Speaker discusses predictive power of Merlin test for low-, high-risk melanoma
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Key takeaways:
- The Merlin test, a clinical-pathologic and gene expression profile, was able to successfully classify 37% of patients as low risk.
- Of those who tested as low risk, 7.1% had positive sentinel lymph node rates.
ORLANDO — A presentation at the American Society for Dermatologic Surgery Annual Meeting detailed new data that showcased the validity of the Merlin test in identifying sentinel lymph node biopsy status in high-risk patients with melanoma.
Sentinel lymph node biopsies (SLNB) are often the first step when it comes to staging melanoma, and dermatologists urge patients with a predicted metastasis risk greater than 10% to undergo this procedure, according to a press release issued by SkylineDx, the co-developer of the Merlin test alongside the Mayo Clinic.
However, patients that undergo SLNBs often do not test positive for metastasis thereby rendering the procedure not only unhelpful but potentially harmful to patients who are at a high risk of complications, the release continued.
As a result, three investigators, including meeting presenter Vernon Sondak, MD, chair of the department of cutaneous oncology at Moffitt Cancer Center, set out to validate the predictive ability of the clinical-pathologic and gene expression profile (CP-GEP) Merlin test in identifying SLNB status in high-risk patients with melanoma in what is known as the largest prospective trial of a genomic assay yet conducted in melanoma, according to the presentation.
“We felt, very strongly, that if we were going to change that standard of care — that you recommend a SLNB to anybody — then it had to be done in a very thoroughly conducted, prospective clinical trial, where everyone was blinded to the result and no one was charged for it,” Sondak said during the presentation. “And that’s exactly what we conducted in what is called the MERLIN-001 trial.”
The MERLIN-001 trial screened 2,141 with melanoma T1-T3, 1,686 of which underwent a SLNB and successful clinicopathologic and gene expression profile (CP-GEP).
Results showed that the Merlin test was able to successfully classify 37% of patients as low risk. Of those who tested as low risk, 7.1% (95%, 5.2%-9.4%) tested positive for SLN involvement. According to Sondak, the low-risk results did not identify patients with a less than 5% SLN positive rate but did identify patients with a less than 10% rate.
In comparison, the test classified 63% of the patients as high risk, with 23.8% (95% CI, 21.3%-26.5%) having a positive SLN rate. This means that cases classified as high risk by the Merlin test were three times more likely to be SLN positive.
The researchers also analyzed the predictive power of the Merlin test among a subset of patients with stage IB melanoma, which comprised 65.6% of the study population.
These patients had a 12.6% positive SLN rate over time. The Merlin test predicted that 49.8% of patients were low risk and 50.2% were high risk. Of those classified as low risk, the SNL positive rate was 6.4% vs. 18.7% in the high-risk group.
“Some patients may say ‘6%? I’ll take my chances’ while others will say ‘over 5%? Let’s do it,’” Sondak said. “But again, we see a three times higher risk in the high-risk group.”
According to the SkylineDx press release, these results were first presented on Oct. 13 during the plenary session for late-breaking abstracts at the Society for Melanoma Research Annual Meeting in New Orleans.
This first set of results from this landmark study, which were again presented at the American Society for Dermatologic Surgery Meeting, showed that the Merlin test has the potential to guide clinical decisions for melanoma treatment.