A research team led by Dr. Sheri Holmen at Huntsman Cancer Institute has discovered a breakthrough combination therapy that effectively overcomes treatment resistance in melanoma patients with the BRAF V600E mutation, while also preventing and treating brain metastases.
The federally funded study, published in Cell Reports Medicine, identified focal adhesion kinase (FAK) as a key contributor to melanoma metastasis. By combining FAK inhibitors with a RAF-MEK clamp, researchers were able to target multiple cellular pathways that regulate cancer cell growth and overcome resistance mechanisms.
"Once melanoma has spread to the brain, it's very hard to treat. Metastasis to the brain is one of the main causes of death from melanoma," explained Dr. Holmen, professor in the Department of Surgery at the University of Utah. "We wanted to find a solution to an unmet clinical need for those patients who had no other treatment options available, and this is a huge step forward."
Understanding Melanoma Resistance Mechanisms
Researchers at the University of California San Diego contributed to understanding the underlying mechanisms of treatment resistance in BRAF-mutated melanoma. Their work revealed that pathways involved in focal adhesion and extracellular matrix (ECM) remodeling play crucial roles in reshaping the tumor microenvironment through the RAF/MEK cell signaling pathway.
These findings align with Dr. Holmen's research, which specifically identified FAK as a potential therapeutic target. FAK is an enzyme that regulates cell growth and significantly contributes to melanoma metastasis.
Clinical Implications for Advanced Melanoma
While early-stage melanoma can often be treated with surgical removal, the disease becomes significantly more challenging to treat once it spreads beyond the skin. Current treatment options for advanced melanoma include:
- Immunotherapy - which leverages the patient's immune system to attack cancer cells
- Targeted oral therapies - which address specific genetic mutations
However, both approaches have limitations. "Patients can become resistant to those drugs over time. And once the disease has reached the brain, they also don't work as well," noted Dr. Holmen. "The window of time to treat a patient with brain metastasis is shortened quite significantly because the average survival from time of diagnosis of brain metastasis is only about a year—even while using these other therapies."
Promising Results in Preclinical Models
The research team found that inhibiting FAK in combination with an inhibitor of RAF and MEK significantly prolonged survival rates in preclinical mouse models. This approach was particularly effective against melanomas with BRAF mutations, which account for approximately 50% of metastatic melanoma cases.
"This combination drug therapy also stopped the development of brain metastasis, and that's where this research is very exciting," said Dr. Holmen. "Not only did it treat the tumor once it spread to and was growing in the brain, it also prevented the cells from getting there in the first place."
Improving Treatment Accessibility
The oral treatment combines two drugs:
- Defactinib - which blocks the FAK protein
- Avutometinib - which blocks RAF and MEK proteins
This combination therapy, developed in partnership with Verastem Oncology, offers potential advantages for patients living in rural areas who face challenges accessing specialized treatment centers.
"Receiving a treatment like immunotherapy requires an infusion, and patients have to travel to a hospital or clinic for that kind of specialized treatment," explained Dr. Holmen. "Having oral drugs available will increase treatment options for our patients, especially those living in rural and frontier areas."
This advancement is particularly significant for regions like the Mountain West, where melanoma rates remain consistently high and where Huntsman Cancer Institute serves many patients from remote locations.
Future Directions
While the current research demonstrates promising results in preclinical models, clinical trials will be necessary to confirm the efficacy and safety of this combination therapy in human patients. The dual mechanism of action—both treating existing brain metastases and preventing new ones—represents a potentially transformative approach for patients with BRAF-mutated melanoma who currently face limited treatment options once the disease spreads to the brain.
