Izabela Tworowska

Validation of Several SUV-Based Parameters Derived from 18F-FDG PET for Prediction of Survival After SIRT of Hepatic Metastases from Colorectal Cancer

90Y radioembolization (selective internal radiation therapy [SIRT]) is a valuable therapeutic option for unresectable hepatic metastases arising from primary colorectal cancer. The present study evaluated the prognostic value of 18F-FDG PET/CT metabolic parameters for predicting survival after SIRT. Methods: Eighty patients with hepatic metastases of colorectal cancer were treated with SIRT. 18F-FDG PET/CT was performed at baseline and 3 mo after the treatment. Metabolic volume, total lesion glycolysis, and maximum and peak standardized uptake value (SUVmax and SUVpeak, respectively) according to PET Response Criteria in Solid Tumors (PERCIST 1.0) were obtained from 3 liver lesions in each patient, and the corresponding percentage changes from baseline to follow-up were calculated. Tumor response was defined as more than a 30% decrease in these parameters. Furthermore, response was evaluated in accordance with Response Evaluation Criteria in Solid Tumors (RECIST 1.1). Toxicity events and survival were recorded. Results: Overall median survival after SIRT was 60 wk. Responders who had a change in metabolic volume or total lesion glycolysis had significantly longer survival (92 vs. 49 wk [P = 0.006] and 91 vs. 48 wk [P = 0.025], respectively). However, neither RECIST 1.1 criteria nor changes in SUVpeak or SUVmax after treatment predicted outcome (P = 0.086 for RECIST; P = 0.310 for change in SUVpeak; P = 0.155 for change in SUVmax). Conclusion: Changes in metabolic volume and total lesion glycolytic rate as measured by 18F-FDG PET predicted survival in patients with hepatic metastases from colorectal cancer, whereas changes in SUVpeak or SUVmax and RECIST 1.1 criteria did not predict survival.

Synthesis of 2′-deoxynucleosid-3′-yl-N,N-diisopropylaminophosphorfluoridites. A new class of stable PIII nucleotides containing a PF bond

Abstract A new methodology based on phosphitylating reagents containing 4-nitrophenoxy leaving group has been employed to synthesize stable 5′-O-(4,4-dimethoxytrityl)nucleosid-3′-yl-N,N-diisopropylaminophosphorfluoridites 1a-d .

2,4-Dinitrophenol: a novel activating reagent in nucleotide synthesis via the phosphoramidite route. Design of new effective phosphitylating reagents☆

Abstract 2,4-Dinitrophenol (DNP) is a remarkably efficient activator in the reaction of P(III) amides with nucleosides to give P(III) esters in excellent yield. Typical examples of this novel procedure are presented herein. Mechanistic features of the activation were elucidated by model studies of the reaction of bis(2-cyanoethyl)diisopropylphosphoroamidite with benzyl alcohol. The importance of the initial protonation stage and formation of an intermediate P(III)-2,4-dinitrophenyl ester were clearly demonstrated by 31 P NMR spectroscopy and independent synthesis. New phosphitylating reagents containing the 2,4-dinitrophenoxy group do not require any activation.

Radiosynthesis of clinical doses of 68Ga-DOTATATE (GalioMedix™) and validation of organic-matrix-based 68Ge/68Ga generators

INTRODUCTION 68Ga-DOTATATE is a radiolabeled peptide-based agonist that targets somatostatin receptors overexpressed in neuroendocrine tumors. Here, we present our results on validation of organic matrix 68Ge/68Ga generators (ITG GmbH) applied for radiosynthesis of the clinical doses of 68Ga-DOTATATE (GalioMedixTM). METHODS The clinical grade of DOTATATE (25 μg±5 μg) compounded in 1 M NaOAc at pH=5.5 was labeled manually with 514±218 MBq (13.89±5.9 mCi) of 68Ga eluate in 0.05 N HCl at 95°C for 10 min. The radiochemical purity of the final dose was validated using radio-TLC. The quality control of clinical doses included tests of their osmolarity, endotoxin level, radionuclide identity, filter integrity, pH, sterility and 68Ge breakthrough. RESULTS The final dose of 272±126 MBq (7.35±3.4 mCi) of 68Ga-DOTATATE was produced with a radiochemical yield (RCY) of 99%±1%. The total time required for completion of radiolabeling and quality control averaged approximately 35 min. This resulted in delivery of 50%±7% of 68Ga-DOTATATE at the time of calibration (not decay corrected). CONCLUSIONS 68Ga eluted from the generator was directly applied for labeling of DOTA-peptide with no additional pre-concentration or pre-purification of isotope. The low acidity of 68Ga eluate allows for facile synthesis of clinical doses with radiochemical and radionuclide purity higher than 98% and average activity of 272±126 MBq (7.3±3 mCi). There is no need for post-labeling C18 Sep-Pak purification of final doses of radiotracer. Advances in knowledge and implications for patient care. The clinical interest in validation of 68Galabeled agents has increased in the past years due to availability of generators from different vendors (Eckert-Ziegler, ITG, iThemba), favorable approach of U.S. FDA agency to initiate clinical trials, and collaboration of U.S. centers with leading EU clinical sites. The list of 68Ga-labeled tracers evaluated in clinical studies should growth because of the sensitivity of PET technique, the simplicity of the shakebake approach for the dose preparation and reliability of 68Ge/68Ga generators. Our studies have confirmed the reproducible elution profile, and high reliability of ITG GmbH generators required for routine doses preparation according to FDA recommendations.

Peptide Receptor Radionuclide Therapy With 177Lu-Octreotate in Patients With Somatostatin Receptor Expressing Neuroendocrine Tumors: Six Yearsʼ Assessment

Objectives Peptide receptor radionuclide therapy (PRRT) with radiolabeled somatostatin analogues is a promising treatment for patients with inoperable, well to moderately differentiated metastatic neuroendocrine tumors (NETs). In continuation of our novel study with the radionuclide lutetium 177Lu, we now present further results of 177Lu DOTATATE therapy in managing NETs and other somatostatin receptor–expressing tumors in a larger and more diverse patient group. Patients and Methods One hundred forty-four consecutive patients (85 men and 59 women; age range, 11–87 years; mean age, 58.5 years) with histologically confirmed NET were enrolled. One hundred forty-three patients received at least 1 cycle of treatment. Among them, 132 were deemed evaluable by having at least 1 cycle of treatment and a posttreatment MRI or CT scan for assessment based on modified Response Evaluation Criteria in Solid Tumors. Response to therapy was evaluated in terms of progression-free survival, overall survival, as well as radiologic, biochemical, and clinical responses. Further, analysis of symptoms was reviewed during therapy and also in subsequent follow-ups for safety evaluation. Renal, gastrointestinal (GI), hepatic, and hematological adverse events were evaluated using National Cancer Institute common toxicities criteria V4.03, through full blood panels, as well as consultation with patients for any symptoms and/or adverse events. Results As of July 2016, median progression-free survival was about to be reached. Of 28 patients who have completed 177Lu DOTATATE therapy (completion of 4 or more cycles of treatment and all designated follow-ups), no patient showed complete response (CR), 8 patients (28.57%) showed partial response (PR), 16 patients (57.14%) showed stable disease (SD), and progressive disease (PD) was observed in 4 patients (14.28%). The objective response rate (CR + PR) of this group was 28.57% (n = 8) with a cumulative disease control (CR + PR + SD) of 85.71% (n = 24). Among 132 evaluable patients, assessment of treatment response using modified Response Evaluation Criteria in Solid Tumors criteria revealed CR in none of the patients, PR in 12 patients (9.09%), SD in 66 patients (50%), whereas PD, which included patients who passed away, was observed in 54 patients (40.90%), yielding an objective response rate of 9.09% (n = 12) and a cumulative disease control rate of 59.09% (n = 78). Symptoms including abdominal pain, diarrhea, flushing, and fatigue improved in over 50% of the patients, whereas weight loss improved in 28.26% of the patients. No grade 3 or grade 4 renal toxicities were found, though eleven grade 3 and five grade 4 hematological as well as three grade 3 hepatotoxicities were reported. Grade 3 hematotoxicity lasted an average of 2.7 months, and grade 4 lasted for only 0.9 months, whereas grade 3 hepatotoxicity lasted an average of 3.1 months. Conclusions 177Lu-octreotate peptide receptor radionuclide therapy has shown promising potential as a safe and effective targeted therapy in inoperable, well to moderately differentiated metastatic neuroendocrine cancers. The results of the multicenter randomized clinical trial conducted in United States and Europe are concordant with current study.

Diastereoisomerically pure dinucleosidylphosphorofluoridites and their application in stereospecific synthesis of dinucleosidylphosphorofluoridothionates

Dinucleosidylphosphorofluoridites with dA(Bz), dC(Bz) or dT at the 3′-end and dT at the 5′-end are synthesised, separated into their diastereoisomers and shown to be converted stereospecifically into the corresponding phosphorofluoridothionates high hydrolytic stability.

Highly selective O-phosphitylation of amino alcohols using PIIIreagents containing 4-nitro and 2,4-dinitro aryloxy leaving groups

A method for direct highly O-selective phosphitylation of amino alcohols by reagents containing a 4-nitrophenoxy or 2,4 dinitrophenoxy leaving group has been developed. This method provides mild reaction conditions to access O-phosphitylated amino alcohols. The flexibility of the synthesis is exemplified by the models of simple amino alcohols and of nucleosides containing unprotected NH2 groups.

Radiolabeling of DOTA-like conjugated peptides with generator-produced 68Ga and using NaCl-based cationic elution method

Gallium-68 (68Ga) is a generator-produced radionuclide with a short half-life (t½ = 68 min) that is particularly well suited for molecular imaging by positron emission tomography (PET). Methods have been developed to synthesize 68Ga-labeled imaging agents possessing certain drawbacks, such as longer synthesis time because of a required final purification step, the use of organic solvents or concentrated hydrochloric acid (HCl). In our manuscript, we provide a detailed protocol for the use of an advantageous sodium chloride (NaCl)-based method for radiolabeling of chelator-modified peptides for molecular imaging. By working in a lead-shielded hot-cell system,68Ga3+ of the generator eluate is trapped on a cation exchanger cartridge (100 mg, ∼8 mm long and 5 mm diameter) and then eluted with acidified 5 M NaCl solution directly into a sodium acetate-buffered solution containing a DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) or DOTA-like chelator-modified peptide. The main advantages of this procedure are the high efficiency and the absence of organic solvents. It can be applied to a variety of peptides, which are stable in 1 M NaCl solution at a pH value of 3–4 during reaction. After labeling, neutralization, sterile filtration and quality control (instant thin-layer chromatography (iTLC), HPLC and pH), the radiopharmaceutical can be directly administered to patients, without determination of organic solvents, which reduces the overall synthesis-to-release time. This procedure has been adapted easily to automated synthesis modules, which leads to a rapid preparation of 68Ga radiopharmaceuticals (12–16 min).

Detection of canonical hedgehog signaling in breast cancer by 131-iodine-labeled derivatives of the sonic hedgehog protein

Activation of hedgehog (HH) pathway signaling is observed in many tumors. Due to a feedback loop, the HH receptor Patched (PTCH-1) is overexpressed in tumors with activated HH signaling. Therefore, we sought to radiolabel the PTCH-1 ligand sonic (SHH) for detection of cancer cells with canonical HH activity. Receptor binding of 131I-SHH was increased in cell lines with high HH pathway activation. Our findings also show that PTCH-1 receptor expression is decreased upon treatment with HH signaling inhibitors, and receptor binding of 131I-SHH is significantly decreased following treatment with cyclopamine. In vivo imaging and biodistribution studies revealed significant accumulation of 131I-SHH within tumor tissue as compared to normal organs. Tumor-to-muscle ratios were approximately 8 : 1 at 5 hours, while tumor to blood and tumor to bone were 2 : 1 and 5 : 1, respectively. Significant uptake was also observed in liver and gastrointestinal tissue. These studies show that 131I-SHH is capable of in vivo detection of breast tumors with high HH signaling. We further demonstrate that the hedgehog receptor PTCH-1 is downregulated upon treatment with hedgehog inhibitors. Our data suggests that radiolabeled SHH derivatives may provide a method to determine response to SHH-targeted therapies.

TRIMETHYLCHLOROSILANE: A NOVEL ACTIVATING REAGENT IN NUCLEOTIDE SYNTHESIS VIA THE PHOSPHORAMIDITE ROUTE

Trimethylchlorosilane (TMSCl) is a remarkably efficient activator in the reaction of phosphorus(III) amides with nucleosides to give phosphorus(III) esters in excellent yield.