Orphan drugs: medicines for rare diseases

An "orphan drug" is a medicinal product developed specifically to diagnose, prevent, or treat a rare disease. Rare diseases are individually uncommon, but collectively they affect hundreds of millions of people worldwide. In the United States, a disease is generally defined as rare if it affects fewer than 200,000 people nationwide, while the European Union uses a threshold of fewer than one in 2,000 individuals. Historically, pharmaceutical companies were reluctant to invest in treatments for these conditions because the patient populations were too small to make research and development commercially viable through traditional mass-market sales. Without financial incentive, these medicines were "orphaned" in the development pipeline. To address this public health gap, governments and regulators introduced special legal frameworks to encourage the creation of therapies for rare conditions.

Incentive schemes and market exclusivity

The modern era of orphan drug development began with the United States Orphan Drug Act of 1983. This legislation provided a package of incentives for manufacturers, including tax credits for clinical research costs, exemptions from certain regulatory fees, and a crucial seven-year period of market exclusivity. Exclusivity means that competitors cannot market the same drug for the same rare disease during that window, even if the original drug's patent has expired. The European Union followed suit in 1999 with its own regulation, offering ten years of market exclusivity alongside similar fee reductions and protocol assistance. These frameworks successfully stimulated investment in rare disease research, transforming the landscape and resulting in hundreds of approved treatments for conditions that previously had no available therapies.

The pricing controversy

While incentive schemes successfully generated new treatments, they also sparked significant and ongoing pricing controversies. Because rare diseases affect small populations, manufacturers often set extremely high prices per patient to recoup fixed development costs and generate a return on investment. The research and development costs for a medicine are largely the same regardless of how many patients will use it; when those costs are spread over only a few hundred or a few thousand patients, the price per patient must be much higher to break even. The guaranteed market exclusivity reduces price competition, allowing developers to maintain these high prices for years.

Additionally, some drugs initially approved as orphan drugs for a narrow indication are later approved for broader, more common conditions. When this happens, the drug can become highly profitable without needing the original orphan drug incentives, raising questions about whether the pricing of these medicines remains justified. This dynamic places an enormous financial strain on national health systems, insurers, and patients, creating a tension between rewarding innovation and keeping essential treatments affordable.

Access in middle-income countries

Access to orphan drugs is particularly challenging in middle-income countries. These nations often lack the immense purchasing power of high-income states to negotiate substantial price discounts, yet they are rarely eligible for the donated or heavily subsidised medicines offered to the world's lowest-income regions. In South Africa, the South African Health Products Regulatory Authority (SAHPRA) evaluates medicines for rare diseases using the same rigorous standards as it does for common conditions. Once a rare disease medicine is registered, it is generally subject to the Single Exit Price (SEP) framework, which standardises what patients pay at the pharmacy.

However, because the SEP is informed by the manufacturer's initial pricing, the final cost to a South African patient can remain prohibitively high. Patients and healthcare providers can use tools like HealthSA to verify whether an orphan drug is registered in South Africa, though registration does not always guarantee affordable access. Consequently, patients in middle-income countries often rely on compassionate use programmes, NGO assistance, or out-of-pocket funding to obtain these therapies.

Global collaboration and future directions

To improve global access to orphan drugs, international bodies are pushing for more coordinated regulatory approaches. The World Health Organization (WHO) has highlighted the need for better global registries for rare diseases, which help pool patient data and make clinical trials more efficient. Because rare disease patient pools are small, conducting large-scale clinical trials is inherently difficult. By sharing regulatory requirements and clinical data across borders, agencies can reduce the duplication of effort and potentially lower development costs.

Health technology assessment bodies are also becoming more rigorous in their evaluations, demanding clearer evidence of clinical value before agreeing to fund high-cost therapies. As the rare disease landscape evolves, regulators and policymakers continue to search for ways to balance the need to stimulate innovation with the moral imperative of ensuring equitable access to life-changing medicines.