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AMCP: The Impact of Orphan Drugs on Rare Diseases: Growth, Spending, and Treatment Options
The status of orphan drug development in 2 rare disease states—as well as key management strategies—were addressed by 2 experts during AMCP Nexus 2015.
Rare diseases are exceptionally diverse. “The only thing in common [between] them is that genetic component,” said Matt Cheung, PhD, RPh, FCSHP, FASHP, adjunct professor of pharmacy practice, Thomas J. Long School of Pharmacy. He provided an update on orphan drugs to treat cystic fibrosis (CF) and pulmonary artery hypertension (PAH).
CYSTIC FIBROSIS
CF is a genetic, life-threatening disease that causes lung infections resulting in a limited ability to breathe, Dr Cheung explained. Individuals diagnosed with CF have inherited 2 copies of the defective CF transmembrane conductance regulator (CFTR) gene, 1 from each parent. Worldwide there are about 70,000 patients living with CF, and 30,000 in the US. Typically, 70% of individuals with CF are diagnosed by the age of 2.
“[Due to] supportive care like antibiotics and enzyme replacement therapy, patients with CF now are expected to live until about 40 years old, unlike in the 1960s, the life expectancy was only about 10 [years],” said Dr Cheung.
Dr Cheung stated that there is optimism for CF because there are currently 2 disease-targeted drugs, which affect the CFTR gene. The first, approved in 2012, is Kalydeco® (ivacaftor) for treatment in CF patients ≥6 years of age with specific CFTR mutations.
Ivacaftor is marketed as one of the most expensive drugs in the US at ≥$300,000 a year.
Orkambi™ (lumacaftor/ivacaftor), the second CF targeted drug, is a combination of 2 categories of molecules: ivacaftor and lumacaftor. This combination drug therapy is designed to treat the root cause of CF, rather than treating the severity of symptoms. According to a report in The New York Times, this combination therapy is priced at $259,000 a year.
Jim Carlson, PharmD, vice president, professional pharmacy services, OmedaRx, emphasized the importance of these key management initiatives for CF:
• Involve specialty providers, since specialty management is crucial
• These high-cost, high-risk drugs should be a part of case management
• Review criteria annually to ensure continued efficacy
PULMONARY ARTERY HYPERTENSION
PAH is a rare and progressive disorder categorized by high blood pressure in the pulmonary arteries. Symptoms include dyspnea, chest pain, and fainting episodes. The exact cause of PAH is unknown, and although treatable, there is no known cure for the disease. Dr Carlson said that the key management initiatives for PAH are the same as CF. Treatment options for PAH include:
- Diuresis, anticoagulation, O2, calcium channel blockers
- Endothelin receptor antagonists (ERAs)
- Phosphodiesterase type 5 inhibitors
- Prostacylins
- Soluble guanlyate cyclase stimulator (GCS)
- Combination therapies
Dr Cheung stressed the importance of using risk evaluation and mitigation strategies for ERAs and GCS. They include:
- Ensuring prescribers and dispensing pharmacies are certified
- Enrolling all female patients and having them sign consents
- Be sure that all females who have reproductive potential:
- Are counseled on birth control, risks, andbirth defects
- Receive a pregnancy test before treatment, monthly, and one month after discontinuation
- Know that they should notify their prescriber if they become pregnant
- Consent to being contacted by a sponsor
- Be sure that pre-pubertal females of non-reproductive potential:
- Receive education on the risks of birth defects
- Are evaluated annually for reproductive status
- Know that they should inform their prescriber if they begin menstruating
- Be sure that post menopausal females of nonreproductive potential know that they should inform their prescriber if their reproductive status is misclassified.
There are a number of orphan drugs approved for treatment of PAH (see accompanying Table). Pharmacological treatment options for PAH range from $9000 to $200,000.—Alessia D’Anna
