OAB: Current options and future challenges
A panel of OAB experts convened in Barcelona on Sunday, presiding over a series of state-of-the-art lectures and case presentations. The case presentations served to illustrate the variety of treatment options for overactive bladder.
Prof. Martin Michel (DE) was invited to discuss the latest developments in OAB drugs, but regrettably had to conclude that the pipeline was empty for the foreseeable future.
“Room for improvement is limited for tolerability of oral OAB treatments. The greatest medical need in OAB efficacy exists for urgency and nocturia (which both have major adverse impacts on QoL),” Michel pointed out.
“Major efficacy gains may not come from new drug classes if the OAB population is targeted as a whole. The priority for OAB research should be to identify and understand subsets of patients with specific pathophysiology and biomarkers. We also need to identify suitable treatment options that address the ‘master switches’ of such pathophysiology.”
Michel noted that OAB was a symptom complex, not a disease entity that can be treated with a single miracle drug. Multiple diseases may be at play in a patient’s OAB, each requiring specific treatment.
Potential for combination therapy?
A similarly cautious talk about the potential of combination therapy followed from Prof. Frank Van Der Aa (BE). “What is the current problem with medical treatment for OAB? Patients typically stop taking antimuscarinics after about one year, because they are found to be ineffective, expensive and perhaps cause side-effects.”
The potential advantages of combination therapy for OAB can be found in the increased efficacy (due to additive and synergistic effects). Each drug can have an optimal dose, leading to dose reduction and better tolerability.
Prof. Van Der Aa summarised the results of the SYNERGY, SYNERGY II and BESIDE trials. The combination of antimuscarinics and Beta3 adrenoceptor agonists led to either clinically insignificant results, or statistically significant results that only offered a very small benefit to patients.
The EAU Guidelines only make cautious recommendations on combination therapy, and mainly suggest the addition of mirabegron if initial solifenacin proves ineffective, rather than immediately starting with a combination of drugs.
“In the end, combination therapy is not a game changer,” Van Der Aa concluded. “The combined effects add up to a small improvement, and it does not have synergistic side-effects.”