JNJ-10280205 and JNJ-10287069: novel PDE5 inhibitors as clinical candidates for erectile dysfunction

In silico design of novel hERG-neutral sildenafil-like PDE5 inhibitors

Cyclic nucleotide phosphodiesterase enzymes (PDEs) have functions in regulating the levels of intracellular second messengers, 3', 5'-cyclic adenosine monophosphate (cAMP) and 3', 5'-cyclic guanosine monophosphate (cGMP), via hydrolysis and decomposing mechanisms in cells. They take essential roles in modulating various cellular activities such as memory and smooth muscle functions. PDE type 5 (PDE5) inhibitors enhance the vasodilatory effects of cGMP in the corpus cavernosum and they are used to treat erectile dysfunction. Patch clamp experiments showed that the IC₅₀ values of the human ether-à-go-go-related gene (hERG1) potassium (K) ion channel blocking affinity of PDE5 inhibitors sildenafil, vardenafil, and tadalafil as 33, 12, and 100 μM, respectively. hERG1 channel is responsible for the regulation of the action potential of human ventricular myocyte by contributing the rapid component of delayed rectifier K⁺ current (I_Kr) component of the cardiac action potential. In this work, interaction patterns and binding affinity predictions of selected PDE5 inhibitors against the hERG1 channel are studied. It is attempted to develop PDE5 inhibitor analogs with lower binding affinity to hERG1 ion channel while keeping their pharmacological activity against their principal target PDE5 using in silico methods. Based on detailed analyses of docking poses and predicted interaction energies, novel analogs of PDE5 inhibitors with lower predicted binding affinity to hERG1 channels without loosing their principal target activity were proposed. Moreover, molecular dynamics (MD) simulations and post-processing MD analyses (i.e. Molecular Mechanics/Generalized Born Surface Area calculations) were performed. Detailed analysis of molecular simulations helped us to better understand the PDE5 inhibitor-target binding interactions in the atomic level. Results of this study can be useful for designing of novel and safe PDE5 inhibitors with enhanced activity and other tailored properties.

Avanafil for the treatment of erectile dysfunction: initial data and clinical key properties

Orally active, selective inhibitors of phosphodiesterase type 5 (PDE 5, cyclic GMP PDE), such as sildenafil, tadalafil and vardenafil, are currently the first-choice treatment options for the clinical management of erectile dysfunction (ED) of various etiologies and severities. However, a significant number of patients remain dissatisfied with the available therapies due a lack of efficacy or discomfort arising from adverse events. Several new PDE5 inhibitors, among which are avanafil (TA-1790), lodenafil, mirodenafil, udenafil, SLX-2101, JNJ-10280205 and JNJ-10287069, have recently been approved and introduced into the market or are in the final stages of their clinical development. Avanafil (marketed in the US under the brand name STENDRA(™)) has been developed by VIVUS Inc. (Mountain View, CA, USA) and has recently received approval from the US Food and Drug Administration (FDA) for use in the treatment of male ED. The drug has demonstrated improved selectivity for PDE5, is rapidly absorbed after oral administration with a fast onset of action and a plasma half-life that is comparable to sildenfil and vardenafil. In phase II and phase III clinical trials that included a large number of patients, avanafil has been shown to be effective and well tolerated. Owing to its favorable pharmacodynamic and pharmacokinetic profile, avanafil is considered as a promising new option in the treatment of ED. The present article summarizes the initial data and clinical key properties of avanafil.

Future prospects in the treatment of erectile dysfunction: focus on avanafil

The treatment of erectile dysfunction (ED) has been revolutionized in the last 15 years with the introduction of type 5 phosphodiesterase (PDE5) inhibitors. Their efficacy, safety, and ease of administration have made them first-line treatment for ED. This article reviews the current therapies available for ED, and the new PDE5 inhibitors that are being investigated. Furthermore, it examines all the current ED treatment options that are in different phases of development (including oral and topical pharmacotherapy, gene therapy, and tissue engineering). A special emphasis is on avanafil, a new PDE5 inhibitor that has been studied extensively in Phase I and II clinical trials and has undergone several Phase III trials. Avanafil is a promising medication for ED due to its favorable pharmacokinetics, safety, and efficacy.

Novel phosphodiesterase-5 (PDE5) inhibitors in the alleviation of erectile dysfunction due to diabetes and ageing-induced oxidative stress

BACKGROUND

Diabetes and ageing are associated with erectile dysfunction (ED). Under these conditions, increased oxidative stress produces superoxide ions, which in turn suppresses the nitric oxide-cyclic guanosine monophosphate pathway. The phophodiesterase-5 (PDE5) inhibitors still remain ineffective in 15 - 57% of impotent men.

OBJECTIVE

To identify the efficacy of conventional and novel PDE5 inhibitors on oxidative stress involved in diabetes and ageing.

METHODS

An electronic search of the literature was conducted to review published information relating diabetes and ageing to ED and to cover late-stage developments of novel PDE5 inhibitors.

RESULTS/CONCLUSION

Safe and more efficacious alternatives that can modulate PDE5 levels in ED regarding oxidative stress conditions are needed. Included in this review are updates on the new PDE5 inhibitors avanafil, udenafil, SLx-2101, and mirodenafil.