Generic fluticasone-salmeterol as good as brand name for COPD
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Key takeaways:
- For approval, generic fluticasone-salmeterol was required to be tested in only patients with asthma, not COPD.
- This postmarketing study supports the clinical equivalence of the generic vs. brand-name version.
Generic fluticasone-salmeterol demonstrated similar safety and effectiveness as the brand-name version among patients with chronic obstructive pulmonary disease, according to researchers.
The FDA approved the generic version, Wixela Inhub (fluticasone-salmeterol; Viatris), as the first generic maintenance inhaler for asthma and chronic obstructive pulmonary disease (COPD) in 2019, William B. Feldman, MD, DPhil, MPH, an instructor in medicine at Brigham and Women’s Hospital, and colleagues wrote in Annals of Internal Medicine.
The generic product “is a substitutable version of the dry powder inhaler Advair Diskus (fluticasone-salmeterol; GlaxoSmithKline), which went off-patent in 2016 after becoming the highest-selling maintenance inhaler in U.S. history,” the researchers added.
When the FDA approves generic inhalers, the researchers said that the agency implements an “aggregate weight-of-evidence approach” that requires in vitro, pharmacokinetic and comparative or pharmacodynamic studies. Despite rigorous protocols, “the clinical studies required by the FDA tend to be limited in scope,” they added.
“When approving Wixela Inhub, the FDA permitted the generic firm to complete its comparative clinical endpoint study only in patients with asthma — the most clinically responsive population — even while giving the product label indications for both asthma and COPD,” the researchers wrote.
Feldman and colleagues pointed out that the FDA allows small differences between generic and brand-name products if the user interfaces are alike, so these inhalers could lead to poor performance in patients with COPD compared with asthma. Therefore, the researchers conducted a 1:1 propensity score-matched cohort study using a longitudinal database to determine the safety and effectiveness of both products in 45,369 patients aged older than 40 years with COPD. The products’ effectiveness outcome was based on the time to the first moderate or severe COPD exacerbation, whereas the safety outcome was time to the first hospitalization for pneumonia.
The matched cohort consisted of 10,012 pairs of brand-name (Advair Diskus) and generic (Wixela Inhub) users. The researchers found that the generic product was associated with a similar incidence of first moderate or severe COPD exacerbation (HR = 0.97; 95% CI, 0.9-1.04) and first pneumonia hospitalization (HR = 0.99; 95% CI, 0.86-1.15) when compared with the brand-name product.
“These findings were robust across a range of prespecified secondary, sensitivity, and subgroup analyses,” they wrote.
Feldman and colleagues noted that recent changes in the Global Obstructive Lung Disease guidelines have prompted questions about the use of inhaled corticosteroid-long-acting beta-agonists (ICS-LABAs) for COPD, but studies evaluating generic vs. brand-name fluticasone-salmeterol remain critical.
“First, these inhalers have an FDA-approved indication for COPD, and rates of ICS-LABAs prescribing have remained persistently high despite guideline changes,” they wrote. “When a physician prescribes Advair Diskus, pharmacists may automatically substitute Wixela Inhub (regardless of the indication). Evidence supporting the therapeutic equivalence of generic ICS-LABAs for use in COPD thus remains valuable given actual prescribing patterns.”
The researchers pointed out that the study demonstrates the value of postmarking trials comparing generic vs. brand-name products, which can be cheaper and quicker than randomized clinical trials when determining clinical equivalency.
“Such postmarketing studies should strengthen the confidence of regulators, clinicians, payers, and professional societies in FDA standards for bioequivalence,” they wrote. “We
believe that postmarketing studies among patients using generic drug-device combinations during clinical care should be routine for regulatory bodies after approval.”
Perspective
Back to TopOverall, this study appears to be well powered, well designed and satisfactorily showing that generic fluticasone-salmeterol, which is currently much less expensive, performs in an equivalent manner vs. its prescription counterpart. This lends confidence to its continued FDA-approved current real-world use. The study limitations include a relatively short follow-up interval but used statistical analysis to match patients and worked to eliminate confounding variables.
Perspective
Back to Top
The study did a successful job looking at the effectiveness of generic vs. brand-name fluticasone-salmeterol for COPD. The outcome of treatment for this group was very similar. As physicians, we are aware of the great difference in cost from these medications and the need for insurance approvals of the brand version. We do believe the generic version is an acceptable alternative treatment in many cases, especially generic medications from the GoodRx program. It remains less expensive than many insurance options with equal effectiveness. The number of patients who will have options increases dramatically. Plus, as physicians who care about our patients, there will be more time spent interacting with them and, hopefully, less phone calls to the office from insurance formulary directors.
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