This will be an open, single-arm, international, multicentre, phase II imaging study to assess the predictive value of \[68Ga\]Ga PentixaFor PET imaging in primary and isolated secondary central nervous system lymphoma (CNSL) patients scheduled to undergo induction chemotherapy.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DIAGNOSTIC
Masking
NONE
Enrollment
1
68Ga-PTF will be injected intravenously at three time points during the course of the standard treatment of the patient.
University Hospital Aalborg
Aalborg, Denmark
University Hospital CHU Nantes
Nantes, France
Negative predictive value (NPV) of interim 68Ga-PTF-PET (after 6 ± 2 weeks of induction chemotherapy) for progression-free survival (PFS)
68Ga-PTF PET negativity for CXCR4 will be determined by visual analysis in central reading. For PFS assessment (yes/no variable), tumour progression or relapse will be determined according to the IPCG response criteria (Abrey et al. 2005) for the time period starting at baseline and ending at approx. 12 months after induction chemotherapy completion. The negative predictive value is defined as follows: Number of patients without tumour progression or relapse / number of patients with interim 68Ga-PTF PET assessed as CXCR4-negative by central reviewer. The proportion obtained will be multiplied by 100 to obtain a percentage value. This NPV will be calculated for the entire study population and also stratified by induction chemotherapy regimen (HD-MTX-based, DeVIC/ICE, HD-AraC-based regimen).
Time frame: after 6 +/-2 weeks of induction chemotherapy (interim examination) up to 12 months after induction chemotherapy completion (end of follow-up period)
Positive predictive value (PPV) of interim 68Ga-PTF PET (after 6 ± 2 weeks of induction chemotherapy) for PFS
68Ga-PTF PET positivity for CXCR4 will be determined by visual analysis in central reading. For PFS assessment (yes/no variable), tumour progression or relapse will be determined according to the IPCG response criteria (Abrey et al. 2005) for the time period starting at baseline and ending at approx. 12 months after induction chemotherapy completion. The positive predictive value is defined as follows: Number of patients with tumour progression or relapse / number of patients with interim 68Ga-PTF PET assessed as CXCR4-positive by central reviewer. The proportion obtained will be multiplied by 100 to obtain a percentage value.
Time frame: after 6 +/-2 weeks of induction chemotherapy (interim examination) up to 12 months after induction chemotherapy completion (end of follow-up period)
Frequency and severity of AEs
The safety will be reported by frequency, system organ class categories, and severity of adverse events (AEs). The numbers and proportions of patients with any treatment-emergent adverse event (TEAE), and any serious TEAE will be summarized.
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Time frame: up to 6 months
Predictive values of 68Ga-PTF PET at the end of induction chemotherapy for PFS
The negative predictive value (NPV) and the positive predictive value (PPV) for the prediction of PFS at the end of induction chemotherapy will be determined as described in outcome 1 and 2.
Time frame: end of induction chemotherapy up to 12 months after induction chemotherapy completion
Predictive values of 68Ga-PTF PET at interim examination (after 6 ± 2 weeks of induction chemotherapy) and end-of-chemotherapy-treatment for complete response (CR)
NPV of interim (after 6 ± 2 weeks of induction chemotherapy) 68Ga-PTF PET for the prediction of 16(±1) months CR. PPV of interim (after 6 ± 2 weeks of induction chemotherapy) 68Ga-PTF PET for the prediction of 16(±1) months CR. NPV of end-of-chemotherapy 68Ga-PTF PET for the prediction of 16(±1)-months CR. PPV of end-of-chemotherapy 68Ga-PTF PET for the prediction of 16(±1)-months CR. Response assessment will be performed 12 months after completion of induction chemotherapy and predictive values will be calculated with the results from the central visual analysis of the 68Ga-PTF PET scans at the different timepoints of induction chemotherapy.
Time frame: after 6 +/-2 weeks of induction chemotherapy (interim examination) up to 12 months after induction chemotherapy completion (end of follow-up period)
Maximum standardized uptake value (SUVmax), SUVpeak and SUV mean
Maximum standardized uptake value (SUVmax), SUVpeak and SUV mean will be determined for the pre-treatment 68Ga-PTF scan and will be analyzed for their association with 16(±1)-months PFS and also with 16(±1) months CR.
Time frame: after pretreatment examination up to 12 months after induction chemotherapy completion (end of follow-up period)
Maximum tumour-to background ratio (TBRmax) and TBRmean
Maximum tumour-to background ratio (TBRmax) and TBRmean will be determined for the pre-treatment 68Ga-PTF scan and will be analyzed for their association with 16(±1)-months PFS and also with 16(±1) months CR.
Time frame: after pretreatment examination up to 12 months after induction chemotherapy completion (end of follow-up period)
Metabolic tumour volume (MTV)
Metabolic tumour volume (MTV) will be determined for the pre-treatment 68Ga-PTF scan by relative and fixed thresholding method and will be analyzed for their association with 16(±1)-months PFS and also with 16(±1) months CR.
Time frame: after pretreatment examination up to 12 months after induction chemotherapy completion (end of follow-up period)
Maximum standardized uptake value (SUVmax), SUVpeak and SUV mean
Maximum standardized uptake value (SUVmax), SUVpeak and SUV mean will be determined for the interim 68Ga-PTF scan and will be analyzed for their association with 16(±1)-months PFS and also with 16(±1) months CR.
Time frame: after 6 +/-2 weeks of induction chemotherapy (interim examination) up to 12 months after induction chemotherapy completion (end of follow-up period)
Maximum tumour-to background ratio (TBRmax) and TBRmean
Maximum tumour-to background ratio (TBRmax) and TBRmean will be determined for the interim 68Ga-PTF scan and will be analyzed for their association with 16(±1)-months PFS and also with 16(±1) months CR.
Time frame: after 6 +/-2 weeks of induction chemotherapy (interim examination) up to 12 months after induction chemotherapy completion (end of follow-up period)
Metabolic tumour volume (MTV)
Metabolic tumour volume (MTV) will be determined for the interim 68Ga-PTF scan by relative and fixed thresholding method and will be analyzed for their association with 16(±1)-months PFS and also with 16(±1) months CR.
Time frame: after 6 +/-2 weeks of induction chemotherapy (interim examination) up to 12 months after induction chemotherapy completion (end of follow-up period)
Predictive values of changes between pre-treatment and interim 68Ga-PTF PET imaging parameters for PFS
The association of ΔSUVmax (change in SUVmax between pre-treatment 68Ga-PTF PET and interim 68Ga PTF PET) with 16(±1)-months PFS will be determined
Time frame: From visit 2 (first 68Ga-PTF PET) up to 12 months after induction chemotherapy completion
Sensitivity of pre-treatment 68Ga-PTF PET for CXCR4-positivity
In the fraction of patients from whom biopsy tissue is available, the sensitivity of the pre-treatment 68Ga-PTF PET to detect CXCR4 overexpression by immunohistochemistry (IHC) will be determined centrally on a patient basis
Time frame: up to 12 months after induction chemotherapy completion
Concordance in the classification as CNSL-suspect ('yes'/'no') by 68Ga-PTF PET and MRI at baseline, on a patient level
Diagnostic agreement between 68Ga-PTF PET and MRI at baseline imaging (after 6 +/-2 weeks of induction chemotherapy) will be determined on a patient level by evaluation of the concordance in the classification as CNSL-suspect ('yes'/'no') by 68Ga-PTF PET and MRI at baseline.
Time frame: after Visit 4 (after 6 +/-2 weeks of induction chemotherapy)
Comparison of lesion numbers categorised as CNSL-suspect by 68Ga-PTF PET and MRI at baseline
Diagnostic agreement between 68Ga-PTF PET and MRI at baseline imaging (after 6 +/-2 weeks of induction chemotherapy) will be determined on a patient level by comparing lesion numbers categorised as CNSL-suspect by 68Ga-PTF PET and MRI at baseline
Time frame: after Visit 4 (after 6 +/-2 weeks of induction chemotherapy)
Observer agreement of 68Ga-PTF PET (inter- and intra-reader agreement)
The following will be calculated with respect to 68Ga-PTF-PET positivity: 1. Inter-reader agreement for pre-treatment 68Ga-PTF PET 2. Inter-reader agreement for interim 68Ga-PTF PET 3. Inter-reader agreement for 68Ga-PTF PET after induction chemotherapy completion 4. Intra-reader agreement for pre-treatment 68Ga-PTF PET 5. Intra-reader agreement for interim 68Ga-PTF PET 6. Intra-reader agreement for 68Ga-PTF PET after induction chemotherapy completion 7. Overall inter-reader agreement 8. Overall intra-reader agreement. The intra-reader assessment will be based on an appropriately sized sample of readings.
Time frame: through study completion, an average of 6 months