Rare diseases (sometimes referred to as orphan diseases) are classified in the US as diseases or conditions that affect fewer than 200,000 individuals. More than 6,800 rare diseases exist, affecting approximately 25 to 30 million people in America. In order to help address the ramifications of these statistics, the Orphan Drug Act of 1983 was established. It provides incentives for drug companies to encourage research and development of rare disease treatments¹, including products referred to as orphan drugs. In the time since the Act became federal law, the FDA has approved more than 400 treatments for rare diseases.² Examples of recent new approvals for drugs with orphan product designation include Impavido (approved to treat a tropical disease called leishmaniasis)³ and Alprolix (for use in adults and children who have Hemophilia B)⁴, both just approved in March 2014. The FDA's Office of Orphan Products Development (OOPD) evaluates scientific and clinical data submissions with the goal of identifying and classifying products that hold promise as treatments for rare diseases. Advances in pharmacotherapy are emerging more and more as the rate of research has increased because of the OOPD's program. With lower costs of late-stage development and an expedited regulatory review process for obtaining orphan drug designation, significant progress has been made in diagnosing and treating many rare diseases.⁵

In this environment, it is important to stay abreast of the conditions classified as rare diseases, of newly approved orphan drugs, and of those drugs that are projected to be the top used products in the coming years (such as Rituxan, Revlimid, Soliris, Afinitor, Tasigna, and Velcade⁵). A familiar condition that is considered a rare disease is cystic fibrosis (CF), or mucoviscidosis, which causes critical mucus accumulation, clogging organs such as the lungs and pancreas. One of its approved orphan drugs is Kalydeco, which is indicated to treat CF in patients ≥6 yrs of age who have one of the following mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene: G551D, G1244E, G1349D, G178R, G551S, S1251N, S1255P, S549N, or S549R. Another rare disease example is Wilson's disease, an inherited disorder where buildup of copper in the body leads to damage in the kidneys, brain, and eyes. One of the orphan drugs associated with the condition is Syprine, which is indicated for treatment of Wilson's disease in patients who are intolerant of penicillamine.¹

Several more examples of rare diseases, and some of their associated orphan drugs that received marketing approval by the FDA within the past twelve months⁶, include:

• Pulmonary Arterial Hypertension: This progressive condition affects the heart and lungs and is characterized by hypertension in the pulmonary artery. Adempas has orphan designation for treatment of adults with persistent/recurrent chronic thromboembolic pulmonary hypertension (CTEPH), (WHO Group 4) after surgical treatment, or inoperable CTEPH, to improve exercise capacity and WHO functional class. It is also indicated for treatment of adults with pulmonary arterial hypertension WHO Group 1, to improve exercise capacity, WHO functional class, and to delay clinical worsening. Additionally, Opsumit has orphan designation for treatment of pulmonary arterial hypertension (WHO Group 1) to delay disease progression.
• Factor XIII Deficiency: This inherited blood disorder is characterized by abnormal blood clotting that may result in abnormal bleeding. Tretten has orphan designation for routine prophylaxis of bleeding in patients with congenital Factor XIII A-subunit deficiency. Corifact is also provided as treatment for the disorder and is indicated for routine prophylactic treatment and perioperative management of surgical bleeding in adult and pediatric patients.
• Non-24-hour Sleep-Wake Disorder: Affecting blind individuals who are without light perception, the disorder has a newly approved orphan drug available, as of January 2014. Hetlioz has been approved to treat the disorder, and acts as a melatonin receptor agonist.⁷

Clinical research for rare diseases is ongoing, and some do not yet have pharmacotherapy options associated that have orphan drug status. One such disorder is Marfan syndrome, which is a disorder of the connective tissue, and affects most organs and tissues, especially the skeleton, lungs, eyes, heart, and aorta. Related clinical trials are numerous ( see current listings at the ClinicalTrials.gov registry and results database website) and with continued research, appropriate orphan drug designations may be established.

PDR Network is a valuable resource for thousands of available products, offering alerts and specific product labeling. Keep current by using PDR.net and by keeping your contact information up to date with us. If you use an electronic health record (EHR), please ask for it to include the PDR drug data feeds, including PDR BRIEF. Updated drug information, full labeling, and safety warnings will be integrated into your electronic prescribing system automatically, and at no cost to you. Drug information in EHRs is often months out of date, which is why PDR BRIEF is available at no cost to providers and EHR vendors.

PDR Network can also help you meet certain reporting requirements under Meaningful Use Stage 2 (MU2). One of the core MU2 objectives, “use certified EHR technology to identify patient-specific education resources,” requires that physicians provide more than 10% of their unique patients with education resources specific to their needs.⁸ PDR+ for Patients drug education guides are an excellent resource that you can provide patients to help you meet this objective. When PDR+ for Patients drug education guides are integrated into your EHR, you can use them to help you fulfill this objective and help your patients start and stay on therapy. Click here to see a sample. If you do not have PDR+ in your EHR, send an email to EHR@pdr.net and tell us the name of your EHR vendor, and we will convey to them that you want PDR included.

Salvatore Volpe, MD, FAAP, FACP, CHCQM
Chief Medical Officer
PDR Network

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