Promising Strategies for Overcoming BRAF Inhibitor Resistance Based on Known Resistance Mechanisms

2020 ◽  
Vol 20 (12) ◽  
pp. 1415-1430 ◽  
Author(s):  
Qing-Shan Li ◽  
Bang-Nian Shen ◽  
Hua-Jian Xu ◽  
Ban-Feng Ruan
Keyword(s):  
Treatment Strategies ◽  
Braf Inhibitor ◽  
Resistance Mechanisms ◽  
Therapeutic Effects ◽  
Braf Inhibitors ◽  
Braf Mutations ◽  
Clinical Benefits ◽  
Melanoma Patients ◽  
Inhibitor Resistance ◽  
Braf Mutant

Background: Almost 50% of metastatic melanomas harbor BRAF mutations. Since 2011, BRAF inhibitors have exhibited striking clinical benefits in BRAF-mutant melanoma patients. Unfortunately, their therapeutic effects are often temporary. The resistance mechanisms vary and can be broadly classified as MAPK reactivation-dependent and -independent. Elucidation of these resistance mechanisms provides new insights into strategies for overcoming resistance. Indeed, several alternative treatment strategies, including changes in the mode of administration, combinations of BRAF and MEK inhibitors, and immunotherapy have been verified as beneficial to BRAF inhibitor-resistant melanoma patients. Prospect: In this review, we discuss promising strategies for overcoming drug resistance and highlighting the prospects for discovering strategies to counteract BRAF inhibitor resistance.

Genomic profiles of BRAF inhibitor resistance mechanisms in metastatic colorectal cancer.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e15527-e15527
Author(s):  
Ting Xu ◽  
Xicheng Wang ◽  
Qi Changsong ◽  
Zhenghang Wang ◽  
Jian Li ◽  
...  
Keyword(s):  
Disease Progression ◽  
Signaling Pathway ◽  
Clinical Decision Making ◽  
Braf Inhibitor ◽  
Resistance Mechanisms ◽  
Genetic Alterations ◽  
Braf V600e ◽  
Plasma Samples ◽  
Braf Inhibitors ◽  
Braf Mutations

e15527 Background: BRAF mutations are present in 5-10% of metastatic colorectal cancers (mCRCs). Patients with mCRC whose tumors harbor BRAF V600 mutation generally respond poorly to standard chemotherapy. Treatment with BRAF inhibitors has been shown to improve outcomes, whereas the resistance develops through undefined mechanisms. Therefore, it is imperative to accurately comprehend the genomic profiling of resistance mechanisms to BRAF inhibitors in mCRC for exploring its clinical treatment strategies. Methods: We analyzed next-generation sequencing results in 520 cancer-associated genes for 22 patients who had BRAF V600E mutant mCRC in order to characterize genomic predictors of treatment outcome and track the acquired resistance (AR) mechanisms during the vemurafenib/dabrafenib/encorafenib treatment in combination with cetuximab +/- trametinib. The median age of the patients was 61 years old, 54.5% were male, 54.5% had right-sided mCRC, and 81.8% received one or more prior chemotherapy lines. Tissue and/or plasma samples were collected at baseline (prior to anti-BRAF treatment) and upon disease progression (PD). Objective tumor responses were radiologically assessed every 6 weeks according to RECIST v1. 1. Results: By Feb 2021, treatment had been discontinued in 15 (63.2%) of the patients due to disease progression, while the other 7 cases were still under treatment. The median PFS (mPFS) for all patients was 4.5 months. The overall response rate was 32%, and the disease control rate was 86%. In addition to BRAF V600E, the most common concomitant mutations were identified in TP53 (20/22), RNF43 (8/22), LRP18 (7/22), APC (7/22) and PIK3CA (5/22). Patients with baseline alterations in RNF43 (n = 8; p = 0.0466), or RECQL4 (n = 4; p = 0.0406) had significantly longer PFS than their respective wild type counterparts. In contrast, baseline alterations in PPP2R2A (n = 3; p = 0.0131), RUNX1T1 (n = 3; p = 0.0147), and receptor tyrosine kinase (RTK) signaling pathway genes (n = 6; p = 0.0057) were each significantly associated with shorter PFS. Among the 15 patients whose disease progressed, 9 were identified with newly developed AR mutations in PD tumor or plasma samples. MET amplification was the most common AR mechanism (n = 4) followed by BRAF amplification, KRAS, NRAS mutations (n = 3 each), and MAP2K1, PIK3R1 mutations (n = 1 each). Q61 substitution was the most dominant form for both KRAS and NRAS AR mutations (83%, 5/6). In terms of signaling pathway, MAPK (67%, 6/9) and RTK (44%, 4/9) pathway alterations were most frequently observed. Conclusions: Our study illustrated the landscape of genetic alterations in patients with BRAF V600E mutant mCRC upon BRAF inhibitor treatment, which could be critical to predict responses to BRAF inhibitors and guide personalized clinical decision-making after disease progression.

scholarly journals BRAF in Melanoma: Pathogenesis, Diagnosis, Inhibition, and Resistance

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Ryan J. Sullivan ◽  
Keith T. Flaherty
Keyword(s):  
Standard Of Care ◽  
Diagnostic Techniques ◽  
Therapeutic Interventions ◽  
Molecular Testing ◽  
Braf Inhibitors ◽  
Testing Methods ◽  
Braf Mutations ◽  
Initial Discovery ◽  
Braf Mutant ◽  
Mutant Braf

Since the initial discovery that a subset of patients with cutaneous melanoma harbor BRAF mutations, substantial research has been focused on determining the pathologic consequences of BRAF mutations, optimizing diagnostic techniques to identify these mutations, and developing therapeutic interventions to inhibit the function of this target in mutation-bearing tumors. Recently, advances have been made which are revolutionizing the standard of care for patients with BRAF mutant melanoma. This paper provides an overview on the pathogenic ramifications of mutant BRAF signaling, the latest molecular testing methods to detect BRAF mutations, and the most recent clinical data of BRAF pathway inhibitors in patients with melanoma and BRAF mutations. Finally, emerging mechanisms of resistance to BRAF inhibitors and ways of overcoming this resistance are discussed.

scholarly journals Rapid BRAF mutation detection in melanoma patients by immunohistochemistry

2017 ◽  
Vol 4 (1) ◽  
pp. 1-5
Author(s):  
László Fülöp ◽  
Katalin Götzer ◽  
Erzsébet Csernák ◽  
Danyil Szergejevics Kuznyecov ◽  
Erika Tóth
Keyword(s):  
Braf Inhibitor ◽  
Pcr Amplification ◽  
Diagnostic Algorithm ◽  
Braf V600e ◽  
Wild Type ◽  
Braf Gene ◽  
Braf Mutations ◽  
Activating Mutation ◽  
Melanoma Patients ◽  
Braf V600 Mutation

The V600E mutation is the most common (~90%) activating mutation of the BRAF gene. BRAF mutations have been frequently investigated in melanoma, colorectal cancer and papillary thyroid carcinoma. The importance of the detection of BRAF mutations has been rising by the routine use of Braf inhibitor therapy. We evaluated the usefulness of the BRAF V600E mutation-specific monoclonal antibody (VE1) in metastatic melanoma patients. To confirm the results of immunohistochemistry (IHC), we used COBAS 4800 BRAF V600 mutation test and PCR amplification followed by Sanger sequencing.36 of 105 patients have wild-type BRAF gene, 64 have V600E mutation and 5 of 105 have V600K mutation. Predicting the mutation only by IHC using VE1 antibody, all 58 positively scored specimen were V600E mutant. The V600K, the wild-type patients and 7 patients from the V600E mutant group scored as negative. Thus the specificity is 100% and the positive predictive value is 1 of the IHC method. After processing our data we could establish a cheaper diagnostic algorithm for rapid detection ofBRAF mutation.

scholarly journals BRAF Mutant Melanoma Adjusts to BRAF/MEK Inhibitors via Dependence on Increased Antioxidant SOD2 and Increased Reactive Oxygen Species Levels

Cancers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1661 ◽  
Author(s):  
Long Yuan ◽  
Rosalin Mishra ◽  
Hima Patel ◽  
Samar Alanazi ◽  
Xin Wei ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Braf Inhibitor ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Braf Mutations ◽  
Mek Inhibitors ◽  
Braf Mutant ◽  
Resistant Cells

B-Rapidly Accelerated Fibrosarcoma (BRAF) mutations are found in about 50% of melanoma patients. Treatment with Food and Drug Administration (FDA)-approved BRAF and MAP/ERK kinase (MEK) inhibitors has improved progression free and overall survival of patients with BRAF mutant melanoma. However, all responders develop resistance typically within 1 year of treatment with these inhibitors. Evidence indicates that reactive oxygen species (ROS) levels are elevated after BRAF pathway inhibition treatment. We aim to decipher the role of mitochondrial antioxidant proteins relative to ROS levels and BRAF pathway inhibitor resistance. We observed BRAF mutant melanoma cells treated with the combination of a MEK inhibitor (trametinib) and a BRAF inhibitor (dabrafenib), exhibited elevated ROS levels, both in in vitro and in vivo melanoma models. We next generated trametinib- and dabrafenib-resistant (TDR) cells and found increased ROS levels after acquisition of resistance. An immunofluorescence experiment showed an increase of DNA damage in TDR cell lines. Furthermore, we observed that TDR cells increased superoxide dismutase 2 (SOD2), an antioxidant, at both mRNA and protein levels, with the upregulation of the transcription factor Nuclear Factor (NF)-κB. Knockdown of SOD2 significantly reduced the growth of BRAF pathway inhibitor-resistant cells. In addition, the results indicate that TDR cells can be re-sensitized to BRAF pathway inhibitors by the ROS scavenger, N-Acetyl Cysteine (NAC). Overall, these data indicate that BRAF pathway inhibitor-resistant cells can compensate for elevated ROS via increased expression of the antioxidant SOD2.

scholarly journals PTEN Loss-of-Function Alterations Are Associated With Intrinsic Resistance to BRAF Inhibitors in Metastatic Melanoma

2017 ◽  
pp. 1-15 ◽  
Author(s):  
Federica Catalanotti ◽  
Donavan T. Cheng ◽  
Alexander N. Shoushtari ◽  
Douglas B. Johnson ◽  
Katherine S. Panageas ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Tumor Regression ◽  
Braf Inhibitor ◽  
Molecular Signature ◽  
Braf Inhibitors ◽  
Next Generation ◽  
Loss Of Function ◽  
Intrinsic Resistance ◽  
Braf Mutant ◽  
Generation Sequencing

Purpose The clinical use of BRAF inhibitors in patients with melanoma is limited by intrinsic and acquired resistance. We asked whether next-generation sequencing of pretreatment tumors could identify coaltered genes that predict for intrinsic resistance to BRAF inhibitor therapy in patients with melanoma as a prelude to rational combination strategies. Patients and Methods We analyzed 66 tumors from patients with metastatic BRAF-mutant melanoma collected before treatment with BRAF inhibitors. Tumors were analyzed for > 250 cancer-associated genes using a capture-based next-generation sequencing platform. Antitumor responses were correlated with clinical features and genomic profiles with the goal of identifying a molecular signature predictive of intrinsic resistance to RAF pathway inhibition. Results Among the 66 patients analyzed, 11 received a combination of BRAF and MEK inhibitors for the treatment of melanoma. Among the 55 patients treated with BRAF inhibitor monotherapy, objective responses, as assessed by Response Evaluation Criteria in Solid Tumors (RECIST), were observed in 30 patients (55%), with five (9%) achieving a complete response. We identified a significant association between alterations in PTEN that would be predicted to result in loss of function and reduced progression-free survival, overall survival, and response grade, a metric that combines tumor regression and duration of treatment response. Patients with melanoma who achieved an excellent response grade were more likely to have an elevated BRAF-mutant allele fraction. Conclusion These results provide a rationale for cotargeting BRAF and the PI3K/AKT pathway in patients with BRAF-mutant melanoma when tumors have concurrent loss-of-function mutations in PTEN. Future studies should explore whether gain of the mutant BRAF allele and/or loss of the wild-type allele is a predictive marker of BRAFi sensitivity.

BRAF Inhibitor Resistance Mechanisms in Metastatic Melanoma: Spectrum and Clinical Impact

2014 ◽  
Vol 20 (7) ◽  
pp. 1965-1977 ◽  
Author(s):  
Helen Rizos ◽  
Alexander M. Menzies ◽  
Gulietta M. Pupo ◽  
Matteo S. Carlino ◽  
Carina Fung ◽  
...  
Keyword(s):  
Metastatic Melanoma ◽  
Braf Inhibitor ◽  
Resistance Mechanisms ◽  
Clinical Impact ◽  
Inhibitor Resistance

scholarly journals Liquid Profiling of Circulating Tumor DNA in Plasma of Melanoma Patients for Companion Diagnostics and Monitoring of BRAF Inhibitor Therapy

2018 ◽  
Vol 64 (5) ◽  
pp. 830-842 ◽  
Author(s):  
Verena Haselmann ◽  
Christoffer Gebhardt ◽  
Ingrid Brechtel ◽  
Angelika Duda ◽  
Claudia Czerwinski ◽  
...  
Keyword(s):  
Clinical Course ◽  
Braf Inhibitor ◽  
Circulating Tumor Dna ◽  
Inhibitor Therapy ◽  
Response To Treatment ◽  
Companion Diagnostics ◽  
Mutational Status ◽  
Melanoma Patients ◽  
Braf Mutant ◽  
Tumor Dna

Abstract BACKGROUND The current standard for determining eligibility of patients with metastatic melanoma for BRAF-targeted therapy is tissue-based testing of BRAF mutations. As patients are rarely rebiopsied, detection in blood might be advantageous by enabling a comprehensive assessment of tumor mutational status in real time and thereby representing a noninvasive biomarker for monitoring BRAF therapy. METHODS In all, 634 stage I to IV melanoma patients were enrolled at 2 centers, and 1406 plasma samples were prospectively collected. Patients were assigned to 3 separate study cohorts: study 1 for assessment of circulating tumor DNA (ctDNA) as part of companion diagnostics, study 2 for assessment of ctDNA for patients with low tumor burden and for follow-up, and study 3 for monitoring of resistance to BRAF inhibitor (BRAFi) or mitogen-activated protein kinase inhibitor therapy. RESULTS Overall, a high degree of concordance between plasma and tissue testing results was observed at 90.9% (study 1) and 90.1% (study 2), respectively. Interestingly, discrepant results were in some cases associated with nonresponse to BRAFi (n = 3) or a secondary BRAF-mutant malignancy (n = 5). Importantly, ctDNA results correlated with the clinical course of disease in 95.7% and with response to treatment. Significantly, the detection of BRAF mutant ctDNA preceded relapse assessed by Response Evaluation Criteria in Solid Tumors, and was more specific than serum S100 and lactate dehydrogenase. CONCLUSIONS Blood-based testing compares favorably with standard-of-care tissue-based BRAF mutation testing. Importantly, blood-based BRAF testing correlates with the clinical course, even for early-stage patients, and may be used to predict response to treatment, recurrence, and resistance before radioimaging under BRAFi therapy, thereby enabling considerable improvements in patient treatment.

scholarly journals Combining Targeted Therapy With Immunotherapy in BRAF-Mutant Melanoma: Promise and Challenges

2014 ◽  
Vol 32 (21) ◽  
pp. 2248-2254 ◽  
Author(s):  
Siwen Hu-Lieskovan ◽  
Lidia Robert ◽  
Blanca Homet Moreno ◽  
Antoni Ribas
Keyword(s):  
Targeted Therapy ◽  
Braf Inhibitor ◽  
Mitogen Activated Protein Kinase ◽  
Braf Inhibitors ◽  
Oncogenic Signaling ◽  
Pathway Activation ◽  
Prolonged Duration ◽  
Trial Testing ◽  
Mitogen Activated Protein ◽  
Braf Mutant

Recent breakthroughs in the treatment of advanced melanoma are based on scientific advances in understanding oncogenic signaling and the immunobiology of this cancer. Targeted therapy can successfully block oncogenic signaling in BRAFV600-mutant melanoma with high initial clinical responses, but relapse rates are also high. Activation of an immune response by releasing inhibitory check points can induce durable responses in a subset of patients with melanoma. These advances have driven interest in combining both modes of therapy with the goal of achieving high response rates with prolonged duration. Combining BRAF inhibitors and immunotherapy can specifically target the BRAFV600 driver mutation in the tumor cells and potentially sensitize the immune system to target tumors. However, it is becoming evident that the effects of paradoxical mitogen-activated protein kinase pathway activation by BRAF inhibitors in non–BRAF-mutant cells needs to be taken into account, which may be implicated in the problems encountered in the first clinical trial testing a combination of the BRAF inhibitor vemurafenib with ipilimumab (anti-CTLA4), with significant liver toxicities. Here, we present the concept and potential mechanisms of combinatorial activity of targeted therapy and immunotherapy, review the literature for evidence to support the combination, and discuss the potential challenges and future directions for rational conduct of clinical trials.

scholarly journals Potential Reasons for Unresponsiveness to Anti-PD1 Immunotherapy in Young Patients with Advanced Melanoma

Life ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1318
Author(s):  
Devayani Machiraju ◽  
Sarah Schäfer ◽  
Jessica C. Hassel
Keyword(s):  
Overall Survival ◽  
Immune System ◽  
Treatment Approach ◽  
Young Patients ◽  
Treatment Strategies ◽  
Resistance Mechanisms ◽  
Advanced Melanoma ◽  
Age Dependent ◽  
Melanoma Patients ◽  
The Impact

The impact of age on the clinical benefit of anti-PD1 immunotherapy in advanced melanoma patients has been evolving recently. Due to a reduced immune function in elderly patients, young patients with a robust immune system are theoretically expected to benefit more from the treatment approach. However, in contrast to this hypothesis, recent studies in patients with metastatic melanoma have demonstrated that immunotherapy, especially with anti-PD1 treatment, is less effective in patients below 65 years, on average, with significantly lower responses and reduced overall survival compared to patients above 65 years of age. Besides, data on young patients are even more sparse. Hence, in this review, we will focus on age-dependent differences in the previously described resistance mechanisms to the treatment and discuss the development of potential combination treatment strategies for enhancing the anti-tumor efficacy of anti-PD1 or PDL1 treatment in young melanoma patients.

scholarly journals THER-10. IMPACT OF BRAF MUTATIONAL STATUS ON THE EFFICACY OF IMMUNOTHERAPY FOR MELANOMA BRAIN METASTASES

2019 ◽  
Vol 1 (Supplement_1) ◽  
pp. i12-i13
Author(s):  
Adam Lauko ◽  
Soumya Sagar ◽  
Addison Barnett ◽  
Wei Wei ◽  
Samuel Chao ◽  
...  
Keyword(s):  
Brain Metastases ◽  
Tertiary Care ◽  
Rank Test ◽  
P Value ◽  
Wild Type ◽  
Braf Mutations ◽  
Mutational Status ◽  
Melanoma Brain Metastases ◽  
Melanoma Patients ◽  
Braf Mutant

Abstract BACKGROUND: BRAF mutations occur in 50% of melanoma patients. Targeted agents – BRAF and MEK inhibitors and immunotherapy improve survival of melanoma patients with BRAF mutations. These agents have intracranial efficacy as shown in clinical trials. However, the efficacy of immunotherapies (immune checkpoint blockade) in melanoma brain metastases and the correlation with BRAF status is not as well characterized. METHODS: We reviewed 351 patients with melanoma brain metastases treated at our tertiary care center between 2000 and 2018, 75 of which received immunotherapy with known BRAF mutational status. Two-year, 5-year, and median overall survival (OS) was calculated from the start of immunotherapy to compare the efficacy of immunotherapy in BRAF mutant and BRAF wild type patients using the log-rank test. RESULTS: At the time of diagnosis of brain metastasis, the median age was 61 (23–87) years, median KPS was 80 (50–100), number of intracranial lesions was 2 (1–15), and 79% had extra-cranial metastases. Sixty-three patients were treated with stereotactic radiosurgery (SRS), 27 underwent whole brain radiation (WBRT) and 21 underwent surgery. When treated with immunotherapy, BRAF mutant and BRAF wild type median survival was 15.7 months (95% CI=9.4 – 42.4) and 6.9 (95% CI=4.1– 26.7) months (p-value=0.205), respectively. Two-year BRAF mutant and BRAF wild type survival was 35% (95% CI=21 – 58) and 28% (95% CI=16 – 51), and 5-year survival was 22% (95% CI=10 – 46) and 23% (95% CI=11 – 47), respectively. CONCLUSIONS: Twenty percent of patients with BRAF mutant and BRAF wild-type patients treated with immunotherapy derive a long-term benefit from immunotherapy and multimodality treatment and are alive 5 years from diagnosis of brain metastases. This was rarely seen in the pre-immunotherapy era in melanoma brain metastases. There was no difference in outcome based on the BRAF mutational status with use of immunotherapy in melanoma brain metastases.

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