An attempt by Roche and Trimeris to develop a needle-free version of their HIV drug Fuzeon has been thwarted – for now – by a US Food and Drug Administration request for more information on the product.

Fuzeon (enfuvirtide) – the first HIV fusion inhibitor to reach the market - is already being used with standard needle-syringe administration for the treatment of patients with resistant HIV infections. But Roche and Trimeris hope to develop a more patient-friendly version.

Filing of the new product will now likely be delayed until at least the first half of 2007, when data from another clinical trial of the device become available.

Although the FDA has acknowledged that administration with the new B2000 injector device achieves similar blood levels of Fuzeon to the current formulation, the agency is concerned about a small number of certain adverse events related to administration with the new device. These reactions – mainly haematomas and nerve pain – seem to occur when Fuzeon is administered in close proximity to bone joints or into scar tissue.

In the current product label, Fuzeon is recommended for injection in the upper arm, upper leg and stomach, and labelling cautions against injecting into scar tissue.

Roche and Trimeris have an ongoing clinical trial of the needle-free version - called BOSS – that has completed enrollment of approximately 330 current or prior Fuzeon patients, and hope that data from this study will help address the FDA’s concerns.

In the meantime, the FDA has requested changes to the current Fuzeon labeling to add precautions regarding haematoma and nerve pain associated with B2000 administration, as well as use of the B2000 device in patients with bleeding disorders.