According to a recent article from healio.com, the drugs known as JAK inhibitors can increase patients’ risks of developing aggressive B-cell lymphoma. Patients who have been prescribed the medication for bone marrow malignancies can develop secondary lymphoma, particularly when they have a certain genetic mutation. Researchers discovered the link between these drugs and lymphoma while analyzing the results of two JAK inhibitor studies.
JAK Inhibitor Indications and Use
Janus-associated kinase (JAK) inhibitors are prescribed for the malignant condition myelofibrosis. They are also prescribed for several other medical conditions, like arthritis and psoriasis. Myelofibrosis is a type of leukemia that affects blood cell production. Myelofibrosis causes patients to develop too many white blood cells and not enough red blood cells, which leads to complications like anemia and rigid scar tissue formation inside the bone marrow.
Scientists still do not understand the exact cause for myelofibrosis, but it is thought to originate with overactive signaling in the Janus kinase pathway. Janus kinase proteins are necessary for the process of blood cell formation. They send signals out to other components of the bone marrow that prompt the production and survival of blood cells. However, when this signaling becomes too active, blood cell production is thrown off. An imbalance in the production of blood cells then leads to the symptoms of myelofibrosis.
JAK inhibitors were developed to treat myelofibrosis by targeting the overactive signaling in the JAK pathway. They prevent (or inhibit) activity at the site of the Janus kinase proteins located at chromosome 1 and chromosome 9 (JAK1 and JAK2). Currently, ruxolitinib is an approved JAK inhibitor for the treatment of myelofibrosis (sold under the brand names Jakafi and Jakavi). And while it has shown some positive treatment effects in patients with myelofibrosis, it has also become the subject of scientific scrutiny.
Researchers Link JAK Inhibitors to Increased Risk of Lymphoma
In a medical publication called “Blood,” researchers analyzed the results of two large studies that focused on JAK inhibitors. The studies both showed a potentially significant association between JAK inhibitors and development of secondary B-cell lymphoma (secondary meaning in addition to or as the result of another condition). The resulting lymphoma was aggressive in nature.
One of the studies, which was conducted at the Medical University of Vienna, saw a 5.8 percent rate of patients treated with a JAK inhibitor developing B-cell lymphoma. Only 0.36 percent of patients treated with other drugs developed lymphoma. In the second study, which was larger and conducted at Hôpital Saint-Louis in Paris, 9.7 percent of patients treated with a JAK inhibitor developed B-cell lymphoma versus only 0.54 percent of patients treated with other drugs.
Researchers noted that many of the myelofibrosis patients in these studies who developed lymphoma had a pre-existing B-cell clone that underwent a transformation during their JAK inhibitor treatment. Up to 16 percent of patients with myelofibrosis have immunoglobulin rearrangements, like B-cell clones, which means a large percentage of patients who take JAK inhibitors could be at great risk of developing B-cell lymphoma. Researchers are continuing to study the link between B-cell clones and JAK inhibitors using a mouse model, which they hope will result in the development of alternative treatments.
For now, according to the researchers, myelofibrosis patients with immunoglobulin rearrangements are most at risk for aggressive lymphoma when treated with JAK inhibitors. For this reason, they recommend doctors perform genetic testing on their myelofibrosis patients before prescribing JAK inhibitors.
At the end of their analysis, the authors of the Blood article concluded that myelofibrosis patients who use JAK inhibitors are 15 to 20 times more likely to develop aggressive B-cell lymphoma than patients who undergo other types of treatment. Myelofibrosis and lymphoma have long had some kind of association, but not at this level or this pronounced. Aggressive B-cell lymphoma results in more complicated treatment regimens for patients with myelofibrosis and the prognoses for these patients is usually poor.
So far, JAK inhibitors seem only to increase the risk of lymphoma in myelofibrosis patients. Patients who take JAK inhibitors for other conditions, like arthritis and psoriasis, have not developed lymphoma at meaningful rates. This could be due to certain predispositions to lymphoma in myelofibrosis patients or because of the differences between the various types of JAK inhibitors. When they are used for arthritis or psoriasis, the drugs are called JAK3 inhibitors. For treatment of myelofibrosis, they are called JAK1 or JAK2 inhibitors. Depending on the condition at hand, the drugs target the Janus kinase proteins on different chromosomes.
Will JAK Inhibitors be Recalled?
JAK inhibitors are still on the market and will probably not be recalled any time soon. Based on the research described above, they certainly will not be recalled for treatment of conditions outside of myelofibrosis because of the lack of association between those types of JAK inhibitors and lymphoma.
JAK inhibitor manufacturers could initiate a voluntary recall, but that is not likely. This action is rare in the pharmaceutical industry, and JAK inhibitors are already defending their drugs against the research above. The manufacturers have said they are aware of the science outlined in the above-linked article but have refuted some of the techniques used during the studies and the analysis by the article authors.
The U.S. Food and Drug Administration could issue a mandatory recall, but that is also not likely to occur at this time. So far, the FDA has remained silent on the issue. If enough research arises, the FDA might issue a safety alert or guidance that addresses the connection between JAK inhibitors and lymphoma and that encourages doctors to perform testing on myelofibrosis patients before selecting a JAK inhibitor for treatment.
The FDA could also order JAK inhibitor manufacturers to place added warnings on their drug labels about the risks of B-cell lymphoma. Currently, no such warning is present on the drug labels. In addition, in light of this new scientific information, the FDA could order JAK inhibitor manufacturers to conduct additional testing of their drugs. The exact response, if any, from manufacturers and federal regulatory agencies remains to be seen.
Parker Waichman LLP Investigating JAK Inhibitor Cases
If you or a loved one developed B-cell lymphoma after receiving treatment with a JAK inhibitor, contact Parker Waichman LLP today. You will be able to speak with one of our product liability attorneys about a potential JAK inhibitor lymphoma lawsuit against the drug manufacturer. Our firm is in the process of investigating cases involving JAK inhibitors and lymphoma, and we are now reviewing new claims.
Our attorneys provide superior client representation backed by our decades of pharmaceutical litigation experience. We know how significantly your drug product injuries have affected your life, and we can help you seek the outcome you need to move forward.
We offer free case consultations on JAK inhibitor lymphoma cases, and our offices can be reached 24 hours a day. We take cases nationwide and provide over-the-phone consultations to accommodate clients across the country. Contact Parker Waichman LLP for your free consultation by calling 1-800-YOURLAWYER (1-800-968-7529) or by filling out the Contact form on our website.
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