The role of methoxsalen in the treatment of chronic graft-versus-host disease

The role of methoxsalen in the treatment of chronic graft-versus-host disease

May, 21 2023 Ethan Blackwood

Methoxsalen: An Overview

Before diving into the role of methoxsalen in the treatment of chronic graft-versus-host disease (GVHD), let's first understand what methoxsalen is. Methoxsalen, also known as 8-methoxypsoralen, is a natural product derived from plants such as Ammi majus and Psoralea corylifolia. It is a potent photosensitizing agent that has been used to treat various skin conditions, including psoriasis, vitiligo, and eczema.

When combined with ultraviolet A (UVA) radiation, methoxsalen forms covalent bonds with DNA, leading to the formation of cross-links that inhibit cell replication. This property has made methoxsalen an effective treatment for various skin disorders and, more recently, a potential option for managing chronic GVHD. With that in mind, let's explore how methoxsalen can help those suffering from this debilitating condition.

Understanding Chronic Graft-Versus-Host Disease

Chronic GVHD is a potentially life-threatening complication that can occur after allogeneic hematopoietic stem cell transplantation (HSCT). This procedure involves the transfer of stem cells from a healthy donor to a recipient with a compromised immune system due to various reasons, such as leukemia, lymphoma, or other blood disorders. The primary aim of HSCT is to restore the recipient's immune system and help them fight infections and malignancies.

Unfortunately, in some cases, the donor's immune cells recognize the recipient's tissues as foreign and mount an attack against them, resulting in GVHD. Chronic GVHD occurs when this immune reaction persists for more than 100 days post-transplantation and can affect various organs, including the skin, liver, and gastrointestinal tract. This condition can significantly impact the quality of life and survival rates of patients.

Methoxsalen in the Treatment of Cutaneous Chronic GVHD

One of the most common manifestations of chronic GVHD is cutaneous GVHD, which affects the skin. Patients with cutaneous GVHD often experience symptoms such as rashes, itching, and skin thickening. These symptoms can be painful and debilitating, making it crucial to find an effective treatment.

Methoxsalen, when used in combination with UVA radiation, has shown promising results in the management of cutaneous GVHD. This treatment, known as psoralen plus ultraviolet A (PUVA) therapy, can help reduce skin inflammation and alleviate symptoms. PUVA therapy can also help regulate the immune response, making it a valuable option for GVHD patients.

Current Research on Methoxsalen for Chronic GVHD

Several studies have been conducted to assess the efficacy of methoxsalen in treating chronic GVHD. A majority of these studies have focused on the use of oral methoxsalen in combination with UVA radiation. Results from these studies have shown significant improvements in GVHD symptoms, with some patients experiencing complete remission.

However, it is essential to note that most of these studies have been small and observational in nature. There is still a need for larger, randomized controlled trials to establish the safety and efficacy of methoxsalen in managing chronic GVHD. Nonetheless, the current body of evidence supports the potential role of methoxsalen in this context.

Side Effects and Precautions

As with any medication, it is essential to be aware of potential side effects and precautions associated with methoxsalen. Some common side effects of methoxsalen include nausea, headache, and dizziness. These side effects are generally mild and manageable. However, patients should consult their healthcare providers if they experience any severe or persistent side effects.

Due to its photosensitizing properties, methoxsalen can increase the risk of sunburn and skin cancer. Therefore, patients undergoing PUVA therapy should take appropriate precautions, such as wearing protective clothing and using sunscreen, to minimize sun exposure. Furthermore, methoxsalen should be used with caution in patients with liver or kidney impairment, as it can cause further damage to these organs.


In summary, methoxsalen shows promise as a treatment option for chronic GVHD, particularly in the management of cutaneous GVHD symptoms. Although current research is limited, existing evidence supports the potential benefits of methoxsalen in this context. However, it is crucial to be aware of the potential side effects and precautions associated with methoxsalen use. As always, patients should consult their healthcare providers before starting any new treatment to ensure it is safe and appropriate for their specific situation.