My rheumatologist reiterated with me yesterday that I have a tough to treat case of RA – called refractory RA. She displayed disappointment that all of the treatment plans we’ve tried over the years have not had the intended impact. We’ve cycled through four TNF inhibitors (Enbrel, Cimzia, Humira, and Remicade), Orencia, and Actemra. And that’s in addition to various DMARDs including sulphasalzine, azathioprine, and leflunomide (Arava). The reasons for stopping the use of these drugs runs the gamut of lack of efficacy to intolerable side effects. My doctor was apologetic, felt bad I wasn’t helped by all of the treatment plans, and genuinely expressed concern for the impact RA has had on my life recently. But I reassured her that I trusted her medical judgement and that the impact comes over time allowing time to adjust. I appreciated her empathy and deep desire to help.
We discussed the few remaining options which includes Xeljanz, Kineret, and Rituxan. Xeljanz (tofacitinib) was approved in the United States but not approved in Europe. We both felt that more data was needed on this “oral biologic” before giving it a try. Kineret, or anakinra is a biological response modifier that targets interleukin 1. My rheumy said that is not used that much anymore because of more effective options. A recently published report indicates that a Swedish company just purchased the rights for Kineret from biological pharmaceutical giant Amgen. Such a move seems like Amgen is dumping the drug likely because it is not profitable and is moving onto other new drugs. After much discussion, we both agreed to try Rituxan and I will continue to inject 20mg of methotrexate weekly.
As I was describing my new treatment regimen to friends and family, I found myself trying to explain the drugs, how they are administered, how they act to treat RA, and the possible side effects. As I read more about these drugs, it struck me as interesting that both medicines were originally developed to treat certain forms of cancer. Methotrexate is a chemotherapy drug developed in the 1950s and is still used to treat forms of leukemia, breast cancer, lung cancer, non-Hodgkin lymphoma, and head and neck cancers (see American Cancer Society). It stops the growth of cancer cells by affecting their metabolism. Given the immunosuppressing nature of methotrexate, it is now commonly used in lower doses to treat various autoimmune diseases including rheumatoid arthritis. It’s also used to treat tubal ectopic pregnancies by inducing abortion. In spite of the low doses used in treating RA, some of the chemotherapy side effects remain including hair loss and nausea. This paints a picture of a rather toxic medicine! But I’ve been injecting 20mg weekly for some time now and seem to tolerate it rather well.
Rituxan is also known by the names MabThera and Rituxamab. This monoclonal antibody is a biological medicine that was originally developed in the late 1990s to target the protein CD20 present in certain phases of B lymphocytes. It was originally approved for the treatment of B cell related lymphomas and leukemias (see the Rituxan website). In the early 2000s, it was shown in clinical trials to be effective in treating rheumatoid arthritis and gained FDA approval for use in refractory RA cases in 2006. The involvement of B cells in autoimmune diseases likely led to the investigation of Rituxan as a treatment for RA. The side effect profile appears similar to other biologicals but with some additional infusion side effects requiring some pre-medications along with a few more rare serious infections.
The use of cancer drugs to treat RA points to the connection of both diseases to the immune system. It also demonstrates the serious nature of RA. Given the fact that both methotrexate and Rituxan were originally designed to treat certain cancers, and that they are now secondarily being used to treat RA, may point to the fact that a much larger proportion of research funding goes to cancer (see this earlier post). While I don’t mind receiving the “leftovers” or being an “afterthought” if the medicines effectively treat RA, the ideal would be for the development of new treatments or even cures specifically designed for the processes involved in autoimmune diseases. In the meantime, I’ll go to the infusion clinic and begin Rituxan infusions along with cancer patients and see if it can take care of this refractory case of RA!