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There are over 7,000 rare diseases that affect more than 30 million people in the United States, and that number is even larger if you look across the globe. Histiocytic disorders make up approximately six of the 7,000 rare diseases. Histiocytosis, just like most rare diseases, can be life-threatening and treatment options are limited. It can feel very frustrating when you are on the patient-family-physician side of the conversation, newly diagnosed and looking for a therapy that you can feel confident will improve your health and help to cure the disease.

The FDA Approval Process

You may ask why there are so few treatments, such limited federal support, and even when there are therapies in clinical trial, why they are not quickly moved to be approved for use by the Food & Drug Administration (FDA) when they seem to be helping patients. This is something that the Histiocytosis Association team feels along with you – and we are also filled with hope because there are many investigators researching new therapies for histiocytosis and administrators within the drug development arena who are trying to make change possible for all rare diseases.

Drug and device development for rare diseases is challenging, and there are many reasons for these challenges. For example, often there are complex biologic aspects to rare diseases – for histiocytosis, there are genetic mutations that cause many of the histiocytic disorders which are not usually discovered until after a diagnosis is made.

Additionally, because there are small numbers of patients diagnosed with each condition, conducting clinical trials can be difficult; the reason being that the more patients you can have in a study, the more data you can gather to show whether the therapy is effective. Although, this is now being evaluated and at times the “rules” have been modified to help rare disease clinical trials move more quickly through this process, knowing these and other hurdles, and the urgency of having the treatment more readily available.

Great Strides for Change

In 1983, the Food & Drug Administration (FDA), signed the Orphan Drug Act was signed into law. From that time, the FDA has approved hundreds of drugs for rare diseases, but even with this advancement, most rare diseases unfortunately still do not have FDA-approved treatments. 

Well, things are changing for histiocytosis as well! Most of the histiocytic disorders are classified as histiocytic neoplasms, otherwise referred to as rare cancers. Like cancer, it is treated primarily with chemotherapy and radiation however knowledge of genetic mutations that cause histiocytosis has advanced our understanding of treatment options and has led to the use of targeted therapies, such as cobimetinib, and combination therapy that uses both common cancer therapies and targeted therapies is more widely recognized. This research is exciting as it has led to better patient outcomes, higher percentages of survivorship, and has brought about much hope for the community.

Exciting Developments this Year

You may have heard the exciting news, that on November 1st, 2022, Memorial Sloan Kettering Cancer Center (MSK) announced that the U.S. Food and Drug Administration (FDA) approved the oral MEK inhibitor drug cobimetinib (Cotellic®) for the treatment of adult patients diagnosed with histiocytic neoplasms (HN). These diseases include Erdheim-Chester disease, Rosai-Dorfman disease, and Langerhans cell histiocytosis. Cobimetinib is an oral inhibitor of genes known as MEK1 and MEK2 and is currently approved to treat melanoma.

When I received the call from Dr. Diamond, the Principal Investigator (PI) for the study, I felt an overwhelming sense of joy, gratitude, and hope. Over the last 35 years, we have seen great strides taken in the knowledge we have about the treatment options for histiocytic disorders. FDA approval will break down barriers for patients worldwide – it means better access to viable therapies, insurance coverage, and increased knowledge and awareness of these rare conditions. “Bringing this treatment from its first concept to FDA approval is one of the biggest highlights of my career,” Dr. Diamond told me. “I am so pleased that there is another option to improve patients’ health.”

Your Part in Research

The Histiocytosis Association is incredibly grateful for the dedication of Dr. Eli Diamond, neuro-oncologist at Memorial Sloan Kettering Cancer Center and the entire study team. This approval means that patients with these specific genetic mutations, which cause the histiocytes to overproduce leading to tumor formation and organ damage, now have a viable treatment option. Even patients without detected mutations are eligible for this treatment as the mutation may be present but difficult to detect. This is one incredible example of the passion that exists within the medical profession and the commitment these investigators and clinicians have in helping YOU see a world free of histiocytosis.

Over the last 35 years, we have seen great strides taken in the knowledge we have about the treatment options for histiocytic disorders.

The histio community has been very active and involved in supporting research. YOU make a difference through participation in studies, YOUR generosity in helping to fund research projects and by sharing feedback as the ‘patient-voice’ to improve trial design.

YOUR support makes advancements like this possible!

Read the full press release here.

Learn more about clinical trial and registry opportunities here. Your help in supporting research upon diagnosis, during treatment, and even after treatment is so important to helping the future of histiocytosis knowledge and therapies.