When is a drug worth more than $145,000 per year? When it saves your life, and when it is only one of two drugs approved to treat amyotrophic lateral sclerosis, commonly known as ALS or Lou Gehrig’s disease.
ALS is a progressive neurological disorder that is fatal within 3 to 5 years after diagnosis. ALS affects the motor neurons, the nerve cells that control the movement of voluntary muscles like those used for chewing, walking, breathing and talking. The upper motor neurons in the brain transmit signals to the lower motor neurons in the spinal cord. The lower motor neurons deliver the signal to the appropriate muscles to initiate or terminate a movement.
In ALS, both the upper and lower motor neurons die and the ability to send their signals to muscles is lost. Muscles that lack connections to neurons gradually weaken, start to twitch and eventually waste away. As ALS progresses, the brain loses its ability to initiate and control voluntary movements. What makes ALS all the more tragic is that the patient retains their higher mental processes, leaving them very much aware of the progression of their disease.
Early on in ALS, symptoms include muscle weakness or stiffness, then patients progressively lose the ability to talk, eat, move limbs and eventually the ability to breathe. There are about 12,000 to 15,000 people in the U.S. with ALS and there is no cure. The disease can be diagnosed at any age, but most commonly between the ages of 55 and 75. It affects more men than women, and can affect people of all races and ethnicities. About 90 percent of the cases are sporadic, with no family history or associated risk factor.
The new drug, Edaravone, recently approved in the U.S., has been used in Japan to treat ALS since 2015, and strokes since 2001, and the success there prompted the FDA to encourage the drug developer, Mitsubishi Tanabe Pharma, to apply for its use in the U.S. In a 12-month clinical trial, the disease progressed more slowly in those on the drug compared to patients receiving a placebo. The most common side effects of the drug were bruising and changes in patients’ gait, or the way they walk. However, the drug is also associated with more serious side effects that can require medical intervention including hives, swelling, shortness of breath and symptoms of anaphylaxis in people with sulfite sensitivity.
Oxidative stress is thought to play a role in the death of neurons in ALS. Normal cell functions generate oxygen free radicals, which can damage cells. Edaravone protects cells by neutralizing the damage that free radicals cause, preventing injury to blood vessels and neurons in the brain. Clinical studies suggest that ALS patients in the early stages of the disease received the most benefit. Patients with more advanced ALS did not gain any benefit from it.
Hopefully, the use of Edaravone can help people with ALS and slow the progression of the disease. If successful, extending people’s lives may be worth the high cost of the drug.