A237 IMPROVEMENT IN ABDOMINAL SYMPTOMS WITH LINACLOTIDE IN PATIENTS WITH IRRITABLE BOWEL SYNDROME WITH CONSTIPATION: RESULTS FROM A PHASE 3B TRIAL

Background

Linaclotide (LIN) is a guanylate cyclase-C agonist approved to treat irritable bowel syndrome with constipation (IBS-C) in adults. Abdominal symptoms are important to patients with IBS-C. In a recent Phase 3b study, LIN significantly improved a composite score of abdominal bloating, pain, and discomfort (Abdominal Score), which was used as the primary endpoint in the study.

Aims

To evaluate the efficacy of LIN for improving additional efficacy abdominal symptom endpoints in a randomized, double-blind, placebo (PBO)-controlled Phase 3 study of LIN in patients with IBS-C.

Methods

Adults with IBS-C were randomized to PBO (N=308) or LIN 290 μg (N=306) once daily for 12 weeks. Patients recorded their daily abdominal symptoms, including the individual items of bloating, pain, and discomfort, using an 11-point scale (0–10; 0=none, 10=worst possible). The primary endpoint was the Abdominal Score. Additional efficacy endpoints included 6/12-week abdominal pain and constipation (APC)+1 responder, 6/12-week abdominal bloating responder, 6/12-week abdominal pain responder, and 6/12-week abdominal discomfort responder. For individual symptoms, a responder was a patient who had an improvement from baseline of ≥2 points in the respective endpoint for ≥6 of the 12 weeks. Changes from baseline (CFB) over 12 weeks in abdominal bloating, pain, and discomfort were evaluated using a mixed model with repeated measures framework. Proportions of responders were compared between groups for each responder endpoint using a Cochran-Mantel-Haenszel test.

Results

614 patients (mean age, 46.7 years; 81% female; similar baseline abdominal symptoms) were randomized. LIN-treated patients had greater least-squares mean (LSM) CFB in abdominal bloating (LSM difference [95% CI]: –0.889 [–1.249, –0.530], p<0.001), pain (–0.881 [–1.238, –0.524], p<0.001), and discomfort (–0.837 [–1.196, –0.478], p<0.001) compared to PBO-treated patients. There was a greater proportion of LIN-treated vs. PBO-treated patients who were 6/12-week APC+1 (29% vs. 17%; p=0.0003), bloating (40% vs. 24%; p<0.001), pain (42% vs. 25%; p<0.001), and discomfort (42% vs. 26%; p<0.001) responders (Figure). Diarrhea was the most common treatment-emergent adverse event (LIN: 4.6%; PBO: 1.6%).

Conclusions

LIN significantly improved multiple abdominal symptom and secondary responder endpoints in patients with IBS-C. These results support the effectiveness of LIN for improving a spectrum of abdominal symptoms in IBS-C.

Funding Agencies

This study was sponsored by Allergan plc, Dublin, Ireland (prior to acquisition by AbbVie Inc.). Writing and editorial assistance were provided to the authors by Brittany Y. Jarrett, PhD, Jane Beck, MA, and Rebecca Fletcher, BA(Hons) of Complete HealthVizion, Inc., Chicago, IL, USA and funded by Allergan plc (prior to acquisition by AbbVie Inc.).

Radar plots: A novel modality for displaying disparate data on the efficacy of eluxadoline for the treatment of irritable bowel syndrome with diarrhea

BACKGROUND

Patients with irritable bowel syndrome with diarrhea (IBS-D) experience a range of abdominal and bowel symptoms; successful management requires alleviation of this constellation of symptoms. Eluxadoline, a locally active mixed μ- and κ-opioid receptor agonist and δ-opioid receptor antagonist, is approved for the treatment of IBS-D in adults based on the results of 2 Phase 3 studies. Radar plots can facilitate comprehensive, visual evaluation of diverse but interrelated efficacy endpoints.

METHODS

Two double-blind, placebo-controlled, Phase 3 trials (IBS-3001 and IBS-3002) randomized patients meeting Rome III criteria for IBS-D to twice-daily eluxadoline 75 or 100 mg or placebo. Radar plots were prepared showing pooled Weeks 1-26 response rates for the primary efficacy composite endpoint (simultaneous improvement in abdominal pain and stool consistency), stool consistency, abdominal pain, urgency-free days, and adequate relief, and change from baseline to Week 26 in IBS-D global symptom score, abdominal discomfort, abdominal pain, abdominal bloating, and daily number of bowel movements.

KEY RESULTS

The studies enrolled 2428 patients. Eluxadoline increased Weeks 1-26 responder proportions vs placebo for the composite endpoint, stool consistency, abdominal pain, urgency-free days, and adequate relief. Changes from baseline to Week 26 in IBS-D global symptom score, abdominal discomfort, abdominal pain, abdominal bloating, and number of bowel movements were greater with eluxadoline vs placebo.

CONCLUSIONS AND INFERENCES

Data presentation in radar plot format facilitates interpretation across multiple domains, demonstrating that eluxadoline treatment led to improvements vs placebo across 13 endpoints representing the range of symptoms experienced by patients with IBS-D.

Changes in estrogen receptor (ER), progesterone receptor (PR) and HER2/neu status with time: Discordance rates between primary and metastatic breast pathology samples

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Background: The occurrence of changes in tumor receptor profile (ER, PR and HER-2/neu) between primary and metastatic tissue has been recognised and may have significant treatment implications. Previous reports on receptor discordance rates have tended to be from sub-studies of clinical trials. We sought to evaluate the degree of ER, PR and HER-2/neu receptor discordance in patients treated at two Canadian cancer centres. Methods: Archival data was collected on patients for whom tissue from both primary and metastatic sites was available. Patients with recurrences in the breast or axilla were excluded. ER, PR and HER-2/neu status in the primary and metastasis were compared. Additional information including adjuvant therapy and time to metastasis biopsy was gathered. Results: To date, data is available on 80 patients. Hormone receptor (HR) status was available for 96% of primaries and 56% of metastases. HR status on both the primary and the metastasis was performed in 51% of cases. The discordance rate for ER was 21% (2-sided p=0.0096). 12% of patients changed from ER+ to ER- and 9% changed from ER- to ER+. The discordance rate for PR was 37% (2-sided p=0.0001), with all of these patients changing from PR+ to PR-. No significant HR discordance was found among different adjuvant hormone therapy subgroups. There was no correlation between HR discordance and time to rebiopsy. No discordance for HER-2/neu was found. Conclusions: Significant discordance for HR status was observed, 21% for ER and 37% for PR. HER-2/neu discordance was not observed. We are currently exploring the practical implications of these discordance rates on the management of advanced breast cancer patients in a prospective trial.

No significant financial relationships to disclose.

Haloperidol blocks increased locomotor activity elicited by carbachol infusion into the ventral hippocampal formation

Previous studies have demonstrated that stimulation of the ventral hippocampal (VH) formation (including the ventral CA1 and subicular areas) elicits increased locomotor activity in rats. The locomotor-activating effects of VH stimulation have been hypothesized to be mediated via hippocampal output to cortical and subcortical dopamine (DA) systems. This study examined whether increased locomotor activity produced by VH stimulation was blocked by pretreatment with a DA receptor antagonist, and whether DA metabolism in subdivisions of the nucleus accumbens, caudate-putamen, and prefrontal cortex was elevated by VH stimulation. Stimulation of the VH (defined as the ventral CA1 and its borders, ventral subiculum, and entorhinal cortex) with the cholinergic agonist carbachol was found to elevate locomotor activity, while pretreatment with the D2 receptor antagonist haloperidol blocked this effect. Stimulation of the VH did not alter DA metabolism (i.e., ratio of the DA metabolites DOPAC or HVA/DA) in any of the brain regions studied. These results indicate that the increased locomotor activity elicited by VH stimulation is not associated with dramatic increases in DA metabolism, but that it does require tonic activation of D2 receptors.

Fine-structural correlates of growth in hyphae of Ascodesmis sphaerospora

Mycelial mats of Ascodesmis sphaerospora were fixed and embedded for electron microscopy, and thin sections of 1-mm blocks, taken from the 1st to the 7th mm behind the hyphal tips, were cut parallel to the long axis of the hyphae. The hyphal tip region is characterized by an outer zone of electron-transparent vesicles, 500 to 1,000 A in diameter, and is apparently associated with wall elaboration. Immediately behind this region, dense granules become evident along convoluted membrane systems and along the plasma membrane; in the same region are numerous small lomasomes in the lateral wall. As the hypha grows, septa are laid down at 3- to 7-min intervals at a distance of 200 to 250 mu behind the hyphal tip. A cylinder of endoplasmic reticulum is intimately involved in cross-wall deposition from its earliest stages; as the wall grows in, it becomes increasingly constricted in the pore region, finally assuming a torus-like configuration. Woronin bodies are shown to have a crystalline substructure and to originate in pouch-like membrane systems. Cross-walls from a 7- to 13-hr-old mycelium frequently show highly ordered structures in the vicinity of the pore. These structures may appear either as laminar stacks of discs to one side of the pore or as series of stubby concentric rings within the pore area itself. In the latter case, a mass of granular material is frequently seen plugging the pore. Other unusual organelles and inclusions in 7- to 13-hr hyphae are vesicles containing swirls of beaded or dilated membrane, membrane-enclosed rods, and stacks of unit membranes associated with spherical, electron-transparent vesicles.