Real-world Impact of Fremanezumab on Migraine-Related Health Care Resource Utilization in Patients with Comorbidities, Acute Medication Overuse, and/or Unsatisfactory Prior Migraine Preventive Response.

INTRODUCTION: Fremanezumab, a humanized monoclonal antibody targeting calcitonin gene-related peptide, is indicated for preventive treatment of migraine in adults. Real-world evidence assessing the effect of fremanezumab on migraine-related medication use, health care resource utilization (HCRU), and costs in patient populations with comorbidities, acute medication overuse (AMO), and/or unsatisfactory prior migraine preventive response (UPMPR) is needed. METHODS: Data for this US, retrospective claims analysis were obtained from the Merative® MarketScan® Commercial and supplemental databases. Eligible adults with migraine initiated fremanezumab between 1 September 2018 and 30 June 2019 (date of earliest fremanezumab claim is the index date), had ≥ 12 months of continuous enrollment prior to initiation (preindex period) and ≥ 6 months of data following initiation (postindex period; variable follow-up after 6 months), and had certain preindex migraine comorbidities (depression, anxiety, and cardiovascular disease), potential AMO, or UPMPR. Changes in migraine-related concomitant acute and preventive medication use, HCRU, and costs were assessed pre- versus postindex. RESULTS: In total, 3193 patients met the eligibility criteria. From pre- to postindex, mean (SD) per patient per month (PPPM) number of migraine-related acute medication and preventive medication claims (excluding fremanezumab), respectively, decreased from 0.97 (0.90) to 0.86 (0.87) (P < 0.001) and 0.94 (0.74) to 0.81 (0.75) (P < 0.001). Migraine-related outpatient and neurologist office visits, emergency department visits, and other outpatient services PPPM decreased pre- versus postindex (P < 0.001 for all), resulting in a reduction in mean (SD) total health care costs PPPM from US$541 (US$858) to US$490 (US$974) (P = 0.003). Patients showed high adherence and persistence rates, with mean (SD) proportion of days covered of 0.71 (0.29), medication possession ratio of 0.74 (0.31), and persistence duration of 160.3 (33.2) days 6 months postindex. CONCLUSIONS: Patients with certain migraine comorbidities, potential AMO, and/or UPMPR in a real-world setting had reduced migraine-related medication use, HCRU, and costs following initiation of fremanezumab. Graphical abstract available for this article.

Burden of migraine with acute medication overuse or psychiatric comorbidities and treatment with CGRP pathway-targeted monoclonal antibodies: A review.

Migraine is a complex and often debilitating neurological disease that affects more than 1 billion people worldwide. It is characterized by moderate-to-intense, throbbing headache attacks that are worsened by activity and is associated with nausea, vomiting, and sensitivity to light and sound. Migraine, ranked the second leading cause of years lived with disability by the World Health Organization, can diminish patients' quality of life and bring significant personal and economic burden. Furthermore, migraine patients with a history of acute medication overuse (AMO) or psychiatric comorbidities, such as depression or anxiety, may experience even greater impairment and burden, and their migraine may be more difficult-to-treat. Appropriate treatment of migraine is essential to reduce this burden and improve patient outcomes, especially for those with AMO or psychiatric comorbidities. There are several available preventive treatment options for migraine, though many of these are not migraine-specific and may have limited efficacy and/or poor tolerability. The calcitonin gene-related peptide pathway plays a key role in the pathophysiology of migraine, and monoclonal antibodies that target the calcitonin gene-related peptide pathway have been developed as specific preventive treatments for migraine. Four of these monoclonal antibodies have been approved for the preventive treatment of migraine after demonstrating favorable safety and efficacy profiles. These treatments offer substantial benefits for migraine patients, including those with AMO or common psychiatric comorbidities, by reducing monthly headache days and migraine days, days of acute medication use, and disability measures, as well as improving quality of life.

Adverse Events Reported with Therapies Targeting the CGRP Pathway During the First 6 Months Post-launch: A Retrospective Analysis Using the FDA Adverse Events Reporting System.

INTRODUCTION: Through 2018, three calcitonin gene-related peptide pathway-targeted monoclonal antibodies (CGRP mAbs) had received US Food and Drug Administration (FDA) approval for migraine prevention: erenumab, fremanezumab, and galcanezumab. METHODS: This retrospective analysis evaluated adverse events (AEs) spontaneously reported to the FDA Adverse Event Reporting System (FAERS) safety surveillance database during the first 6 months post-approval of erenumab (May 2018 to November 2018), fremanezumab (September 2018 to March 2019), and galcanezumab (September 2018 to March 2019). Reporting rates (RR) per 1000 exposed patients were calculated from number of reported events (when product classified as "primary suspect") in each AE category and estimated number of treated patients based on de-identified prescription data (IQVIA database) and were ranked on the basis of frequency for each product. RESULTS: RR per 1000 exposed patients for "migraine" (erenumab, 4.89; fremanezumab, 1.01; galcanezumab, 2.99), "headache" (3.32, 1.27, 3.07), and "drug ineffective" (3.68, 1.14, 1.69) were commonly reported for all three products, as were migraine-associated symptoms ("nausea": 2.94, 0.91, 1.09) and "injection-site" reactions ("pain": 2.94, 0.8, 4.9; "swelling": 0.56, 0.53, 1.25; "pruritus": 0.26, 0.63, 1.14; "erythema": 0.58, 0.71, 1.58). "Constipation" ranked second for erenumab (4.90) but did not make the top ten events for fremanezumab (0.46) or galcanezumab (0.76); cardiovascular events did not rank in the top ten AEs for any product. The frequency of serious outcomes was low, with ≤ 2% of AEs categorized as serious across the CGRP mAbs. CONCLUSION: These results aid in supporting the safety profile of CGRP mAbs in the real-world setting and may provide clinicians and patients with additional insight when considering migraine preventive treatments.

Reducing the Burden of Migraine: Safety and Efficacy of CGRP Pathway-Targeted Preventive Treatments.

Migraine is a highly disabling and often chronic neurological disease that affects more than one billion people globally. Preventive migraine treatment is recommended for individuals who have frequent and/or disabling attacks; however, many of the medications used for migraine prevention (e.g., antiepileptics, antidepressants, antihypertensives) were not specifically developed for migraine, and often have limited efficacy or poor tolerability. Four monoclonal antibodies targeting the calcitonin gene-related peptide (CGRP) pathway, which is believed to play a crucial role in the pathophysiology of migraine, have been approved by the US Food and Drug Administration for the preventive treatment of migraine in adults. All four migraine-specific treatments have demonstrated efficacy based on reductions in monthly days with migraine for patients with both episodic and chronic migraine, including those with comorbidities. They have also demonstrated favorable safety and tolerability profiles. Based on these accounts, CGRP pathway-targeted monoclonal antibodies have the potential to revolutionize preventive treatment for patients with migraine.

Real-world effectiveness after initiating fremanezumab treatment in US patients with episodic and chronic migraine or difficult-to-treat migraine.

BACKGROUND: Fremanezumab, a fully humanized monoclonal antibody (mAb; IgG2Δa) that selectively targets calcitonin gene-related peptide (CGRP), is approved for the preventive treatment of migraine in adults. The efficacy and safety of fremanezumab for migraine prevention have been demonstrated in randomized, double-blind, placebo-controlled trials. Real-world effectiveness data are needed to complement clinical trial data. This study assessed the effectiveness of fremanezumab across different subgroups of adult patients with episodic migraine (EM), chronic migraine (CM), or difficult-to-treat (DTT) migraine in real-world clinical settings. METHODS: This retrospective, panel-based online chart review used electronic case report forms. Patient inclusion criteria were a physician diagnosis of EM or CM; age ≥ 18 years at the time of first fremanezumab initiation; ≥ 1 dose of fremanezumab treatment; ≥ 1 follow-up visit since first initiation; and ≥ 2 measurements of monthly migraine days (MMD; with 1 within a month before or at first initiation and ≥ 1 after first initiation). Changes in MMD and monthly headache days were assessed during the follow-up period. These endpoints were evaluated in subgroups of patients by migraine type (EM/CM) and in subgroups with DTT migraine (diagnosis of medication overuse [MO], major depressive disorder [MDD], generalized anxiety disorder [GAD], or prior exposure to a different CGRP pathway-targeted mAb [CGRP mAb]). RESULTS: Data were collected from 421 clinicians and 1003 patients. Mean (percent) reductions from baseline in MMD at Month 6 were - 7.7 (77.0%) in EM patients, - 10.1 (68.7%) in CM patients, - 10.8 (80.6%) in the MO subgroup, - 9.9 (68.3%) in the MDD subgroup, - 9.5 (66.4%) in the GAD subgroup, and - 9.0 (68.7%) in the prior CGRP mAb exposure subgroup. Improvements in MDD or GAD severity were reported by 45.5% and 45.8% of patients with comorbid MDD or GAD, respectively. CONCLUSIONS: In this real-world study, fremanezumab demonstrated effectiveness for migraine regardless of migraine type or the presence of factors contributing to DTT migraine (MO, GAD, MDD, or prior exposure to a different CGRP mAb).

Real-world effectiveness of fremanezumab in migraine patients initiating treatment in the United States: results from a retrospective chart study.

BACKGROUND: The efficacy and tolerability of fremanezumab, a fully humanized monoclonal antibody (IgG2Δa) that selectively targets calcitonin gene-related peptide (CGRP) and is approved for the preventive treatment of migraine in adults, have been demonstrated in randomized, double-blind, placebo-controlled trials. Real-world data can further support those clinical trial data and demonstrate the full clinical benefits of fremanezumab. This chart review assessed the effectiveness of fremanezumab for improving clinical outcomes in adult patients with migraine treated according to real-world clinical practice. METHODS: This retrospective, panel-based, online physician chart review study used electronic case report forms with US physicians. Patient inclusion criteria were a physician diagnosis of migraine, fremanezumab treatment initiation at ≥ 18 years of age after US Food and Drug Administration approval, ≥ 1 dose of fremanezumab treatment, and ≥ 2 assessments of monthly migraine days (MMD; 1 within 30 days before treatment initiation and ≥ 1 after initiation). Changes from baseline in MMD, monthly headache days (MHD), and Migraine Disability Assessment (MIDAS) and 6-item Headache Impact Test (HIT-6) scores were assessed over 6 months. These endpoints were evaluated in the overall population and subgroups divided by dosing schedule and number of prior migraine preventive treatment failures. RESULTS: This study included data from 421 clinicians and 1003 patients. Mean age at fremanezumab initiation was 39.7 years, and most patients were female (75.8%). In the overall population, mean baseline MMD and MHD were 12.7 and 14.0, respectively. Mean (percent) reductions from baseline in MMD and MHD, respectively, were - 4.6 (36.2%) and - 4.7 (33.6%) at Month 1, - 6.7 (52.8%) and - 6.8 (48.6%) at Month 3, and - 9.2 (72.4%) and - 9.8 (70.0%) at Month 6. Mean (percent) reductions from baseline in MIDAS and HIT-6 scores also increased over the 6-month study period, from - 6.2 (21.6%) and - 8.4 (14.0%) at Month 1 to - 18.1 (63.1%) and - 16.2 (27.0%) at Month 6, respectively. Improvements in these outcomes over 6 months were observed across all evaluated subgroups. CONCLUSIONS: This real-world study demonstrated effectiveness of fremanezumab treatment for up to 6 months, irrespective of dosing regimen or number of prior migraine preventive treatment failures, reflecting ongoing, clinically meaningful improvements in patient outcomes.

Efficacy and quality-of-life improvements with fremanezumab treatment in patients with difficult-to-treat migraine with associated neurological dysfunction.

BACKGROUND AND PURPOSE: Fremanezumab, a fully humanized monoclonal antibody (IgG2Δa) that selectively targets calcitonin-gene-related peptide, has demonstrated efficacy as a preventive treatment for adults with episodic migraine or chronic migraine and inadequate response to two to four prior preventive treatment classes in the phase 3b FOCUS study. In this post hoc analysis, efficacy and effects on quality-of-life outcomes for fremanezumab were evaluated in subgroups of patients with and without aura or similar neurological symptoms, here referred to as migraine with or without associated neurological dysfunction. METHODS: In the FOCUS study, 838 patients were randomized (1:1:1) to quarterly fremanezumab, monthly fremanezumab or matched placebo for 12 weeks of double-blind treatment. For this post hoc analysis, subgroups of patients with migraine with and without associated neurological dysfunction at baseline were identified based on patient response to questions about symptoms. RESULTS: In patients with migraine with associated neurological dysfunction at baseline, fremanezumab significantly reduced monthly average days with neurological symptoms (quarterly, -1.7 days; monthly, -1.8 days) compared to placebo (-0.5 days; both p ≤ 0.01). In comparison with placebo, both dosing regimens of fremanezumab yielded greater reductions in monthly migraine days over 12 weeks (p < 0.0001) and improvements in Headache Impact Test 6 and Migraine-Specific Quality of Life scores over the last 4 weeks (p < 0.05), regardless of neurological dysfunction at baseline. CONCLUSIONS: Fremanezumab reduced days with neurological symptoms, effectively prevented migraine, and improved quality of life in patients with migraine with associated neurological dysfunction, including those with previous inadequate response to two to four migraine preventive medication classes.

Effects of fremanezumab in patients with chronic migraine and comorbid depression: Subgroup analysis of the randomized HALO CM study.

OBJECTIVE: To evaluate the efficacy of fremanezumab in patients with chronic migraine (CM) and moderate to severe depression. BACKGROUND: Fremanezumab, a fully humanized monoclonal antibody that selectively targets calcitonin gene-related peptide, has been approved for the preventive treatment of migraine in adults. CM and depression are highly comorbid. METHODS: The 12-week, Phase 3 HALO trial randomized patients with CM to fremanezumab quarterly (675 mg/placebo/placebo), fremanezumab monthly (675/225/225 mg), or placebo. Post hoc analyses evaluated the effects of fremanezumab in patients with moderate to severe depression (baseline 9-item Patient Health Questionnaire sum score ≥10) on monthly number of headache days of at least moderate severity; monthly migraine days; Patient Global Impression of Change (PGIC); 6-item Headache Impact Test (HIT-6) scores; and depression. RESULTS: For the 219/1121 (19.5%) patients with moderate to severe depression at baseline, fremanezumab was associated with a significant reduction in monthly number of headache days of at least moderate severity for active treatment versus placebo (least-squares mean change ± standard error for quarterly dosing: -5.3 ± 0.77; for monthly dosing: -5.5 ± 0.72; and for placebo: -2.2 ± 0.81; both p < 0.001). More patients achieved a ≥50% reduction in headache days of at least moderate severity with fremanezumab (quarterly: 31/78 [39.7%]; monthly: 39/96 [40.6%]) than placebo (9/67 [13.4%]; both p < 0.001). Compared with placebo, fremanezumab improved PGIC and HIT-6 scores. CONCLUSIONS: Fremanezumab demonstrated efficacy in the preventive treatment of CM and reduced headache impact in patients with comorbid depression.

Immunogenicity of biologic therapies for migraine: a review of current evidence.

BACKGROUND: Monoclonal antibodies (mAbs) targeting the calcitonin gene-related peptide (CGRP) pathway have been shown to be effective in migraine prevention. Eptinezumab, erenumab, fremanezumab, and galcanezumb have shown efficacy in clinical trials along with favorable safety and tolerability profiles. Although erenumab is a human mAb and the others have been humanized to varying degrees, they all have the capacity to provoke immune reactions. The present review article aims to discuss the current relationship between mAbs targeting the CGRP pathway (CGRP mAbs) and immunogenicity and their potential clinical implications. FINDINGS: The incidence of patients developing anti-drug antibodies (ADAs), their titer, and clinical significance are highly variable and depend on a variety of different drug and patient factors. Neutralizing ADAs (NAbs) bind to and inhibit or reduce the pharmacologic activity of the biologic drug molecule, whereas non-neutralizing antibodies (Non-NAbs) bind to the biologic drug molecule without affecting pharmacologic activity in an in vitro test, although pharmacokinetics and drug clearance may be affected. A direct comparison of immunogenicity data across clinical trials with different biologics is not possible due to a lack of standardized assays. Several phase 2, phase 3, and long-term studies evaluating CGRP mAbs for migraine prevention have reported immunogenicity data (5 studies each for eptinezumab, erenumab, fremanezumab, and galcanezumab). Across these studies, prevalence of ADAs varied, ranging from < 1% to ~ 18%. Neutralizing ADAs were slightly less common, with a prevalence ranging from 0 to 12%. Adverse events related to ADA formation were rare. CONCLUSIONS: As more CGRP mAb studies are conducted and more long-term follow-up data become available, evidence is increasing that immunogenicity rates of biologic therapies for migraine are low, and adverse events related to ADAs are rare. Taken together, these results add to the growing body of evidence for the safety and tolerability of this class of migraine medications.

Reversion From Chronic Migraine to Episodic Migraine in Patients Treated With Fremanezumab: Post Hoc Analysis From HALO CM Study.

BACKGROUND: Migraine preventive medications are used to reduce headache frequency, severity, and duration. In patients with chronic migraine (CM), reversion to episodic migraine (EM) is an important treatment goal. OBJECTIVE: To evaluate the effect of fremanezumab on the rate of reversion from CM to EM. METHODS: This phase 3, randomized, double-blind, placebo-controlled, parallel-group trial included a 28-day pretreatment period and a 3-month treatment period. Patients with CM received subcutaneous fremanezumab quarterly (675 mg at baseline) or monthly (675 mg at baseline; 225 mg at Weeks 4 and 8), or placebo. Post hoc analyses evaluated the proportion of patients who reverted from CM to EM, defined as either a reduction to an average of <15 headache days per month during the 3-month treatment period or a reduction to <15 headache days per month in all 3 months of the treatment period. RESULTS: This analysis included data from 1088 CM patients (quarterly, n = 366; monthly, n = 365; placebo, n = 357). More fremanezumab-treated patients with CM reverted to EM using either the monthly average number of headache days criteria for reversion (quarterly: 50.5% [185/366], P = .108; monthly: 53.7% [196/365], P = .012; vs placebo: 44.5% [159/357]) or the monthly headache day count at Months 1, 2, and 3 criteria for reversion (quarterly: 31.2% [114/366], P = .008; monthly: 33.7% [123/365], P = .001; vs placebo: 22.4% [80/357]). Patients with CM who reported previous topiramate or onabotulinumtoxinA use, concomitant preventive medication use, or medication overuse were less likely to revert to EM. CONCLUSIONS: Fremanezumab may offer the benefit of reversion from CM to EM, based on a reduction in the number of headache days over 3 months of treatment.

No "Wearing-Off Effect" Seen in Quarterly or Monthly Dosing of Fremanezumab: Subanalysis of a Randomized Long-Term Study.

OBJECTIVE: To evaluate whether quarterly or monthly administration of fremanezumab for migraine prevention exhibits a pattern of decreased efficacy toward the end of the dosing interval (wearing-off effect). BACKGROUND: The main goals of migraine preventive treatment are to reduce the frequency, severity, and duration of migraine attacks, and migraine-associated disability. Wearing-off refers to the phenomenon whereby clinical symptoms return or worsen before the next dose of a drug is due and has been reported previously with migraine preventive medications. DESIGN AND METHODS: This was a long-term, 12-month, multicenter, randomized, double-blind, parallel-group phase 3 study (NCT02638103) that included chronic (CM) and episodic migraine (EM) patients who rolled over from the 12-week phase 3 HALO CM (NCT02621931) and EM trials (NCT02629861), as well as an additional subset of 312 new patients. Patients with CM or EM received fremanezumab either monthly or quarterly. In this post hoc analysis, for selected months, the difference in the average number of migraine days between weeks 1-2 and weeks 3-4, between weeks 1-3 and week 4, and between weeks 1-2 and weeks 11-12 were calculated. RESULTS: A total of 1890 patients (CM, 1110; EM, 780) were enrolled. At months 3, 6, 9, and 15, there were no substantial differences in mean weekly migraine days between weeks 1-2 and weeks 3-4 or between weeks 1-3 and week 4 with quarterly or monthly fremanezumab in the CM or EM subgroups. There were no substantial increases in mean weekly migraine days between weeks 1-2 and weeks 11-12 during the first quarter of treatment (months 1-3) or the second quarter of treatment (months 4-6) with quarterly or monthly fremanezumab in the CM or EM subgroups. Across both dosing subgroups in CM and EM patients, the mean weekly number of migraine days decreased substantially (30%-42%) during the first 2 weeks; decreases in weekly migraine days remained steady during the last 2 weeks of the first quarter, with a similar maintenance of response during the second quarter. CONCLUSIONS: This analysis of data from a long-term, phase 3 study showed that patients receiving quarterly fremanezumab or monthly fremanezumab did not experience a wearing-off effect toward the end of the dosing interval.

The impact of fremanezumab on medication overuse in patients with chronic migraine: subgroup analysis of the HALO CM study.

BACKGROUND: We evaluated the efficacy of fremanezumab, a fully humanized monoclonal antibody that selectively targets calcitonin gene-related peptide, in patients with chronic migraine (CM) with and without medication overuse (MO). METHODS: In a 12-week, phase 3 trial, patients with CM were randomized to fremanezumab quarterly (675 mg/placebo/placebo), monthly (675 mg/225 mg/225 mg), or placebo. Post hoc analyses assessed the impact of fremanezumab in patients with and without MO (monthly use of acute headache medication ≥15 days, migraine-specific acute medication ≥10 days, or combination medication ≥10 days) on efficacy outcomes, including headache days of at least moderate severity (HDs), and six-item Headache Impact Test (HIT-6) and Migraine-Specific Quality of Life (MSQoL) questionnaire scores. RESULTS: Of 1130 patients enrolled, 587 (51.9%) had baseline MO. Fremanezumab reduced placebo-adjusted least-squares mean (95% confidence interval) monthly HDs (- 2.2 [- 3.1 to - 1.2] and - 2.7 [- 3.7 to - 1.8]; P < 0.0001) in patients with MO and without MO (quarterly - 1.4 [- 2.3 to - 0.5], P = 0.0026; monthly - 1.4 [- 2.3 to - 0.6], P = 0.0017). Significantly more fremanezumab-treated patients had ≥ 50% reduction in HDs versus placebo, regardless of baseline MO (with: quarterly 70/201 [34.8%], monthly 78/198 [39.4%] vs placebo 26/188 [13.8%]; without: quarterly 71/174 [40.8%], monthly 75/177 [42.4%] vs placebo 41/183 [22.4%]). Fremanezumab improved HIT-6 and MSQoL scores. Significantly more fremanezumab-treated patients reverted to no MO (quarterly 111/201 [55.2%], monthly 120/198 [60.6%]) versus placebo (87/188 [46.3%]). CONCLUSIONS: Fremanezumab is effective for prevention of migraine in patients with CM, regardless of MO, and demonstrated a benefit over placebo in reducing MO. TRIAL REGISTRATION: ClinicalTrials.gov NCT02621931 (HALO CM), registered December 12, 2012.

Discovery of a Highly Selective Sigma-2 Receptor Ligand, 1-(4-(6,7-Dimethoxy-3,4-dihydroisoquinolin-2(1H)-yl)butyl)-3-methyl-1H-benzo[d]imidazol-2(3H)-one (CM398), with Drug-Like Properties and Antinociceptive Effects In Vivo.

The sigma-2 receptor has been cloned and identified as Tmem97, which is a transmembrane protein involved in intracellular Ca2+ regulation and cholesterol homeostasis. Since its discovery, the sigma-2 receptor has been an extremely controversial target, and many efforts have been made to elucidate the functional role of this receptor during physiological and pathological conditions. Recently, this receptor has been proposed as a potential target to treat neuropathic pain due to the ability of sigma-2 receptor agonists to relieve mechanical hyperalgesia in mice model of chronic pain. In the present work, we developed a highly selective sigma-2 receptor ligand (sigma-1/sigma-2 selectivity ratio > 1000), 1-(4-(6,7-dimethoxy-3,4-dihydroisoquinolin-2(1H)-yl)butyl)-3-methyl-1H- benzo[d]imidazol-2(3H)-one (CM398), with an encouraging in vitro and in vivo pharmacological profile in rodents. In particular, radioligand binding studies demonstrated that CM398 had preferential affinity for sigma-2 receptor compared with sigma-1 receptor and at least four other neurotransmitter receptors sites, including the norepinephrine transporter. Following oral administration, CM398 showed rapid absorption and peak plasma concentration (Cmax) occurred within 10 min of dosing. Moreover, the compound showed adequate, absolute oral bioavailability of 29.0%. Finally, CM398 showed promising anti-inflammatory analgesic effects in the formalin model of inflammatory pain in mice. The results collected in this study provide more evidence that selective sigma-2 receptor ligands can be useful tools in the development of novel pain therapeutics and altogether, these data suggest that CM398 is a suitable lead candidate for further evaluation.

Benzimidazolone-based selective σ2 receptor ligands: Synthesis and pharmacological evaluation.

Sigma receptors (σRs) are considered to be a significant and valid target for developing new medications to address several diseases. Their potential involvement in numerous central nervous system disorders, neuropathic pain, addiction, and cancer has been extensively reported. In particular, the σ2R has been identified as potential target for the development of pharmaceutical agents intended to treat the negative effects associated with drugs of abuse. As a continuation of our previous efforts to develop new selective σ2R ligands, a series of benzimidazolone derivatives were designed, synthesized, and characterized. The newly synthesized ligands were evaluated through in vitro radioligand binding assays to determine their affinity and selectivity towards both σ1 and σ2 receptors. Several derivatives displayed high affinity for the σ2R (Ki = 0.66-68.5 nM) and varied from preferring to selective, compared to σ1R (σ1/σ2 = 5.8-1139). Among them, compound 1-{4-[4-(4-fluorophenyl)piperazin-1-yl]butyl}-3-propyl-1,3-dihydrobenzimidazol-2-one dihydrochloride (14) displayed the ability to produce a dose-dependent reduction in the convulsive effects of cocaine in a rodent model after injecting 10 mg/kg (i.p.). These preliminary results support the use of selective σ2R ligands in the development of useful pharmacological tools or potential pharmacotherapies for cocaine toxicity.

Metabolism of megestrol acetate in vitro and the role of oxidative metabolites.

1. There is limited knowledge regarding the metabolism of megestrol acetate (MA), as it was approved by FDA in 1971, prior to the availability of modern tools for identifying specific drug-metabolizing enzymes. We determined the cytochrome P450s (P450s) and UDP-glucuronosyltransferases (UGTs) that metabolize MA, identified oxidative metabolites and determined pharmacologic activity at the progesterone, androgen and glucocorticoid receptors (PR, AR and GR, respectively). 2. Oxidative metabolites were produced using human liver microsomes (HLMs), and isolated for mass spectral (MS) and nuclear magnetic resonance (NMR) analyses. We screened recombinant P450s using MA at 62 µM (HLM Km for metabolite 1; M1) and 28 µM (HLM Km for metabolite 2; M2). UGT isoforms were simultaneously incubated with UDPGA, nicotinamide adenine dinucleotide phosphate (NADPH), CYP3A4 and MA. Metabolites were evaluated for pharmacologic activity on the PR, AR and GR. CYP3A4 and CYP3A5 are responsible for oxidative metabolism of 62 µM MA. 3. At 28 µM substrate concentration, CYP3A4 was the only contributing enzyme. Mass spectral and NMR data suggest metabolism of MA to two alcohols. After oxidation, MA is converted into two secondary glucuronides by UGT2B17 among other UGTs. MA, M1 and M2 had significant pharmacologic activity on the PR while only MA showed activity on the AR and GR.

In vitro glucuronidation of aprepitant: a moderate inhibitor of UGT2B7.

1. Aprepitant, an oral antiemetic, commonly used in the prevention of chemotherapy-induced nausea and vomiting, is primarily metabolized by CYP3A4. Aprepitant glucuronidation has yet to be evaluated in humans. The contribution of human UDP-glucuronosyltransferase (UGT) isoforms to the metabolism of aprepitant was investigated by performing kinetic studies, inhibition studies and correlation analyses. In addition, aprepitant was evaluated as an inhibitor of UGTs. 2. Glucuronidation of aprepitant was catalyzed by UGT1A4 (82%), UGT1A3 (12%) and UGT1A8 (6%) and Kms were 161.6 ± 15.6, 69.4 ± 1.9 and 197.1 ± 28.2 µM, respectively. Aprepitant glucuronidation was significantly correlated with both UGT1A4 substrates anastrazole and imipramine (rs = 0.77, p < 0.0001 for both substrates; n = 44), and with the UGT1A3 substrate thyroxine (rs = 0.58, p < 0.0001; n = 44). 3. We found aprepitant to be a moderate inhibitor of UGT2B7 with a Ki of ∼10 µM for 4-MU, morphine and zidovudine. Our results suggest that aprepitant can alter clearance of drugs primarily eliminated by UGT2B7. Given the likelihood for first-pass metabolism by intestinal UGT2B7, this is of particular concern for oral aprepitant co-administered with oral substrates of UGT2B7, such as zidovudine and morphine.

Methamphetamine-induced toxicity: an updated review on issues related to hyperthermia.

Reports of methamphetamine-related emergency room visits suggest that elevated body temperature is a universal presenting symptom, with lethal overdoses generally associated with extreme hyperthermia. This review summarizes the available information on methamphetamine toxicity as it pertains to elevations in body temperature. First, a brief overview of thermoregulatory mechanisms is presented. Next, central and peripheral targets that have been considered for potential involvement in methamphetamine hyperthermia are discussed. Finally, future areas of investigation are proposed, as further studies are needed to provide greater insight into the mechanisms that mediate the alterations in body temperature elicited by methamphetamine.

Evaluation of utility of pharmacokinetic studies in phase I trials of two oncology drugs.

PURPOSE: There are many phase I trials of oncology drug combinations, very few of which report clinically significant pharmacokinetic interactions. We hypothesized that the utility of such pharmacokinetic drug-drug interaction (DDI) studies is low in the absence of a mechanistic hypothesis. EXPERIMENTAL DESIGN: We retrospectively reviewed 152 phase I (two drug) combination studies published between 2007 and 2011. RESULTS: Only 28 (18%) studies had an implicit or explicit rationale, either inhibition/induction of a drug-metabolizing enzyme or transporter, cosubstrates for the same enzyme or transporter, potential for end-organ toxicity, or protein binding. Only 12 (8%) studies demonstrated a statistically significant DDI, on the basis of change in clearance (or area under the curve) of parent drug and/or active metabolite. There was a strong association between a rationale and a demonstrable drug interaction, as only 2% of studies without a rationale demonstrated a DDI, compared with 32% of studies with a rationale (Fisher exact test; P < 10(-6)). CONCLUSION: DDI studies should not be routinely performed as part of phase I trials of oncology combinations.

Effect of ring-constrained phenylpropyloxyethylamines on sigma receptors.

A series of ring-constrained phenylpropyloxyethylamines, partial opioid structure analogs and derivatives of a previously studied sigma (σ) receptor ligand, was synthesized and evaluated at σ and opioid receptors for receptor selectivity. The results of this study identified several compounds with nanomolar affinity at both σ receptor subtypes. Compounds 6 and 9 had the highest selectivity for both σ receptor subtypes, compared to µ opioid receptors. In addition, compounds 6 and 9 significantly reduced the convulsive effects of cocaine in mice, which would be consistent with antagonism of σ receptors.

σ Receptor antagonist attenuation of methamphetamine-induced neurotoxicity is correlated to body temperature modulation.

BACKGROUND: Methamphetamine (METH) causes hyperthermia and dopaminergic neurotoxicity in the rodent striatum. METH interacts with σ receptors and σ receptor antagonists normally mitigate METH-induced hyperthermia and dopaminergic neurotoxicity. The present study was undertaken because in two experiments, pretreatment with σ receptor antagonists failed to attenuate METH-induced hyperthermia in mice. This allowed us to determine whether the ability of σ receptor antagonists (AZ66 and AC927) to mitigate METH-induced neurotoxicity depends upon their ability to modulate METH-induced hyperthermia. METHODS: Mice were treated using a repeated dosing paradigm and body temperatures recorded. Striatal dopamine was measured one week post-treatment. RESULTS: The data indicate that the ability of σ receptor antagonists to attenuate METH-induced dopaminergic neurotoxicity is linked to their ability to block METH-induced hyperthermia. CONCLUSION: The ability of σ receptor antagonists to mitigate METH-induced hyperthermia may contribute to its neuroprotective actions.