Patients who stop taking their antiretroviral medicines may experience viral rebound in as little as a month after cessation of therapy, said Andrew Gray of the University of Kwazulu-Natal in Durban, South Africa. He was one of the speakers at a session entitled ‘Clinical consequences of medicine shortages’ at the 74th FIP congress in Bangkok on 3 September 2014.
It was evident from presentations and posters at the conference that medicine shortages are a worldwide phenomenon, affecting developed and developing countries alike. They encompass a range of products from widely used parenterals to orphan drugs and anti-venoms for snake bite. The clinical consequences when a product is not available will be determined by the condition requiring treatment. Therefore, effects can be immediate or delayed, depending on how tolerant a disease process is of interruptions to or lack of drug therapy. Clinical consequences for the patient will also depend on whether there are readily available alternatives which can be implemented immediately.
Gray gave an overview of the risks of HIV/AIDS treatment interruptions. There are approximately 35 million patients living with HIV worldwide, with an estimated 6,300 new infections identified daily. Around 95% of cases occur in low and middle income countries (LMIC). Successful prevention has reduced the number of new infections and deaths, resulting in an increasing number of people requiring chronic treatment. In 2011, it was estimated that 8 million people in LMIC were receiving antiretroviral therapy, equivalent to about 50% coverage
. Improved global access to antiretrovirals (ARVs), along with changes to treatment policies so that children are treated as soon as they are diagnosed, mean that there is an ever expanding population requiring a secure supply of antiretroviral drugs. However, poor supply chain management, such as poor procurement or distribution practices or natural or other disasters, can threaten this access.
The aim of antiretroviral therapy is full and long-lasting virus suppression in order to reduce HIV-related morbidity and mortality. A lack of adherence to drug treatment, for example as a result of shortages, can have a drastic effect. Treatment interruptions can result in viral resistance emerging. A recent study in Malawi indicated that, following a treatment interruption, the re-emerging virus demonstrated resistance to the first-line drugs in a quarter of patients, requiring second line regimens to be adopted
. When efavirenz- or nevirapine-based antiretroviral therapy was interrupted, the resulting resistant virus was much harder to repress. Treatment interruptions therefore increase the risk of development of viral resistance, leading to the re-emergence of immune deficiency and a much higher risk of fatal opportunistic infections and neoplasms. As well as poor clinical outcomes, interruptions in treatment have implications on HIV transmission. Gray also commented that the broader implications of drug shortages are not known. For example, patients are counselled that they must adhere rigidly to the regimen, however if a drug is in short supply, this delivers a mixed message to the recipient, with unknown implications for future patient behaviour.
Gray commented that so much work had been done to achieve affordable, evidence-based drugs, “let us not fail because our health and supply systems are not reliable. We have to protect the gains that we have got, from all the fighting that we have done to ensure access”.
 Kredo T, Ford N, Adeniyi FB, et al. Decentralising HIV treatment in lower and middle income countries. Cochrane Database of Systematic Reviews 2013. doi:10.1002/14651858.CD009987.pub2 (accessed 26 September 2014).
 Luebbert J, Tweya H, Phiri S, et al. Virological failure and drug resistance in patients on antiretroviral therapy after treatment interruption in Lilongwe, Malawi. Clin Infect Dis 2012; 55: 441-8. doi:10.1093/cid/cis438 (accessed 26 September 2014).