Teva Launches Generic Version of PAH Therapy Letairis in US

Teva Pharmaceutical Industries launched a generic version of Letairis (ambrisentan) in the United States for the treatment of pulmonary arterial hypertension. Generic ambrisentan will be available as 5 and 10 mg tablets.

Letairis is marketed by Gilead in the U.S., while in Europe it is sold by Glaxo Smith Kline (GSK) under the brand name Volibris.

Ambrisentan is an approved therapy for WHO group 1 PAH patients in the U.S. and E.U., both as a standalone treatment and in combination with Adcirca (tadalafil; marketed by Eli Lilly in the U.S., while GSK holds the marketing rights in Europe).

A generic medicine is developed based on the same active components — in this case, ambrisentan — of an existing marketed treatment. It is designed to function like the approved, patented product, and to provide the same clinical benefits.

“The launch of ambrisentan tablets in the U.S. is an important addition to Teva’s growing generic portfolio of nearly 60 cardiovascular medicines,” Brendan O’Grady, executive vice president and head of North America commercial at Teva, said in a press release.

“Our ability to help treat this disease is a testament to our commitment to providing affordable, generic treatment options to people living with chronic, lifelong conditions,” O’Grady said.

Ambrisentan works as a vasodilator — it helps relax (dilate) blood vessels. The therapy is an endothelin type-A receptor antagonist. Endothelin type A receptors are present throughout the body, including in blood vessels. When activated, they promote the smooth muscles in blood vessels to contract, narrowing the vessels and blocking blood flow. As an endothelin type-A receptor antagonist, ambrisentan blocks the activation of these receptors, alleviating blood vessel contraction and improving blood flow.

According to several clinical studies, the therapy can improve PAH patients’ exercise ability, and delay the worsening of disease symptoms. Also, studies showed that Letairis-Adcirca therapeutic combination significantly lowered the chances of PAH worsening and associated hospitalizations. The patient’s exercise capacity also increased significantly with the combination treatment.

The most common side effects associated with ambrisentan tablets include swelling of the ankles and feet, headache, and fluid retention. 

Letairis’ label has a safety warning, as the therapy can be harmful to fetuses and cause severe birth defects. Therefore, women can only receive the treatment through a safety program called Ambrisentan Risk Evaluation and Mitigation (REMS) to manage the risk associated with its use. The Ambrisentan REMS is required by the U.S. Food and Drug Administration (FDA).