Research Highlights the Use of Anti-TNF Drugs in Treating RA

Today, at the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) 23rd Annual International Meeting, held in Baltimore, Maryland, researchers addressed the complexities of using anti—tumor necrosis factor (anti-TNF) therapy in patients with rheumatoid arthritis (RA).

Women and Patients With Co-occurring RA and Diabetes Have Higher Infection Risk

Infections are a notable safety issue for patients with RA who receive anti-TNF therapy or conventional disease-modifying antirheumatic drugs (DMARDs), and researchers from Mississippi presented the findings of a retrospective cohort study using the state’s Medicaid claims data for patients with RA from 2014 to 2017 that sought to identify risk factors that predict infections.¹

The 1217 patients included in the study were aged 18 to 64 years, had medical claims for primary diagnoses of RA, and were receiving treatment with either DMARDs or anti-TNF agents. The patients were divided into a conventional DMARD group (n = 671) and an anti-TNF agent group (n = 546).

The rate of all-cause infection in the full study population was 30.29%, which could be divided into the following:

• Bacterial infections, 11.8%
• Viral infections, 11.36%
• Fungal infections, 13.2%

A multivariable logistic regression showed that patients who also had diabetes had higher odds of acquiring infections (odds ratio [OR], 1.85; 95% CI, 1.37-2.51). Women also had higher risk of infection (OR, 2.50; 95% CI, 1.31-4.79), and patients receiving monotherapy with DMARDs had a higher risk of viral infection (OR, 1.65; 95% CI, 1.12-2.41).

According to the authors, these findings can help assist health plans and policy makers to develop appropriate chronic disease care models that ensure patient safety, reduce costs, and improve outcomes.

Anti-TNF Therapy Could Help Reduce the Risk of Depression

Depression is another concern for patients with RA because of the overall burden of systemic inflammation, and additional research found that patients with RA who received and responded to treatment with anti-TNF agents were less likely to develop depression than patients who did not respond to anti-TNF drugs.²

Using commercial claims data from QuintilesIMS that covered a period from 2009 to 2015, researchers from West Virginia University and the West Virginia University School of Pharmacy sought to evaluate the association of anti-TNF treatment and the risk of developing depression among adults with RA who were aged 18 to 62 years. In total, 4222 patients had 1-year follow-up data available.

The researchers found that, during the 1-year follow-up period:

• 39.8% of patients responded to anti-TNF treatment.
• 8.5% of all patients developed depression, and a lower percentage of responders (7.1%) than nonresponders (9.4%) developed depression (P <.001).
• After controlling for risk factors, responders were 20% less likely to develop depression during the follow-up period than were nonresponders.

The researchers concluded that effective anti-TNF treatment reduces the risk of depression in this patient population.

Switching Away From Anti-TNF Agents Could Reduce Costs

For those patients who do not respond to an anti-TNF therapy, a switch to a different anti-TNF drug or a non-TNF agent is often undertaken. To measure differences in healthcare costs for patients with RA who switched from their initial anti-TNF treatment to another drug, researchers used health insurance claims from the IMS PharMetrics database for the years 2010 to 2016 to assess total and RA-specific postswitch monthly costs.³

Of 1940 patients who initiated an anti-TNF agent, 1467 (76%) switched to another anti-TNF option and 473 (24%) switched to other drug types. Using an ordinary least squares approach to determining costs, the researchers found that switching to non—anti-TNF drugs was associated with lower total costs (–$426; P = .035) as well as lower RA-specific costs (—$475; P <.001). Using instrumental variables regression, the marginal effect of switching to non—anti-TNF drugs reduced all-cause spending (–$2532; P = .047).

The researchers stated that typical estimates of the effect of medication choice after anti-TNF therapy can be biased if providers prescribe selectively; using an instrumental variables approach to control for that bias, they found that traditional methods may underestimate all-cost savings from switching to non—anti-TNF therapies.

References

1. Dibie C, Rong Y, Ramachandran S, Banahan III B, Noble S. Association of disease modifying antirheumatic drugs (DMARD) and tumor necrosis factor (TNF)- alpha inhibitor therapy and infection in rheumatoid arthritis patients in a Medicaid population. Presented at the International Society for Pharmacoeconomics and Outcomes Research 23rd Annual International Meeting, May 21, 2018; Baltimore, Maryland. Abstract PRM9. ispor.org/ScientificPresentationsDatabase/Presentation/80383.

2. Deb A, Bwibedi N, LeMaster TJ, Hornsby J, Wei W, Sambamoorthi U. Tumor necrosis factor inhibitor therapy and the risk of developing depression among working-age adults with rheumatoid arthritis. Presented at the International Society for Pharmacoeconomics and Outcomes Research 23rd Annual International Meeting, May 21, 2018; Baltimore, Maryland. Abstract PMS2. ispor.org/ScientificPresentationsDatabase/Presentation/81641.

3. Shahabi A, Shafrin J, Zhao L, et al. The effect of medication choice after tumor necrosis factor inhibitor (TNFI) use on the healthcare costs for patients with rheumatoid arthritis: an instrumental variables approach. Presented at the International Society for Pharmacoeconomics and Outcomes Research 23rd Annual International Meeting, May 21, 2018; Baltimore, Maryland. Abstratct PMS28. ispor.org/ScientificPresentationsDatabase/Presentation/80294/.