A Combination Clinical Study of PLX3397 and Pembrolizumab To Treat Advanced Melanoma and Other Solid Tumors

Phase 1/2a Study of Double-Immune Suppression Blockade By Combining a CSF1R Inhibitor (PLX3397) With An Anti-PD-1 Antibody (Pembrolizumab) To Treat Advanced Melanoma And Other Solid Tumors

The goal of this clinical research study is to learn how PLX3397 and pembrolizumab work together to affect cancer cells.

PLX3397 is designed to target the receptor for CSF1 (CSF1R). Pembrolizumab is designed to block the interaction between the receptor PD-1 and molecules that bind PD-1. In this study, PLX3397 and pembrolizumab are being given together in order to study their combined effects on patients' immune responses to their tumors. Tumor-specific immune responses have been shown to kill cancer cells and/or to stop tumors from growing.

Part 1 of the study (dose-escalation phase) will establish the safest dose of PLX3397 to be given in combination with pembrolizumab. Part 2 of the study (expansion phase) will include an evaluation of efficacy of this combination in the following tumor types:

• Advanced melanoma: prior anti-PD-1/PD-L1 therapy but never responded
• Advanced melanoma: prior anti-PD-1/PD-L1 therapy and responded but later progressed as defined by irRECIST while on therapy
• Non-small cell lung cancer
• Ovarian cancer
• Gastrointestinal Stromal Tumor (GIST)
• Squamous cell cancer of the head and neck

Study Overview

• Status: Terminated
• Conditions: Melanoma; Ovarian Cancer; Squamous Cell Carcinoma of the Head and Neck; Non-small Cell Lung Cancer; Gastrointestinal Stromal Tumor (GIST)
• Intervention / Treatment: Drug: PLX3397; Biological: Pembrolizumab

• Study Type: Interventional
• Enrollment (Actual): 78
• Phase: Phase 2; Phase 1

Contacts and Locations

Study Locations

• United States
  • Arizona
    • Scottsdale, Arizona, United States, 85258
      • HonorHealth Research Institute
  • California
    • Greenbrae, California, United States, 94904
      • Marin Cancer Care
    • Los Angeles, California, United States, 90095
      • Ronald Reagan UCLA Medical Center
  • Massachusetts
    • Boston, Massachusetts, United States, 02215
      • Dana-Farber Cancer Institute
    • Boston, Massachusetts, United States, 02114
      • Massachusetts General Hospital
    • Boston, Massachusetts, United States, 02115
      • Beth Israel Deaconess Medical Center
  • Michigan
    • Detroit, Michigan, United States, 48201
      • Karmanos Cancer Institute
  • Missouri
    • Saint Louis, Missouri, United States, 63130
      • Washington University St. Louis Siteman Cancer Center
  • New York
    • New York, New York, United States, 10065
      • Memorial Sloan Kettering Cancer Center
  • South Carolina
    • Charleston, South Carolina, United States, 29425
      • Medical University Health Hollings Cancer Center
  • Tennessee
    • Nashville, Tennessee, United States, 37212
      • Vanderbilt Ingram Cancer Center
  • Texas
    • San Antonio, Texas, United States, 78229
      • South Texas Accelerated Research Therapeutics

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

A subject must satisfy all of the following criteria to be considered for inclusion in the study:

• Subjects with histologically or cytologically-confirmed diagnosis of cancer that is recurrent, metastatic, or persistent, who have relapsed from or are refractory to treatment and who also meet the following corresponding requirements for the cohort or phase of the study into which they will enroll:
• Dose-escalation Phase: Subjects with advanced solid tumors (any tumor type) considered to have no standard-of care treatment for their malignancy with a curative intent, either as initial therapy or after progressing to prior therapies; subjects who have been treated previously with a CSF1R inhibitor or an anti PD1/PDL1 inhibitor may enroll.
• Expansion Phase: Subjects with 1 of the tumor types who have relapsed from or are refractory to standard treatment. Subjects with non-small-cell lung cancer (non-squamous; EGFR, ALK wild type), advanced melanoma, ovarian cancer, unresectable RCC with component of clear-cell histology and/or component of sarcomatoid histology, glioblastoma or gliosarcoma, gastrointestinal stromal tumor.
• Subjects with melanoma must have a histologically confirmed diagnosis of stage III disease not amenable to local therapy. Melanoma subjects may have received any number of prior lines of therapy for metastatic disease and must have measurable disease per RECISTv1.1. Subjects with melanoma who have received prior treatment with a BRAF/MEK inhibitor are acceptable candidates.
• Expansion cohorts: Subjects must have relapsed or been refractory to standard treatment. NSCLC, SCCHN, and Melanoma must show primary progression with antiPD1/anti-PDL1 therapy. They must have tumor accessible for sequential biopsy (core needle biopsy or excision required) and be willing to provide on study tumor tissue biopsy. Subjects for whom newly obtained samples cannot be obtained (e.g. inaccessible or patient safety concern) may submit an archived specimen onlyupon agreement from the Sponsor.
• ECOG performance status 0 or 1.
• Women of childbearing potential must have a negative serum pregnancy test within 72 hours prior to initiation of dosing.
• Women of childbearing potential should be willing to use 2 methods of birth control or be surgically sterile or abstain from heterosexual activity for the course of the study through 120 days after the last dose of study medication. Women of non-child bearing potential may be included if they are either surgically sterile or have been postmenopausal for ≥1 year.
• Fertile men must agree to use an effective method of birth control starting with the first dose of study treatment through 120 days after the last dose of study treatment.
• Adequate organ function as demonstrated by laboratory values.

Exclusion Criteria:

A subject who meets any of the following criteria will be disqualified from entering the study:

• Disease that is suitable for local therapy administered with curative intent.
• 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 study treatment.
• Is currently participating and receiving study therapy or has participated in a study of an investigational agent and received study therapy or used an investigational device within 28 days prior to the first dose of study treatment.
• Has had monoclonal antibody within 28 days of first dose of study treatment or has not recovered from AEs due to agents administered more than 28 days earlier.
• Has had chemotherapy, targeted small molecule therapy, or radiation therapy within 14 days prior to first dose of study treatment or who has not recovered from AEs due to a previously administered agent.
• Note: Subjects with ≤ Grade 2 neuropathy or ≤ Grade 2 alopecia are an exception to this criterion and may qualify for the study.
• Note: If a subject received major surgery, he or she must have recovered adequately from the toxicity and/or complications from the intervention prior to starting study treatment.
• Has received transfusion of blood products (including platelets or red blood cells [RBC]) or administration of colony stimulating factors (including granulocyte colony-stimulating factor, granulocyte macrophage colony-stimulating factor, or recombinant erythropoietin) within 28 days prior to Day 1.
• Evidence of interstitial lung disease or active, noninfectious pneumonitis.
• Has a known additional malignancy that is progressing or requires active treatment. Exceptions include basal cell carcinoma of the skin, squamous cell carcinoma of the skin that has undergone potentially curative therapy, in situ cervical cancer and isolated elevation of prostate-specific antigen. Subjects with a completely treated prior malignancy with no evidence of disease for ≥ 2 years are eligible.
• For Dose escalation cohort: patients with liver metastases, inclusion of patients with liver metastases in subsequent cohorts will be based upon clinical data.
• For Expansion cohort subjects who have previously received an anti-PD-1, anti-PD-L1, or anti#PD-L2 agent or has previously participated in pembrolizumab clinical trials are excluded, except the following tumor types Melanoma, NSCLC and SCCHN (who must show primary progression to anti-PD1/anti-PDL1 therapy).
• Radiation therapy within 14 days of first dose of study treatment.- remove since it's repetitive
• Has active autoimmune disease that has required systemic treatment in past 2 years (i.e., with use of disease modifying agents, corticosteroids, or immunosuppressive drugs). Replacement therapy is not considered a form of systemic treatment.
• Has an active infection requiring systemic therapy.

• Has known central nervous system metastases and/or carcinomatous meningitis.

  o Note: Subjects with previously treated brain metastases may participate if they meet the following criteria: 1) are stable for at least 28 days prior to the first dose of study treatment and if all neurologic symptoms returned to baseline); 2) have no evidence of new or enlarging brain metastases; and 3) have not been using steroids for at least 7 days prior to first dose of study treatment. This exception does not include carcinomatous meningitis, which is excluded regardless of clinical stability.

• Uncontrolled intercurrent illness.
• Refractory nausea and vomiting, malabsorption, external biliary shunt, or significant small bowel resection that would preclude adequate absorption.
• QT interval corrected using Fridericia's formula (QTc) ≥ 450 msec (males) or ≥ 470 msec (females) at Screening.
• Congenital long QT syndrome or patients taking concomitant medications known to prolong the QT interval.
• Major surgery within 28 days prior to first dose of study treatment.
• Has received a live vaccine administered within 30 days prior to first dose of study treatment.
• 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.
• Active and clinically significant bacterial, fungal or viral infection, including hepatitis B virus (HBV), hepatitis C virus (HCV), known human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome related illness (HIV testing is not required), including subjects who have an active infection requiring systemic therapy.
• Any of the following within 48 weeks (~1 year) prior to first dose of study treatment: myocardial infarction, uncontrolled angina, coronary/peripheral artery bypass graft, symptomatic congestive heart failure, cerebrovascular accident or transient ischemic attack.
• Is pregnant or breastfeeding, or expecting to conceive or father children within the projected duration of the trial, starting with the screening visit through 120 days after the last dose of study treatment.
• Has known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial.
• Has had prior exposure to PLX3397.
• Has had hypersensitivity (≥Grade 3) reaction to pembrolizumab and/or any of its excipients.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: TREATMENT
• Allocation: NON_RANDOMIZED
• Interventional Model: SINGLE_GROUP
• Masking: NONE

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: PLX3397 and Pembrolizumab (Part 1); Open-label, sequential PLX3397 dose escalation with a fixed dose of pembrolizumab in approximately 24 patients with advanced solid tumors. (Enrollment complete- 33 enrolled)	Drug: PLX3397; PLX3397 capsules, 200 mg; Other Names: Pexidartinib; Biological: Pembrolizumab; Pembrolizumab, 200 mg, IV; Other Names: Keytruda, MK-3475, SCH 900475
EXPERIMENTAL: PLX3397 and Pembrolizumab (Part 2); Extension cohort at the RP2D of PLX3397 in combination with pembrolizumab in approximately 376 patients with advanced solid tumors (Enrollment Complete- 45 enrolled)	Drug: PLX3397; PLX3397 capsules, 200 mg; Other Names: Pexidartinib; Biological: Pembrolizumab; Pembrolizumab, 200 mg, IV; Other Names: Keytruda, MK-3475, SCH 900475

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Treatment-emergent Adverse Events (TEAEs) in Participants Regardless of Causality While Taking PLX3397 in Combination With Pembrolizumab	Treatment-emergent Adverse Events (TEAEs) in participants regardless of causality while taking PLX3397 in combination with pembrolizumab are reported	1 year (Dose Escalation); 2 years (Dose Expansion)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Summary of the Percentage of Participants With Objective Response Rate Assessed by RECIST v1.1 During Pembrolizumab and PLX3397	Objective response rate was defined as the proportion of subjects who achieved a best disease response of either Complete or Partial (CR or PR) based on the Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.1) for target lesions and assessed generally by MRI, CT, or PET-CT and are summarized as: Complete Response (CR), Disappearance of all target lesions; Partial Response (PR), >=30% decrease in the sum of the longest diameter of target lesions. Participants who discontinued study therapy due to clinical progression, radiographic progression, or death without the required tumor assessments were considered to be non-responders in the Objective Response Rate (ORR) calculation. The efficacy analysis included all subjects with baseline tumor measurements who received at least 1 dose of study drug.	1 year (Dose Escalation); 2 years (Dose Expansion)

Collaborators and Investigators

• Sponsor: Daiichi Sankyo, Inc.
• Collaborators: Merck Sharp & Dohme LLC; Plexxikon

Study record dates

Study Major Dates

• Study Start (ACTUAL): July 2, 2015
• Primary Completion (ACTUAL): August 17, 2018
• Study Completion (ACTUAL): October 12, 2018

Study Registration Dates

• First Submitted: May 20, 2015
• First Submitted That Met QC Criteria: May 20, 2015
• First Posted (ESTIMATE): May 22, 2015

Study Record Updates

• Last Update Posted (ACTUAL): March 5, 2020
• Last Update Submitted That Met QC Criteria: February 18, 2020
• Last Verified: February 1, 2020

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Digestive System Diseases; Neoplasms, Connective and Soft Tissue; Neoplasms by Histologic Type; Neoplasms; Neoplasms by Site; Carcinoma; Neoplasms, Glandular and Epithelial; Gastrointestinal Neoplasms; Digestive System Neoplasms; Gastrointestinal Diseases; Head and Neck Neoplasms; Neuroectodermal Tumors; Neoplasms, Germ Cell and Embryonal; Neoplasms, Nerve Tissue; Neoplasms, Connective Tissue; Neuroendocrine Tumors; Nevi and Melanomas; Carcinoma, Squamous Cell; Gastrointestinal Stromal Tumors; Melanoma; Squamous Cell Carcinoma of Head and Neck; Antineoplastic Agents; Antineoplastic Agents, Immunological; Pembrolizumab
• Other Study ID Numbers: PLX108-14; KEYNOTE-103 (OTHER: Merck Sharp & Dohme Corp.)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: De-identified individual participant data (IPD) and applicable supporting clinical trial documents may be available upon request at https://vivli.org/. In cases where clinical trial data and supporting documents are provided pursuant to our company policies and procedures, Daiichi Sankyo will continue to protect the privacy of our clinical trial participants. Details on data sharing criteria and the procedure for requesting access can be found at this web address: https:// vivli.org/ourmember/daiichi-sankyo/
• IPD Sharing Time Frame: Studies for which the medicine and indication have received European Union (EU) and United States (US), and/or Japan (JP) marketing approval on or after 01 January 2014 or by the US or EU or JP Health Authorities when regulatory submissions in all regions are not planned and after the primary study results have been accepted for publication.
• IPD Sharing Access Criteria: Formal request from qualified scientific and medical researchers on IPD and clinical study documents from clinical trials supporting products submitted and licensed in the United States, the European Union and/or Japan from 01 January 2014 and beyond for the purpose of conducting legitimate research. This must be consistent with the principle of safeguarding study participants' privacy and consistent with provision of informed consent.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No