INI1-negative Tumors, Malignant Rhabdoid Tumor of Ovary, Rhabdoid Tumors, Synovial Sarcoma
Conditions
Brief summary
This is a Phase I, open-label, dose escalation and dose expansion study with BID (suspension) and TID (tablet) oral dose of the enhancer of zeste homolog-2 (EZH2) inhibitor, tazemetostat. Subjects will be screened for eligibility within 14 days of the planned first dose of tazemetostat. A treatment cycle will be 28 days. Response assessment will be evaluated after 8 weeks of treatment and subsequently every 8 weeks while on study.
Detailed description
The study has two parts: Dose Escalation and Dose Expansion. Dose escalation for subjects with the following relapsed/refractory malignancies: * Rhabdoid tumors: * Atypical teratoid rhabdoid tumor (ATRT) * Malignant rhabdoid tumor (MRT) * Rhabdoid tumor of kidney (RTK) * Selected tumors with rhabdoid features * Integrase interactor 1 (INI1)-negative tumors: * Epithelioid sarcoma * Epithelioid malignant peripheral nerve sheath tumor * Extraskeletal myxoid chondrosarcoma * Myoepithelial carcinoma * Renal medullary carcinoma * Other INI1-negative malignant tumors (e.g., dedifferentiated chordoma) * Synovial Sarcoma with a SS18-SSX rearrangement Dose Escalation cohorts are closed to enrollment. Dose Expansion at the maximum tolerated dose (MTD) or the recommended phase 2 dose (RP2D) * Cohort 1 - ATRT * Cohort 2 - MRT/RTK/selected tumors with rhabdoid features * Cohort 3 - INI-negative tumors: * Epithelioid sarcoma * Epithelioid malignant peripheral nerve sheath tumor * Extraskeletal myxoid chondrosarcoma * Myoepithelial carcinoma * Renal medullary carcinoma * Chordoma (poorly differentiated or de-differentiated) * Other INI1-negative malignant tumors (e.g., dedifferentiated chordoma) * Cohort 4 - Tumor types eligible for Cohorts 1 through 3 or synovial sarcoma with SS18-SSX rearrangement
Interventions
DRUGTazemetostat
Tazemetostat (EPZ-6438) is a selective small molecule inhibitor of the histone-lysine methyltransferase EZH2 gene.
Sponsors
Epizyme, Inc.
Study design
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Intervention model description
Participants were enrolled either to the dose escalation or the dose expansion portion of the study. Participants in the dose expansion portion of the study were separated into cohorts based on their disease-type.
Eligibility
Sex/Gender
ALL
Age
6 Months to 17 Years
Healthy volunteers
No
Inclusion criteria
1. Age (at the time of consent/assent): ≥6 months to \<18 years \- Cohort 4 only: ≥10 years to \<18 years 2. Performance Status: * If \<12 years of age: Lanksy Performance Status \>50% * If ≥12 years of age: Karnofsky Performance Status \>50% NOTE: If subject is unable to walk due to paralysis, but is mobile in a wheelchair, subject is considered to be ambulatory for the purpose of assessing their performance status. 3. Has provided signed written informed consent/assent 4. Has a life expectancy of \>3 months 5. Has relapsed or refractory disease and no standard treatment options as determined by locally or regionally available standards of care and treating physician's discretion 6. Is ineligible or inappropriate for other treatment regimens known to have effective potential 7. Has a documented local diagnostic pathology of original biopsy confirmed by a Clinical Laboratory Improvement Amendments (CLIA)/College of American Pathologists (CAP) or equivalent laboratory certification 8. Has all prior treatment (i.e., chemotherapy, immunotherapy, radiotherapy) related clinically significant toxicities resolve to ≤ Grade 1 per CTCAE, version 4.03 or are clinically stable and not clinically significant, at time of enrollment 9. Has completed a prior therapy (ies) according to the criteria below: * Other investigational study agent (any medicinal product that is not approved in the country of treatment for any indication, adult or pediatric) (At least 30 days or five half-lives, whichever is longer, since last dose prior to the first dose of tazemetostat) * Chemotherapy: cytotoxic (At least 14 days since last dose of chemotherapy prior to first dose of tazemetostat) * Chemotherapy: nitrosoureas (At least 6 weeks since last dose of nitrosoureas prior to first dose of tazemetostat) * Chemotherapy: non-cytotoxic (e.g., small molecule inhibitor) (At least 14 days since last dose of non-cytotoxic chemotherapy prior to first dose of tazemetostat) * Monoclonal antibody (ies) (At least 28 days since the last dose of any monoclonal antibody prior to first dose of tazemetostat) * Immunotherapy (e.g., tumor vaccine) At least 6 weeks since last dose of immunotherapy agent(s) prior to first dose of tazemetostat) * Radiotherapy (RT) (At least 14 days from last local site RT prior to first dose of tazemetostat/At least 21 days from stereotactic radiosurgery prior to first dose of tazemetostat/At least 12 weeks from craniospinal, ≥ 50% radiation of pelvis, or total body irradiation prior to first dose of tazemetostat) * Hematopoietic growth factor (At least 14 days from last dose of hematopoietic growth factor prior to first dose of tazemetostat) * Hematopoietic cell transplantation (At least 60 days from infusion of hematopoietic cells prior to first dose of tazemetostat) 10. Has adequate hematologic (bone marrow and coagulation factors), renal and hepatic function as defined by criteria below: * Hematologic (BM Function): * Hemoglobin ≥ 8 g/dL * Platelets ≥100,000/mm\^3 (≥100 x 10\^9/L) * ANC ≥1,000/mm\^3 (≥1.0 x 10\^9/L) * Hematologic (Coagulation Factors): * INR/ PTd ≤1.5 ULN * PTT ≤1.5 ULN * Fibrinogen ≥0.75 LLN * Renal Function (creatinine clearance or serum creatinine): * Calculated creatinine clearance ≥50 mL/min/1.73m\^2 * Serum creatinine 6 months to 1 year: male 0.6 mg/dL (53 µmol/L) female 0.5 mg/dL (44 µmol/L) * Serum creatinine 1 to \< 2 years: male 0.6 mg/dL (53 µmol/L) female 0.6 mg/dL (53 µmol/L) * Serum creatinine 2 to \< 6 years: male 0.8 mg/dL (71 µmol/L) female 0.8 mg/dL (71 µmol/L) * Serum creatinine 6 to \<10 years: male 1 mg/dL (88 µmol/L) female 1 mg/dL (88 µmol/L) * Serum creatinine 10 to \<13 years: male 1.2 mg/dL (106 µmol/L) female 1.2 mg/dL (106 µmol/L) * Serum creatinine 13 to \<16 years: male 1.5 mg/dL (133 µmol/L) female 1.4 mg/dL (125 µmol/L) * Serum creatinine ≥16 years: male 1.7 mg/dL (150 µmol/L) female 1.4 mg/dL (125 µmol/L) * Hepatic Function: * Total bilirubin \<1.5 x ULN * ALT or AST \<3 x ULN Eligibility can be determined by either total or conjugated bilirubin 11. For subjects with CNS involvement: Subjects must have deficits that are stable for a minimum of 14 days prior to enrollment, or seizures that are stable, not increasing in frequency or severity and controlled on current anti-seizure medication(s) for a minimum of 7 days prior to enrollment NOTE: Subjects with leptomeningeal disease or brain tumors with positive cerebral spinal fluid cytology are eligible for this study. Subjects may receive glucocorticoids (at stable or tapering dose) to control CNS symptoms prior to enrollment; however, subjects should receive a stable or tapering dose for at least 7 days prior to enrollment. 12. Has a shortening fraction of \>27% or an ejection fraction of ≥50% by echocardiogram or multi-gated acquisition scan and New York Heart Association Class\<2 13. Has a QT interval corrected by Fridericia's formula (QTcF) ≤450 msec 14. Is able to swallow and retain orally administered medication and does not have any uncontrolled gastrointestinal (GI) condition such as nausea, vomiting, or diarrhea, or any clinically significant GI abnormalities that may alter absorption such as malabsorption syndromes, hereditary fructose intolerance, glucose-galactose malabsorption, sucrose-isomaltase insufficiency, or major resection of stomach and/or bowels NOTE: Nasogastric and gastrostomy tube administration of the oral suspension formulation of study drug is permitted. 15. Has sufficient tumor tissue (slides or blocks) available for central confirmatory testing of immunohistochemistry and/or cytogenetics/fluorescence in situ hybridization (FISH) and/or deoxyribonucleic acid mutation analysis (required for study entry but enrollment based on local results) 16. Is willing and able to comply with all aspects of the protocol as judged by Investigator 17. For female subjects of childbearing potential: Subject must: * Have a negative beta-human chorionic gonadotropin (β-hCG) pregnancy test at time of Screening and within 72 hours prior to planned first dose of tazemetostat (urine or serum test is acceptable however, positive urine tests must be confirmed with serum testing), and * Agree to use effective contraception, as defined in Section 8.6.11 start of Screening until 6 months following the last dose of study treatment and have a male partner who uses a condom, or * Practice true abstinence (when this is in line with the preferred and usual lifestyle of the subject, see Section 8.6.11, or * Have a male partner who is vasectomized with confirmed azoospermia 18. For male subjects with a female partner of childbearing potential: Subject must: * Be vasectomized or * Agree to use condoms as defined in Section 8.5.11 from first dose of tazemetostat until 3 months following the last dose of tazemetostat, or * Have a female partner who is NOT of childbearing potential For Dose Escalation Only: To be eligible for enrollment in dose escalation, a subject must meet ALL of the following criteria in addition to the inclusion criteria listed above for all subjects: 1. Has evaluable disease as defined as lesions that can be accurately measured at least in one dimension by radiographic examination or physical examination and other lesions such as bone lesions, leptomeningeal disease, ascites, hepatosplenomegaly from disease. 2. Has one of the following histologically confirmed tumors: (NOTE: Evidence of diagnostic pathology of original biopsy confirmed by a CLIA/CAP certified laboratory must be available) * Rhabdoid tumor: * ATRT * MRT * RTK * Selected tumors with rhabdoid features * NI1-negative tumor: * Epithelioid sarcoma * Epithelioid malignant peripheral nerve sheath tumor * Extraskeletal myxoid chondrosarcoma * Myoepithelial carcinoma * Renal medullary carcinoma * Other INI1-negative malignant tumors (e.g., dedifferentiated chordoma) with Sponsor approval * Synovial sarcoma with SS18-SSX rearrangement (NOTE: Evidence of diagnostic pathology of original biopsy confirmed by a CLIA/CAP certified laboratory must be available) (Closed to enrollment) 3. For subjects with ATRT, MRT, RTK, or selected tumors with rhabdoid features only: the following test results must be available: Morphology and immunophenotypic panel consistent with rhabdoid tumor and Loss of INI1 or SMARCA4 confirmed by IHC, or Molecular confirmation of tumor bi-allelic INI1 or SMARCA4 loss/mutation when INI1 or SMARCA4 IHC is equivocal or unavailable 4. For subjects with INI1 negative tumor only: the following test results must be available: Morphology and immunophenotypic panel consistent with INI1-negative tumors, and Loss of INI1 confirmed by IHC, or Molecular confirmation of tumor bi-allelic INI1 loss/mutation when INI1 IHC is equivocal or unavailable 5. For subjects with synovial sarcoma only: The following test results must be available: Morphology consistent with synovial sarcoma, and Cytogenetics or FISH and/or molecular confirmation (e.g., DNA sequencing) of SS18 rearrangement t(X;18)(p11;q11) For Dose Expansion Only: Note: To be eligible for enrollment in Dose Expansion, a subject must meet ALL of the following criteria in addition to the inclusion criteria for ALL subjects listed above 1. Has measurable disease 2. Has one of the following histologically confirmed tumors: * Cohort 1 - ATRT (Closed to enrollment) * Cohort 2 - MRT/RTK/selected tumors with rhabdoid features (Closed to enrollment) * Cohort 3 - INI-negative tumors (Closed to enrollment): * Epithelioid sarcoma * Epithelioid malignant peripheral nerve sheath tumor * Extraskeletal myxoid chondrosarcoma(EMC) * Myoepithelial carcinoma * Renal medullary carcinoma * Chordoma (poorly differentiated or de-differentiated) * Other INI1-negative malignant tumors (e.g., dedifferentiated chordoma) with Sponsor approval * Cohort 4 - Tumor types eligible for Cohorts 1 through 3 or synovial sarcoma with SS18-SSX rearrangement (Closed to enrollment) NOTE: Evidence of diagnostic pathology of original biopsy confirmed by a CLIA/CAP or other Sponsor-approved certified laboratory must be available. 3. For subjects with ATRT/MRT/RTK only - have the following test results available: * Morphology and immunophenotypic panel consistent with rhabdoid tumor, and * Loss of INI1 or SMARCA4 confirmed by IHC, or * Molecular confirmation of tumor bi-allelic INI1 or SMARCA4 loss/mutation when INI1 or SMARCA4 IHC is equivocal or unavailable 4. For subjects with INI1-negative tumors only: The following test results must be available: * Morphology and immunophenotypic panel consistent with INI1-negative tumors, and * Loss of INI1 confirmed by IHC, or * Molecular confirmation of tumor bi-allelic INI1 loss/mutation when INI1 IHC is equivocal or unavailable 5. For subjects with synovial sarcoma with SS18-SSX rearrangement (in Cohort 4 ONLY - Closed to enrollment): The following test results must be available: * Morphology consistent with synovial sarcoma, and * Cytogenetics or FISH and/or molecular confirmation (e.g., deoxyribonucleic acid \[DNA\] sequencing) of SS18 rearrangement t(X;18)(p11;q11) 6. For subjects to be enrolled in Cohort 4 (Closed to enrollment): Able to swallow and retain orally administered tablets
Exclusion criteria
1. Has had prior exposure to tazemetostat or other inhibitor(s) of EZH2 2. Is being actively treated for another concurrent malignancy or is less than five years from completion of treatment for another malignancy 3. Has participated in another interventional clinical study and received investigational drug within 30 days or 5 half-lives, whichever is longer, prior to the planned first dose of tazemetostat 4. Has had major surgery within 2 weeks prior to enrollment NOTE: Minor surgery (e.g., minor biopsy of extracranial site, central venous catheter placement, shunt revision) is permitted within 2 weeks prior to enrollment. 5. Has thrombocytopenia, neutropenia, or anemia of Grade ≥3 (per CTCAE 4.03 criteria) or any prior history of myeloid malignancies, including myelodysplastic syndrome (MDS). Has abnormalities known to be associated with MDS (e.g. del 5q, chr 7 abn) and MPN (e.g. JAK2 V617F) observed in cytogenetic testing and DNA sequencing. Note: Bone marrow aspirate/biopsy will be conducted following abnormal peripheral blood smear morphology assessment conducted by central lab at screening. Cytogenetic testing and DNA sequencing will be conducted following an abnormal result of bone marrow aspirate/biopsy. 6. Has a prior history of T-LBL/T-ALL. 7. Has clinically active heart disease including prolonged corrected QTcF (\>450 msec) 8. Is currently taking any prohibited medication(s) as described in Section 7.3. 9. Is unwilling to exclude grapefruit juice, Seville oranges and grapefruit from the diet and all foods that contain those fruits from time of enrollment to while on study 10. Has an active infection requiring systemic treatment 11. Is immunocompromised (i.e. congenital immunodeficiencies), including subjects known history of infection with human immunodeficiency virus (HIV) 12. Has known history of chronic infection with hepatitis B virus (hepatitis B surface antigen positive) or hepatitis C virus (detectable HCV RNA) 13. Has had a symptomatic venous thrombosis within the 14 days prior to study enrollment NOTE: Subjects with a history of a deep vein thrombosis 14 days prior to study enrollment who are on anticoagulation therapy with low molecular weight heparin are eligible for this study 14. For subjects with CNS involvement (primary tumor or metastatic disease): Have any active bleeding, or new intratumoral hemorrhage of more than punctate size on Screening MRI obtained within 14 days of starting study drug,or known bleeding diathesis or treatment with anti-platelet or anti-thrombotic agents 15.15. Has known hypersensitivity to any of the components of tazemetostat or other inhibitor(s) of EZH2, or hypersensitivity to Ora-sweet or methylparaben 16\. Has an uncontrolled intercurrent illness including, but not limited to, uncontrolled infection, or psychiatric illness/social situations that would limit compliance with study requirements 17. For female subjects of childbearing potential: Is pregnant or nursing For male subjects: Is unwilling to adhere to contraception criteria from time of enrollment in study to at least 30 days after last dose of tazemetostat.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Recommended Phase 2 Dose (RP2D) (Dose Escalation Only) | Cycle 1, from the start of study treatment (Day 1) until the end of the first Cycle (Day 28) of treatment | The incidence and severity of treatment-emergent adverse events qualifying as protocol-defined dose-limiting toxicities that occurred during the first month of treatment was used to determine the RP2D and/or maximum tolerated dose (MTD) in pediatric patients treated with tazemetostat. |
| Number of Dose-limiting Toxicities (Dose Escalation Only) | Cycle 1, from the start of study treatment (Day 1) until the end of the first Cycle (Day 28) of treatment | The RP2D in pediatric patients treated with tazemetostat as determined by the incidence and severity of treatment-emergent adverse events qualifying as protocol-defined dose-limiting toxicities that occurred during the first month of treatment. |
| Overall Response Rate (ORR) (Dose Expansion Only) | RECIST assessments performed at screening (within 14 days before start of study intervention) and every 8 weeks post start of dosing, approximately up to 302 weeks | ORR is defined as the percentage of patients who achieved a confirmed complete response (CR) and/or partial response (PR) defined by response evaluation criteria in solid tumors (RECIST) or response assessment in neuro-oncology (RANO) criteria from the start of tazemetostat treatment until disease progression or the start of subsequent anticancer therapy, whichever occurs first. CR is defined as disappearance of all target and non-target lesions (with all lymph nodes must be non-pathological in size or under 10 millimeters \[mm\] in short axis) and PR is defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters. ORR= CR+PR. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| ORR (Dose Escalation Only) | RECIST assessments performed at screening (within 14 days before start of study intervention) and every 8 weeks post start of dosing, approximately up to 302 weeks | ORR is defined as the percentage of patients who achieved a confirmed CR and/or PR defined by RECIST or RANO criteria from the start of tazemetostat treatment until disease progression or the start of subsequent anticancer therapy, whichever occurs first. CR is defined as disappearance of all target and non-target lesions (with all lymph nodes must be non-pathological in size or under 10 mm in short axis) and PR is defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters. ORR= CR+PR. |
| Progression Free Survival (PFS) (Dose Expansion Only) | RECIST assessments performed at screening (within 14 days before start of study intervention) and every 8 weeks post start of dosing, approximately up to 302 weeks | PFS was defined as the interval of time (in weeks) from the date of first dose of study drug and the earliest date of disease progression or death, from any cause defined by RECIST or RANO criteria. Disease progression is defined as at least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study (including at least a 5 mm absolute increase). The presence of new lesions also constitutes to disease progression. |
| Overall Survival (Dose Expansion Only) | RECIST assessments performed at screening (within 14 days before start of study intervention) and every 8 weeks post start of dosing, approximately up to 302 weeks | Overall survival was defined as the time (in weeks) from the first dose of study drug to the date of death due to any cause. |
Countries
Australia, Canada, Denmark, France, Germany, Italy, Netherlands, United Kingdom, United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Dose Escalation Level 1 Patients with relapsed/refractory rhabdoid tumors, INI1-negative tumors, or synovial sarcoma with SS18-SSX rearrangement received oral tazemetostat 240 mg/m\^2 BID in continuous 28-day cycles. | 8 |
| Dose Escalation Level 2 Patients with relapsed/refractory rhabdoid tumors, INI1-negative tumors, or synovial sarcoma with SS18-SSX rearrangement received oral tazemetostat 300 mg/m\^2 BID in continuous 28-day cycles. | 6 |
| Dose Escalation Level 3 Patients with relapsed/refractory rhabdoid tumors, INI1-negative tumors, or synovial sarcoma with SS18-SSX rearrangement received oral tazemetostat 400 mg/m\^2 BID in continuous 28-day cycles. | 6 |
| Dose Escalation Level 4 Patients with relapsed/refractory rhabdoid tumors, INI1-negative tumors, or synovial sarcoma with SS18-SSX rearrangement received oral tazemetostat 520 mg/m\^2 BID in continuous 28-day cycles. | 7 |
| Dose Escalation Level 5 Patients with relapsed/refractory rhabdoid tumors, INI1-negative tumors, or synovial sarcoma with SS18-SSX rearrangement received oral tazemetostat 700 mg/m\^2 BID in continuous 28-day cycles. | 6 |
| Dose Escalation Level 6 Patients with relapsed/refractory rhabdoid tumors, INI1-negative tumors, or synovial sarcoma with SS18-SSX rearrangement received oral tazemetostat 900 mg/m\^2 BID in continuous 28-day cycles. | 6 |
| Dose Escalation Level 7 Patients with relapsed/refractory rhabdoid tumors, INI1-negative tumors, or synovial sarcoma with SS18-SSX rearrangement received oral tazemetostat 1200 mg/m\^2 BID in continuous 28-day cycles. | 7 |
| Dose Expansion Cohort 1 Patients with ATRT who participated in the dose expansion portion of the study received 1200 mg/m\^2 open-label, tazemetostat BID orally in continuous 28-day cycles. | 19 |
| Dose Expansion Cohort 2 Patients with MRT/ RTK/select tumors with rhabdoid features who participated in the dose expansion portion of the study. Patients whose disease was without CNS involvement received 520 mg/m\^2 open-label, tazemetostat BID orally in continuous 28-day cycles. Patients whose disease had CNS involvement received 1200 mg/m\^2 open-label, tazemetostat BID orally in continuous 28-day cycles. | 20 |
| Dose Expansion Cohort 3 Patients with INI-negative tumors who participated in the dose expansion portion of the study.
Patients whose disease was without CNS involvement received 520 mg/m\^2 open-label, tazemetostat BID orally in continuous 28-day cycles. Patients whose disease had CNS involvement received 1200 mg/m\^2 open-label, tazemetostat BID orally in continuous 28-day cycles. | 18 |
| Dose Expansion Cohort 4 Patients with one of the tumor types defined in Cohorts 1 through 3 or synovial sarcoma with SS18-SSX rearrangement received 800 mg/m\^2 tazemetostat TID orally in continuous 28-day cycles. | 6 |
| Total | 109 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 | FG002 | FG003 | FG004 | FG005 | FG006 | FG007 | FG008 | FG009 | FG010 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Period 1: Dose Escalation Phase | Adverse Event | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 |
| Period 1: Dose Escalation Phase | Patient refused further treatment of study drug | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 |
| Period 1: Dose Escalation Phase | Progressive disease | 7 | 6 | 5 | 6 | 6 | 4 | 6 | 0 | 0 | 0 | 0 |
| Period 1: Dose Escalation Phase | Unacceptable toxicity | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Period 2: Dose Expansion Cohort | Adverse Event | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 |
| Period 2: Dose Expansion Cohort | Death | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 |
| Period 2: Dose Expansion Cohort | Other | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 2 | 0 |
| Period 2: Dose Expansion Cohort | Patient refused further treatment of study drug | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 0 | 0 | 0 |
| Period 2: Dose Expansion Cohort | Physician Decision | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 |
| Period 2: Dose Expansion Cohort | Progressive disease | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 16 | 17 | 14 | 4 |
Baseline characteristics
| Characteristic | Dose Escalation Level 2 | Dose Escalation Level 3 | Dose Escalation Level 4 | Dose Escalation Level 5 | Dose Escalation Level 6 | Dose Escalation Level 7 | Dose Expansion Cohort 1 | Dose Expansion Cohort 2 | Dose Expansion Cohort 3 | Dose Escalation Level 1 | Dose Expansion Cohort 4 | Total |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Age, Categorical <=18 years | 6 Participants | 6 Participants | 7 Participants | 6 Participants | 6 Participants | 7 Participants | 19 Participants | 20 Participants | 17 Participants | 8 Participants | 4 Participants | 106 Participants |
| Age, Categorical >=65 years | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical Between 18 and 65 years | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 1 Participants | 0 Participants | 2 Participants | 3 Participants |
| Age, Continuous | 11.5 years STANDARD_DEVIATION 5.24 | 4.6 years STANDARD_DEVIATION 3.98 | 4.5 years STANDARD_DEVIATION 3.5 | 7.0 years STANDARD_DEVIATION 4.82 | 4.0 years STANDARD_DEVIATION 2.79 | 4.8 years STANDARD_DEVIATION 4.97 | 4.4 years STANDARD_DEVIATION 4.25 | 3.4 years STANDARD_DEVIATION 3.31 | 12.8 years STANDARD_DEVIATION 5.26 | 2.5 years STANDARD_DEVIATION 1.89 | 14.7 years STANDARD_DEVIATION 3.61 | 6.6 years STANDARD_DEVIATION 5.66 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 0 Participants | 3 Participants | 0 Participants | 1 Participants | 0 Participants | 1 Participants | 5 Participants | 2 Participants | 4 Participants | 0 Participants | 1 Participants | 17 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 4 Participants | 2 Participants | 7 Participants | 4 Participants | 5 Participants | 5 Participants | 13 Participants | 14 Participants | 12 Participants | 8 Participants | 5 Participants | 79 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 2 Participants | 1 Participants | 0 Participants | 1 Participants | 1 Participants | 1 Participants | 1 Participants | 4 Participants | 2 Participants | 0 Participants | 0 Participants | 13 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants | 1 Participants | 1 Participants | 0 Participants | 1 Participants | 0 Participants | 0 Participants | 1 Participants | 0 Participants | 0 Participants | 0 Participants | 4 Participants |
| Race (NIH/OMB) Black or African American | 0 Participants | 0 Participants | 1 Participants | 1 Participants | 1 Participants | 1 Participants | 2 Participants | 0 Participants | 1 Participants | 1 Participants | 0 Participants | 8 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 1 Participants | 0 Participants | 1 Participants | 0 Participants | 1 Participants | 3 Participants | 7 Participants | 3 Participants | 0 Participants | 2 Participants | 18 Participants |
| Race (NIH/OMB) White | 6 Participants | 4 Participants | 5 Participants | 4 Participants | 4 Participants | 5 Participants | 14 Participants | 12 Participants | 14 Participants | 7 Participants | 4 Participants | 79 Participants |
| Sex: Female, Male Female | 4 Participants | 5 Participants | 5 Participants | 2 Participants | 4 Participants | 2 Participants | 12 Participants | 7 Participants | 11 Participants | 4 Participants | 3 Participants | 59 Participants |
| Sex: Female, Male Male | 2 Participants | 1 Participants | 2 Participants | 4 Participants | 2 Participants | 5 Participants | 7 Participants | 13 Participants | 7 Participants | 4 Participants | 3 Participants | 50 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk | EG003 affected / at risk | EG004 affected / at risk | EG005 affected / at risk | EG006 affected / at risk | EG007 affected / at risk | EG008 affected / at risk | EG009 affected / at risk | EG010 affected / at risk |
|---|---|---|---|---|---|---|---|---|---|---|---|
| deaths Total, all-cause mortality | 7 / 8 | 6 / 6 | 4 / 6 | 4 / 7 | 5 / 6 | 4 / 6 | 7 / 7 | 15 / 19 | 18 / 20 | 16 / 18 | 4 / 6 |
| other Total, other adverse events | 8 / 8 | 5 / 6 | 6 / 6 | 7 / 7 | 6 / 6 | 6 / 6 | 6 / 7 | 19 / 19 | 19 / 20 | 18 / 18 | 6 / 6 |
| serious Total, serious adverse events | 4 / 8 | 1 / 6 | 3 / 6 | 2 / 7 | 3 / 6 | 4 / 6 | 2 / 7 | 12 / 19 | 10 / 20 | 9 / 18 | 3 / 6 |
Outcome results
Primary
Number of Dose-limiting Toxicities (Dose Escalation Only)
The RP2D in pediatric patients treated with tazemetostat as determined by the incidence and severity of treatment-emergent adverse events qualifying as protocol-defined dose-limiting toxicities that occurred during the first month of treatment.
Time frame: Cycle 1, from the start of study treatment (Day 1) until the end of the first Cycle (Day 28) of treatment
Population: Dose-Limiting Toxicity (DLT) population included all patients in the safety population set who experienced a DLT during Cycle 1 or were not removed from Cycle 1 for reasons other than toxicity and did not have an interruption in study treatment for more than 14 days during Cycle 1. Only those patients with data collected at Cycle 1 are reported.
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| Overall Dose Escalation | Number of Dose-limiting Toxicities (Dose Escalation Only) | 0 Participants |
| Dose Escalation Level 2 | Number of Dose-limiting Toxicities (Dose Escalation Only) | 1 Participants |
| Dose Escalation Level 3 | Number of Dose-limiting Toxicities (Dose Escalation Only) | 0 Participants |
| Dose Escalation Level 4 | Number of Dose-limiting Toxicities (Dose Escalation Only) | 0 Participants |
| Dose Escalation Level 5 | Number of Dose-limiting Toxicities (Dose Escalation Only) | 0 Participants |
| Dose Escalation Level 6 | Number of Dose-limiting Toxicities (Dose Escalation Only) | 1 Participants |
| Dose Escalation Level 7 | Number of Dose-limiting Toxicities (Dose Escalation Only) | 0 Participants |
Primary
Overall Response Rate (ORR) (Dose Expansion Only)
ORR is defined as the percentage of patients who achieved a confirmed complete response (CR) and/or partial response (PR) defined by response evaluation criteria in solid tumors (RECIST) or response assessment in neuro-oncology (RANO) criteria from the start of tazemetostat treatment until disease progression or the start of subsequent anticancer therapy, whichever occurs first. CR is defined as disappearance of all target and non-target lesions (with all lymph nodes must be non-pathological in size or under 10 millimeters \[mm\] in short axis) and PR is defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters. ORR= CR+PR.
Time frame: RECIST assessments performed at screening (within 14 days before start of study intervention) and every 8 weeks post start of dosing, approximately up to 302 weeks
Population: The ITT population included all patients who received at least one dose of tazemetostat.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Overall Dose Escalation | Overall Response Rate (ORR) (Dose Expansion Only) | 26.3 Percentage of participants |
| Dose Escalation Level 2 | Overall Response Rate (ORR) (Dose Expansion Only) | 0 Percentage of participants |
| Dose Escalation Level 3 | Overall Response Rate (ORR) (Dose Expansion Only) | 16.7 Percentage of participants |
| Dose Escalation Level 4 | Overall Response Rate (ORR) (Dose Expansion Only) | 16.7 Percentage of participants |
Primary
Recommended Phase 2 Dose (RP2D) (Dose Escalation Only)
The incidence and severity of treatment-emergent adverse events qualifying as protocol-defined dose-limiting toxicities that occurred during the first month of treatment was used to determine the RP2D and/or maximum tolerated dose (MTD) in pediatric patients treated with tazemetostat.
Time frame: Cycle 1, from the start of study treatment (Day 1) until the end of the first Cycle (Day 28) of treatment
Population: The ITT population included all patients who received at least one dose of tazemetostat.
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Overall Dose Escalation | Recommended Phase 2 Dose (RP2D) (Dose Escalation Only) | RP2D for patients without CNS involvement | 520 mg/m^2 BID |
| Overall Dose Escalation | Recommended Phase 2 Dose (RP2D) (Dose Escalation Only) | RP2D for patients with ATRT or CNS involvement | 1200 mg/m^2 BID |
Secondary
ORR (Dose Escalation Only)
ORR is defined as the percentage of patients who achieved a confirmed CR and/or PR defined by RECIST or RANO criteria from the start of tazemetostat treatment until disease progression or the start of subsequent anticancer therapy, whichever occurs first. CR is defined as disappearance of all target and non-target lesions (with all lymph nodes must be non-pathological in size or under 10 mm in short axis) and PR is defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters. ORR= CR+PR.
Time frame: RECIST assessments performed at screening (within 14 days before start of study intervention) and every 8 weeks post start of dosing, approximately up to 302 weeks
Population: The ITT population included all patients who received at least one dose of tazemetostat.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Overall Dose Escalation | ORR (Dose Escalation Only) | 0 Percentage of participants |
| Dose Escalation Level 2 | ORR (Dose Escalation Only) | 0 Percentage of participants |
| Dose Escalation Level 3 | ORR (Dose Escalation Only) | 0 Percentage of participants |
| Dose Escalation Level 4 | ORR (Dose Escalation Only) | 14.3 Percentage of participants |
| Dose Escalation Level 5 | ORR (Dose Escalation Only) | 16.7 Percentage of participants |
| Dose Escalation Level 6 | ORR (Dose Escalation Only) | 16.7 Percentage of participants |
| Dose Escalation Level 7 | ORR (Dose Escalation Only) | 0 Percentage of participants |
Secondary
Overall Survival (Dose Expansion Only)
Overall survival was defined as the time (in weeks) from the first dose of study drug to the date of death due to any cause.
Time frame: RECIST assessments performed at screening (within 14 days before start of study intervention) and every 8 weeks post start of dosing, approximately up to 302 weeks
Population: The ITT population included all patients who received at least one dose of tazemetostat.
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Overall Dose Escalation | Overall Survival (Dose Expansion Only) | 21.4 weeks |
| Dose Escalation Level 2 | Overall Survival (Dose Expansion Only) | 14.1 weeks |
| Dose Escalation Level 3 | Overall Survival (Dose Expansion Only) | 41.8 weeks |
| Dose Escalation Level 4 | Overall Survival (Dose Expansion Only) | 103.1 weeks |
Secondary
Progression Free Survival (PFS) (Dose Expansion Only)
PFS was defined as the interval of time (in weeks) from the date of first dose of study drug and the earliest date of disease progression or death, from any cause defined by RECIST or RANO criteria. Disease progression is defined as at least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study (including at least a 5 mm absolute increase). The presence of new lesions also constitutes to disease progression.
Time frame: RECIST assessments performed at screening (within 14 days before start of study intervention) and every 8 weeks post start of dosing, approximately up to 302 weeks
Population: The ITT population included all patients who received at least one dose of tazemetostat.
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Overall Dose Escalation | Progression Free Survival (PFS) (Dose Expansion Only) | 7.9 weeks |
| Dose Escalation Level 2 | Progression Free Survival (PFS) (Dose Expansion Only) | 7.7 weeks |
| Dose Escalation Level 3 | Progression Free Survival (PFS) (Dose Expansion Only) | 15.9 weeks |
| Dose Escalation Level 4 | Progression Free Survival (PFS) (Dose Expansion Only) | 28.3 weeks |