Study of ES414 in Metastatic Castration-Resistant Prostate Cancer

Aptevo Therapeutics35 enrolled

Overview

The study will be conducted in 2 Stages. The primary objective of Stage 1 of the study is to identify the maximum tolerated dose (MTD) of ES414 administered intravenously to patients with mCRPC. Secondary objectives are to evaluate the tolerability, pharmacokinetics (PK), pharmacodynamics (PD), immunogenicity, cytokine response, and clinical activity of ES414. The primary objective of Stage 2 of the study is to evaluate the clinical activity of ES414 in patients that have or have not received prior chemotherapy. Secondary objectives are to further characterize the safety profile, PK, PD, and immunogenicity of ES414.

Stage 1 - Dose Escalation: The dose escalation stage of the study will test weekly doses of 0.2 mcg/kg to 300 mcg/kg over 9 dose levels (cohorts). Cohorts 1 to 3 consist of single patients and Cohorts 4 - 9 will consist of a minimum of 3 patients; an additional 3 patients may be added to the cohort if adverse events possibly related to ES414 or dose-limiting toxicities (DLT) occur. The next dose cohort will only enroll after the patient(s) in the current dose cohort have completed the first cycle of dosing (4 weeks) with no significant adverse events or DLTs. Six patients will be enrolled at the maximum tolerated dose (MTD) and this dose will be used for Stage 2. Stage 2 - Expansion: The continuous intravenous infusion MTD dose regimen will be further examined in 2 expansion cohorts; the first cohort are patients that have received prior chemotherapy, such as docetaxel for mCRPC, and the second cohort are those that have not received prior chemotherapy for mCRPC. Serum samples will be collected for serial PK assessment for ES414 drug levels and antibody formation. Response will be assessed every 2 months during the first 6 months of treatment and then every 3 months until progression of mCRPC, intolerable side effects, or withdrawal of consent.

Study Type

INTERVENTIONAL

Allocation

Purpose

TREATMENT

Masking

NONE

Enrollment

Conditions

Prostate Cancer

Interventions

ES414BIOLOGICAL

ES414 is a novel humanized bispecific antibody which is designed to treat mCRPC by redirecting T-cell cytotoxicity against prostate cancer cells expressing prostate-specific membrane antigen (PSMA).

Eligibility

Sex: MALE

Medical Language ↔ Plain English

Inclusion Criteria: * Histologically or cytologically confirmed adenocarcinoma of the prostate. No evidence of neuroendocrine differentiation or small cell features. * Surgically or medically castrated, with testosterone ≤ 50 ng/dL (≤ 1.7 nmol/L). * Progressive prostate cancer by either serum PSA levels, soft tissue or bone disease as defined by the PCWG2 criteria. * In Stage 1, patients may or may not have received prior chemotherapy for mCRPC. In Stage 2, patients will be enrolled into two cohorts based on whether or not they have received prior chemotherapy for mCRPC. Any prior chemotherapy must have been completed ≥ 4 weeks prior to administration of ES414. Additionally, in countries where abiraterone or enzalutamide are commercially available, patients in Stage 1 and 2 must have progressed on abiraterone and/or enzalutamide prior to study entry. * ECOG ≤ 1 * Life expectancy \> 6 months per investigator * Adequate hematologic, renal, and hepatic parameters Exclusion Criteria: * Any chemotherapy, sipuleucel-T, or investigational drug in prior 4 weeks, or abiraterone or enzalutamide in prior 2 week * Any radiation therapy in prior 2 weeks * Any prior therapy targeted against PSMA * History of seizures * History of central nervous system metastasis * History of nephrotic syndrome * Spot urine total protein:creatinine ratio \>1,000 mg/gm * Planned palliative procedures for alleviation of bone pain * Active infection requiring treatment with systemic anti-infectives or major surgery in prior 4 weeks. * Any prednisone (or equivalent corticosteroids) use within 2 weeks of study entry * Chronic immunosuppressive therapy * Known history of HIV, hepatitis B, or hepatitis C infection * Evidence of severe or uncontrolled systemic diseases * History of bleeding disorders or thromboembolic events in prior 3 months

Locations (7)

University of California

San Francisco, California, United States

Roswell Park Cancer Institute

Buffalo, New York, United States

Central Texas Veterans Health Care System

Temple, Texas, United States

University of Washington/Seattle Cancer Care Alliance

Seattle, Washington, United States

Outcomes

Primary Outcomes

Maximum Tolerated Dose of ES414

Identify the maximum tolerated dose in dose-escalation stage (Stage 1) by assessment of dose-limiting toxicities

Time frame: during first 28 days of treatment

Secondary Outcomes

Safety Profile of ES414

The safety profile of ES414 will be assessed by monitoring incidence and severity of adverse events

Time frame: Patients will be followed for the duration of treatment, an expected average of 6 months, and for 28 days following last treatment

Maximum Serum Drug Concentration (Cmax)

Blood samples will be obtained from all patients for determination of the maximum serum concentration of ES414.

Time frame: Pre- and post-infusion at least weekly during first 28-day cycle, and on Days 1 and 15 of subsequent cycles for an expected duration of 6 months, and for up to 8 weeks following last treatment

Area under the concentration versus time curve (AUC)

Blood samples will be obtained from all patients for determination of the AUC of ES414.

Elimination half-life (T1/2)

Blood samples will be obtained from all patients for determination of the T1/2 of ES414.

Immune-Related Response Criteria (irRC)

Investigator measurements of target lesions

Data from ClinicalTrials.gov

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