MPOWERED Trial Open-Label Extension: Long-term Efficacy and Safety Data for Oral Octreotide Capsules in Acromegaly

CONTEXT

The MPOWERED core trial (NCT02685709) and open-label extension (OLE) phase investigated long-term efficacy and safety of oral octreotide capsules (OOC) in patients with acromegaly. Core trial primary endpoint data demonstrated noninferiority to injectable somatostatin receptor ligands (iSRLs). Core trial completers were invited to participate in the OLE phase.

OBJECTIVE

To assess long-term efficacy and safety of OOC in patients with acromegaly who previously responded to and tolerated both OOC and injectable octreotide/lanreotide and completed the core phase.

METHODS

The unique study design of transitioning between OOC and iSRLs allowed within-patient evaluations. The proportion of biochemical responders (insulin-like growth factor I < 1.3 × upper limit of normal) at end of each extension year who entered that year as responders was the main outcome measure.

RESULTS

At year 1 extension end, 52/58 patients from both the monotherapy and the combination therapy groups were responders (89.7%; 95% CI 78.8-96.1), 36/41 (87.8%; 95% CI 73.8-95.9) in year 2, and 29/31 (93.5%; 95% CI 78.6-99.2) in year 3. No new or unexpected safety signals were detected; 1 patient withdrew owing to treatment failure. Patients who transitioned from iSRLs in the core trial to OOC in the OLE phase reported improved treatment convenience/satisfaction and symptom control.

CONCLUSION

Patient-reported outcome data support for the first time that transitioning patients randomized to iSRL (who previously responded to both OOC and iSRLs) back to OOC had a significant effect on patients' symptoms score in a prospective cohort. The MPOWERED OLE showed long-term maintenance of response and sustained safety with OOC.

RF13 | PMON159 Long-term Efficacy and Safety Data for Oral Octreotide Capsules in Acromegaly: MPOWERED Trial Open-Label Extension Phase

Background

Oral octreotide capsules (OOC) are a treatment option for patients with acromegaly in the United States. The MPOWERED trial (NCT02685709) showed that OOC were noninferior to injectable somatostatin receptor ligands (iSRLs; octreotide or lanreotide) in maintenance of biochemical control in patients previously responding to both treatments, as well as demonstrated improvements in patient-reported outcomes among patients receiving OOC.

Objective

Report long-term safety and efficacy outcomes with OOC from the open-label extension (OLE) of MPOWERED.

Methods

Patients were eligible for and could voluntarily enroll into the OLE if they had completed the 15-month core treatment phase of MPOWERED (6-month Run-in phase plus 9-month randomized controlled treatment [RCT] phase or, for OOC nonresponders during/at end of Run-in at participating sites, combination sub-study evaluating OOC in combination with cabergoline) and were adequately biochemically controlled per investigator assessment. Maintenance of response (definition: IGF-I &lt;1.3×ULN; single timepoint) was assessed in each year of the OLE in patients responding at the start of that year. Additional analyses were performed on patients switching to OOC in the OLE from iSRLs in the core study.

Results

Sixty patients elected to enroll in the OLE (35 who received OOC and 19 who received iSRLs in the RCT phase, 6 from the combination sub-study). Median and maximal OOC exposure durations in the OLE were 2.2 and 3.5 years, respectively. A total of 94%, 90%, and 93% of patients receiving OOC monotherapy maintained biochemical response at the end of years 1, 2, and 3 of the OLE, respectively (using last observation carried forward imputation). Of patients switching from iSRLs to OOC during the OLE, 79% reported very good (47%) or excellent (32%) symptom control at the end of the OLE, compared with 47% (42% very good, 5% excellent) at the end of the RCT phase while receiving iSRLs. Patients switching from iSRLs also experienced significant improvements in the treatment convenience and treatment satisfaction domains (both P&lt;0.05) of the Acromegaly Treatment Satisfaction Questionnaire. Median OOC compliance rate during the OLE was 99%. OOC safety during the OLE was consistent with that observed during the core study, with no new safety signals observed with long-term exposure.

Conclusions

The OLE of MPOWERED demonstrated a high percentage (≥90%) of patients maintaining biochemical response while receiving OOC monotherapy with a favorable long-term safety profile of OOC. Those who switched from iSRLs to OOC demonstrated improvements in symptom control, treatment convenience, and treatment satisfaction.

Presentation: Sunday, June 12, 2022 1:12 p.m. - 1:17 p.m., Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

Maintenance of response to oral octreotide compared with injectable somatostatin receptor ligands in patients with acromegaly: a phase 3, multicentre, randomised controlled trial

BACKGROUND

Despite biochemically responding to injectable somatostatin receptor ligands (iSRLs), many patients with acromegaly experience treatment burdens. We aimed to assess maintenance of biochemical response and symptomatic control with oral octreotide capsules versus iSRLs in patients with acromegaly who previously tolerated and responded to both.

METHODS

This global, open-label, randomised controlled phase 3 trial was done in 29 clinical sites in Austria, France, Germany, Hungary, Italy, Lithuania, Russia, Serbia, Spain, and the USA. Eligible patients were adults aged 18-75 years with acromegaly who were receiving iSRLs (long-acting octreotide or lanreotide autogel) for at least 6 months before baseline with a stable dose for at least 4 months, and were deemed to be biochemically responding (insulin-like growth factor I [IGF-I] <1·3 × upper limit of normal [ULN] and mean integrated growth hormone <2·5 ng/mL). In the 26-week run-in phase, all patients received oral octreotide (40 mg a day, optional titration to 60 or 80 mg a day). Eligibility for the randomised treatment phase was completion of the run-in phase as a biochemical responder (IGF-I <1·3 × ULN and mean integrated growth hormone <2·5 ng/mL at week 24) and investigator assessment of acromegaly being adequately controlled. Patients were randomly assigned (3:2) to oral octreotide capsules or iSRL at the same dose and interval as before enrolment. Randomisation and drug dispensing were conducted through a qualified randomisation service provider (eg, interactive web or voice response system). The primary endpoint was a non-inferiority assessment (margin -20 percentage points) of proportion of participants maintaining biochemical response throughout the randomised treatment phase (IGF-I <1·3 × ULN using time-weighted average; assessed by comparing the lower bound of the 2-sided 95% CI for the difference in biochemical response between groups). IGF-I was assessed once a month during the run-in and randomised treatment phases (single sample). Efficacy and safety assessments were performed on the randomised population. This trial is registered with ClinicalTrials.gov, NCT02685709.

FINDINGS

Between Feb 11, 2016, and Aug 20, 2020, 218 patients were assessed for eligibility. 72 patients were excluded, and 146 participants were enrolled into the run-in phase. 116 patients completed the run-in phase and 30 participants discontinued treatment. 92 participants were randomly assigned to oral octreotide (n=55) or iSRL (n=37). 50 (91%) of 55 participants who received oral octreotide (95% CI 44-53) and 37 (100%) of 37 participants who received iSRLs (34-37) maintained biochemical response. The lower bound of the 2-sided 95% CI for the adjusted difference in proportions between the two treatment groups achieved the prespecified non-inferiority criterion of -20% (95% CI -19·9 to 0·5). 19 (35%) of 55 participants in the oral octreotide group and 15 (41%) of 37 participants in the iSRL group had treatment-related adverse events; the most common of which in both groups were gastrointestinal.

INTERPRETATION

Oral octreotide was non-inferior to iSRL treatment, and might be a favourable alternative to iSRLs for many patients with acromegaly.

FUNDING

Chiasma.

TRANSLATION

For the Russian translation of the abstract see Supplementary Materials section.

Oral Octreotide Capsules Lowered Incidence and Improved Severity of Acromegaly Symptoms Compared to Injectable Somatostatin Receptor Ligands—Results From the MPOWERED Trial

Background: Patients with acromegaly may have high symptom burden. The phase 3 MPOWERED trial assessed control of acromegaly by oral octreotide capsules (OOC; MYCAPSSA^®) in comparison to injectable somatostatin receptor ligands (iSRLs) in patients responding to both OOC and iSRLs. iSRLs have been first-line medical treatment for patients with acromegaly for decades. OOC are newly approved in the US for patients previously controlled on iSRLs.

Methods: Eligibility criteria for MPOWERED included acromegaly diagnosis, biochemical control of acromegaly (insulin-like growth factor I <1.3 × upper limit of normal; mean integrated growth hormone, <2.5 ng/mL) and ≥6 months’ iSRL (octreotide, lanreotide) treatment. Eligible patients entered a 26-week Run-in phase to determine the effective OOC dose; responders at week 24 then entered a 36-week randomized controlled treatment (RCT) phase receiving OOC or iSRLs. Acromegaly symptom number and severity (mild to severe, 1-3) were collected. Total score was calculated by summating all severity scores (Acromegaly Index of Severity [AIS]). Symptom results were assessed using total AIS score and proportion of patients experiencing individual symptoms.

Results: At beginning of Run-in, average AIS score of 92 randomized patients was 4.52, representative of symptoms experienced while previously receiving iSRLs. After 26 weeks’ OOC treatment at end of Run-in, average AIS score was significantly reduced to 3.46 (P<0.001). More than 80% of patients on OOC improved or maintained AIS score during Run-in compared to baseline. Over this 26-week period, there was a significant reduction in extremity swelling (P=0.01) and fatigue (P=0.03). During the RCT, of patients randomized to OOC (n=55), 73% maintained or improved AIS score, and 75% maintained or reduced overall number of active symptoms. In comparison, 68% of those randomized to iSRLs (n=37) maintained or improved AIS score, and 70% maintained or reduced overall number of active symptoms.

Conclusion: Results from MPOWERED show that patients receiving OOC had significant improvement in number and severity of acromegaly symptoms after switching from iSRLs. These findings validate previous results from a phase 3 study of OOC in acromegaly in which patients switching to OOC from iSRLs showed significant reduction in joint pain, extremity swelling, and fatigue.¹

¹Melmed S, et al. JCEM. 2015;100(4):1699-1708.

Addition of Cabergoline to Oral Octreotide Capsules May Improve Biochemical Control in Patients With Acromegaly Who Are Inadequately Controlled With Monotherapy

Background: Oral octreotide capsules (OOC; MYCAPSSA®) are approved in the US for individuals with acromegaly who responded to and tolerated treatment with injectable somatostatin receptor ligands (iSRLs). Add-on cabergoline therapy has shown effectiveness in patients previously inadequately controlled with iSRLS.1 The phase 3 MPOWERED trial assessed maintenance of response with OOC compared to iSRLs. Patients receiving OOC and ineligible for randomized controlled treatment (RCT) phase were eligible for a sub-study evaluating combination therapy with cabergoline, a dopamine agonist.

Methods: Patients who fail to respond to 80 mg/d OOC for ≥2 weeks during the 26-week Run-in phase, or ineligible to enter the RCT on 80 mg/d OOC, due to inadequate biochemical control (insulin-like growth factor I [IGF-I] ≥1.3 × upper limit of normal [ULN] to &lt;2 × ULN or IGF-I &lt;1.3 × ULN and mean integrated growth hormone [GH] ≥2.5 ng/mL) were eligible for sub-study combination OOC 80 mg/d and cabergoline ≤3.5 mg/wk (fixed algorithm) for 36 weeks. End points included categorical changes in IGF-I and mean GH levels at sub-study end and adverse event (AE) incidence and severity. Echocardiogram was performed at sub-study start and every 12 weeks after.

Results: Of 146 patients enrolled in MPOWERED, 14 entered the combination sub-study, 9 having IGF-I ≥1.3 × ULN at sub-study start. Final cabergoline doses were 1 (n=5), 2 (n=3), 3 (n=1), and 3.5 mg (n=5) with 25.4-week (SD, 14.1) mean treatment duration. Week 36 IGF-I improved in most patients (n=12; 85.7%). Of 9 patients with IGF-I ≥1.3 × ULN at sub-study start, 5 (55.6%; 95% CI, 21.2%-86.3%) exhibited IGF-I decreased to predefined responder range (&lt;1.3 × ULN) by week 36. AE incidence and nature with combined treatment were similar to known octreotide safety profile and acromegaly disease burden. There were no serious AEs or AEs leading to discontinuation of either sub-study drug.

Conclusion: We have shown for the first time the benefit of an all-oral combination treatment for acromegaly and avoidance of injection-related burdens. Addition of cabergoline to OOC yielded biochemical control improvement (IGF-I reduction) in patients inadequately controlled with OOC monotherapy. As both combination and OOC monotherapy safety profiles were similar, adjunctive cabergoline may be helpful in patients with acromegaly who do not achieve adequate biochemical control on OOC alone.

1Giustina A, et al. Nat Rev Endocrinol. 2014;10(4):243-248.

Improved Acromegaly Patient Satisfaction With Oral Octreotide Capsules Compared With Injectable Somatostatin Receptor Ligands in the MPOWERED Trial

Background: Improved patient-reported outcomes (PROs) are increasingly becoming a key treatment objective in acromegaly. Validated PROs were used to assess disease and treatment burden in the MPOWERED phase 3 trial in acromegaly, which also assessed safety and efficacy of oral octreotide capsules (OOC; MYCAPSSA^®) compared to injectable SRLs (iSRLs).

Methods: Eligible patients had acromegaly diagnosis, biochemical control of acromegaly (insulin-like growth factor I <1.3 × upper limit of normal; mean integrated growth hormone, <2.5 ng/mL) and ≥6 months’ iSRL treatment (octreotide or lanreotide). Eligible patients entered a 26-week Run-in phase to determine the effective OOC dose; responders at week 24 then entered a 36-week randomized controlled treatment (RCT) phase receiving OOC or iSRLs in a 3:2 ratio. The Acromegaly Treatment Satisfaction Questionnaire (Acro-TSQ) is a recently validated tool that includes 27 items in 6 domain scores for PROs in acromegaly.¹ Acro-TSQ data were collected at baseline (reflecting outcomes on iSRLs), end of Run-in (reflecting outcomes on OOC), and end of RCT (OOC or iSRLs).

Results: Of 146 enrolled patients, 92 entered RCT (OOC, N=55; iSRLs, N=37). Acro-TSQ scores at the end of Run-in (26 weeks’ OOC treatment) were compared to baseline (iSRLs). In the 92 patients randomized, 3 of 5 Acro-TSQ domains (emotional reaction, treatment convenience, and treatment satisfaction) showed significant improvement at end of Run-in compared to baseline. Injection site interference was not assessed as no injection site reactions were observed with OOC. Other domains showed a nonstatistically significant pattern of improvement at end of Run-in when compared to baseline. Patients randomized to iSRLs in the RCT after receiving OOC in the Run-in (N=37) reported more anxiety (RCT end, 53%; Run-in end, 29%) and frustration (RCT end, 45%; Run-in end, 34%) with iSRLs compared to OOC. Overall treatment satisfaction was higher while receiving OOC (Run-in end, 92%; after receiving iSRLs in RCT, 75%). Breakthrough symptoms were reported more frequently with iSRLs (31%) than OOC (15%) at the end of RCT.

Conclusion: Higher patient satisfaction, convenience and emotional well-being, and improved symptom control based on the newly validated Acro-TSQ PRO reporting tool were observed with OOC compared to iSRLs in patients enrolled in the MPOWERED trial.

¹Fleseriu M, et al. Pituitary. 2020 Aug;23(4):347-358.

Safety Results From MPOWERED, a Phase 3 Trial of Oral Octreotide Capsules in Adults With Acromegaly

Background: Injectable somatostatin receptor ligands (iSRLs) have been a mainstay in acromegaly treatment. Oral octreotide capsules (OOC; MYCAPSSA^®) were recently approved in the United States. Results from the placebo-controlled CHIASMA OPTIMAL and open-label CH-ACM-01 studies showed an OOC safety profile consistent with that of iSRLs with no new or unexpected safety signals. Results of the MPOWERED trial have enabled a comparison of OOC safety and efficacy with iSRLs.

Methods: To enter MPOWERED, patients must have the following: acromegaly diagnosis, biochemical control of acromegaly (insulin-like growth factor I <1.3 × upper limit of normal; mean integrated growth hormone <2.5 ng/mL), and ≥6 months’ iSRLs treatment (octreotide or lanreotide). Eligible patients entered a 26-week Run-in phase to determine the effective OOC dose; responders at week 24 then entered a 36-week randomized controlled treatment (RCT) phase receiving OOC or iSRLs. Safety was monitored as adverse events (AEs) in both arms throughout the trial, including the RCT.

Results: In the RCT, incidence of treatment-emergent adverse events (TEAEs) was similar between groups; 39 patients (70.9%) in the OOC group and 26 (70.3%) in the iSRL group had ≥1 TEAE. 19 patients (34.5%) in the OOC and 15 (40.5%) in the iSRL group had treatment-related TEAEs. Occurrence was similar for serious AEs (OOC, 5.5%; iSRL, 8.1%) as well as TEAEs classified as severe (OOC, 9.1%; iSRL, 10.8%). One patient in the OOC group discontinued due to a TEAE. The most common gastrointestinal TEAEs were flatulence (OOC, 25.5%; iSRL, 21.6%), nausea (OOC, 20.0%; iSRL, 8.1%), diarrhea (OOC, 10.9%; iSRL, 13.5%), abdominal pain (OOC, 9.1%; iSRL, 8.1%), and constipation (OOC, 5.5%; iSRL, 13.5%). AEs of interest were infrequent, including cholelithiasis (OOC, n=0; iSRL, n=1 [2.7%]) and secondary hypothyroidism (OOC, n=1 [1.8%]; iSRL, n=0). In the iSRL group, 32.4% of patients reported injection site reactions (ISRs) during the RCT, and 47% of patients reported ISRs as part of the Acromegaly Treatment Satisfaction Questionnaire, a newly validated patient-reported outcome tool.¹

Conclusion: Safety results from MPOWERED align with prior trials, showing that the OOC safety profile is consistent with that of iSRLs as well as the acromegaly disease burden. No new or unexpected safety signals were identified during the trial. Safety results were mostly similar between OOC and iSRLs, although patients in the OOC group did not experience any ISRs.

¹Fleseriu M, et al. Pituitary. 2020 Aug;23(4):347-358.

A Phase 3 Large International Noninferiority Trial (MPOWERED): Assessing Maintenance of Response to Oral Octreotide Capsules in Comparison to Injectable Somatostatin Receptor Ligands

Background: MPOWERED, a large phase 3 trial, assessed maintenance of response to oral octreotide capsules (OOC; MYCAPSSA^®) compared to injectable somatostatin receptor ligands (iSRLs) in patients with acromegaly who responded to OOC and iSRLs (octreotide or lanreotide). OOC were recently approved in the US for patients with acromegaly who responded to and tolerated iSRLs.

Methods: Eligibility criteria included age 18-75 years at screening, acromegaly diagnosis, disease evidence, biochemical control (insulin-like growth factor I [IGF-I] <1.3 × upper limit of normal [ULN] and mean integrated growth hormone [GH] <2.5 ng/mL) at screening, and ≥6 months’ iSRL treatment. Effective OOC dose was determined in a 26-week Run-in phase. Eligible patients (IGF-I <1.3 × ULN and mean integrated GH <2.5 ng/mL, week 24) were randomized to a 36-week controlled treatment phase (RCT), receiving OOC or iSRLs starting at week 26. The primary end point was a noninferiority assessment of proportion of patients biochemically controlled in the RCT (IGF-I <1.3 × ULN using time-weighted average). Other end points included nonresponse imputation of the primary end point, landmark analysis using proportion of responders based on average of last 2 IGF-I values at end of RCT, and change from baseline RCT (week 26) IGF-I and GH levels.

Results: Of 146 enrolled patients, 92 entered the RCT (OOC, n=55; iSRLs, n=37). Both arms were well balanced for age, sex, and acromegaly duration. OOC demonstrated noninferiority to iSRLs in maintaining biochemical response, with 91% (CI, 80%-97%) of OOC and 100% (CI, 91%-100%) of iSRL groups maintaining control during the RCT. Of those responding at end of Run-in, 96% of patients on OOC maintained response during RCT. Using nonresponse imputation, 89% of OOC and 95% of iSRL groups were biochemically controlled in RCT. Landmark analysis of those respnding at end of Run-in showed that 94% of patients in each group maintained response at RCT end. In both groups, IGF-I levels were stable in the RCT, average IGF-I at baseline and RCT end being 0.9 × ULN (OOC) and 0.8 × ULN (iSRL). Mean change in GH from RCT start to RCT end was -0.03 ng/mL (OOC) and +0.29 ng/mL (iSRL). Safety data were mostly similar between groups; the OOC group did not experience injection site reactions.

Conclusion: In this noninferiority trial in patients with acromegaly, OOC demonstrated maintenance of biochemical response compared to iSRLs. Results support the efficacy of OOC as a possible iSRL alternative.

Disease and Treatment-Related Burden in Patients With Acromegaly Who Are Biochemically Controlled on Injectable Somatostatin Receptor Ligands

Medical treatment for acromegaly commonly involves receiving intramuscular or deep subcutaneous injections of somatostatin receptor ligands (SRLs) in most patients. In addition to side effects of treatment, acromegaly patients often still experience disease symptoms even when therapy is successful in controlling GH and IGF-1 levels. Symptoms and side effects can negatively impact patients' health-related quality of life. In this study, we examine the disease- and treatment-related burden associated with SRL injections as reported through the use of the Acromegaly Treatment Satisfaction Questionnaire (Acro-TSQ ^©) and clinician-reported symptom severity through the Acromegaly Index of Severity (AIS). Patients included in this analysis were enrolled in a randomized phase 3 study, were biochemically-controlled (an IGF-1 < 1.3 × the upper limit of normal [ULN] and average GH < 2.5 ng/ml) and receiving SRL injections for ≥6 months with a stable dose of either long-acting octreotide or lanreotide monotherapy for ≥4 months. The sample (N = 91) was 65% female, 91% Caucasian, with a mean [standard deviation (SD)] age of 53 (1) years. Two-thirds of patients reported that they still experience acromegaly symptoms; 82% of these said they experience symptoms all of the time. Three-fourths experienced gastrointestinal (GI) side effects after injections, and 77% experienced treatment-related injection site reactions (ISRs). Patients commonly reported that these interfered with their daily life, leisure, and work activities. Those with higher symptom severity, as measured by the AIS, scored significantly worse on several Acro-TSQ domains: Symptom Interference, GI Interference, Treatment Satisfaction, and Emotional Reaction. Despite being biochemically controlled with injectable SRLs, most patients reported experiencing acromegaly symptoms that interfere with daily life, leisure, and work. GI side effects and ISRs were also common. This study highlights the significant disease burden that still persists for patients with acromegaly that have achieved biochemical control with the use of injectable SRLs.

MON-323 IGF-I Variability and Its Association with Demographic and Clinical Characteristics in Patients with Acromegaly Treated with Injectable Somatostatin Receptor Ligands (SRLS); Results from an International Prospective Phase III Study

Background: In clinical practice, most patients responding to injectable somatostatin receptor ligands exhibit IGF-I variability around the upper limit of normal (ULN) during long-term follow up. These fluctuations are thought to result from various factors such as assay variability, nutrition, comorbid conditions, concomitant medications and other unknown factors. The magnitude of this variability, and the factors affecting it, is not well understood in patients with acromegaly treated with injectable SRLs. Methods: IGF-I levels of patients responding to and stably treated with injectable SRLs were measured over time in the CHIASMA OPTIMAL phase III study. Two time periods were assessed - Period 1, three assessments during screening phase before randomization to octreotide capsules (N=56), and Period 2 - multiple assessments up to week 36, in patients rescued with SRL injections for at least 12 weeks (N=21). The time from the last injection to each of the 3 assessments in period 1 [Screening visits 1 and 2 (SV1 & SV2), and Baseline (BL)], was on average 6.8 ± 10.7 (SD), 15.8 ± 2.7, and 29.0 ± 1.8 days respectively. Correlation with various demographics and Baseline characteristics, including age, gender, weight, BMI and residual tumor size to IGF-I variability was assessed. Percent change for each individual patient from Minimal to Maximal IGF-I values within each period was computed and the overall population mean was calculated (lowest value was used as the denominator and all other values were expression as a positive % above this value). Results: The overall mean within-patient percent change of IGF-I levels during Period 1 was 20.48 ± 15.56 (range: 0.6-81). Mean IGF-I levels for SV1, SV2 and BL were 0.78 ± 0.18, 0.79 ± 0.18, and 0.85 ± 0.22 x ULN respectively. The overall increase in mean IGF-I levels from SV1 to BL (longest time interval) was statistically significant (p=0.0002; paired T-test). Analysis of IGF-I levels in patients during Period 2, revealed that the overall mean within-patient percent change of IGF-I levels was 15.27 ± 12.20 (range: 0-41.5). The mean duration of follow up during this period, after patients were already treated for ≥12 weeks with injectable SRL, was 1.72 (± 1.29) months. The variability observed in Period 2 was similar to that observed in the entire sample evaluated in Period 1. No significant differences were found in the mean IGF-I percent change between any demographic or baseline characteristic subgroup examined. Conclusion: IGF-I levels fluctuate in patients with acromegaly who are responsive to injectable SRLs. These fluctuations are wide and can be up to 81% higher than the lowest (most controlled) value, with an average increase of approximately 20%. Significant IGF-I increases were observed at the end of the long acting SRL injection interval.

Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. Abstracts presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.

Central nervous system effects of the histamine-3 receptor antagonist CEP-26401, in comparison with modafinil and donepezil, after a single dose in a cross-over study in healthy volunteers

AIMS

In previous studies, the histamine-3 receptor antagonist CEP-26401 had a subtle effect on spatial working memory, with the best effect seen at the lowest dose tested (20 μg), and a dose-dependent disruption of sleep. In the current study, 3 low-dose levels of CEP-26401 were compared with modafinil and donepezil.

METHODS

In this double-blind, placebo- and positive-controlled, randomized, partial 6-way cross-over study, 40 healthy subjects received single doses of placebo, CEP-26401 (5, 25 or 125 μg) or modafinil 200 mg or donepezil 10 mg. Pharmacokinetic and pharmacodynamic measurements were performed predose and at designated time points postdose.

RESULTS

The main endpoint between-errors of the spatial working memory-10-boxes task only improved for the 125 μg dose of CEP-26401 with a difference of 2.92 (confidence interval [CI] -1.21 to 7.05), 3.24 (CI -1.57 to 8.04) and 7.45 (CI 2.72 to 12.19) for respectively the 5, 25 and 125 μg dose of CEP-26401, -1.65 (CI -0.572 to 1.96) for modafinil and - 3.55 (CI -7.13 to 0.03) for donepezil. CEP-26401 induced an improvement of adaptive tracking, saccadic peak velocity and reaction time during N-back, but a dose-related inhibition of sleep and slight worsening of several cognitive parameters at the highest dose. CEP-26401 significantly changed several subjective visual analogue scales, which was strongest at 25 μg, causing the same energizing and happy feeling as modafinil, but with a more relaxed undertone.

DISCUSSION

Of the doses tested, the 25 μg dose of CEP-26401 had the most optimal balance between favourable subjective effects and sleep inhibition. Whether CEP-26401 can have beneficial effects in clinical practice remains to be studied.

Placebo-controlled evaluation of a bioengineered, cocaine-metabolizing fusion protein, TV-1380 (AlbuBChE), in the treatment of cocaine dependence

BACKGROUND

TV-1380 (AlbuChE) is a novel recombinant fusion protein of mutated butyrylcholinesterase (BChE) that has increased catalytic efficiency for cocaine metabolism compared to wild-type BChE.

METHODS

Intra-muscular injections of TV-1380 (150mg or 300mg) or placebo were administered once weekly to participants (n=66-69 per group) in a randomized, double-blind study to evaluate the ability of TV-1380 to facilitate abstinence in treatment-seeking, cocaine-dependent individuals. The primary endpoint was the proportion of participants achieving abstinence from cocaine during the last three weeks of the 12 week treatment phase, based on daily self-report of "no use" confirmed by urine testing.

RESULTS

Although there were no significant differences between the TV-1380 treatment groups and placebo for the primary endpoint, 6% of participants in the 150mg and 300mg TV-1380 groups and no participants in the placebo group achieved abstinence. For the only declared secondary endpoint, there was a dose-dependent increase in the group mean percentage of urine samples testing negative for cocaine metabolites during weeks 5-12 (8.1% and 14.6% for the 150mg and 300mg TV-1380 groups, respectively, compared to 4.7% for the placebo group; p=0.0056 for 300mg vs. placebo). No meaningful differences in adverse events were seen between treatment groups.

CONCLUSIONS

While the apparent reduction in cocaine use may be of insufficient magnitude to justify further trials of TV-1380 in cocaine dependence, the results argue for development of improved enzymes with greater catalytic activity.

Pathological and clinical aspects of alpha/beta synuclein in Parkinson's disease and related disorders

Parkinson's disease (PD) and related synucleinopathies are characterized by extensive neuronal cell loss, which is potentially triggered by α-synuclein misfolding and aggregation. Therefore it is reasonable to suggest that treatments targeting α-synuclein could reduce its levels and toxicity, rescue neuronal cells and halt the neurodegeneration process. Several approaches to decrease α-synuclein levels were employed thus far, mainly by using β-synuclein, another protein from the same family, or immunotherapies. These treatments demonstrated some positive results in preclinical studies, which may pave the road to the development of new promising disease-modifying therapies (DMTs). This approach should be further examined in preclinical and clinical settings, together with a clear process in order to advance candidates, enable the ability to define when there are target engagements and to detect what is a meaningful pharmacological response, and how it will be translated in clinical efficacy.

Sub-analysis of geographical variations in the 2-year observational COPTIMIZE trial of patients with relapsing-remitting multiple sclerosis converting to glatiramer acetate

BACKGROUND

Studies suggest that patients with relapsing-remitting multiple sclerosis (RRMS) who fail to benefit from a disease-modifying treatment (DMT) may benefit from converting to another DMT class. COPTIMIZE was a 24-month observational study designed to assess the disease course of patients converting to glatiramer acetate (GA) 20 mg daily from another DMT and the association of disease characteristics and reasons for converting. This sub-analysis was to determine if any findings varied by three geographic locations: Latin America (LA), Canada and Western Europe (CWE), and Eastern Europe (EE).

METHODS

A total of 668 patients were included (263 LA, 248 CWE, 157 EE) in an analysis of annualized relapse rate (ARR) and annualized rate of deterioration (ARD), as well as secondary endpoints including reason for DMT switch and changes in disability and fatigue scores. Repeated-measures analysis of variance and log transformation were used to analyze ARR and ARD, whereas the Wilcoxon signed rank test was used for secondary endpoints.

RESULTS

The sub-analysis of treatment outcomes stratified by region showed that Latin American patients had higher ARR before conversion to GA compared with patients from the other two areas and subsequently experienced the largest reduction in ARR. Latin American patients also had higher baseline rates of comorbidities and relapses with incomplete remissions and improved more than those in the other two regions based on measures of fatigue, quality of life, depression, and cognition scores. Latin American patients also generally had a better perception of the benefits associated with their conversion to GA in terms of efficacy and adverse events.

CONCLUSIONS

These findings indicate that, in RRMS patients, converting to GA is associated with positive treatment outcomes regardless of geographic location. However, the reasons for converting and the type and degree of any associated benefits appear to vary depending on various factors, including patients' geographical location.

Safety, pharmacokinetics, and pharmacodynamics of TV-1380, a novel mutated butyrylcholinesterase treatment for cocaine addiction, after single and multiple intramuscular injections in healthy subjects

Human plasma butyrylcholinesterase (BChE) contributes to cocaine metabolism and has been considered for use in treating cocaine addiction and cocaine overdose. TV-1380 is a recombinant protein composed of the mature form of human serum albumin fused at its amino terminus to the carboxy-terminus of a truncated and mutated BChE. In preclinical studies, TV-1380 has been shown to rapidly eliminate cocaine in the plasma thus forestalling entry of cocaine into the brain and heart. Two randomized, blinded phase I studies were conducted to evaluate the safety, pharmacokinetics, and pharmacodynamics of TV-1380, following single and multiple administration in healthy subjects. TV-1380 was found to be safe and well tolerated with a long half-life (43-77 hours) and showed a dose-proportional increase in systemic exposure. Consistent with preclinical results, the ex vivo cocaine hydrolysis, TV-1380 activity clearly increased upon treatment in a dose-dependent manner. In addition, there was a direct relationship between ex vivo cocaine hydrolysis (kel ) and TV-1380 serum concentrations. There was no evidence that TV-1380 affected heart rate, the uncorrected QT interval, or the heart-rate-corrected QTcF interval. TV-1380, therefore, offers a safe once-weekly therapy to increase cocaine hydrolysis.

A randomized placebo-controlled phase III trial of oral laquinimod for multiple sclerosis

The phase III placebo-controlled BRAVO study assessed laquinimod effects in patients with relapsing-remitting MS (RRMS), and descriptively compared laquinimod with interferon beta (IFNβ)-1a (Avonex(®) reference arm). RRMS patients age 18-55 years with Expanded Disability Status Scale (EDSS) scores of 0-5.5 and documented pre-study relapse (≥ 1 in previous year, 2 in previous 2 years, or 1 in previous 1-2 years and ≥ 1 GdE lesion in the previous year) were randomized (1:1:1) to laquinimod 0.6 mg once-daily, matching oral placebo, or IFNβ-1a IM 30 μg once-weekly (rater-blinded design), for 24 months. The primary endpoint was annualized relapse rate (ARR); secondary endpoints included percent brain volume change (PBVC) and 3-month confirmed disability worsening. In all, 1,331 patients were randomized: laquinimod (n = 434), placebo (n = 450), and IFNβ-1a (n = 447). ARR was not significantly reduced with laquinimod [-18 %, risk ratio (RR) = 0.82, 95 % CI 0.66-1.02; p = 0.075] vs. placebo. Laquinimod significantly reduced PBVC (28 %, p < 0.001). Confirmed disability worsening was infrequent (10 % laquinimod, 13 % placebo). The change in confirmed disability worsening with laquinimod measured using EDSS was -31 % [hazard ratio (HR) 0.69, p = 0.063], and using Multiple Sclerosis Functional Composite (MSFC) z-score was -77 % (p = 0.150), vs. placebo. IFNβ-1a reduced ARR 26 % (RR = 0.74, 95 % CI 0.60-0.92, p = 0.007), showed no effect on PBVC loss (+11 %, p = 0.14), and changes in disability worsening were -26 and -66 % as measured using the EDSS (HR 0.742, p = 0.13) and MSFC (p = 0.208), respectively. Adverse events occurred in 75, 82, and 70 % of laquinimod, IFNβ-1a, and placebo patients, respectively. Once-daily oral laquinimod 0.6 mg resulted in statistically nonsignificant reductions in ARR and disability progression, but significant reductions in brain atrophy vs. placebo. Laquinimod was well-tolerated.

Anti-inflammatory drugs in the treatment of neurodegenerative diseases: current state

Increasing evidence indicates that inflammation is involved in the pathogenesis of many neurological, particularly neurodegenerative diseases. Even if inflammation is not a primary causative process, its presence may contribute to the continued loss of CNS neurons. Therefore, it seems reasonable to propose that use of anti-inflammatory drugs might diminish the cumulative effects of inflammation in the brain. Indeed, some epidemiological studies performed to date, especially in Alzheimer's disease, suggests that sustained use of anti-inflammatory drugs (AIDs) may prevent or slow down the progression of neurodegenerative diseases. However, small number of clinical trials carried out so far using AIDs, were minimal and equivocal in their outcome. Potential reasons for these mixed results include timing of AIDs administration, nonselective inhibition of cyclooxygenase (COX), inappropriate use of particular anti-inflammatory drugs for a given disease or disease progression/ severity, sub-optimal dose in target site, or limited penetration to the brain through the blood-brain barrier (BBB). Therefore, design of AIDs for the treatment of neurodegenerative diseases based upon better BBB penetration, and with minimal adverse events, would be appropriate. In addition, relevant genetic differences among patients should be considered planning new AIDs, for improved efficacy. Furthermore, due to the possible co-involvement of oxidative stress and excitotoxicity in the pathogenesis of these diseases, combination therapy with antioxidants or glutamate antagonists or a multi-potent drug might be much more effective in successfully treating neurodegenerative diseases.

A novel brain-targeted antioxidant (AD4) attenuates haloperidol-induced abnormal movement in rats: implications for tardive dyskinesia

BACKGROUND

Tardive dyskinesia (TD), characterized by abnormal movements, is the major late-onset chronic side effect of antipsychotic treatment found in about 30% of those patients. The association of oxidative stress and the release of free radicals is one of the hallmarks of dopaminergic malfunctions and is one of the leading theories suggested for the pathophysiology of TD. To this day, no brain-targeted antioxidant has been tested as a potential treatment of TD. In light of this assumption, the authors chose a novel, low-molecular weight thiol antioxidant, N-acetyl cysteine amide (AD4), that crosses the blood-brain barrier as a possible treatment of TD.

OBJECTIVE

To examine the protective effects of the novel brain-penetrating antioxidant AD4 on TD experimental models.

METHODS

The typical vacuous chewing movement occurs in rats following chronic haloperidol injections (1.5 mg/kg/day intraperitoneally for 21 days). This purposeless mouth opening in the vertical plane is similar to TD symptoms in humans. The authors tested rats treated with haloperidol without or with AD4 in the drinking water (1 g/kg orally). Thiobarbituric acid reactive substances and anticarbonyl antibodies were used to measure oxidation of membranes and proteins.

RESULTS

Haloperidol increased the vacuous chewing movements to 66.5 +/- 7.6 movements/5 minutes compared with 16.4 +/- 2.4 movements/5 minutes in untreated rats (P < 0.01). Coadministration of haloperidol and AD4 decreased the vacuous chewing movements level to 42.1 +/- 6.7 movements/5 minutes (P < 0.05). Haloperidol also increased the level of lipid peroxidation and protein oxidation in the rat brain, whereas coadministration with AD4 preserved their normal levels.

CONCLUSION

Haloperidol causes behavioral abnormalities associated with oxidative stress in rats, similar to TD. AD4, the brain-targeted potent antioxidant, reduces the cellular oxidation markers and improves the typical clinical behavior. Hence, AD4 is a potential new treatment of antipsychotic-induced TD.

Therapeutic potential of neurotrophic factors in neurodegenerative diseases

There is a vast amount of evidence indicating that neurotrophic factors play a major role in the development, maintenance, and survival of neurons and neuron-supporting cells such as glia and oligodendrocytes. In addition, it is well known that alterations in levels of neurotrophic factors or their receptors can lead to neuronal death and contribute to the pathogenesis of neurodegenerative diseases such as Parkinson disease, Alzheimer disease, Huntington disease, amyotrophic lateral sclerosis, and also aging. Although various treatments alleviate the symptoms of neurodegenerative diseases, none of them prevent or halt the neurodegenerative process. The high potency of neurotrophic factors, as shown by many experimental studies, makes them a rational candidate co-therapeutic agent in neurodegenerative disease. However, in practice, their clinical use is limited because of difficulties in protein delivery and pharmacokinetics in the central nervous system. To overcome these disadvantages and to facilitate the development of drugs with improved pharmacotherapeutic profiles, research is underway on neurotrophic factors and their receptors, and the molecular mechanisms by which they work, together with the development of new technologies for their delivery into the brain.

A novel thiol antioxidant that crosses the blood brain barrier protects dopaminergic neurons in experimental models of Parkinson's disease

It is believed that oxidative stress (OS) plays an important role in the loss of dopaminergic nigrostriatal neurons in Parkinson's disease (PD) and that treatment with antioxidants might be neuroprotective. However, most currently available antioxidants cannot readily penetrate the blood brain barrier after systemic administration. We now report that AD4, the novel low molecular weight thiol antioxidant and the N-acytel cysteine (NAC) related compound, is capable of penetrating the brain and protects neurons in general and especially dopaminergic cells against various OS-generating neurotoxins in tissue cultures. Moreover, we found that treatment with AD4 markedly decreased the damage of dopaminergic neurons in three experimental models of PD. AD4 suppressed amphetamine-induced rotational behaviour in rats with unilateral 6-OHDA-induced nigral lesion. It attenuated the reduction in striatal dopamine levels in mice treated with 1-methyl-4-phenyl-1,2,3,6,-tetrahydropyridine (MPTP). It also reduced the dopaminergic neuronal loss following chronic intrajugular administration of rotenone in rats. Our findings suggest that AD4 is a novel potential new neuroprotective drug that might be effective at slowing down nigral neuronal degeneration and illness progression in patients with PD.

Analysis of Gene Expression in MOG-Induced Experimental Autoimmune Encephalomyelitis After Treatment With a Novel Brain-Penetrating Antioxidant

Accumulating data from experimental studies indicate that oxidative stress has a major role in the pathogenesis of multiple sclerosis (MS). It has been suggested that local production of reactive oxygen species, probably by macrophages, mediates axonal damage in both MS patients and the mouse model experimental autoimmune encephalomyelitis (EAE). We have shown previously that our novel brain-penetrating antioxidant, N-acetylcysteine amide (AD4), reduces the clinical and pathological symptoms, including inflammation and axonal damage in myelin oligodendrocyte glycoprotein (MOG)-induced chronic EAE in mice. The aim of this study was to examine the molecular mechanism by which AD4 exerts protection in MOG-induced EAE mice. Therefore, we analyzed gene-expression profile in the spinal cords of MOG-induced chronic EAE mice and compared them with MOG-induced mice treated with AD4, using a cDNA microarray. We found that MOG treatment up-regulated genes encoding growth factors, cytokines, death receptors, proteases, and myelin structure proteins, whereas MOG- and AD4-treated mice demonstrated gene expression profiles similar to that seen in naive healthy mice. In conclusion, our study shows that chronic AD4 administration suppresses the induction of various pathological pathways that play a role in EAE and probably in MS.

Antioxidant treatment in Alzheimer's disease: current state

Accumulating data from experimental and human studies indicate that oxidative stress (OS) plays a major role in the pathogenesis of Alzheimer's disease (AD). The production of reactive oxygen species (ROS), which leads to OS, can occur very early, even before the appearance of symptoms and molecular events (beta-amyloid plaques and neurofibrillary tangles), leading to tissue damage via several different cellular molecular pathways. ROS can cause damage to cardinal cellular components such as lipids, proteins, and nucleic acids (e.g., RNA, DNA), causing cell death by modes of necrosis or apoptosis. The damage can become more widespread because of the weakened cellular antioxidant defense systems. Therefore, treatment with antioxidants might theoretically act to prevent propagation of tissue damage and improve both survival and neurological outcome. Indeed, several studies preformed to date examined whether dietary intake of several antioxidants, mainly vitamins, might prevent or reduce the progression of AD. Although a few of the antioxidants showed some efficacy in these trials, no answer is yet available as to whether antioxidants are truly protective against AD. Reasons for these results might include, in part, blood-brain barrier (BBB) permeability, inappropriate timing of administration, or suboptimal drug levels at the target site in the central nervous system. Thus, antioxidant cocktails or antioxidants combined with other drugs may have more successful synergistic effects. Further, well-designed intervention, as well as observational investigations based on large cohorts studied over a long period of time with several methods for assessing antioxidant exposure, including relation to BBB penetration, are needed to test this hypothesis.

Polymorphism in candidate genes: implications for the risk and treatment of idiopathic Parkinson's disease

Idiopathic Parkinson's disease (IPD) is a progressive neurodegenerative disorder for which no restorative or neuroprotective therapy is available. Interest has recently been directed to association studies on polymorphisms of various genes, mainly those related to dopamine metabolism and transport, and their effect on response to PD, which includes primarily levodopa and dopaminomimetics. Approximately 15-20% of patients with PD do not respond to levodopa, and the majority of those who do respond develop adverse fluctuations in motor response, primarily levodopa-induced dyskinesias. This review summarizes the influence of polymorphisms in various genes on the relative risk of IPD and on levodopa efficacy. It focuses on the importance of well-designed polymorphism studies that include large samples of patients with IPD and tightly matched controls and use identical methodologies. Valid data on such polymorphisms might increase the efficacy of levodopa, decrease its side effects, and reduce the occurrence of levodopa-induced dyskinesias. They might also provide a novel diagnostic tool for PD.

A low molecular weight copper chelator crosses the blood-brain barrier and attenuates experimental autoimmune encephalomyelitis

Increasing evidence suggests that enhanced production of reactive oxygen species (ROS) activates the MAP kinases, c-Jun N-terminal protein kinase (JNK) and mitogen-activated protein kinase MAPK (p38). These phosphorylated intermediates at the stress-activated pathway induce expression of matrix metalloproteinases (MMPs), leading to inflammatory responses and pathological damages involved in the etiology of multiple sclerosis (MS). Here we report that N-acetylcysteine amide (AD4) crosses the blood-brain barrier (BBB), chelates Cu(2+), which catalyzes free radical formation, and prevents ROS-induced activation of JNK, p38 and MMP-9. In the myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE), a mouse model of MS, oral administration of AD4 drastically reduced the clinical signs, inflammation, MMP-9 activity, and protected axons from demylination damages. In agreement with the in vitro studies, we propose that ROS scavenging by AD4 in MOG-treated animals prevented MMP's induction and subsequent damages through inhibition of MAPK pathway. The low toxicity of AD4 coupled with BBB penetration makes this compound an excellent potential candidate for the therapy of MS and other neurodegenerative disorders.

The role of oxidative stress in the pathogenesis of multiple sclerosis: the need for effective antioxidant therapy

Accumulating data indicate that oxidative stress (OS) plays a major role in the pathogenesis of multiple sclerosis (MS). Reactive oxygen species (ROS), leading to OS, generated in excess primarily by macrophages, have been implicated as mediators of demyelination and axonal damage in both MS and experimental autoimmune encephalomyelitis (EAE), its animal model. ROS cause damage to cardinal cellular components such as lipids, proteins and nucleic acids (e. g., RNA, DNA), resulting in cell death by necrosis or apoptosis. In addition, weakened cellular antioxidant defense systems in the central nervous system (CNS) in MS, and its vulnerability to ROS effects may increase damage. Thus, treatment with antioxidants might theoretically prevent propagation of tissue damage and improve both survival and neurological outcome. Indeed, several experimental studies have been performed to see whether dietary intake of several antioxidants prevents or reduces the progression of EAE. Although a few antioxidants showed some efficacy in these studies, little information is available on the effect of treatments with such compounds in patients with MS. Well-designed clinical studies using antioxidant intake, as well as investigations based on larger cohorts studied over a longer periods of time, are needed in order to assess whether antioxidant intake together with other conventional treatments, might be beneficial in treating MS.

Axonal damage is reduced following glatiramer acetate treatment in C57/bl mice with chronic-induced experimental autoimmune encephalomyelitis

Glatiramer acetate (GA) is efficacious in reducing demyelinating-associated exacerbations in patients with relapsing-remitting multiple sclerosis (RRMS) and in several experimental autoimmune encephalomyelitis (EAE) models. Here we report that GA reduced the clinical and pathological signs of mice in chronic EAE induced by myelin oligodendrocyte glycoprotein (MOG). GA-treated mice demonstrated only mild focal inflammation, and less demyelination, compared with controls. Moreover, we also found minimal axonal disruption, as assessed by silver staining, antibodies against amyloid precursor protein (APP) and non-phosphorylated neurofilaments (SMI-32), in the GA-treated group. In conclusion, our study demonstrated for the first time that axonal damage is reduced following GA treatment in C57/bl mice with chronic MOG-induced EAE.

Riluzole suppresses experimental autoimmune encephalomyelitis: implications for the treatment of multiple sclerosis

Recent studies suggest that glutamate neurotoxicity is involved in the pathogenesis of multiple sclerosis (MS), and that treatment with glutamate receptor (AMPA/kainate) antagonists inhibits experimental autoimmune encephalomyelitis (EAE), the conventional model of MS. Therefore, we examined whether riluzole, an inhibitor of glutamate transmission, affects the pathogenesis and clinical features of MS-like disease in myelin oligodendrocyte glycoprotein (MOG)-induced EAE in mice. Here we report that riluzole (10 mg/kgx2/day, i.p.), administered before and even after the appearance of clinical symptoms, dramatically reduced the clinical severity of MOG-induced EAE, while all the MOG-immunized control mice developed significant clinical manifestations. Moreover, the riluzole-treated mice demonstrated only mild focal inflammation, and less demyelination, compared to MOG-treated mice, using histological methods. Furthermore, riluzole markedly reduced axonal disruption, as assessed by Bielshowesky's silver staining and by antibodies against non-phosphorylated neurofilaments (SMI-32). No difference was detected in the immune system potency, as T-cell proliferative responses to MOG were similar in both groups. In conclusion, our study demonstrates, for the first time, that riluzole can reduce inflammation, demyelination and axonal damage in the CNS and attenuate the clinical severity of MOG-induced EAE. These results suggest that riluzole, a drug used in amyotrophic lateral sclerosis (ALS), might be beneficial for the treatment of MS.

The CB1 cannabinoid receptor agonist, HU-210, reduces levodopa-induced rotations in 6-hydroxydopamine-lesioned rats

Parkinson's disease is a chronic neurodegenerative disease of the extrapyramidal system associated with dopaminergic neuronal loss in the basal ganglia. However, several other neurotransmitters, such as serotonin, gamma-amino-butyric acid and glutamate, are also related to the symptoms of Parkinson's disease patients and their response to levodopa treatment. The co-expression of cannabinoid and dopamine receptors in the basal ganglia suggests a potential role for endocannabinoids in the control of voluntary movement in Parkinson's disease. In the present study we treated unilaterally 2,4,5-trihydroxyphenethylamine (6-hydroxydopamine)-lesioned rats with the enantiomers of the synthetic cannabinoid 7-hydroxy-delta6-tetrahydrocannabinol 1,1-dimethylheptyl. Treatment with its (-)- (3R, 4R) enantiomer (code-name HU-210), a potent cannabinoid receptor type 1 agonist, reduced the rotations induced by levodopa/carbidopa or apomorphine by 34% and 44%, respectively. In contrast, treatment with the (+)- (3S, 4S) enantiomer (code-name HU-211), an N-methyl-D-aspartate antagonist, as well as the psychotropically inactive cannabis constituent: cannabidiol and its primary metabolite, 7-hydroxy-cannabinol, did not show any reduction of rotational behavior. Our results indicate that activation of the CB1 stimulates the dopaminergic system ipsilaterally to the lesion, and may have implications in the treatment of Parkinson's disease.

Antioxidant therapy in acute central nervous system injury: current state

Free radicals are highly reactive molecules generated predominantly during cellular respiration and normal metabolism. Imbalance between cellular production of free radicals and the ability of cells to defend against them is referred to as oxidative stress (OS). OS has been implicated as a potential contributor to the pathogenesis of acute central nervous system (CNS) injury. After brain injury by ischemic or hemorrhagic stroke or trauma, the production of reactive oxygen species (ROS) may increase, sometimes drastically, leading to tissue damage via several different cellular molecular pathways. Radicals can cause damage to cardinal cellular components such as lipids, proteins, and nucleic acids (e.g., DNA), leading to subsequent cell death by modes of necrosis or apoptosis. The damage can become more widespread due to weakened cellular antioxidant defense systems. Moreover, acute brain injury increases the levels of excitotoxic amino acids (such as glutamate), which also produce ROS, thereby promoting parenchymatous destruction. Therefore, treatment with antioxidants may theoretically act to prevent propagation of tissue damage and improve both the survival and neurological outcome. Several such agents of widely varying chemical structures have been investigated as therapeutic agents for acute CNS injury. Although a few of the antioxidants showed some efficacy in animal models or in small clinical studies, these findings have not been supported in comprehensive, controlled trials in patients. Reasons for these equivocal results may include, in part, inappropriate timing of administration or suboptimal drug levels at the target site in CNS. Better understanding of the pathological mechanisms of acute CNS injury would characterize the exact primary targets for drug intervention. Improved antioxidant design should take into consideration the relevant and specific harmful free radical, blood brain barrier (BBB) permeability, dose, and time administration. Novel combinations of drugs providing protection against various types injuries will probably exploit the potential synergistic effects of antioxidants in stroke.

Oxidative stress induced-neurodegenerative diseases: the need for antioxidants that penetrate the blood brain barrier

Oxidative stress (OS) has been implicated in the pathophysiology of many neurological, particularly neurodegenerative diseases. OS can cause cellular damage and subsequent cell death because the reactive oxygen species (ROS) oxidize vital cellular components such as lipids, proteins, and DNA. Moreover, the brain is exposed throughout life to excitatory amino acids (such as glutamate), whose metabolism produces ROS, thereby promoting excitotoxicity. Antioxidant defense mechanisms include removal of O(2), scavenging of reactive oxygen/nitrogen species or their precursors, inhibition of ROS formation, binding of metal ions needed for the catalysis of ROS generation and up-regulation of endogenous antioxidant defenses. However, since our endogenous antioxidant defenses are not always completely effective, and since exposure to damaging environmental factors is increasing, it seems reasonable to propose that exogenous antioxidants could be very effective in diminishing the cumulative effects of oxidative damage. Antioxidants of widely varying chemical structures have been investigated as potential therapeutic agents. However, the therapeutic use of most of these compounds is limited since they do not cross the blood brain barrier (BBB). Although a few of them have shown limited efficiency in animal models or in small clinical studies, none of the currently available antioxidants have proven efficacious in a large-scale controlled study. Therefore, any novel antioxidant molecules designed as potential neuroprotective treatment in acute or chronic neurological disorders should have the mandatory prerequisite that they can cross the BBB after systemic administration.