Two recent studies from researchers at Washington University School of Medicine in St. Louis have identified a promising way to treat certain blood cancers using a drug originally developed for breast cancer.
These findings could potentially change how doctors approach the treatment of these challenging diseases.
The studies focused on a group of blood cancers called myeloproliferative neoplasms (MPNs) and an aggressive type of acute myeloid leukemia (AML). MPNs are slow-growing blood cancers that can linger for years, while AML is a faster, more aggressive disease.
Patients with MPNs often have no effective options to prevent their condition from worsening or progressing into AML, which has poor outcomes.
The researchers found that a protein called RSK1 plays a key role in driving inflammation and cancer progression in these blood diseases.
By blocking this protein using a drug called PMD-026, which is already being tested in clinical trials for breast cancer, they were able to stop the progression of these cancers in lab and animal studies. This discovery opens the door to testing the drug’s effectiveness for blood cancers.
The first study, published in Nature Communications, showed that using PMD-026 in mice significantly reduced cancer activity in the bone marrow. After just four weeks of treatment, up to 96% of cancer cells were eliminated. The drug also reduced scarring in the bone marrow and prevented MPN from turning into AML.
The second study, in Blood Cancer Journal, examined a specific form of AML called FLT3-ITD AML, which doesn’t arise from MPNs. This type of AML is typically treated with FLT3 inhibitors, but these drugs often lose their effectiveness over time as the cancer becomes resistant.
Since PMD-026 blocks a different pathway, it might work where FLT3 inhibitors fail, giving doctors another option for treatment.
MPNs are often managed by treating symptoms like fatigue, weight loss, and an enlarged spleen, but current therapies don’t stop the disease from progressing or prevent it from turning into AML.
The goal of using PMD-026 is not just to slow disease progression but also to help some patients become eligible for stem cell transplants, which can offer long-term remission.
The research team, led by Dr. Stephen T. Oh, has been working on ways to stop MPNs from worsening. A previous study by Oh’s group found that a protein called DUSP6 contributes to the progression of MPNs.
This led them to investigate RSK1, which is part of the same signaling pathway. They hypothesized that blocking RSK1 could halt the disease process, and their new studies confirmed this.
PMD-026 is an experimental drug that targets RSK1 and related proteins in the same family. It has already shown promise in early trials for metastatic breast cancer, with patients tolerating it well and experiencing only mild side effects.
The drug blocks multiple forms of the RSK protein, including RSK1, which appears to be the most important for blood cancers.
Dr. Oh’s team collaborated with Phoenix Molecular Designs, the company developing PMD-026, to test the drug’s effects on blood cancers.
The researchers are now planning clinical trials to test the drug in patients with MPNs or AML who are not responding to standard treatments or cannot undergo a stem cell transplant due to their age or health.
These findings are exciting because they suggest a new way to target blood cancers that currently have limited treatment options. If further testing confirms the effectiveness of PMD-026, it could become a vital tool for doctors treating MPNs and AML.
Although much work remains before the drug can be approved for this use, the researchers are optimistic that this approach could improve the lives of many patients.
By identifying RSK1 as a critical driver of these diseases and testing an existing drug in a new way, the studies highlight how repurposing medications can accelerate the development of new treatments. For patients with MPNs and AML, this research offers hope for better care and new possibilities for remission.
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The research findings can be found in Nature Communications.
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