A study of cancer occurrence in users of mirabegron and antimuscarinic treatments for overactive bladder

Lessons learned from a multi-data source research collaboration: The mirabegron post-authorization safety study program

BACKGROUND

Many factors contribute to developing and conducting a successful multi-data source, non-interventional, post-authorization safety study (NI-PASS) for submission to multiple health authorities. Such studies are often large undertakings; evaluating and sharing lessons learned can provide useful insights to others considering similar studies.

OBJECTIVES

We discuss challenges and key methodological and organizational factors that led to the delivery of a successful post-marketing requirement (PMR)/PASS program investigating the risk of cardiovascular and cancer events among users of mirabegron, an oral medication for the treatment of overactive bladder.

RESULTS

We provide context and share learnings, including sections on research program collaboration, scientific transparency, organizational approach, mitigation of uncertainty around potential delays, validity of study outcomes, selection of data sources and optimizing patient numbers, choice of comparator groups and enhancing precision of estimates of associations, potential confounding and generalizability of study findings, and interpretation of results.

CONCLUSIONS

This large PMR/PASS program was a long-term commitment from all parties and benefited from an effective coordinating center and extensive scientific interactions across research partners, scientific advisory board, study sponsor, and health authorities, and delivered useful learnings related to the design and organization of multi-data source NI-PASS.

Published registry-based pharmacoepidemiologic associations show limited concordance with agnostic medication-wide analyses

OBJECTIVES

To assess how the results of published national registry-based pharmacoepidemiology studies (where select associations are of interest) compare with an agnostic medication-wide approach (where all possible drug associations are tested).

STUDY DESIGN AND SETTING

We systematically searched for publications that reported drug associations with any, breast, colon/colorectal, or prostate cancer in the Swedish Prescribed Drug Registry. Results were compared against a previously performed agnostic medication-wide study on the same registry.

PROTOCOL

https://osf.io/kqj8n.

RESULTS

Most published studies (25/32) investigated previously reported associations. 421/913 (46%) associations had statistically significant results. 134 of the 162 unique drug-cancer associations could be paired with 70 associations in the agnostic study (corresponding drug categories and cancer types). Published studies reported smaller effect sizes and absolute effect sizes than the agnostic study, and generally used more adjustments. Agnostic analyses were less likely to report statistically significant protective associations (based on a multiplicity-corrected threshold) than their paired associations in published studies (McNemar odds ratio 0.13, P = 0.0022). Among 162 published associations, 36 (22%) showed increased risk signal and 25 (15%) protective signal at P < 0.05, while for agnostic associations, 237 (11%) showed increased risk signal and 108 (5%) protective signal at a multiplicity-corrected threshold. Associations belonging to drug categories targeted by individual published studies vs. nontargeted had smaller average effect sizes; smaller P values; and more frequent risk signals.

CONCLUSION

Published pharmacoepidemiology studies using a national registry addressed mostly previously proposed associations, were mostly "negative", and showed only modest concordance with their respective agnostic analyses in the same registry.

Identification of Drug-Cancer Associations: A Nationwide Screening Study

The main tool in drug safety monitoring, spontaneous reporting of adverse effects, is unlikely to detect delayed adverse drug effects including cancer. Hypothesis-free screening studies based on administrative data could improve ongoing drug safety monitoring. Using Danish health registries, we conducted a series of case-control studies by identifying individuals with incident cancer in Denmark from 2001 to 2018, matching each case with 10 population controls on age, sex, and calendar time. ORs were estimated using conditional logistic regression accounting for matching factors, educational level, and selected comorbidities. A total of 13,577 drug-cancer associations were examined for individual drugs and 8,996 for drug classes. We reviewed 274 drug-cancer pairs where an association with high use and a cumulative dose-response pattern was present. We classified 65 associations as not readily attributable to bias of which 20 were established as carcinogens by the International Agency for Research on Cancer and the remaining 45 associations may warrant further study. The screening program identified drugs with known carcinogenic effects and highlighted a number of drugs that were not established as carcinogens and warrant further study. The effect estimates in this study should be interpreted cautiously and will need confirmation targeted epidemiologic and translational studies.

Significance

This study provides a screening tool for drug carcinogenicity aimed at hypothesis generation and explorative purposes. As such, the study may help to identify drugs with unknown carcinogenic effects and, ultimately, improve drug safety as part of the ongoing safety monitoring of drugs.

Clinical Utility of β3-Adrenoreceptor Agonists for the Treatment of Overactive Bladder: A Review of the Evidence and Current Recommendations

This nonsystematic review provides a summary of current evidence on the use of β₃-adrenoreceptor agonists (β₃-ARAs) for the treatment for lower urinary tract symptoms. Soon after their discovery in 1989, β₃-ARs were identified as a predominant adrenoreceptor subtype in the human urinary bladder. Although it is widely believed that β₃-ARAs cause detrusor relaxation, the effect on bladder afferent signaling likely plays an important role in their mechanism of action as well. In 2011 and 2012, mirabegron was approved for clinical use in overactive bladder (OAB) patients. Pooled analysis of data from prospective randomized studies on >60,000 OAB patients showed that when compared to placebo, mirabegron was superior with respect to reducing the frequency, number, and severity of urgency episodes, number of incontinence episodes and increasing dry rate, but not in reduction of nocturia episodes. The only side effect showing significantly higher incidence than placebo was nasopharyngitis. Mirabegron is approved for OAB treatment in all age-groups and in pediatric patients with neurogenic bladder. Vibegron is another β₃-ARA approved for OAB treatment in the US and Japan. Several large, multicenter, double-blind, randomized trials have documented statistically significant superiority of vibegron over placebo on all efficacy end points. Other β₃-ARAs are being developed; however, to date none has been introduced to clinical use. All β₃-ARAs provide efficacy similar to anticholinergics. They have a favorable safety profile and are well tolerated. Due to their different mechanisms of action, combination of β₃-ARAs with anticholinergic compounds allows for increased efficacy.