Cheryl Allen, BS Pharm, MBA: There are several products available with multiple mechanisms of action to treat rheumatoid arthritis in the biologic space. We have the anti-TNFs that block tumor necrosis factor, we have the JAK inhibitors that are acting on the JAK pathway, the interleukins that are blocking the interleukin cytokine pathway, and then CD80 and CD86 affecting that T cell pathway. Now, it’s really important to understand all the different mechanisms of action and then to understand how patients may respond differently to those different products. So, after the appropriate trials of these agents—which would typically be 3 months where we should begin seeing the positive effects of the drugs—it may be time to move on to another agent, keeping in mind that treat-to-target goal from the guidelines to verify that we are moving on to the appropriate agent.
The most important drug-drug interactions to keep in mind when we’re looking at the agents used to treat rheumatoid arthritis in the biologic space are not to use these biologic agents together. These agents cause immunosuppression, so, therefore, we wouldn’t want to use these together. The other thing to keep in mind is vaccines. We wouldn’t want to use the live vaccines in these patients, again, for the purposes of additional immunosuppression with these agents that could cause some latent virus to erupt.
For the safety profile for biologics used for rheumatoid arthritis, the most common thing we’ve seen is pain at the injection site. Other than that, it’s the immunosuppression that we really want to be aware of. And we want these patients to be completely educated on the immunosuppression so that they’re cognizant of just simple things like hand washing but also making sure that they are taking good care of themselves and keeping themselves healthy.
A large majority of the patients whom we see on subcutaneous methotrexate are also on a biologic. We’re not sure if we’re seeing these patients in specialty because they’ve already been on oral methotrexate or if they started with injectable methotrexate. Many times, these patients aren’t necessarily specialty patients until they are prescribed a biologic. Patients may, in early disease, start on either oral or subcutaneous methotrexate, and they could progress to the addition of anti-TNFs or other biologics.