Safety profile of vonoprazan compared with proton pump inhibitors: insight from a pharmacovigilance study.

Proton pump inhibitors (PPIs) are used to treat acid-related disorders such as peptic ulcer and gastroesophageal reflux disease. Recently, vonoprazan, a novel potassium-competitive acid blocker (P-CAB), has been introduced as more effective treatment option. The purpose of this study was to clarify the adverse events associated with vonoprazan compared to PPIs using a spontaneous reporting system database. We performed a retrospective pharmacovigilance disproportionality analysis using the Japanese Adverse Drug Event Report (JADER) database. Adverse event reports submitted to the Pharmaceuticals and Medical Devices Agency between 2004 and 2017 were analyzed, and the reporting odds ratio (ROR) and 95% confidence interval (CI) for each adverse event were calculated. The database comprised 11,433 reports associated with PPIs, and 636 reports with vonoprazan. Hepatic and skin disorders were commonly detected in both PPIs and vonoprazan. There was a significant association of interstitial lung disease with PPIs as a class (ROR: 1.61, 95%CI: 1.47-1.77), but not with vonoprazan. Vonoprazan was strongly associated with haemorrhagic enterocolitis (ROR, 86.5; 95%CI, 59.7125). Among the PPIs, the signal score of microscopic colitis was noteworthy in the case of lansoprazole (ROR, 405; 95%CI, 348-472). It is suggested that there is a diversity in the strength of the association between PPIs and vonoprazan with adverse events. Our results may provide useful information for the treatment of acid-related disorders, but further research with more data is needed to finally clarify this.

Evaluation of adverse events associated with filgrastim originator and biosimilar using a spontaneous reporting system database.

Biosimilar products of filgrastim have become available for improved sustainability of cancer care; however, the real-world safety profile remains unknown. The purpose of this study was to clarify the adverse events associated with filgrastim originator and its biosimilar using the Japanese Adverse Drug Event Report (JADER) database. Adverse event reports submitted to the Pharmaceuticals and Medical Devices Agency between 2014-2018 were extracted. We calculated the reporting odds ratio and 95% confidence interval for each adverse event. We obtained 584 reports of adverse events associated with filgrastim originator and 102 reports with its biosimilar. Signals were detected for bone marrow failure and febrile neutropenia with both filgrastim originator and its biosimilar; whereas those for drug resistance and hypoxia only involved filgrastim originator, and those for interstitial lung disease only involved its biosimilar. The safety profiles of filgrastim originator and its biosimilar were partly different. Further studies are needed to confirm these findings.

Evaluation of the compliance with antiemetic guidelines for prevention of chemotherapy-induced nausea and vomiting in patients with hematologic malignancy.

To assess compliance with the Japanese antiemetic guidelines for chemotherapy-induced nausea and vomiting (CINV), the frequencies of CINV occurrence and use of antiemetic rescue medications were examined in patients with hematological malignancy. A total of 40 patients with hematologic malignancy were eligible in this study. This study was performed in the Department of Hematology, Kyushu University Hospital, as a subgroup analysis from a nationwide, multicenter prospective cohort study conducted by the CINV Study Group of Japan. In the patients with hematological malignancy, the guideline compliance rate was 45 %. Five patients (22.7 %) experienced vomiting during the observation period after receiving non-guideline-consistent antiemetic prophylaxis, whereas no patient experienced vomiting after receiving guideline-consistent antiemetic prophylaxis. The study was not sufficiently powered to reach a statistical significance in its frequency of occurrence between the compliance and non-compliance groups. In the entire study period, 8 out of 40 patients required rescue medication, but there was no association between the status of compliance and the antiemetic guidelines. A total of 22 (55.0 %) patients achieved complete response, which was defined as no vomiting and no use of antiemetic rescue medication, during the study period. The rate of compliance with the prophylactic antiemetic treatment guidelines seemed to be low in patients with hematological malignancy, although the status of the guideline compliance did not always influence the antiemetic effects.

Comparison of antiemetic effects of granisetron and palonosetron in patients receiving bendamustine-based chemotherapy.

The antiemetic effects and safety of granisetron and palonosetron against chemotherapy-induced nausea and vomiting (CINV) were retrospectively evaluated in patients with non-Hodgkin lymphoma receiving bendamustine-based chemotherapy. A total of 61 patients were eligible for this study. Before starting the bendamustine-based chemotherapy, granisetron or palonosetron were intravenously administered with or without aprepitant and/or dexamethasone. The proportions of patients with complete control (CC) during the overall (during the 6 days after the start of the chemotherapy), acute (up to 2 days), and delayed (3 to 6 days) phases were assessed. CC was defined as complete response with only grade 0-1 nausea, no vomiting, and no use of antiemetic rescue medication. Granisetron or palonosetron alone were administered to 9 and 19 patients, respectively. Aprepitant and/or dexamethasone were combined with granisetron and palonosetron in 28 and 5 patients, respectively. Acute CINV was completely controlled in all patients. Both granisetron monotherapy and palonosetron combination therapy could provide good control of delayed CINV, although the CC rates during the delayed and overall phases were not significantly different among mono- and combination therapy of the antiemetics. There was no significant difference in the frequencies of adverse drug events between the granisetron and palonosetron treatment groups. The present study showed that the antiemetic efficacy and safety of granisetron-based therapy were non-inferior to those of palonosetron-based therapy. Taken together with treatment costs, granisetron monotherapy would be adequate to prevent CINV in patients with non-Hodgkin lymphoma receiving bendamustine-based chemotherapy.

Differential impacts of CYP2C19 gene polymorphisms on the antiplatelet effects of clopidogrel and ticlopidine.

We examined the influence of CYP2C19 polymorphisms on the antiplatelet effects of clopidogrel and ticlopidine. The platelet aggregation induced by 20 µmol/l adenosine diphosphate (ADP) and CYP2C19 single-nucleotide polymorphisms (*2 and *3) was determined in patients with coronary artery disease (CAD) who were taking aspirin alone (n = 21), aspirin plus clopidogrel (n = 97), or aspirin plus ticlopidine (n = 47). The degree of platelet aggregation in the clopidogrel group, although not in the ticlopidine group, depended on the CYP2C19 polymorphism, and the maximal platelet aggregation in poor metabolizers (PMs) taking clopidogrel was equivalent to that in the group taking aspirin alone. After being switched from clopidogrel to ticlopidine, all seven of the PMs showed markedly lower platelet aggregation. These results suggest that CYP2C19 polymorphisms have a profound impact on the antiplatelet effect of clopidogrel but not on that of ticlopidine. Ticlopidine may be an effective therapeutic option for CYP2C19 PMs.

Synthesis, biology, NMR and conformation studies of the topographically constrained delta-opioid selective peptide analogs of [beta-iPrPhe(3)]deltorphin I.

Replacement of Phe3 in the endogenous delta-opioid selective peptide deltorphin I with four optically pure stereoisomers of the topographically constrained, highly hydrophobic novel amino acid beta-isopropylphenylalanine (beta-iPrPhe) produced four pharmacologically different deltorphin I peptidomimetics. Radiolabeled ligand-binding assays and in vitro biological evaluation indicate that the stereoconfiguration of the iPrPhe residue plays a crucial role in determining the binding affinity, bioactivity and selectivity of [beta-iPrPhe3]deltorphin I analogs: a (2S,3R) configuration of the iPrPhe3 residue in [beta-iPrPhe3]deltorphin I provided the most desirable biological properties with binding affinity (IC50 = 2 nM), bioassay potency (IC50 = 1.23 nM in MVD assay) and exceptional selectivity for the delta-opioid receptor over the mu-opioid receptor (30 000). Further conformational studies based on two-dimensional NMR and computer-assisted molecular modeling suggested a model for the possible bioactive conformation in which the Tyr1 and (2S,3R)-beta-iPrPhe3 residues adopt trans side-chain conformations, and the linear peptide backbone favors a distorted beta-turn conformation.

Biological properties of Phe(o)-opioid peptide analogues.

Biological properties of new analogues, which represent Phe(o)-propeptides of a variety of opioid peptides, are described. All Phe(o)-opioid analogues expressed both receptor binding affinities and in vitro biological activities at least at the level of the primary opioid peptides. Surprisingly, some of the propeptides expressed slightly higher activity than the primary opioid peptides. Nevertheless, no significant shift in receptor selectivity was observed, which indicate that these Phe(o)-analogues undoubtedly are propeptides. The possible role of membrane proteolytic enzymes associated with opioid receptors in transformation of propeptides is discussed.

The role of the G protein gamma(2) subunit in opioid antinociception in mice.

We examined the role of the gamma(2) subunit of G proteins (Ggamma(2)) in the antinociception produced by c[D-Pen(2), D-Pen(5)]enkephalin (DPDPE) in mice. DPDPE produced 84.0+/-9.0% antinociception in vehicle-treated mice. After intracerebroventricular (i.c.v.) treatment with an antisense phosphorothioate oligodeoxynucleotide to the Ggamma(2) subunit, DPDPE-mediated antinociception decreased to 24.4+/-7.4%. The mismatch phosphorothioate oligodeoxynucleotide-treated mice showed 65.1+/-10.3% antinociception, while the missense phosphorothioate oligodeoxynucleotide-treated mice showed 76.4+/-23.6% antinociception by DPDPE. The reduction of analgesia in antisense phosphorothioate oligodeoxynucleotide-treated mice was significant in comparison with vehicle-treated (P<0.001), mismatch phosphorothioate oligodeoxynucleotide-treated (P<0.01) and missense phosphorothioate oligodeoxynucleotide-treated (P<0.05) mice. These results suggest that the G protein gamma(2) subunit is involved in the transduction pathway leading to antinociception by DPDPE.

(2S,3R)TMT-L-Tic-OH is a potent inverse agonist at the human delta-opioid receptor.

We examined the pharmacologic effect of beta-methyl-2',6'-dimethyltyrosine-L-tetrahydroisoquinone-3- carboxylic acid ((2S,3R)TMT-L-Tic-OH) on G protein activation in membranes prepared from Chinese Hamster Ovary cells transfected with cDNA of the human delta-opioid receptor. (2S,3R)TMT-L-Tic-OH inhibited G protein activation to 58% of basal with an EC50 of 0.72 nM as determined by [35S]GTPgammaS binding. These findings suggest that (2S,3R)TMT-L-Tic-OH is a highly potent inverse agonist at the human delta-opioid receptor.

Exploring the structure-activity relationships of [1-(4-tert-butyl-3'-hydroxy)benzhydryl-4-benzylpiperazine] (SL-3111), a high-affinity and selective delta-opioid receptor nonpeptide agonist ligand.

SL-3111 [1-(4-tert-butyl-3'-hydroxy)benzhydryl-4-benzylpiperazine] is a de novo designed, high-affinity and selective nonpeptide peptidomimetic agonist of the delta-opioid receptor. In a previous report we had described the unique biological characteristics of this ligand and also a need for further structural evaluation.(6) To pursue this, we have introduced a completely different heterocyclic template (2 and 3), which, based on molecular modeling studies, may present the required structural features to properly orient the pharmacophore groups. We also have made more subtle changes to the original piperazine scaffold (5 and 11). The biological activities of these compounds revealed an important participation of the scaffold in the ligand-receptor interaction. To further explore functional diversity on the scaffold, we have maintained the original piperazine ring and introduced four different functionalities at position 2 of the heterocyclic ring (15a-d; a = CH(2)-O-CH(2)-Ph; b = Me; c = CH(2)Ph; d = CH(2)OH). The biological activities observed for these compounds showed a very interesting trend in terms of the steric effects of the groups introduced at this position. A decrease of almost 2000-fold in affinity and potency at the delta-receptor was observed for 15c compared with 15b. This difference may be explained if we postulate that the bioactive conformation of these peptidomimetics is close to the minimal energy conformations calculated in our study. On the basis of these findings we have realized the importance of this position to further explore and simplify the structure of future generations of peptidomimetic ligands.

Relationship between hydrophobicity and beta-blocking potencies, affinities or dissociation of beta-blockers from beta-adrenoceptors.

The present study was performed to assess the relationship between the hydrophobicity of drugs and (1) inhibitory strength (pA2) on chronotropic or inotropic actions, (2) displacemental potencies of 3H-CGP12177 or 125I-iodocyanopindolol binding to beta-adrenoceptors (beta-ARs) (pKi) or (3) dissociating potencies of these drugs from beta-ARs of atria strips pretreated with drugs. The beta-blockers used in the present study were bopindolol, active metabolite of bopindolol (18-502), atenolol, propranolol, pindolol, nadolol, alprenolol, oxprenolol, metoprolol, labetalol and acebutolol. The value of the partition coefficient of propranolol was the highest, and that of the beta1-selective blocker atenolol was the lowest. Although low correlation coefficients between hydrophobicity and inhibitory beta-blocking potencies determined by pharmacological experiments or displacemental potencies by the radioligand binding assay using 3H-CGP12177 and 125I-iodocyanopindolol were observed, significant relationships between hydrophobicities of these drugs and dissociating potencies from beta-ARs were observed. These results suggest that the hydrophobicity of drugs may be important for the slow dissociation from beta-ARs, but not for the beta-blocking action.

De novo design, synthesis, and biological activities of high-affinity and selective non-peptide agonists of the delta-opioid receptor.

On the basis of the structure-activity relationships of delta-opioid-selective peptide ligands and on a model of the proposed bioactive conformation for a potent and selective, conformationally constrained delta-opioid peptide ligand [(2S, 3R)-TMT1]DPDPE, a series of small organic peptide mimetic compounds targeted for the delta-opioid receptor have been designed, synthesized, and evaluated in radiolabeled ligand binding assays and in vitro bioassays. The new non-peptide ligands use piperazine as a template to present the most important pharmacophore groups, including phenol and phenyl groups and a hydrophobic moiety. This hydrophobic group was designed to mimic the hydrophobic character of the D-Pen residues in DPDPE, which has been found to be extremely important for increasing the binding affinity and selectivity of these non-peptide ligands for the delta-opioid receptor over the mu-opioid receptor. Compound 6f (SL-3111) showed 8 nM binding affinity and over 2000-fold selectivity for the delta-opioid receptor over the mu-opioid receptor. Both enantiomers of SL-3111 were separated, and the (-)-isomer was shown to be the compound with the highest affinity for the delta-opioid receptor found in our study (IC50 = 4.1 nM), with a selectivity very similar to that observed for the racemic compound. The phenol hydroxyl group of SL-3111 turned out to be essential to maintain high affinity for the delta-opioid receptor, which also was observed in the case of the delta-opioid-selective peptide ligand DPDPE. Binding studies of SL-3111 and [p-ClPhe4]DPDPE on the cloned wild-type and mutated human delta-opioid receptors suggested that the new non-peptide ligand has a binding profile similar to that of DPDPE but different from that of (+)-4-[((alphaR)-alpha(2S,5R)-4-allyl-2, 5-dimethyl-1-piperazinyl)-3-methoxybenzyl]-N,N-diethylbenzamide (SNC-80), another delta-opioid-selective non-peptide ligand.

Endomorphin-1 and endomorphin-2 are partial agonists at the human mu-opioid receptor.

Recently two tetrapeptide ligands that bind preferentially to the mu-opioid receptor were identified and named endomorphin-1 and endomorphin-2. We examined the ability of these peptides to stimulate G protein activation in human mu-opioid receptor transfected B82 fibroblasts as measured by [35S]GTPgammaS binding to cell membranes. Both endomorphin-1 and -2 act as partial agonists in this assay system compared with the mu-selective agonist [D-Ala2,N-Me-Phe4, Gly-ol5]enkephalin (DAMGO). In addition, endomorphins demonstrate efficacy similar to morphine. These findings demonstrate that endomorphin peptides have similar activity at the mu-opioid receptor as morphine and suggest that these peptides have the potential to modulate neuronal activity in vivo.

The efficacy of delta-opioid receptor-selective drugs.

Delta-opioid receptor-selective drugs may provide an alternative to mu-opioid-selective drugs currently used for the relief of pain. To develop improved delta-opioid receptor-selective drugs, better measures of drug activity are necessary. In this review we suggest that efficacy calculations provide a superior measure of drug activity as compared to dissociation constants and drug potencies in functional assays. Efficacy, as discussed in this review, is defined as a quantitative measurement of the ability of a drug to stimulate second messenger systems or measurable functional responses in cells or tissues under standard conditions. Efficacy values will allow medicinal chemists to understand the contributions of both the coupling efficiency and dissociation constant to drug potencies in the development of new delta-opioid receptor-selective drugs.

Relative efficacies of delta-opioid receptor agonists at the cloned human delta-opioid receptor.

The present study was conducted to determine the relative efficacies of the selective delta-opioid receptor agonists SNC80 ((+)-4-[(alphaR)-alpha-((2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl )-3-methoxybenzyl]-N,N-diethylbenzamide), pCl-DPDPE (cyclic[D-Pen2,4'-ClPhe4,D-Pen5]enkephalin) and (-)-TAN67 ((-)-2-methyl-4a alpha-(3-hydroxyphenyl)-1,2,3,4,4a,5,12,12a alpha-octahydro-quinolino-[2,3,3-g]isoquinoline). Experiments compared the abilities of the three drugs to competitively inhibit [3H]naltrindole binding and also stimulate [35S]GTPgammaS binding in membranes prepared from stably transfected Chinese hamster ovary (CHO) cells that express the cloned human delta-opioid receptor. Efficacy was determined according to the formula: efficacy = (E(max-A)/Emax)(A'/A + 1) X 0.5. Results show that SNC80 and pCl-DPDPE had efficacy values that were about 6-7 times greater than that of (-)-TAN67.

AM630 antagonism of cannabinoid-stimulated [35S]GTP gamma S binding in the mouse brain.

This research was designed to determine the action of the novel aminoalkylindole AM630 (6-iodo-pravadoline) at the cannabinoid receptor by studying its interaction with the cannabinoid receptor agonist WIN 55,212-2 (R(+)-[2,3-dihydro-5-methyl-3-[(morpholinyl)methyl]pyrrolo [1,2,3-de]-1,4-benzoxazin-y]-(1-naphthalenyl)methanone mesylate) on guanosine-5'-O-(3-[35S]thio) triphosphate ([35S]GTP gamma S) binding in mouse brain. WIN 55,212-2 stimulated [35S]GTP gamma S binding, while AM630 had no effect. AM630 antagonized WIN 55,212-2-2induced [35S]GTP gamma S binding and shifted the WIN 55,212-dose-response curve to the right. These results clearly demonstrate that AM630 exerts cannabinoid receptor antagonist properties in the brain.

AM630 is a competitive cannabinoid receptor antagonist in the guinea pig brain.

AM630 has been demonstrated to be a cannabinoid receptor antagonist in the mouse brain and vas deferens. Conversely, it was recently reported that AM630 acts as a cannabinoid agonist in the guinea pig ileum. This research was designed to determine whether the difference in the action of AM630 is species specific. Studies conducted in guinea pig brain reveal that AM630 antagonizes the stimulatory effect of the cannabinoid agonist WIN 55,212-2 on [35S]GTPgammaS binding suggesting that difference in AM630 activity in different tissues is not due to species variation.