V600 Mutation Research Articles

Emerging paradigm: Molecularly targeted therapy with Dabrafenib and Trametinib in recurring pediatric gliomas with BRAF mutations: A narrative review.

Gliomas are tumors arising in the central nervous system, frequently associated with Class I mutations and BRAF fusions. These mutations are adverse prognostic factors in juvenile gliomas, leading to high rates of recurrence and poor response to current treatments. The blood-brain barrier and the heterogeneity of gliomas complicate the development of a single treatment strategy for all cases. This review aims to evaluate the efficacy and safety of combination therapies, particularly Dabrafenib and Trametinib, in pediatric gliomas with BRAF V600 mutations and discusses their potential in improving clinical outcomes. A review of recent clinical trials was conducted to assess the impact of targeted therapies, especially the combination of Dabrafenib and Trametinib, on glioma treatment outcomes. Additional therapies are also explored. Combination therapy with Dabrafenib, a BRAF kinase inhibitor, and Trametinib, a MEK inhibitor, has shown significant improvement in overall survival and progression-free survival for pediatric patients with BRAF V600-mutant gliomas. Recent clinical data from 2023 demonstrated enhanced tumor control, reduced relapse rates, and improved safety profiles compared to conventional therapies. Dabrafenib and Trametinib offer a promising targeted therapy for juvenile gliomas with BRAF V600 mutations, with better survival outcomes and manageable safety profiles. However, challenges remain in managing side effects such as fever, headache, lethargy, and rash. Further research into resistance mechanisms and long-term effects is necessary to optimize treatment strategies. Other therapies, such as everolimus and Selumetinib, also show potential and warrant further investigation.

Abstract B047: Monitoring treatment response and toxicity in BRAF V600-mutant metastatic melanoma with circulating cell-free DNA

Abstract Background: The DREAMseq trial (EA6134, NCT02224781) was a national multi-center randomized phase III trial coordinated by ECOG-ACRIN that found that immune checkpoint inhibitor (IO) treatment achieves improved survival outcomes compared to targeted therapy (TT) in patients with BRAF V600-mutant metastatic melanoma. Still, approximately 40% of patients do not respond to IO, and existing biomarkers fail to distinguish this subset of patients who do not benefit from IO therapy. Additionally, as many as 80% of patients may experience immune- related adverse events (irAEs), which range from mild dermatological symptoms to life- threatening myocarditis. Here, we explore the use of the methylation status of cell-free DNA (cfDNA) in serially collected blood samples to measure response and toxicity in the context of IO- and TT-treated metastatic melanoma. Methods: Serial serum samples were collected from patients with BRAF V600-mutant metastatic melanoma treated with ipilimumab/nivolumab (IO) or dabrafenib/trametinib (TT). Circulating cfDNA was isolated from serially collected serum samples, enriched for regions of interest by hybridization capture and sequenced using enzymatic methyl-seq. Cell-type deconvolution was performed to determine the abundance of cell type- specific methylation patterns of cfDNA molecules in patient serum at different time points of treatment. The BRAF V600 mutation abundance in total cfDNA was also assessed. Results: We identified melanocyte lineage-specific DNA methylation regions and demonstrate that the methylation status of these regions remains conserved in malignant melanoma. We characterized the changes in abundance of the melanocyte-lineage cfDNA over the course of treatment and show that these changes distinguish responders from non-responders to either IO or TT. Furthermore, we track the abundance of cell type-specific DNA from normal tissues to identify markers indicative of adverse effects or disease progression. Conclusions: We established melanocyte-lineage methylation markers and evaluated the use of cell-type specific DNA methylation to monitor treatment effects of immune checkpoint or BRAF/MEK inhibitors in metastatic melanoma using serially collected blood samples. Citation Format: Sidharth S Jain, A. Patrick IV McDeed, Megan E McNamara, Amber R Alley, Dori S Rosenstrauch, Harry Sun, Natalie Thompson, John M Kirkwood, Geoffrey T Gibney, Michael B Atkins, Anton Wellstein. Monitoring treatment response and toxicity in BRAF V600-mutant metastatic melanoma with circulating cell-free DNA [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr B047.

PATH-34. IT NEVER RAINS BUT IT POURS - DIAGNOSING ANAPLASTIC PLEOMORPHIC XANTHASTROCYTOMA TWICE IN A FORTNIGHT - OUR EXPERIENCE IN A RESOURCE CONSTRAINED SETTING

Abstract Grade 3 Pleomorphic Xanthastrocytoma is a rare tumour (less than 1% of all astrocytic glial neoplasms). Present most commonly with seizures. Surgery and Radiation remain the mainstay of treatment with no clear role for traditional systemic chemotherapies; BRAF inhibitors show some benefit. We report two cases who were diagnosed within a month of each other - one was initially diagnosed in 2017- presented with altered smell, headache and diplopia. Found to have a well-defined lobulated heterogeneously enhancing suprasellar parasellar lesion. After Gross Total Resection, was diagnosed from various centers as Anaplastic Ependymoma WHO Grade III; Gllioblastoma WHO Grade IV; Anaplastic Pleomorphic Xanthastrocytoma WHO Grade III. Based on immunohistochemistry, was considered Anaplastic Ependymoma WHO Grade III. Spine screening was negative; received adjuvant Radiation 60Gy in 30 fractions. After a disease free interval of 6 years, developed a recurrence at the post op site. He underwent repeat decompression and the histopathology showed Grade 3 Pleomorphic Xanthastrocytoma. Immunohistochemistry- OLIG2: diffuse positive; R132H p.IDH1: negative; ATRX: intact nuclear expression; Mismatch repair proteins (MSH2, MSH6, MLH1, PMS2); intact nuclear expression; MIB-1 labelling index: 10-12%; H3 p.K27M: negative; GFAP: variable positivity; Podoplanin and p53 shows focal positivity; EMA, CD 34 are negative. He competed Reirradiation in January 2024. He is asymptomatic and on follow up. The second case -15 year old boy presented with episodes of absence seizures. Imaging showed a predominantly extraaxial lesion at tentorial apex. He underwent decompression and histopathology showed Grade 3 Pleomorphic Xanthastrocytoma. Immunohistochemistry - cells positive for S100 and variably positive for GFAP, OLIG2 and vimentin; ATRX: Retained expression, IDH1p.R132H, EMA, Synaptophysin, Neu N: Negative, p53: Focally positive, CD34: Positive in few tumour cells, Ki-67: 14-16 %.V600 mutation detected in the BRAF gene. Had Adjuvant RT 60 Gy in 30 fractions -completed in March 2024. MRI at 1 month - no significant change in overall tumour burden compared to post operative MRI. Was offered Dabrafenib with Trametinib.

High BRAF V600 Mutation Level Associated with Worse Outcome in Metastatic Melanoma Patients Receiving BRAF and MEK Inhibitors.

The prognostic value of BRAF V600 mutation level on clinical outcomes in patients with BRAF V600-mutated metastatic melanoma treated with BRAF and MEK inhibitors remains uncertain. The association was retrospectively analysed between BRAF V600 mutation level (defined as the ratio of the quantification of the BRAF V600 allele to the percentage of tumoral cells in the sample analysed) and progression-free and overall survival (PFS and OS, respectively) and 3-month response rate in a cohort of 58 patients with metastatic melanoma who harboured BRAF V600E/K mutations and received dual targeted-therapy BRAF/MEK inhibitors. The BRAF mutation level cut-off determined by the area under the receiver operating characteristic curve after internal validation by bootstrap methods was 0.44. Risk of poor PFS and OS was associated with BRAF V600 mutation level > 0.44 on multivariate analysis (p = 0.02 and p = 0.02, respectively) after adjusting for major confounding factors (age, sex, lactate dehydrogenase level, brain metastasis, and treatment line). No association was found between BRAF mutation level and 3-month response rate. Our study shows that high BRAF V600 mutation level in melanoma tissue was associated with poor prognosis in patients with metastatic melanoma treated with BRAF and MEK inhibitors.

European consensus-based interdisciplinary guideline for melanoma. Part 1: Diagnostics - Update 2024

This guideline was developed in close collaboration with multidisciplinary experts from the European Association of Dermato-Oncology (EADO), the European Dermatology Forum (EDF) and the European Organization for Research and Treatment of Cancer (EORTC). Recommendations for the diagnosis and treatment of melanoma were developed on the basis of systematic literature research and consensus conferences. Cutaneous melanoma (CM) is the most dangerous form of skin tumor and accounts for 90% of skin cancer mortality. The diagnosis of melanoma can be made clinically and must always be confirmed by dermoscopy. If melanoma is suspected, a histopathological examination is always required. Sequential digital dermoscopy and whole-body photography can be used in high-risk patients to improve the detection of early-stage melanoma. If available, confocal reflectance microscopy can also improve the clinical diagnosis in special cases. Melanoma is classified according to the 8th version of the American Joint Committee on Cancer classification. For thin melanomas up to a tumor thickness of 0.8 mm, no further diagnostic imaging is required. From stage IB, lymph node sonography is recommended, but no further imaging examinations. From stage IIB/C, whole-body examinations with computed tomography or positron emission tomography CT in combination with magnetic resonance imaging of the brain are recommended. From stage IIB/C and higher, a mutation test is recommended, especially for the BRAF V600 mutation. It is important to perform a structured follow-up to detect relapses and secondary primary melanomas as early as possible. A stage-based follow-up regimen is proposed, which in the experience of the guideline group covers the optimal requirements, although further studies may be considered. This guideline is valid until the end of 2026.

Two Decades of Progress in Personalized Medicine of Colorectal Cancer in Serbia-Insights from the Institute for Oncology and Radiology of Serbia.

It is projected that, by 2040, the number of new cases of colorectal cancer (CRC) will increase to 3.2 million, and the number of deaths to 1.6 million, highlighting the need for prevention strategies, early detection and adequate follow-up. In this study, we aimed to provide an overview of the progress in personalized medicine of CRC in Serbia, with results and insights from the Institute for Oncology and Radiology of Serbia (IORS), and to propose guidance for tackling observed challenges in the future. Epidemiological data were derived from official global and national cancer registries and IORS electronic medical records. Germline genetic testing for Lynch syndrome was performed by Next Generation Sequencing. RAS and BRAF mutation analyses were performed using qPCR diagnostic kits. Epidemiology and risk factors, prevention and early detection programs, as well as treatment options and scientific advances have been described in detail. Out of 103 patients who underwent germline testing for Lynch syndrome, 19 (18.4%) showed a mutation in MMR genes with pathogenic or likely pathogenic significance and 8 (7.8%) in other CRC-associated genes (APC, CHEK2, MUTYH). Of 6369 tested patients, 50.43% had a mutation in KRAS or NRAS genes, while 9.54% had the V600 mutation in the BRAF gene. Although significant improvements in CRC management have occurred globally in recent years, a strategic approach leading to population-based systemic solutions is required. The high incidence of young-onset CRC and the growing elderly population due to a rise in life expectancy will be especially important factors for countries with limited healthcare resources like Serbia.

Treatment of advanced skin melanoma with BRAF V600 mutation with central nervous system metastases with encorafenib in combination with binimetinib

Treatment of advanced skin melanoma with BRAF V600 mutation with central nervous system metastases with encorafenib in combination with binimetinib

Efficacy of targeted therapies in the treatment of patients with melanoma harboring BRAF V600 mutation with central nervous system metastases

Efficacy of targeted therapies in the treatment of patients with melanoma harboring BRAF V600 mutation with central nervous system metastases

Effectiveness of rechallenge with BRAF/ /MEK inhibitors in patient with advanced melanoma with BRAF V600 mutation

Effectiveness of rechallenge with BRAF/ /MEK inhibitors in patient with advanced melanoma with BRAF V600 mutation

A case of a patient treated with targeted therapy in brain metastases of melanoma with BRAF V600 mutation

A case of a patient treated with targeted therapy in brain metastases of melanoma with BRAF V600 mutation

Weekly carboplatin plus paclitaxel chemotherapy in advanced melanoma patients resistant to anti-PD-1 inhibitors: a retrospective, monocentric experience

Immunotherapy with anti-PD-1 antibodies significantly improved the prognosis in advanced melanoma patients, but most of them develop primary or secondary resistance to the treatment. In this study, we evaluated efficacy and safety of a chemotherapy regimen with weekly carboplatin plus paclitaxel (wCP) in patients previously treated with anti-PD-1 antibodies. We retrospectively identified 30 patients with advanced melanoma treated at our Institute over the last eight years with wCP. The co-primary endpoints of the study were overall survival (OS) and progression-free survival (PFS). In addition, we evaluated treatment tolerability. For this patient cohort, median PFS and OS were 3.25 and 7.69 months, respectively. All included patients had previously received anti-PD-1 immunotherapy, most of them had ECOG PS 0–1, and only 5 patients had a BRAF V600 mutation. In univariable analysis, we observed shorter OS in patients with > 2 involved metastatic sites, superficial spreading histology, and serum lactate dehydrogenase (LDH) values above the median. Liver metastases were associated with worse outcomes, while radiotherapy treatment of brain metastases was associated with improved OS. However, in a multivariable Cox regression model, only LDH above the median, superficial spreading histology, and female sex were significantly associated with worse OS. We reported grade 3 and 4 treatment-related toxicities in 4 and 0 patients, respectively. In conclusion, chemotherapy with wCP is a valid palliative treatment in advanced melanoma who progressed with anti-PD-1 antibodies.

Targeting Non-V600 Mutations in BRAF: A Single Institution Retrospective Analysis and Review of the Literature.

While successful treatment paradigms for BRAF V600 mutations have been developed, 10% of BRAF mutations are not at V600 and lack a standard treatment regimen. This study summarizes the current body of knowledge on the treatment of non-V600 mutations and reports a single institution experience. We conducted a literature review to summarize relevant preclinical and clinical published data on the response of non-V600 mutations to targeted therapies. We performed a retrospective analysis of INOVA Schar Cancer patients registered in our Molecular Tumor Board database with non-V600 BRAF mutations who were recipients of targeted therapy and assessed their time to next treatment and best response. Published preclinical and clinical data have demonstrated limiting results in the response of non-V600 mutated cancers to targeted therapies. Response rates were variable for the major classes of BRAF mutations including class II and class III mutations as well as, BRAF fusions. Data collected from our INOVA cohort offered promising results with one patient achieving partial remission and two patients achieving stable disease. This article reflects the current understanding of targeted therapies in non-V600 mutations. Further large-scale studies separating BRAF mutations based on their mechanism of activation will expand our understanding.

Tovorafenib: First Approval.

Tovorafenib (OJEMDA™) is a once-weekly oral, selective, brain-penetrant, type II RAF kinase inhibitor being developed by Day One Biopharmaceuticals, Inc., under a license from Takeda Oncology, for the treatment of paediatric low-grade glioma (pLGG) and solid tumours. Most pLGGs harbour alterations in the MAPK pathway, such as a BRAF mutation or BRAF fusion, which result in aberrant intracellular signalling. Tovorafenib is an inhibitor of mutant BRAF V600E, wild-type BRAF and wild-type CRAF kinases and BRAF fusions. In April 2024, tovorafenib received its first approval in the USA for the treatment of patients aged ≥ 6 months with relapsed or refractory pLGGs harbouring a BRAF fusion or rearrangement, or BRAF V600 mutation. It received accelerated approval for this indication based on the response rate and duration of response achieved in this population in the ongoing, pivotal, phase 2 FIREFLY-1 study. Clinical development of tovorafenib is underway in numerous countries worldwide. This article summarizes the milestones in the development of tovorafenib leading to this first approval for relapsed or refractory pLGG with an activating BRAF alteration.

An Automated Real-Time PCR Assay versus Next-Generation Sequencing in the Detection of BRAF V600 Mutations in Melanoma Tissue Samples.

Next-generation sequencing (NGS) is the most commonly used method for determining BRAF mutational status in patients with advanced melanoma. Automated PCR-based methods, such as the IdyllaTM system, are increasingly used for mutation diagnostics, but it is unclear what impact the choice of diagnostic method has on the management of melanoma. To compare the concordance rate of BRAF V600 mutational analysis using IdyllaTM and NGS and to analyze the technical and clinical turnaround time. The clinical relevance is compared by analyzing the impact on the treatment decision. In this monocentric prospective cohort study, the BRAF mutation status of 51 patients was determined using both methods in parallel. BRAF V600 mutation was detected in 23/51 cases (45%). IdyllaTM showed a 100% concordant result with a faster turnaround time (0.2 days) compared to NGS (12.2 days). In general, less tumor material was required for IdyllaTM than for NGS. Most patients received immunotherapy as a first-line therapy regardless of the BRAF V600 status. IdyllaTM testing proved to be a reliable and rapid alternative to NGS in the determination of BRAF V600 mutation. Although BRAF. status was available earlier, this had no influence on the treatment decision in most cases.

Efficacy of axitinib in a US cohort of patients with programmed cell death protein 1-resistant mucosal melanoma.

Mucosal melanoma is a rare melanoma subtype, accounting for about 1% of all diagnosed melanomas. It is characterized by an aggressive phenotype with a poor prognosis and a low response rate to approved treatments. We retrospectively analyzed the clinical features, treatments, and outcomes of patients diagnosed with mucosal melanoma treated with axitinib ± anti-programmed cell death protein 1 (PD-1) therapy at a single US referral center between 2018 and 2021. Radiologic response was assessed according to Response Evaluation Criteria in Solid Tumors (RECIST), v1.1. Twenty-three patients were included in this study. In all, 78% were females with a median age of 62 years. The originating site of mucosal melanoma was the sinonasal (35%), genitourinary (35%), and gastrointestinal (30%) tracts. Sixty-five percent of patients had M1c or M1d disease and 0% had BRAF V600 mutations detected. The majority (96%) had prior treatment inclusive of anti-PD-1, with a median of 2 prior lines, and 78% of patients received a combination of axitinib and PD-1 and the median duration of treatment was 3.2 months. The overall response rate was 13% and the disease control rate was 26%. The median progression-free survival was 3.2 months, and the median overall survival was 8.2 months. Overall, the regimen was well tolerated with 39% of patients requiring dose reduction and 9% requiring treatment cessation. Axitinib with anti-PD-1 therapy has modest clinical activity in heavily pretreated patients with mucosal melanoma outside of Asia, including some with long-term benefits. This data supports the worldwide clinical trials evaluating this combination and the role of incorporating vascular endothelial growth factor-based therapy in the therapeutic paradigm for patients with mucosal melanoma.

Investigation of BRAF V600E Mutation in Breast Cancer Patients

The B-Raf is the essential protein in signal pathways inside cells which is affected by cell growth direction. The B-Raf protein encoded by the BRAF gene that is located at chromosome 7, BRAF gene is also pointed out as proto-oncogene. This study aimed to detect the substitution at codon 600 causing a change of valine to glutamic acid (V600E) mutation in Iraqi females to assist its role in initiating breast cancer. Sixty biopsies tissue from breast cancer Iraqi women and 20 women with benign lesions were enrolled in this study. DNA was extracted from breast cancer biopsies samples. PCR and DNA Sequencing techniques were used to screen the BRAF V600E gene mutation as it is an essential event in the initiation of cancer. The results revealed that none Iraqi breast cancer women had BRAF V600E mutation, The annotated BRAF gene has been deposited in DDBJ/GenBank under the accession number LC547435. In conclusion: The present data indicate no BRAF V600E mutation in Iraqi breast cancer females and may not possess a role in breast cancer initiation. The current results may be refer to ineffectiveness of Vemurafenib and Encorafenib therapies that specific for patients with the BRAF V600 mutation. Other studies with large numbers of patients are needed to confirm the result of this study, as the high prevalence of breast cancer among Iraqi women.

Final Results for Adjuvant Dabrafenib plus Trametinib in Stage III Melanoma

BackgroundThe 5-year results of this trial showed that adjuvant therapy with dabrafenib plus trametinib resulted in longer relapse-free survival and distant metastasis–free survival than placebo among patients with BRAF V600–mutated stage III melanoma. Longer-term data were needed, including data regarding overall survival.MethodsWe randomly assigned 870 patients with resected stage III melanoma with BRAF V600 mutations to receive 12 months of dabrafenib (150 mg twice daily) plus trametinib (2 mg once daily) or two matched placebos. Here, we report the final results of this trial, including results for overall survival, melanoma-specific survival, relapse-free survival, and distant metastasis–free survival.ResultsThe median duration of follow-up was 8.33 years for dabrafenib plus trametinib and 6.87 years for placebo. Kaplan–Meier estimates for overall survival favored dabrafenib plus trametinib over placebo, although the benefit was not significant (hazard ratio for death, 0.80; 95% confidence interval [CI], 0.62 to 1.01; P=0.06 by stratified log-rank test). A consistent survival benefit was seen across several prespecified subgroups, including the 792 patients with melanoma with a BRAF V600E mutation (hazard ratio for death, 0.75; 95% CI, 0.58 to 0.96). Relapse-free survival favored dabrafenib plus trametinib over placebo (hazard ratio for relapse or death, 0.52; 95% CI, 0.43 to 0.63), as did distant metastasis–free survival (hazard ratio for distant metastasis or death, 0.56; 95% CI, 0.44 to 0.71). No new safety signals were reported, a finding consistent with previous trial reports.ConclusionsAfter nearly 10 years of follow-up, adjuvant therapy with dabrafenib plus trametinib was associated with better relapse-free survival and distant metastasis–free survival than placebo among patients with resected stage III melanoma. The analysis of overall survival showed that the risk of death was 20% lower with combination therapy than with placebo, but the benefit was not significant. Among patients with melanoma with a BRAF V600E mutation, the results suggest that the risk of death was 25% lower with combination therapy. (Funded by GlaxoSmithKline and Novartis; COMBI-AD ClinicalTrials.gov number, NCT01682083; EudraCT number, 2012-001266-15.)

Phase II study of vemurafenib in children and young adults with tumors harboring BRAF V600 mutations: NCI-COG pediatric MATCH trial (APEC1621) Arm G.

This is a phase II subprotocol of the NCI-COG Pediatric MATCH study evaluating vemurafenib, a selective oral inhibitor of BRAF V600 mutated kinase, in patients with relapsed or refractory solid tumors harboring BRAF V600 mutations. Patients received vemurafenib at 550 mg/m2 (maximum 960 mg/dose) orally twice daily for 28-day cycles until progression or intolerable toxicity. The primary aim was to determine the objective response rate and secondary objectives included estimating progression-free survival and assessing the tolerability of vemurafenib. Twenty-two patients matched to the subprotocol and 4 patients (18%) enrolled. Primary reasons for non-enrollment were ineligibility due to exclusions of low-grade glioma (n = 7) and prior BRAF inhibitor therapy (n = 7). Enrolled diagnoses were one each of histiocytosis, ameloblastoma, Ewing sarcoma, and high-grade glioma, all with BRAF V600E mutations. Treatment was overall tolerable with mostly expected grade 1/2 adverse events (AE). Grade 3 or 4 AE on treatment were acute kidney injury, hyperglycemia, and maculopapular rash. One patient came off therapy due to AE. One patient (glioma) had an objective partial response and remained on protocol therapy for 15 cycles. There was a low accrual rate on this MATCH subprotocol, with only 18% of those who matched with BRAFV600 mutations enrolling, resulting in early termination, and limiting study results (ClinicalTrials.gov Identifier: NCT03220035).

Tovorafenib (Ojemda) for pediatric low-grade glioma.

Tovorafenib (Ojemda – Day One), a type II RAF kinase inhibitor, has received accelerated approval from the FDA for treatment of patients ≥6 months old with relapsed or refractory pediatric low-grade glioma harboring a BRAF fusion or rearrangement or a BRAF V600 mutation. Tovorafenib is the first systemic treatment to be approved in the US for pediatric low-grade gliomas with BRAF fusions. Accelerated approval of tovorafenib was based on response rates and duration of response.

Neoadjuvant pembrolizumab and lenvatinib in resectable mucosal melanoma: NeoPlus study update.

9580 Background: Combination therapy of anti-PD1 agent with VEGFR inhibitor is a promising therapeutic approach in unresectable or metastatic mucosal melanoma. We conducted this study evaluating neoadjuvant lenvatinib and pembrolizumab in pts with resectable mucosal melanoma. Methods: This was a single-arm, open-label, single-center, phase 2 study conducted from Sep 2021. Eligible pts were adults (18-75 yr) with histologically confirmed, resectable mucosal melanoma. Pts received lenvatinib 20mg qd and pembrolizumab 200mg q3w for 2 cycles, followed by surgery. Pembrolizumab (200mg q3w) continued post operatively for further 15 cycles. The primary endpoint was complete pathologic response (pCR). Secondary endpoints were Relapse free survival (RFS, time from surgery to any event), Overall survival (OS) and safety. Results: Between Sep 2021 and Apr 2023, 26 pts were enrolled, median age was 57 yrs(range: 49-75), 19 were female. Primary sites included: 11 female genital, 8 ano-rectal, 5 head & neck (1 nasal, 4 oral),2 esophageal. 15 pts (58%) were localized disease,11 (42%) were regional lymphatic disease. BRAF V600, NRAS or KIT mutations were presented in 1, 3 and 2 pts, respectively. 21 pts underwent surgery, 2 pts had a pCR (9.5%), 2 near PCR, 4 pPR, with a pathologic response rate of 38% (8/21,95%CI 18-62%). 5 pts did not proceed with planned surgery for pts preference. As of Dec 2023, 12 of 21 resected pts had relapsed (9/11 in female genital,2/4 in ano-rectal, 1/5 in head & neck). Median follow up time was 19.1 months (95%CI 13.7-24.5). Median RFS was 12.4 months (95%CI 4.0-20.8), no difference was observed among these primary sites (female genital: 6.6 months, ano-rectal: 14.1 months, head & neck: not reached). Median DMFS was not reached. IHC data of the resected tumor showed higher CD8+ T cells density in responders (R: pCR+near PCR+ pPR) than non-responders (NR: pNR) (p = 0.046). Tertiary lymphoid structures were detected in 9 pts. Most common TRAEs were hypertension (13, 50%), proteinuria (12, 46%), LDH increased (9,35%), hypothyroidism (8, 31%). Three pts experienced a dose reduction and 5 experienced a dose interruption due to an AE. No grade 4-5 toxicities were observed. Conclusions: Updated results confirmed that the combination of pembrolizumab plus lenvatinib as neoadjuvant therapy had moderate anti-tumor efficacy in resectable mucosal melanoma. Increased CD8+ T cell infiltration was observed in tumor with pathologic response, supporting further investigation in mucosal melanoma.