Potential barriers to use of T-20: results from patient and physician interviews

Use of T-20 in the UK has been growing steadily since European approval in May 2003, but patient uptake is still substantially lower than initially expected. Although this may largely relate to a smaller pool of treatment-experienced patients on failing regimens, attitudes to the use of an injectable treatment, together with concerns of cost have also both been suggested as barriers to wider access to T-20.

Horne and colleagues reported results from a survey of around 600 treatment-experienced patients, 10% of whom were currently using T-20. Only 150/542 non-users of T-20 had discussed using an injectable ARV with their doctors, and this had resulted in 56 patients using T-20, 17 of whom subsequently discontinued the drug.

When non-users were given information about T-20, 180 and 214 out of 516 responders (35% and 41%) said they would be very likely or moderately likely to accept treatment with an injectable drug, with only 122/516 (24%) saying that they would not use the drug.

Approximately 60% of patients thought that they would be sufficiently motivated to use an injectable drug and would be able to deal with the additional complexity required. The importance of their doctors recommendations was also highlighted in the responses, with 85% believing that their doctor could explain the benefits of an injectable treatment. Around one quarter decided that even with a strong recommendation, they would opt to continue using only oral medication.

In a second study, Youle and colleagues reported results from interviews with almost 500 European HIV doctors (> 3 years experience, with >15% of patients in clinic exposed to >8 ARVs). Sixty percent of the doctors managed between 100-300 patients, and 25% of these clinic populations were exposed to >8 ARVs. 24% 41% and 34 % of the doctors had 0, 1-4 and >5 patients using T-20 (defined as non, lower and higher T-20 use).

Significant differences between these groups showed that doctors who currently used T-20 were more likely to believe that T-20 had greater efficacy than oral-based regimens (which would be expected). They also had less difficulty justifying the cost of T-20, and believed that their patients perceived the benefits to outweigh the disadvantages. Non-prescribers identified cost as a barrier to prescription, but also believed less in the efficacy of the drug. Higher prescribers were more likely to be involved in research as investigators or paper authors.

These two complementary studies (doctors taking part in the second study were the source for patients in the first study) highlighted the importance of clinicians attitudes and beliefs in relation to whether a patient is likely to be offered a particular treatment.

It is not surprising that a doctors use of a drug was closely related to their belief in its effectiveness and tolerability. It is a concern that these beliefs do not always closely match those expressed by treatment-experienced patients themselves.

The recent approval of tipranavir/r and availability of TMC114/r (darunavir) on named-patient access (both of which showed approximately a doubling of the chance of viral suppression when used with T-20 as a new drug), together with this research, should hopefully broaden the group of patients whose treatment is currently failing and to whom T-20 should be offered.

In the long run, adherence and continued use of T-20 is also limited by injection site reactions that are experienced by nearly all patients. Although ISRs can be managed, they can be painful and long lasting. The use of the needle-free Biojector device that Roche is developing, may provide addition benefits in reducing incidence and severity of these skin reactions.