Safety and Efficacy Study of SL-701, a Glioma-Associated Antigen Vaccine To Treat Recurrent Glioblastoma Multiforme

Study Overview
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Brief Summary
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The purpose of this study is to determine the safety and efficacy of SL-701 as a treatment for recurrent glioblastoma multiform (GBM).

Detailed Description
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This is a multicenter, open-label Phase 1/2 study evaluating the efficacy and safety of SL-701 as a treatment for recurrent GBM, divided into 2 stages. Seventy-four (74) patients were treated in the study, 46 in Stage 1 and 28 in Stage 2, men and women at least 18 years of age, all of whom showed unequivocal evidence of either a first tumor recurrence or progression during or following an initial treatment regimen before enrollment in this study. At least 54 of the 74 treated patients had measurable disease based on contrast-enhanced magnetic resonance imaging or computed tomography scans.

Official Title
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A Phase 1/2 Study of SL-701, a Subcutaneously Injected Multivalent Glioma-Associated Antigen Vaccine, in Adult Patients With Recurrent Glioblastoma Multiforme (GBM)

Conditions
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Adult Brain Glioblastoma, Glioblastoma Multiforme

Intervention / Treatment
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* Drug: SL-701; poly-ICLC (polyinosinic-polycytidylic acid stabilized with polylysine and carboxymethyl cellulose)
* Drug: Bevacizumab
* Drug: SL-701 + GM-CSF
* Drug: Imiquimod


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 18 years of age or older. Histologically confirmed GBM or World Health Organization (WHO) Grade IV variants (gliosarcoma, glioblastoma with oligodendroglial features, or giant cell glioblastoma). Unequivocal evidence of a first tumor recurrence or progression on the initial treatment regimen (prior to enrollment on this study), consisting of surgical intervention (biopsy and/or resection), radiation, and temozolomide chemotherapy, as assessed by MRI or CT scan of the brain with or without contrast within 14 days prior to the start of SL-701. If receiving corticosteroids, the dose must be stable or decreasing for at least 5 days prior to the scan. Patients unable to undergo MRI because of non-compatible devices can be enrolled, provided CT scans are obtained and are of sufficient quality. For each patient, the same imaging technique should be performed throughout the study, for purposes of assessing tumor response or PD. For patients who have undergone resection of recurrent or progressive tumor prior to study enrollment, the following conditions must apply: Recovery from the effects of surgery. Residual disease following resection of recurrent tumor is not mandated for eligibility into the study. To best assess the extent of residual disease post-operatively, an MRI should be performed: No later than 96 hours (h) in the immediate post-operative period; or At least 4 weeks post-craniotomy (7 days for stereotactic biopsy), within 14 days prior to the start of SL-701, and on a corticosteroid dosage that has been stable or decreasing for at least 5 days. Patients who have not had resection of recurrent or progressive disease must have measurable disease. At least 56 of the approximately 76 patients treated must have measurable disease, defined as at least one, contrast-enhancing lesion measuring at least 1 cm in 2 planes (axial, coronal, or sagittal). No evidence of hemorrhage on the baseline MRI or CT scan other than those that are Grade ≤ 1 and either post-operative or stable on at least two consecutive scans. Recovery from prior therapy toxicity, defined as resolution of all treatment-related adverse events (AEs) to Grade ≤ 1 or pre-treatment baseline (except alopecia and lymphopenia). At least 12 weeks from prior radiotherapy to the start of SL-701 unless there is new enhancement outside of the radiation field or unequivocal histopathologic evidence of recurrent tumor subsequent to radiotherapy. No chemotherapy or investigational agent for at least 3 weeks prior to the start of SL-701. Human leukocyte antigen (HLA)-A2 positive. A tumor tissue sample is provided for immunohistochemical analysis of relevant antigens, immune markers and potential prognostic factors. Preferably a paraffin block or 10-12 unstained slides will be submitted prior to study entry. Patients for whom tumor samples are unavailable or inadequate are permitted to participate in the study; however, the absence of available/adequate tumor specimen must be documented. Karnofsky performance status (KPS) score ≥ 70%. Adequate organ function, including the following: Absolute neutrophil count (ANC) ≥ 1,000/μL, platelets ≥ 100,000/μL. Serum creatinine < 1.5 × the upper limit of normal (ULN). Bilirubin < 1.5 × ULN. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) < 2.5 × ULN. Women of childbearing potential must have a negative serum or urine pregnancy test within 3 days prior to the start of SL-701 treatment. Female patients of childbearing potential and sexually active male patients must agree to use an acceptable form of contraception for heterosexual activity (ie, oral contraceptives, double barrier methods, hormonal injectable, transdermal, or implanted contraceptives, tubal ligation, or vasectomy of their sexual partner(s) for > 40 days before Screening, during the study, and for 60 days after the last dose of study drug. Men should not donate semen during the study and for 60 days after the last dose of study drug. Female patients without childbearing potential (spontaneous amenorrhea for > 12 months or surgically sterilized by tubal ligation, hysterectomy, or bilateral oophorectomy > 6 months before Screening) are eligible for inclusion without contraceptive use restriction. Able and willing to comply with protocol requirements, in the opinion of the investigator. A written and voluntarily signed informed consent must be obtained from the patient or legally authorized representative, in accordance with local regulations, before the initiation of any study related procedures. The patient or legally authorized representative must be able to read and understand the informed consent form (ICF). Exclusion Criteria: Prior cancer chemotherapy, bevacizumab (or other vascular endothelial growth factor [VEGF]/VEGF receptor [VEGFR]-directed agent), or an investigational agent for recurrent/progressive GBM or prior bevacizumab as part of initial therapy (prior chemotherapy or investigational agents are permitted as part of initial therapy; VEGF/VEGFR-directed agents are not permitted). Contrast-enhancing tumor that is any of the following: Multi-focal (defined as two separate areas of contrast enhancement measuring at least 1 cm in 2 planes that are not contiguous on either fluid-attenuated inversion recovery (FLAIR) or T2 sequences); Associated with either diffuse subependymal or leptomeningeal dissemination; or ≥ 4 cm in any dimension. Requirement of systemic corticosteroid therapy > 4 mg/day of dexamethasone or equivalent or requirement of increasing dose of systemic corticosteroids during the 7 days prior to the start of SL-701 treatment. Surgical resection or major surgical procedure within 4 weeks prior to the start of SL-701, or stereotactic biopsy within 7 days prior to the start of SL-701. Radiation therapy, local therapy (except for surgical re-resection), or systemic therapy following first recurrence/progressive disease. Excluded local therapies include stereotactic radiation boost, implantation of carmustine biodegradable wafers (Gliadel), intratumoral or convection-enhanced delivery administered agents, etc. Active infection requiring intravenous antibiotics. History of cancer (other than GBM) within the past 2 years that has metastatic or local recurrence potential and could negatively impact survival and/or potentially confound tumor response assessments within this study. Clinically significant cardiovascular disease (eg, uncontrolled or any New York Heart Association Class 3 or 4 congestive heart failure, uncontrolled angina, history of myocardial infarction or stroke within 6 months of study entry, uncontrolled hypertension or clinically significant arrhythmias not controlled by medication). Known immunosuppressive disease or active systemic autoimmune disease such as systemic lupus erythematosus, human immunodeficiency virus infection, Hepatitis B, or Hepatitis C, or has taken an immunosuppressive agent within 4 weeks prior to the start of SL-701 treatment. Patients with vitiligo, type 1 diabetes mellitus, hypothyroidism due to autoimmune condition only requiring hormone replacement therapy, psoriasis not requiring systemic therapy, or conditions not expected to recur in the absence of an external trigger are permitted to enroll. Any condition which in the investigator's opinion makes the patient unsuitable for study participation. Requires therapeutic anticoagulation with warfarin at baseline; patients must be off warfarin or warfarin-derivative anti-coagulants for at least 7 days prior to starting study drug; however, therapeutic or prophylactic therapy with low-molecular weight heparin is allowed. Has history of known coagulopathy that increases risk of bleeding or a history of clinically significant hemorrhage within 12 months of start of study drug. Has evidence of intratumoral or peritumoral hemorrhage on baseline MRI scan other than those that are ≤Grade 1 and either post-operative or stable on at least 2 consecutive MRI scans Has gastrointestinal bleeding or any other hemorrhage/bleeding event National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) >Grade 3 within 6 months of start of study drug.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: SL-701 + GM-CSF + Imiquimod<br>Patients will receive SL-701 with the vaccine adjuvants granulocyte macrophage-colony stimulating factor (GM-CSF) injection and imiquimod topical cream. A complete dose of study drug consists of the administration of a sequence of 3 agents, SL-701 emulsion SC injection, GM-CSF SC injection, and imiquimod topical cream, within a 5-minute time frame. Topical application of imiquimod cream at the injection site is repeated at 24 hours after each SL-701 emulsion injection. For each patient, SL-701 emulsion (SL-701 in Montanide®) will be administered by SC injection beginning on Day 1 with imiquimod topical cream 5% applied immediately (within 5 minutes after SL-701 emulsion injection) to the SL-701 emulsion injection site. In addition to the SL-701 emulsion injection, the patient will receive a SC injection of GM-CSF 150 μg close to the injection site of SL-701 emulsion. An additional dose of imiquimod cream will be applied at the same site by the patient 24 hours later. | Drug: SL-701 + GM-CSF<br>* 1.0 mL injection taken from 0.7 mL of SL-701 mixed at a 1:1 (v/v) ratio with 0.7 mL of Montanide. Preferred site of SC injection is in the right or left upper arms. 150 μg GM-CSF should be administered as a SC injection immediately after SL-701 emulsion administration and within 1 cm from the center of the SL-701 emulsion injection site.<br>Drug: Imiquimod<br>* Within 5 minutes following the administration of the SL-701 emulsion, approximately 125 mg of imiquimod cream will be applied topically on the injection site. The imiquimod cream should be rubbed in until the cream is no longer visible.<br>|
| Experimental: SL-701; poly-ICLC 1.6mg; bevacizumab<br>SL-701 emulsion and the adjuvant poly-ICLC will be administered twice weekly for the initial 2 weeks, every 7 days during the subsequent 3 doses, and subsequently every 14 days for the subsequent 9 doses (16 doses total) through Week 22, and every 4 weeks thereafter. Bevacizumab will be administered every 2 weeks, subsequent to the administration of SL-701/poly-ICLC. | Drug: SL-701; poly-ICLC (polyinosinic-polycytidylic acid stabilized with polylysine and carboxymethyl cellulose)<br>* 1.0 mL injection taken from 0.7 mL of SL-701 mixed at a 1:1 (v/v) ratio with 0.7 mL of Montanide. Preferred site of SC injection is in the right or left upper arms. Within 20 minutes following the administration of the SL-701 emulsion, poly-ICLC should be administered as an IM injection in the same extremity (within 3 cm whenever possible) as was administered the SL-701 (deltoid muscle, unless contraindicated).<br>* Other names: Avastin;Drug: Bevacizumab<br>* Following the administration of SL-701 and poly-ICLC, bevacizumab will be administered IV at a dose of 10 mg/kg. Bevacizumab infusions may occur over 30, 60 or 90 minutes in accordance with institutional practices and guidelines.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Overall Survival at 12 Months (OS-12) | OS-12 after the initiation of SL-701, per Kaplan-Meier estimate. | up to 12 months | 
| Objective Response Rate (ORR) | The ORR was the percentage of subjects who had at least 1 overall tumor response of CR or PR documented on 2 consecutive MRIs ≥4 weeks apart by modified Response Assessment in Neuro-Oncology criteria. | 3 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Complete Response (CR) or Partial Response (PR) | Measure the number of subjects with a CR or PR. A CR requires all of the following: complete disappearance of all enhancing measurable and nonmeasurable disease sustained for at least 4 weeks; no new lesions; and stable or improved nonenhancing (T2/FLAIR) lesions. Patients must be off corticosteroids (or on physiologic replacement doses only) and stable or improved clinically. A PR requires all of the following: ≥50% decrease, compared with baseline; the sum of products of perpendicular diameters of all measurable enhancing lesions sustained for at least 4 weeks; no progression of nonmeasurable disease; no new lesions; stable or improved nonenhancing (T2/FLAIR) lesions on the same or a lower dose of corticosteroids compared with baseline scan; and the patient being on a corticosteroid dose not greater than the dose at time of the baseline scan and stable or improved clinically. | 3 years | 
| Progression-free Survival at 6 Months (PFS-6) | Estimate the percent of patients alive and progression-free survival at 6 months (PFS-6) after the initiation of SL-701. | Up to 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Glioma Associated Antigen, Vaccine, Adult, Recurrent Glioblastoma, Immunotherapy