An inhaled formulation of the drug apomorphine, developed by UK company Vectura, could provide a new treatment for erectile dysfunction with a faster onset of action than current oral drugs for the condition, according to the results of a Phase IIb study.

The product, VR004, delivers a dry powder formulation of apomorphine into the lungs using Vectura’s Aspirair inhaler. The Phase IIb trial showed that at the highest dose tested (300mcg), two thirds of men were able to maintain an erection suitable for successful intercourse, compared to 38% of the placebo group. The men enrolled in the study used VR004 or a matched placebo at home over a 12 week period.

The erectile dysfunction market is well-served with orally-active treatments, with three phosphodiesterase 5 inhibitors, Pfizer’s Viagra (sildenafil), Lilly ICOS’ Cialis (tadalafil) and GlaxoSmithKline/Bayer’s Levitra (vardenafil), already available in most markets around the world. These drugs have typically shown an efficacy rate of around 70% in trials.

But while there is no question that the PDE 5 inhibitors have transformed the management of the condition, which previously had to be managed with intra-penile injections, they can still take half an hour or more to exert their effects. Half of the men using Vectura’s product, on the other hand, reported an erection within five minutes, 80% within 10 minutes and some even within a minute of dosing.

Vectura is hopeful that VR004, if successful in additional trials will capture a slice of the $3.8 billion market for erectile dysfunction therapies, which has been dominated in recent years by the PDE 5 inhibitors, though positioning as a product that can be used with greater spontaneity than its orally-active rivals.

Some of the regulatory risk has been taken out of the VR004 project because apomorphine is already used as a treatment for erectile dysfunction, with an oral formulation of the drug, Uprima/Ixense, sold by Abbott Laboratories, although Abbott recently withdrew its marketing authorisation for the product in Europe after sluggish sales.

Meanwhile, other competitors to the established products on the horizon include VIVUS/Tanabe’s avanafil, shortly to start Phase III testing and billed as having faster onset of action than the current crop of PDE 5 inhibitors, and earlier-stage drugs in this class such as Surface Logix’ SLx-2101 in Phase I/II.

Discussing VR004’s potential in the marketplace, Chris Blackwell, Vectura’s chief executive, said the product: “meets our target profile and the unmet need for a spontaneous product, providing activity on demand for patients with erectile dysfunction.” The company plans to secure a licensing partner for the product prior to the start of Phase III testing, he added.

Vectura has a second dose-ranging Phase IIb trial underway that should report results in the first half of next year.

Vectura has also just announced that it hopes to raise £43 million ($78m) net of expenses through a placing of shares, with the proceeds used to take its key projects through clinical development and bolster its early-stage R&D pipeline.

- Meanwhile, Vectura and Sosei of Japan have completed a Phase IIb trial of NVA237, an inhaled treatment for chronic obstructive pulmonary disease (COPD). The once-daily bronchodilator was as effective as Boehringer Ingelheim and Pfizer’s already-marketed Spiriva (tiotropium), which achieved sales of close to a billion euros last year.