GlaxoSmithKline PLC is building up its respiratory franchise with the Nov. 4 approval of Nucala (mepolizumab) as an add-on maintenance treatment of patients with severe asthma aged 12 years and older who have an eosinophilic phenotype.

The targeted use is in line with the recommendations of FDA’s Pulmonary-Allergy Drugs Advisory Committee. In June the panel unanimously voted to recommend that the interleukin-5 monoclonal antibody be approved for add-on treatment of severe asthma with eosinophilic inflammation.

The panel concluded that there was not adequate data to show safety, efficacy or rationale for approval in the age 12-to-17 population ([A#00150622009]).

The drug will launch by the end of the year. The wholesale acquisition cost is $2,500 per vial. Patients receive one 100mg vial administered subcutaneously every four weeks in addition to their normal medication, which consists of high-dose inhaled corticosteroids plus at least one additional asthma control medicine.

“This is our first biologic approved for patients with respiratory disease,” Steve Yancey, GSK’s VP-medicine development leader, said in an interview. “It represents an innovation in personalized medicine.”

That targeted approach could aid reimbursement. "Because of the specificity of the drug, the conversations [with payers] have been very positive ones," Deborah Waterhouse, GSK's senior VP-primary care, said in an interview last month.

Nucala acts by binding interleukin-5, the protein that causes the overproduction of eosinophils, a type of white blood cell that contributes to the development of asthma. Yancey noted that it took 19 years to develop the drug and that it is the only targeted treatment for this small group of patients.

Speaking on a panel at FasterCures’ Partnering for Cures meeting in New York Nov. 2, GSK Chief Medical Officer Murray Stewart noted that the company had almost dropped development of the drug when it failed initial tests for treatment of mild to moderate asthma.

But upon discovering that it worked best in patients with high eosinophil levels the company focused development of the drug on that specific population ([A#14151103003]).

Relevant Population Is 300,000 To 400,000 Patients

According to GSK, an estimated 242 million people live with asthma worldwide, including 25.7 million in the US, and about 5% cannot control symptoms with existing therapies.

Mepolizumab will be relevant for about 300,000 to 400,000 patients. “Whilst severe asthmatics make up somewhere between 5% and 10% of all asthmatics, 50% of the health care costs are associated with that small group, because it’s such a difficult disease to tackle,” Waterhouse said.

In June, analysts from both Deutsche Bank and Leerink Partners projected mepolizumab peak annual sales of about $1.2 billion.

Nucala joins GSK’s large portfolio of respiratory medicines. Since May 2013, the company has had four other respiratory products approved by FDA, including Breo (fluticasone/vilanterol), Anoro (umeclidinium/vilanterol), and Incruse (umeclidinium) for chronic obstructive pulmonary disease, and Arnuity (fluticasone) and Breo for asthma, all with the Elipta inhaler. The company’s top respiratory drug Advair Diskus loses patent protection in August 2016.

Sales Force To Target Specialists

As a post-marketing commitment, GSK has an ongoing Phase II study in children aged 6 to 11 years old. The study includes about 30 subjects who will be followed for up to 12 months.

FDA’s advisory panel expressed concern that the drug’s pivotal program lacked data for long-term use beyond 12 months. The company said patients have received the drug in open label extension studies that have extended beyond two years.

GSK will only be detailing to pulmonologists and allergists.

The company won’t talk to primary care physicians. “If you had too many people talking about mepolizumab to sort of maybe too broad a population, you might create an impression that the product was applicable more broadly than it’s appropriate to be. So we’re being very careful with that,” Waterhouse said.

“I think the biggest hurdle from a patient perspective is ensuring that their physician and they are proactive about how they want to manage the severe asthma differently and taking this step into a biologic versus an oral corticosteroid and an understanding of inhaled therapy, because it’s quite a step change in the way in which you’re treating a disease,” Waterhouse said.

“So I think the bigger challenges will be getting people mentally in the right place to step up to such a different type of therapy” and then getting people to comply so they take the therapy regularly.

The company did not disclose details about its sales force but said the sales teams will be educating specialists primarily on unmet need and benefits of Nucala.

Fewer Exacerbations Vs. Placebo

In a release announcing Nucala’s approval, FDA said the safety and efficacy of the drug were established in three double-blind, randomized, placebo-controlled trials in patients with severe asthma on currently available therapies. Participants received Nucala or a placebo every four weeks as an add-on asthma treatment.

The labeling states that compared with placebo, subjects receiving Nucala experienced significantly fewer exacerbations and fewer exacerbations requiring hospitalization and/or emergency department visits and exacerbations requiring only in-patient hospitalization.

In the MENSA study, Nucala 100mg subcutaneous injection added to standard of care reduced exacerbations by 53% in severe asthma patients who experience frequent attacks compared with placebo plus standard of care (p<0.001). it="" also="" significantly="" reduced="" exacerbations="" resulting="" in="" hospitalizations="" and/or="" emergency="" department="" visits="" compared="" with="" placebo="" plus="" standard="" of="" care="" by="" 61%="" (p="">

The labeling warns that hypersensitivity reactions have occurred after administration of Nucala and that herpes zoster infections have occurred in patients receiving the drug. The most common adverse reactions with an incidence greater than or equal to 5% include headache, injection site reaction, back pain and fatigue.

Nucala is the first anti-IL-5 drug to reach the market. Teva Pharmaceutical Industries Ltd. has filed its IL-5 drug reslizumab for treatment of inadequately controlled asthma in adult and adolescent patients with elevated blood eosinophils with an expected action date in March 2016.

GSK To Launch Mepolizumab For Severe Asthma By Year-End

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