolled. PK effect will be declared to be significant if at least 2 of the 8 patients demonstrate a PK response (presence of LB100 in tumor tissue).

• INCLUSION CRITERIA:
• Patients must have histologically confirmed glioblastoma/gliosarcoma, grades II-III astrocytoma and oligodendroglioma.
• Patients must have recurrent disease for which there is a clinical indication for resection.
• Age greater than or equal to18 years.
• Karnofsky greater than or equal to 60%.
• Patients must have adequate bone marrow function (white blood count (WBC) greater than or equal to 3,000/uL absolute neutrophil count (ANC) greater than or equal to 1,500/mm^3, platelet count of greater than or equal to 100,000/mm^3, and hemoglobin greater than or equal to 10 gm/dL), adequate liver function (SGOT and bilirubin < 2 times upper limit of normal (ULN). These tests must be performed within 28 days prior to receiving drug. Eligibility level for hemoglobin may be reached by transfusion.
• Patients must have a serum creatinine of <=1.7 mg/dL. If the serum creatinine is greater than 1.7 mg/dl, a 24-hour urine creatinine clearance will be obtained and if the result of this study is within normal limits*, the patient would be eligible to enroll onto study. This test must be performed within 28 days prior to registrationreceiving drug. (*Normal Creatinine Clearance Range: Male: 90 - 130 ml/min; Female: 80 - 125 ml/min)
• Patients must be in adequate general medical health to safely tolerate a craniotomy.
• At the time of registration, all subjects must be removed greater than or equal to 28 days from any investigational agents.
• The effects of LB100 on the developing human fetus are unknown. For this reason, women of child-bearing potential and 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 she or her partner is participating in this study, she should inform her treating physician immediately.
• Ability of subject to understand and the willingness to sign a written informed consent document indicating that they are aware of the investigational nature of this study, and that this is not a therapeutic clinical trial.

Exclusion criteria

• Patients who are receiving any other investigational agents.
• 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.
• Patients unwilling to undergo craniotomy.
• Pregnant women are excluded from this study because the safety of Protein Phosphatase 2A (PP2A) inhibition on a developing fetus has not been established. Because there is an unknown but potential risk for adverse events in nursing infants secondary to treatment of the mother with LB100, breastfeeding should be discontinued if the mother is treated with LB100.
• Patients may not have had prior chemotherapy or biologic therapy in the 4 weeks prior to study entry. For patients who have been treated with targeted therapy, 5 half-lives of that therapy (or 28 days, whichever is shorter) must have passed prior to enrollment in the study.
• Known human immunodeficiency virus (HIV)-positive patients on combination antiretroviral therapy are ineligible because of the potential for pharmacokinetic interactions with LB100. Appropriate studies will be undertaken in patients receiving combination antiretroviral therapy when indicated.
• Patients who are receiving strong cytochromes P450 (CYP450) inducers or inhibitors are ineligible
• Recruitment Strategies

Patients with recurrent disease will be identified by the Neuro-Oncology Branch, Clinical Center. This study will be posted on National Institutes of Health (NIH) websites and on NIH Social media forums.