Automated radiosynthesis of [11 C]MTP38-a phosphodiesterase 7 imaging tracer-using [11 C]hydrogen cyanide for clinical applications.

We have developed 8-amino-3-(2S,5R-dimethyl-1-piperidyl)-[1,2,4]triazolo[4,3-a]pyrazine-5-[11 C]carbonitrile ([11 C]MTP38) as a positron emission tomography (PET) tracer for the imaging of phosphodiesterase 7. For the fully automated production of [11 C]MTP38 routinely and efficiently for clinical applications, we determined the radiosynthesis procedure of [11 C]MTP38 using [11 C]hydrogen cyanide ([11 C]HCN) as a PET radiopharmaceutical. Radiosynthesis of [11 C]MTP38 was performed using an automated 11 C-labeling synthesizer developed in-house within 40 min after the end of irradiation. [11 C]MTP38 was obtained with a relatively high radiochemical yield (33 ± 5.5% based on [11 C]CO2 at the end of irradiation, decay-corrected, n = 15), radiochemical purity (>97%, n = 15), and molar activity (47 ± 12 GBq/µmol at the end of synthesis, n = 15). All the results of the quality control (QC) testing for the [11 C]MTP38 injection complied with our in-house QC and quality assurance specifications. We successfully automated the radiosynthesis of [11 C]MTP38 for clinical applications using an 11 C-labeling synthesizer and sterile isolator. Taken together, this protocol provides a new radiopharmaceutical [11 C]MTP38 suitable for clinical applications.

Radiosynthesis and quality control testing of the tau imaging positron emission tomography tracer [18 F]PM-PBB3 for clinical applications.

Recently, we produced 11 C-labeled 2-((1E,3E)-4-(6-(methylamino)pyridin-3-yl)buta-1,3-dienyl)benzo[d]thiazol-6-ol ([11 C]PBB3) as a clinically useful positron emission tomography (PET) tracer for in vivo imaging of tau pathologies in the human brain. To overcome the limitations (i.e., rapid in vivo metabolism and short half-life) of [11 C]PBB3, we further synthesized 18 F-labeled 1-fluoro-3-((2-((1E,3E)-4-(6-(methylamino)pyridine-3-yl)buta-1,3-dien-1-yl)benzo[d]thiazol-6-yl)oxy)propan-2-ol ([18 F]PM-PBB3). [18 F]PM-PBB3 is also a useful tau PET tracer for imaging tau pathologies. In this study, we developed a routine radiosynthesis and quality control testing of [18 F]PM-PBB3 for clinical applications. [18 F]PM-PBB3 was synthesized by direct 18 F-fluorination of the tosylated derivative, followed by removal of the protecting group. [18 F]PM-PBB3 was obtained with sufficient radioactivity (25 ± 6.0% of the nondecay-corrected radiochemical yield at the end of synthesis, EOS), radiochemical purity (98 ± 0.6%), and molar activity (350 ± 94 GBq/µmol at EOS; n = 53). Moreover, [18 F]PM-PBB3 consistently retained >95% of radiochemical purity for 60 min without undergoing photoisomerization using a new UV-cutoff light (yellow light) fixed in the hot cell to monitor the synthesis. All the results of the quality control testing for the [18 F]PM-PBB3 injection complied with our in-house quality control and quality assurance specifications. We have accomplished >200 production runs of [18 F]PM-PBB3 in our facility for various research purposes.

Comparison between [18F]fluorination and [18F]fluoroethylation reactions for the synthesis of the PDE10A PET radiotracer [18F]MNI-659.

INTRODUCTION: 2-(2-(3-(4-(2-[18F]Fluoroethoxy)phenyl)-7-methyl-4-oxo-3,4-dihydroquinazolin-2-yl)ethyl)-4-isopropoxyisoindoline-1,3-dione ([18F]MNI-659, [18F]1) is a useful PET radiotracer for imaging phosphodiesterase 10A (PDE10A) in human brain. [18F]1 has been previously prepared by direct [18F]fluorination of a tosylate precursor 2 with [18F]F-. The aim of this study was to determine the conditions for the [18F]fluorination reaction to obtain [18F]1 of high quality and with sufficient radioactivity for clinical use in our institute. Moreover, we synthesized [18F]1 by [18F]fluoroethylation of a phenol precursor 3 with [18F]fluoroethyl bromide ([18F]FEtBr), and the outcomes of [18F]fluorination and [18F]fluoroethylation were compared. METHODS: We performed the automated synthesis of [18F]1 by [18F]fluorination and [18F]fluoroethylation using a multi-purpose synthesizer. We determined the amounts of tosylate precursor 2 and potassium carbonate as well as the reaction temperature for direct [18F]fluorination. RESULTS: The efficiency of the [18F]fluorination reaction was strongly affected by the amount of 2 and potassium carbonate. Under the determined reaction conditions, [18F]1 with 0.82±0.2GBq was obtained in 13.6%±3.3% radiochemical yield (n=8, decay-corrected to EOB and based on [18F]F-) at EOS, starting from 11.5±0.4GBq of cyclotron-produced [18F]F-. On the other hand, the [18F]fluoroethylation of 3 with [18F]FEtBr produced [18F]1 with 1.0±0.2GBq and in 22.5±2.5 % radiochemical yields (n=7, decay-corrected to EOB and based on [18F]F-) at EOS, starting from 7.4GBq of cyclotron-produced [18F]F-. Clearly, [18F]fluoroethylation resulted in a higher radiochemical yield of [18F]1 than [18F]fluorination. CONCLUSION: [18F]1 of high quality and with sufficient radioactivity was successfully radiosynthesized by two methods. [18F]1 synthesized by direct [18F]fluorination has been approved and will be provided for clinical use in our institute.

Efficient radiosynthesis and non-clinical safety tests of the TSPO radioprobe [(18)F]FEDAC: Prerequisites for clinical application.

INTRODUCTION: [(18)F]FEDAC ([(18)F]1) has potent binding affinity and selectivity for translocator protein (18kDa, TSPO), and has been used to noninvasively visualize neuroinflammation, lung inflammation, acute liver damage, nonalcoholic fatty liver disease, and liver fibrosis. We had previously synthesized [(18)F]1 in two steps: (i) preparation of [(18)F]fluoroethyl bromide and (ii) coupling of [(18)F]fluoroethyl bromide with the appropriate precursor (2) for labeling. In this study, to clinically utilize [(18)F]1 as a PET radiopharmaceutical and to transfer the production technique of [(18)F]1 to other PET centers, we simplified its preparation by using a direct, one-step, tosyloxy-for-fluorine substitution. We also performed an acute toxicity study as a major non-clinical safety test, and determined radiometabolites using human liver microsomes. METHODS: [(18)F]1 was prepared via direct (18)F-fluorination by heating the corresponding tosylated derivative (3) with [(18)F]fluoride as its Kryptofix 222 complex in dimethyl sulfoxide at 110°C for 15min, following by HPLC purification. Non-clinical safety tests were performed for the extended single-dose toxicity study in rats, and for the in vitro metabolite analysis with human liver microsomal incubation. RESULTS: High quality batches of [(18)F]1, compatible with clinical applications, were obtained. At the end of irradiation, the decay-corrected radiochemical yield of [(18)F]1 using 1 and 5mg of precursor based on [(18)F]fluoride was 18.5±7.9% (n=10) and 52.0±5.8% (n=3), respectively. A single-dose of [(18)F]1 did not show toxicological effects for 14 days after the injection in male and female rats. In human liver microsomal incubations, [(18)F]1 was easily metabolized to [(18)F]desbenzyl-FEDAC ([(18)F]10) by CYPs (4.2% of parent compound left 60min after incubation). CONCLUSION: We successfully synthesized clinical grade batches of [(18)F]1 and verified the absence of innocuity of this radiotracer. [(18)F]1 will be used to first-in-human studies in our facility.

Identification of a major radiometabolite of [11C]PBB3.

INTRODUCTION: [(11)C]PBB3 is a clinically used positron emission tomography (PET) probe for in vivo imaging of tau pathology in the brain. Our previous study showed that [(11)C]PBB3 was rapidly decomposed to a polar radiometabolite in the plasma of mice. For the pharmacokinetic evaluation of [(11)C]PBB3 it is important to elucidate the characteristics of radiometabolites. In this study, we identified the chemical structure of a major radiometabolite of [(11)C]PBB3 and proposed the metabolic pathway of [(11)C]PBB3. METHODS: Carrier-added [(11)C]PBB3 was injected into a mouse for in vivo metabolite analysis. The chemical structure of a major radiometabolite was identified using LC-MS. Mouse and human liver microsomes and liver S9 samples were incubated with [(11)C]PBB3 in vitro. In silico prediction software was used to assist in the determination of the metabolite and metabolic pathway of [(11)C]PBB3. RESULTS: In vivo analysis showed that the molecular weight of a major radiometabolite of [(11)C]PBB3, which was called as [(11)C]M2, was m/z 390 [M+H(+)]. In vitro analysis assisted by in silico prediction showed that [(11)C]M2, which was not generated by cytochrome P450 enzymes (CYPs), was generated by sulfated conjugation mediated by a sulfotransferase. CONCLUSION: The major radiometabolite, [(11)C]M2, was identified as a sulfated conjugate of [(11)C]PBB3. [(11)C]PBB3 was metabolized mainly by a sulfotransferase and subsidiarily by CYPs.

[Outcomes of high-risk prostate cancer patients at Hakodate Goryoukaku Hospital].

We assessed the outcomes of high-risk prostate cancer patients who received radical prostatectomy (RP), external beamradiation therapy (EBRT) or androgen deprivation therapy (ADT). Two hundred nineteen patients who were diagnosed with pathologically confirmed high-risk prostate cancer as defined by D'Amico between 2005 and 2011 were included in this study. Of them, 74 patients underwent RP. The 5-year cancer-specific survival (5yCSS) and 5-year PSA recurrence-free survival (5yPRFS) rates were 100 and 67.2%, respectively. A positive surgical margin and Gleason score≧8 were risk factors for PSA recurrence. The 5yPRFSs were 100, 74.4% and 'unmeasurable' for patients with 0, 1 and 2 risk factors, respectively. Ninety patients underwent EBRT. The 5yCSS and 5yPRFS rates were 95.2 and 74.2%, respectively. Fifty-five patients underwent ADT alone. Their 5yCSS and 5yPRFS rates were 93. 3 and 64. 3%, respectively. There was no significant difference in 5yCSS and 5yPRFS rates among the treatment groups. These results show that RP can be a treatment option for high-risk prostate cancer patients.

Radiosynthesis, photoisomerization, biodistribution, and metabolite analysis of 11C-PBB3 as a clinically useful PET probe for imaging of tau pathology.

UNLABELLED: 2-((1E,3E)-4-(6-((11)C-methylamino)pyridin-3-yl)buta-1,3-dienyl)benzo[d]thiazol-6-ol ((11)C-PBB3) is a clinically useful PET probe that we developed for in vivo imaging of tau pathology in the human brain. To ensure the availability of this probe among multiple PET facilities, in the present study we established protocols for the radiosynthesis and quality control of (11)C-PBB3 and for the characterization of its photoisomerization, biodistribution, and metabolism. METHODS: (11)C-PBB3 was synthesized by reaction of the tert-butyldimethylsilyl desmethyl precursor ( 1: ) with (11)C-methyl iodide using potassium hydroxide as a base, followed by deprotection. Photoisomerization of (11)C-PBB3 under fluorescent light was determined. The biodistribution and metabolite analysis of (11)C-PBB3 was determined in mice using the dissection method. RESULTS: (11)C-PBB3 was synthesized with 15.4% ± 2.8% radiochemical yield (decay-corrected, n = 50) based on the cyclotron-produced (11)C-CO2 and showed an averaged synthesis time of 35 min from the end of bombardment. The radiochemical purity and specific activity of (11)C-PBB3 were 98.0% ± 2.3% and 180.2 ± 44.3 GBq/µmol, respectively, at the end of synthesis (n = 50). (11)C-PBB3 showed rapid photoisomerization, and its radiochemical purity decreased to approximately 50% at 10 min after exposure to fluorescent light. After the fluorescent light was switched off, (11)C-PBB3 retained more than 95% radiochemical purity over 60 min. A suitable brain uptake (1.92% injected dose/g tissue) of radioactivity was observed at 1 min after the probe injection, which was followed by rapid washout from the brain tissue. More than 70% of total radioactivity in the mouse brain homogenate at 5 min after injection represented the unchanged (11)C-PBB3, despite its rapid metabolism in the plasma. CONCLUSION: (11)C-PBB3 was produced with sufficient radioactivity and high quality, demonstrating its clinical utility. The present results of radiosynthesis, photoisomerization, biodistribution, and metabolite analysis could be helpful for the reliable production and application of (11)C-PBB3 in diverse PET facilities.

High-yield automated synthesis of [18F]fluoroazomycin arabinoside ([18F]FAZA) for hypoxia-specific tumor imaging.

The aim of this study was to develop an efficient fully automated synthesis method to achieve a high radiochemical yield of [(18)F]FAZA with a small amount of precursor. A small cartridge containing 25mg of the QMA resin was prepared and evaluated to obtain [(18)F]F(-) in a small quantity of base (K(2)CO(3)), which might allow the use of a small amount of precursor. The labeling and hydrolyzing conditions for [(18)F]FAZA synthesis were also investigated manually. No-carrier-added [(18)F]F(-) was trapped on the small QMA cartridge and eluted with a mixture of Krytofix 222 (2.26 mg, 6.0 µmol) and K(2)CO(3) (0.69 mg, 5.0 µmol) in 70% MeCN (0.4 mL). The automated synthesis of [(18)F]FAZA was optimally performed with a modified NIRS original synthesis system for clinical use, by labeling 2.5mg (5.2 µmol) of the precursor in DMSO (0.4 mL) at 120°C for 10 min, and then by hydrolyzing the (18)F-labeled intermediate with 0.1M NaOH (0.5 mL) at room temperature for 3 min. Using the above condition, the [(18)F]FAZA injection was obtained with a high radiochemical yield of 52.4±5.3% (decay-corrected, n=8) within 50.5±1.5 min.

Clinical outcomes of patients with pT0 bladder cancer after radical cystectomy: a single-institute experience.

OBJECTIVE: To investigate the clinical outcomes of patients who underwent radical cystectomy for bladder cancer at a single institution and compare those who had pT0 specimens with those who had residual cancer. METHODS: From January 1990 to December 2006, 186 patients underwent radical cystectomy with or without neoadjuvant chemotherapy for cT2 or higher stage urothelial carcinoma in the bladder in our hospital. We estimated the 5-year disease-free survival, cancer-specific survival and overall survival by the pathological stage. RESULTS: The median follow-up of the 186 patients was 38.5 months (0-194). Of these, 51 received neoadjuvant chemotherapy. For all subjects, the 5-year disease-free survival was 54.9%, cancer-specific survival 61.0% and overall survival 57.1%. Of the 186 patients, 24 (12.9%) had no residual cancer in the bladder specimen at radical cystectomy. Of the 24 patients with pT0, only 1 (4.2%) died of bladder cancer. The 5-year disease-free survival, cancer-specific survival and overall survival rates in patients with pT0 were ∼96.0%. We found pT0 histology in 11 of the 51 patients (21.6%) with neoadjuvant chemotherapy and in 13 of the 135 patients (9.6%) with radical cystectomy alone (P = 0.047). CONCLUSIONS: We demonstrated that the outcomes of patients who underwent radical cystectomy were similar to those in previous reports. Patients with pT0 showed favorable outcomes for disease-free survival, cancer-specific survival and overall survival in our study. However, they should be periodically followed up because pT0 does not always mean cure.

[Retrospetive analysis of early postoperative complications of radical cystectomy and urinary diversion performed during a 17-year period].

We retrospectively analyzed early postoperative complications in 293 consecutive patients withbladder cancer who underwent radical cystectomy with urinary diversion from 1990 to 2007 at the Department of Urology of the Sapporo Medical University School of Medicine. The Common Terminology Criteria for Adverse Events (ver 3.0) was used to evaluate complications that occurred within 30 days after surgery, and grade 3 and higher grades according to the criteria were defined as complications in this study. The guidelines of the Centers for Disease Control and Prevention were used for the classification of surgical site infection. Early postoperative complications were found in 158 cases (54%). Acute pyelonephritis (APN), which was related to the removal of the ureteral catheter, was the most frequent complication, found in 96 (33%), followed by surgical site infection in 39 (13%), and ileus in 33 (11%). When transient APN was excluded, the rate for complications was 30%. Possible life-threatening complications were experienced in 15 patients (5%) including 2 (0.7%) who eventually died of the complications. The preoperative grade 3 score of the American Society of Anesthesiologists (ASA score) was significantly related to development of early postoperative complications in univariate analysis. In multivariate analysis, a grade 3 ASA score and the estimated blood loss were independent factors to predict development of early complications. Postoperative nasogastric tubing was not related to ileus after surgery, suggesting that postoperative indwelling of the tube is not routinely needed. Although about half of the patients experienced early postoperative complications, they were usually transient and manageable. Thus, careful evaluation of the preoperative ASA score and a reduction in the amount of bleeding during surgery may lower the development of early postoperative complications.

[Scleroderma-like skin sclerosis induced by docetaxel chemotherapy for hormone refractory prostate cancer: a case report].

We report the first case of scleroderma-like skin sclerosis induced by docetaxel chemotherapy for prostate cancer in Japan. A 67-year-old man underwent radical prostatectomy for cT3aN0M0 prostate cancer in 2003. Thereafter PSA recurrence developed and antiandrogen deprivation therapy was used. However, we diagnosed this case as hormone refractory prostate cancer and began docetaxel chemotherapy in October 2008. There were no nonhematological adverse events through two courses of treatment. He presented to dermatology due to pain and swelling of both upper arms on the second day of the third course. However, when treated with a cooling method, swelling of the upper arms became worse and CPK rose to 1,921 IU/I on the eighth day. We administered a steroid ointment and an antibiotic due to suspicion of thrombophlebitis. Nevertheless, CPK rose to 2,791 IU/I and a skin biopsy was done. In consequence, scleroderma-like skin sclerosis induced by docetaxel chemotherapy was diagnosed. Swelling appeared in both lower limbs and the pain got worse on the 17th day. Therefore docetaxel chemotherapy was discontinued and prednisolone was increased to 30 mg/day, in addition to beginning codeine use for the pain. Thereafter, the painful sclerosis was ameliorated.

[Prognosis of local recurrence after radical cystectomy for bladder cancer].

The clinical outcome is poor for patients who have local recurrence after radical cystectomy for bladder cancer. We investigated clinical outcomes of patients with isolated local recurrence and with both local recurrence and distant metastasis. From 1990 to 2006, 299 patients who had bladder cancer without distant metastasis underwent radical cystectomy in our hospital. We included 200 patients who had a negative surgical margin at radical cystectomy and urothelial carcinoma, and who had not had upper urinary tract cancer or other active cancer. Fifteen (7.5%) had isolated local recurrence (isolated group) and 18 (9.0%) had local recurrence and distant metastasis simultaneously (simultaneous group). The median overall survival time and that for survival after recurrence were 24 and 13 months, respectively, in the isolated group, and 18 and 5 months, respectively, in the simultaneous group. Although we did not find a significant difference in overall survival (p = 0.314), there was one for survival after recurrence (p = 0.001) between the two groups. In the isolated group, 13 died of cancer, 1 of another cause and 1 was alive without cancer. All patients in the simultaneous group died of cancer. Three patients in the isolated group underwent surgery for residual tumors after systemic chemotherapy, and 2 of the 3 survived for more than 2 years after recurrence. Some patients with isolated local recurrence benefited from multimodal therapies. In these patients, surgery for the residual tumor after systemic chemotherapy was likely to be effective if a negative margin was achieved in surgical specimens.