GSK, a world leading research-based pharmaceutical and health care company, recently announced that the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) has released a positive outlook for a variation to increase the current therapeutic indication for Volibris® (ambrisentan) so it can be used combined with other drug agents to treat patients with a diagnosis of pulmonary arterial hypertension (PAH).
“Today’s decision represents an important milestone for the PAH community, supporting the potential for initial combination treatment in this highly debilitating and limiting disease,” said Jonathan Langley, Clinical Investigation Lead PAH, GSK Rare Diseases, in a press release. “If approved, this could help improve clinical outcomes for patients across Europe suffering from this rare condition. We look forward to receiving a final decision from the European Commission in the coming months.”
This positive opinion was based on the results from the AMBITION Phase 3b/4 trial that compared the safety and the efficacy of a first-line combined treatment of tadalafil plus ambrisentan to first-line monotherapy of either treatment alone in PAH treatment-naïve patients. The study results were published in the New England Journal of Medicine entitled, “Initial Use of Ambrisentan plus Tadalafil in Pulmonary Arterial Hypertension,” and demonstrate the that the combined treatment with tadalafil plus ambrisentan significantly reduced the risk of clinical failure by 50% in PAH treatment-naïve patients in comparison to pooled tadalafil and ambrisentan alone. The AMBITION trial was co-funded by Gilead and GSK, with the additional support of Eli Lilly.
The CHMP positive outlook is a formal recommendation to increase the existing marketing authorization for ambrisentan to include combination treatment. A final decision from the European Commission is expected to be released in December. Additional regulatory proposals to incorporate the AMBITION results in the ambrisentan label are ongoing and prearranged in other countries.
Pulmonary arterial hypertension (PAH) is a rare disease, with an estimated prevalence of 15-50 cases per million, but the prevalence of PAH in certain at-risk groups is substantially higher. For example, in HIV-infected patients the prevalence is 0.5%, in patients with systemic sclerosis it has been reported to be 7-12%, and in patients with sickle cell disease the prevalence is around 2-3.75%.
Ambrisentan is indicated for use in the treatment of pulmonary hypertension. The peptide endothelin constricts muscles in blood vessels, increasing blood pressure. Ambrisentan, which relaxes those muscles, is an endothelin receptor antagonist, and is selective for the type A endothelin receptor (ETA).