It is increasingly common for certain pharmaceutical drugs to be used to treat diseases without first receiving approval to do so from a regulatory body, such as the US Food and Drug Administration (FDA) or the European Medicines Agency (EMA). Therapies used for unapproved purposes are known as ‘off-label’ drugs for that specific indication. There are many reasons why this practice is common.
In the context of rare diseases, off-label drugs can be cheaper than approved therapies. One example of this would be rituximab, which is used as an off-label therapy for the treatment of myasthenia gravis, compared to Alexion’s Soliris (eculizumab), which is approved for this indication. One year’s supply of rituximab is considerably cheaper than the annual cost of therapy of Soliris, which exceeds $500,000 in the US. Similarly, Roche’s Avastin (bevacizumab) has long been used for the off-label treatment of wet age-related macular degeneration because approved drugs such as Bayer/Regeneron’s Eylea (aflibercept) and Novartis’ Beovu (brolucizumab) are more expensive, despite the fact that Eylea and Beovu are administered less frequently than Avastin.
Another major reason for the use of off-label drugs is when a patient is refractory to standard-of-care (SOC) therapies. This is common in the neurology space, where psychoactive drugs can have unpredictable effects on people who receive pharmacotherapy for mental illnesses. Anticonvulsants such as lamotrigine and atypical antipsychotics such as aripiprazole have been used to treat patients with post-traumatic stress disorder (PTSD) and have shown varied results in improving symptoms such as insomnia, hypervigilance and dissociation.
Symptomatic improvement is not the only measure of success when treating patients with intractable conditions. Significant variability in the safety profiles of different drugs means that it is imperative for off-label therapies to be included in clinical trials involving patients who have been diagnosed with the target indication. For example, the off-label use of benzodiazepines in the treatment of PTSD is controversial, yet many psychiatrists prescribe these drugs to patients who do not respond to Pfizer’s Zoloft (sertraline hydrochloride) or GlaxoSmithKline’s Paxil (paroxetine hydrochloride), both of which are approved for the treatment of PTSD. The controversy around benzodiazepines arises from the addictogenic properties of these drugs, coupled with the fact that a significant percentage of patients with PTSD also live with at least one substance use disorder.
Multisite, double-blind, placebo-controlled clinical trials are considered the most robust method of establishing the efficacy and safety profiles of pharmaceutical products. Reliable data that confirm whether or not benzodiazepines are safe to prescribe for patients with PTSD could settle the debate and avert any potential harmful consequences that result from their use, as there is little evidence to suggest that the therapies have favourable efficacy and side-effect profiles.
Over time, physicians around the world have become increasingly encouraged to opt for the most cost-effective approach to managing refractory patients with pharmacotherapy. This has led to greater use of polypharmacy and the recruitment of off-label drugs that may increase the efficacy of SOC treatments. The impact of metabolic enzymes on drug concentrations and other pharmacokinetic considerations should be explored in clinical trials so that reliable information can be made available to prescribing physicians who are treating patients with debilitating illnesses.