Needle-free injections for T-20 in US

People in the US using the entry inhibitor T-20 (enfuvirtide) have started to use a needle-free injection method of delivery for this drug. The system, called Biojector 2000, uses compressed carbon dioxide to force the drug at pressure through the skin from a pre-mixed syringe.

This process reduces the processes involved in preparing T-20, and eliminates the need for needles. The new system started to be used after a presentation of a study at a medical meeting in December showed that the two systems produced equivalent drug concentrations. [1]

The benefits from T-20 are limited by for many patients by the difficultly of twice-daily sub-cutaneous injection. The process, while manageable successfully by many patients is more complicated and time-consuming than an oral medication. It is also associated with a range of injection site reaction in nearly all patients, which although is not a major reason for discontinuation, certainly impacts on quality of life. These difficulties are an additional hurdle for patients, who could potentially benefit from T-20 earlier at an earlier stage treatment failure, to overcome.

T-20 is virologically effective for many patients particularly when combined with an additional active drug such as tipranavir that is now available in the UK on an expanded access programme

Comment

Biojector was approved in the US in 1996 to deliver subcutaneous and intramuscular injections and has been used in vaccine delivery, chronic therapy and other settings. The device is not widely registered outside the US, is not commercially supplied outside the US and does not have European approval. It is therefore unclear when this may become available for patients in Europe.

This system will not eliminate injections site reactions associated with T-20, as this is linked to contact with the active compound rather that the delivery system. It does however simplify the process and has been welcomed by US patients, who also report a reduction in skin reactions.

True AL, Zhang Y, Chiu Y-Y et al. Needle-free Administration of Enfuvirtide with Biojector 2000 demonstrates bioequivalence to standard needle administration. Frontiers in Developemnt of Antiretroviral Therapy (HIV DART), 2004. Poster 57.