Anti-CEA Pretargeted Immuno-PET Shows Higher Sensitivity Than DOPA PET/CT in Detecting Relapsing Metastatic Medullary Thyroid Carcinoma: Post Hoc Analysis of the iPET-MTC Study.

Pretargeting parameters for the use of anti-carcinoembryonic antigen (CEA) bispecific monoclonal antibody TF2 and the 68Ga-labeled IMP288 peptide for immuno-PET have been optimized in a first-in-humans study performed on medullary thyroid carcinoma (MTC) patients (the iPET-MTC study). The aim of this post hoc analysis was to determine the sensitivity of immuno-PET in relapsing MTC patients, in comparison with conventional imaging and 18F-l-dihydroxyphenylalanine (18F-DOPA) PET/CT. Methods: Twenty-five studies were analyzed in 22 patients. All patients underwent immuno-PET 1 and 2 h after 68Ga-IMP288 injection pretargeted by TF2, in addition to neck, thoracic, abdominal, and pelvic CT; bone and liver MRI; and 18F-DOPA PET/CT. The gold standard was histology or confirmation by one other imaging method or by imaging follow-up. Results: In total, 190 lesions were confirmed by the gold standard: 89 in lymph nodes, 14 in lungs, 46 in liver, 37 in bone, and 4 in other sites (subcutaneous tissue, heart, brain, and pancreas). The number of abnormal foci detected by immuno-PET was 210. Among these, 174 (83%) were confirmed as true-positive by the gold standard. Immuno-PET showed a higher overall sensitivity (92%) than 18F-DOPA PET/CT (65%). Regarding metastatic sites, immuno-PET had a higher sensitivity than CT, 18F-DOPA PET/CT, or MRI for lymph nodes (98% vs. 83% for CT and 70% for 18F-DOPA PET/CT), liver (98% vs. 87% for CT, 65% for 18F-DOPA PET/CT, and 89% for MRI), and bone (92% vs. 64% for 18F-DOPA PET/CT and 86% for MRI), whereas sensitivity was lower for lung metastases (29% vs. 100% for CT and 14% for 18F-DOPA PET/CT). Tumor SUVmax at 60 min ranged from 1.2 to 59.0, with intra- and interpatient variability. Conclusion: This post hoc study demonstrates that anti-carcinoembryonic antigen immuno-PET is an effective procedure for detecting metastatic MTC lesions. Immuno-PET showed a higher overall sensitivity than 18F-DOPA PET/CT for disclosing metastases, except for the lung, where CT remains the most effective examination.

Head-to-Head Comparison of 18F-DOPA PET/CT and 68Ga-DOTANOC PET/CT in Patients With Midgut Neuroendocrine Tumors.

PURPOSE: The aim of this study was to compare retrospectively 18F-DOPA PET/CT versus 68Ga-DOTANOC PET/CT in a group of patients affected by midgut NET. PATIENTS AND METHODS: Patients with histologically proven grade 1 or grade 2 midgut NET were explored after injection of 150 MBq of 68Ga-DOTANOC and 210 MBq of 18F-DOPA. The PET/CTs were analyzed visually and semiquantitatively at the patient level, regional level (7 defined regions), and lesion level (maximum of 5 lesions/organ). The criterion standard was determined on the basis of histology and imaging follow-up. RESULTS: Thirty patients (17 males and 13 females; median age, 63.5 years [37-82 years]) were included. Both PET/CTs were negative in 3 patients and positive in 25 patients. PET/CTs were discordant in 2 patients, with 18F-DOPA positive and 68Ga-DOTANOC negative. 18F-DOPA PET/CT detected more involved regions and more metastatic lesions than 68Ga-DOTANOC PET/CT in 6 (20%) and 10 (33.3%) patients, respectively. Of the 81 confirmed affected regions, 77 (95%) were detected by 18F-DOPA PET/CT and 71 (87.7%) by 68Ga-DOTANOC PET/CT (P < 0.0001). 18F-DOPA PET/CT detected significantly more lesions (211/221) than 68Ga-DOTANOC PET/CT (195/221), corresponding to a sensitivity of 95.5% and 88.2%, respectively (P < 0.0001). Tumor-to-background ratios were more favorable in liver for 18F-DOPA than for 68Ga-DOTANOC. Interestingly, a correlation was found between 18F-DOPA SUVmax and tumor burden and especially with the number of regions involved by the disease (P = 0.019). CONCLUSIONS: 18F-DOPA PET/CT is superior to 68Ga-DOTANOC PET/CT for the detection of lesions, and when available, this tracer may be recommended as the first-line examination for an accurate staging of midgut NET.

Initial Clinical Results of a Novel Immuno-PET Theranostic Probe in Human Epidermal Growth Factor Receptor 2-Negative Breast Cancer.

This prospective study evaluated the imaging performance of a novel pretargeting immunologic PET (immuno-PET) method in patients with human epidermal growth factor receptor 2 (HER2)-negative, carcinoembryonic antigen (CEA)-positive metastatic breast cancer, compared with CT, bone MRI, and 18F-FDG PET. Methods: Twenty-three patients underwent whole-body immuno-PET after injection of 150 MBq of 68Ga-IMP288, a histamine-succinyl-glycine peptide given after initial targeting of a trivalent anti-CEA, bispecific, antipeptide antibody. The gold standards were histology and imaging follow-up. Tumor SUVs (SUVmax and SUVmean) were measured, and tumor burden was analyzed using total tumor volume and total lesion activity. Results: The total lesion sensitivity of immuno-PET and 18F-FDG PET were 94.7% (1,116/1,178) and 89.6% (1,056/1,178), respectively. Immuno-PET had a somewhat higher sensitivity than CT or 18F-FDG PET in lymph nodes (92.4% vs. 69.7% and 89.4%, respectively) and liver metastases (97.3% vs. 92.1% and 94.8%, respectively), whereas sensitivity was lower for lung metastases (48.3% vs. 100% and 75.9%, respectively). Immuno-PET showed higher sensitivity than MRI or 18F-FDG PET for bone lesions (95.8% vs. 90.7% and 89.3%, respectively). In contrast to 18F-FDG PET, immuno-PET disclosed brain metastases. Despite equivalent tumor SUVmax, SUVmean, and total tumor volume, total lesion activity was significantly higher with immuno-PET than with 18F-FDG PET (P = 0.009). Conclusion: Immuno-PET using anti-CEA/anti-IMP288 bispecific antibody, followed by 68Ga-IMP288, is a potentially sensitive theranostic imaging method for HER2-negative, CEA-positive metastatic breast cancer patients and warrants further research.

Immuno-PET Using Anticarcinoembryonic Antigen Bispecific Antibody and 68Ga-Labeled Peptide in Metastatic Medullary Thyroid Carcinoma: Clinical Optimization of the Pretargeting Parameters in a First-in-Human Trial.

Earlier clinical studies reported a high sensitivity of pretargeted immunoscintigraphy using murine or chimeric anticarcinoembryonic antigen (CEA) bispecific antibody (BsMAb) and peptides labeled with 111In or 131I in medullary thyroid carcinoma (MTC). Preclinical studies showed that new-generation humanized recombinant anti-CEA × antihistamine-succinyl-glycine (HSG) trivalent BsMAb TF2 and radiolabeled HSG peptide (IMP288) present good features for PET. This study aimed at optimizing molar doses and pretargeting interval of TF2 and 68Ga-labeled IMP288 for immuno-PET in relapsed MTC patients with calcitonin serum levels greater than 150 pg/mL. METHODS: Five cohorts (C1-C5) of 3 patients received variable molar doses of TF2 and approximately 150 MBq of 68Ga-IMP288 after different pretargeting time intervals (C1: 120 nmol TF2, 6 nmol IMP288, 24 h; C2: 120 nmol TF2, 6 nmol IMP288, 30 h; C3: 120 nmol TF2, 6 nmol IMP288, 42 h; C4: 120 nmol TF2, 3 nmol IMP288, 30 h; and C5: 60 nmol TF2, 3 nmol IMP288, 30 h). TF2 and 68Ga-IMP288 pharmacokinetics were monitored. Whole-body PET was recorded 60 and 120 min after 68Ga-IMP288 injection. Tumor maximal SUV (T-SUVmax) and T-SUVmax-to-mediastinum blood-pool (MBP) SUVmean ratios (T/MBP) were determined. RESULTS: In C1, T-SUVmax and T/MBP ranged from 4.09 to 8.93 and 1.39 to 3.72 at 60 min and 5.14 to 11.25 and 2.73 to 5.38 at 120 min, respectively. Because of the high MBP, the delay was increased to 30 h in C2, increasing T-SUVmax and T/MBP. Further increasing the delay to 42 h in C3 decreased T-SUVmax and T/MBP, showing that 30 h was the most favorable delay. In C4, the TF2-to-peptide mole ratio was increased to 40 (delay 30 h), resulting in high T-SUVmax but with higher MBP than in C2. In C5, the molar dose of TF2 was reduced, resulting in lower imaging performance. Pharmacokinetics demonstrated a fast TF2 clearance and a clear relationship between blood activity clearance and the ratio between the molar amount of injected peptide to the molar amount of circulating TF2 at the time of peptide injection. CONCLUSION: High tumor uptake and contrast can be obtained with pretargeted anti-CEA immuno-PET in relapsed MTC patients, especially using optimized pretargeting parameters: a BsMAb-to-peptide mole ratio of 20 and 30 h pretargeting delay.

Pharmacokinetics and Dosimetry Studies for Optimization of Pretargeted Radioimmunotherapy in CEA-Expressing Advanced Lung Cancer Patients.

OBJECTIVES: A phase I pretargeted radioimmunotherapy trial (EudractCT 200800603096) was designed in patients with metastatic lung cancer expressing carcinoembryonic antigen (CEA) to optimize bispecific antibody and labeled peptide doses, as well as the delay between their injections. METHODS: Three cohorts of three patients received the anti-CEA × anti-histamine-succinyl-glycine (HSG)-humanized trivalent bispecific antibody (TF2) and the IMP288 bivalent HSG peptide. Patients underwent a pretherapeutic imaging session S1 (44 or 88 nmol/m(2) of TF2 followed by 4.4 nmol/m(2), 185 MBq, of (111)In-labeled IMP288) and, 1-2 weeks later, a therapy session S2 (240 or 480 nmol/m(2) of TF2 followed by 24 nmol/m(2), 1.1 GBq/m(2), of (177)Lu-labeled IMP288). The pretargeting delay was 24 or 48 h. The dose schedule was defined based on preclinical TF2 pharmacokinetic (PK) studies, on our previous clinical data using the previous anti-CEA-pretargeting system, and on clinical results observed in the first patients injected using the same system in Netherlands. RESULTS: TF2 PK was represented by a two-compartment model in which the central compartment volume (Vc) was linearly dependent on the patient's surface area. PK was remarkably similar, with a clearance of 0.33 ± 0.03 L/h/m(2). (111)In- and (177)Lu-IMP288 PK was also well represented by a two-compartment model. IMP288 PK was faster (clearance 1.4-3.3 L/h). The Vc was proportional to body surface area, and IMP288 clearance depended on the molar ratio of injected IMP288 to circulating TF2 at the time of IMP288 injection. Modeling of image quantification confirmed the dependence of IMP288 kinetics on circulating TF2, but tumor activity PK was variable. Organ-absorbed doses were not significantly different in the three cohorts, but the tumor dose was significantly higher with the higher molar doses of TF2 (p < 0.002). S1 imaging predicted absorbed doses calculated in S2. CONCLUSION: The best dosing parameters corresponded to the shorter pretargeting delay and to the highest TF2 molar doses. S1 imaging session accurately predicted PK as well as absorbed doses of S2, thus potentially allowing for patient selection and dose optimization. TRIAL REGISTRATION: ClinicalTrials.gov NCT01221675 (EudractCT 200800603096).

T-cell therapy using a bank of EBV-specific cytotoxic T cells: lessons from a phase I/II feasibility and safety study.

We report herein the results we obtained and the limitations we experienced during the production and use of a bank of Epstein-Barr virus (EBV)-transformed human cytotoxic T lymphocytes (EBV-CTLs). To assess the feasibility and toxicity of this strategy, we selected and stored, in liquid nitrogen, 4 billion EBV-CTLs from each of the 13 selected donors. Subsequently, in a multicenter phase I/II study, 11 patients with EBV-associated lymphoma resistant to conventional treatments received 1-3 doses of 5 million EBV-CTLs/kg with 1-3 and 0-4 compatibilities for human leukocyte antigen (HLA)-I and HLA-II, respectively. Except for one event of fever after injection, no immediate or delayed toxicity, no graft versus host disease, and no graft rejection attributable to CTL infusion were observed. Three patients presented complete remission and 1 partial remission after treatment. Considering the clinical options currently available, and the constrains associated with CTL preparation and implementation, we conclude that CTL banks should consist of a reasonably small number of cell lines with documented specificities. This objective could be more easily achieved if the few homozygous donors for the most frequent HLA alleles of the targeted population could be made available for such a project.

Memantine in behavioral variant frontotemporal dementia: negative results.

We tested the efficacy and tolerability of one-year treatment with memantine (10 mg bid) in behavioral variant frontotemporal dementia (bvFTD). BvFTD patients aged 45 to 75 years, with a Mini-Mental Status Examination (MMSE) score ≥19, were enrolled in a national, randomized, double-blind, placebo-controlled (DBPC), Phase II trial. The primary endpoint was the CIBIC-Plus (Clinician's Interview-Based Impression of Change Plus Caregiver Input). The secondary endpoints included: Neuropsychiatric Inventory (NPI), Frontal Behavioral Inventory (FBI), Mattis Dementia Rating Scale (MDRS), MMSE, Disability Assessment for Dementia (DAD), and the Zarit Burden Inventory (ZBI). Forty-nine patients were analyzed. At baseline, mean age was 65.6 years and mean MMSE was 25.0 (range: 19-30). On the CIBIC-Plus, 52 weeks after baseline, there were no significant differences between the memantine group (n = 23) and the placebo group (n = 26); p = 0.4458; however, 10 patients had worsened in the memantine group versus 17 in the placebo group. For the secondary endpoints there were no differences in the evolution of score between the memantine group and the placebo group (MMSE, p = 0.63); (MDRS, p = 0.95); (NPI, p = 0.25); (ZBI, p = 0.43); (DAD, p = 0.10) except for the FBI score, which was lower in the memantine group (p = 0.0417). Memantine was well-tolerated. This is the first DBPC trial in a large group of bvFTD patients involving neuroprotective treatment. A multinational study with a larger number of patients is now needed in order to verify the results of our study. The trial is registered with ClinicalTrials.gov; number NCT 00200538.