Vectura, the UK company specialising in inhaled therapies for the treatment of respiratory and neurological conditions, has reported promising results from a second Phase II clinical trial with VR040, its inhaled formulation of apomorphine for combating “off” episodes in people with Parkinson’s disease.

The new data build on the results of a Phase II proof-of-concept study with VR040 published in August 2006. Although not powered for meaningful statistical comparisons, the previous trial found that five of 24 patients converted to a full “on” state after inhaling VR040, compared with one patient on placebo.

The follow-up was a randomised, double-blind, placebo-controlled study evaluating the safety and efficacy of four different VR040 fine particle doses (rising to 3.2mg) in 47 patients diagnosed with idiopathic Parkinson’s disease. The drug is delivered to the bloodstream by oral inhalation through the lungs using Vectura’s proprietary dry powder inhalation technology.

The main outcomes were:

- A statistically significant improvement in the primary endpoint of mean change in the Unified Parkinson Disease Rating Scale III (UPDRS III) compared with placebo. UPDRS III includes 14 different items of motor function and is routinely employed in clinical studies to measure motor changes in response to treatment administration.

- A high level of restored mobility, with 81% of patients achieving responses “essentially the same” as those attained with their usual dose of the standard Parkinson’s treatment levodopa.

- A rapid onset of action. The majority of patients achieved conversions from their “off” state within 10 minutes of inhaling apomorphine, Vectura said. Some reported converting as little as two minutes after taking the drug.

- Durability of response, with a mean duration of 75 minutes. VR040 is intended as an on-demand, rescue therapy for “off” episodes in Parkinson’s.

- “Excellent” tolerability, with only five out of 32 patients reporting a total of seven treatment-related adverse events. There were no reports of serious or severe treatment-related adverse events, and no patient withdrawals resulting from safety concerns.

“The results of this study confirm our original enthusiasm for VR040’s potential,” commented Vectura’s chief executive, Dr Chris Blackwell. The company will now focus on determining optimal titrated dosing for VR040 in an ‘at home’ setting.

‘Off” episodes are the debilitating motor complications experienced by people with Parkinson’s as the disease progresses and therapeutic control diminishes. It is estimated that around 10% of people with Parkinson’s undergo severe on/off motor fluctuations requiring apomorphine treatment.