High bone tumor burden to identify advanced non-small cell lung cancer patients with survival benefit upon bone targeted agents and immune checkpoint inhibitors.

BACKGROUND: Bone-targeted agents (BTA), such as denosumab (DN) and zoledronic acid (ZA), have historically reduced the risk of skeletal related events in cancer patients with bone metastases (BM), with no improvement in survival outcomes. In the immunotherapy era, BM have been associated with poor prognosis upon immune-checkpoint inhibitors (ICI). Currently, the impact of bone tumor burden on survival upon BTAs in advanced non-small cell lung cancer (aNSCLC) patients treated with ICI remains unknown. METHODS: Data from ICI-treated aNSCLC patients with BM (4/2013-5/2022) in one institution were retrospectively collected. BTA-ICI concurrent treatment was defined as BTA administration at any time before or within 90 days from ICI start. High bone tumor burden (HBTB) was defined as ≥ 3 sites of BM. Median OS (mOS) was estimated with Kaplan-Meier. Aikaike's information criterion (AIC) was used to select the best model for data analysis adjusted for clinical variables. RESULTS: Of 134 patients included, 51 (38 %) received BTA. At a mFU of 39.6 months (m), BTA-ICIs concurrent treatment did not significantly impact on mOS [8.3 m (95% CI 3.9-12.8) versus (vs) 6.8 m (95% CI 4.0-9.6) p = 0.36]; these results were confirmed after adjustment for clinical variables selected by AIC. A multivariate model showed a significant interaction between BTA use and HBTB or radiation therapy to BM. In subgroup analyses, only HBTB confirmed to be associated with significantly longer mOS [8.3 m (95% CI 2.4-14.2) vs 3.5 m (95% CI 2.9-4.1), p = 0.003] and mPFS [3.0 m (95% CI 1.6-4.4) vs 1.8 m (95% CI 1.6-2.0) p = 0.001] upon BTA-ICI concurrent treatment, with the most pronounced OS benefit observed for DN-ICI concurrent regimen [15.2 m (95% CI 0.1-30.7) vs 3.5 m (95% CI 2.9-4.1) p = 0.002]. CONCLUSIONS: In the immunotherapy era, HBTB can identify patients experiencing survival benefit with BTA, especially with DN-ICI combination. HBTB should be included as a stratification factor in the upcoming trials assessing BTA and ICI combinations in patients with aNSCLC and BM.

Sex dimorphism and cancer immunotherapy: May pregnancy solve the puzzle?

In the immunoncology era, growing evidence has shown a clear sex dimorphism in antitumor immune response with a potential impact on outcomes upon immunecheckpoint blockade (ICI) in patients with cancer. Sex dimorphism could affect tumor microenvironment composition and systemic anticancer immunity; however, the modifications induced by sex are heterogeneous. From a clinical perspective, six metanalyses have explored the role of sex in cancer patients receiving ICI with conflicting results. Environmental and reproductive factors may further jeopardize the sex-related heterogeneity in anticancer immune response. In particular, pregnancy is characterized by orchestrated changes in the immune system, some of which could be long lasting. A persistence of memory T-cells with a potential fetal-antigen specificity has been reported both in human and mice, suggesting that a previous pregnancy may positively impact cancer development or response to ICI, in case of fetal-antigen sharing from tumor cells. On the other hand, a previous pregnancy may also be associated with a regulatory memory characterized by increased tolerance and anergy towards cancer-fetal common antigens. Finally, fetal-maternal microchimerism could represent an additional source of chronic exposure to fetal antigens and may have important immunological implications on cancer development and ICI activity. So far, the role of pregnancy dimorphism (nulliparous vs parous) in women and the impact of pregnancy-related variables remain largely underexplored in cancer patients. In this review, we summarize the evidence regarding sex and pregnancy dimorphism in the context of immune response and anticancer immunotherapy and advocate the importance of analyzing pregnancy variables on ICIs clinical trials.

The Revolution of Immunotherapy in Gynecological Cancers: The Lazarus Effect in Endometrial Cancer.

Patients with solid tumors and mismatch repair deficiency (dMMR) or microsatellite instability-high (MSI-H) are eligible for immunotherapy. Recently, different reports described patients with poor performance status (PS), unrelated to comorbidities, which showed a rapid improvement of their clinical conditions under immunotherapy, which evoked a Lazarus response. Very few data on the efficacy and safety of immunotherapy in patients with gynecological malignancies and poor PS are available. Based on the GARNET trial, Dostarlimab, a monoclonal antibody anti-programmed death receptor-1 (PD-1), has been approved in advanced or recurrent mismatch repair deficient endometrial cancer (EC) which progressed after platinum-based therapy. For the first time, in gynecological oncology, an immune checkpoint inhibitor drastically changed the clinical practice. We collected a multicenter case series of six patients with advanced endometrial carcinoma and PS ECOG 3-4 treated with Dostarlimab, showing exceptionally quick responses and significant improvement of PS to configure a Lazarus response.

[Treatments for rare ovarian tumors: What's new?] / Avancées thérapeutiques dans la prise en charge des tumeurs rares malignes ovariennes.

Even if each rare ovarian tumor (ROT) has a low incidence, the sum of all these entities represents almost the half of all ovarian neoplasms. Thus, development of dedicated clinical trial emerged as a prerequisite to improve their managements. Owing to the spreading of dedicated institutional networks and (supra)national collaborations, the number of clinical trials has increased the past few years, with different types of trials; while some focused on specific molecular features, others assessed innovative molecules. Furthermore, relevant randomized clinical trials were designed as a mean to position new treatment options. Currently, innovative molecular-driven trials, based on master protocol trials are emerging and may shed light towards the improvement of personalized medicine regarding ROT.

BYL719 (alpelisib) for the treatment of PIK3CA-mutated, recurrent/advanced cervical cancer.

PURPOSE: Advanced/recurrent cervical cancer has limited therapeutic options, with a median progression-free survival after the failure of systemic treatments ranging between 3.5 and 4.5 months. Here, we reported our preliminary experience in the use of BYL719 (alpelisib) in advanced/recurrent cervical cancer after failure of at least 2 lines of treatment. The Istituto Nazionale dei Tumori di Milano approved this investigation. METHODS: From April 2020 to September 2020, 17 consecutive patients with recurrent cervical cancer had Next Generation Sequencing (NGS). Of these, six patients harboring the PIK3CA mutation were included in the study. All patients had been treated with at least 2 previous lines of systemic treatment: 3 patients received >2 prior lines of treatment in the recurrent or metastatic setting; 60% had received prior bevacizumab in combination with chemotherapy. All patients started alpelisib at the daily dosage of 300 mg. RESULTS: Investigator-assessed confirmed objective response rate (ORR) was 33%. The disease control rate (DCR) was 100%. According to RECIST 1.1, two patients had a partial response (PR), and four patients had stable disease (SD). No complete response was observed. The mean duration of response (DOR) was 11.5 (SD 3.75) months; five patients had PR lasting for >9 months. One patient stopped the treatment at 0.82 months due to the onset of a grade 2 adverse event (AE) (skin rash). Grade 3 treatment-related AEs included: lymphoedema (n = 1, 17%) and rash (n = 1, 17%). No treatment-related grade 4-5 AEs occurred. CONCLUSIONS: Our preliminary data highlighted a high level of efficacy in this setting of patients. Further trials are needed to assess the safety and effectiveness of alpelisib in PIK3CA-mutated recurrent/advanced cervical cancer.

Update on new treatments for rare ovarian tumours.

PURPOSE OF REVIEW: In spite of their rarity when considered individually, the sum of all rare ovarian tumours (ROT) represent almost half of all ovarian malignancies. As such, their appropriate inclusion within dedicated clinical trials is essential for enhanced management. RECENT FINDINGS: Supported by institutional expert national (e.g. TMRG) and international (e.g. ESGO) networks and owing to national (e.g. ARCAGY-GINECO) and international (e.g. ENGOT) collaborations dedicated to clinical research, the last few years have shown increased number of clinical trials dedicated to ROT. These either were based on specific molecular features of ROT (e.g. expression of oestrogen receptors for low-grade serous ovarian carcinomas and anastrazole evaluation in the PARAGON trial) or on the evaluation of innovative therapies (e.g. pembrolizumab within the ROT cohort from the AcSé Pembrolizumab multicentric basket trial). Furthermore, recent years have also shown the advent of randomized clinical trials. For instance, the ALIENOR trial positioned weekly paclitaxel as a new option for relapsed sex cord-stromal tumours, while the GOG281/LOGS trial raised trametinib as a new standard-of-care option for recurrent low-grade serous carcinomas. SUMMARY: The last few years have exhibited a paradigm shift towards the possibility to develop dedicated trials for ROT, owing to international collaborations supported by institutional networks. Current trials, molecular-driven and based on innovative designs, are highly promising, as they may bring ROT management towards more personalized medicine.

Endometrial carcinosarcoma.

Endometrial carcinosarcoma is a rare and aggressive high-grade endometrial carcinoma with secondary sarcomatous trans-differentiation (conversion theory). The clinical presentation and diagnostic work-up roughly align with those of the more common endometrioid counterpart, although endometrial carcinosarcoma is more frequently diagnosed at an advanced stage. Endometrial carcinosarcoma is not a single entity but encompasses different histological subtypes, depending on the type of carcinomatous and sarcomatous elements. The majority of endometrial carcinosarcomas are characterized by p53 abnormalities. The proportion of POLE and microsatellite instablity-high (MSI-H) is directly related to the epithelial component, being approximately 25% and 3% in endometrioid and non-endometrioid components.The management of non-metastatic disease is based on a multimodal approach with optimal surgery followed by (concomitant or sequential) chemotherapy and radiotherapy, even for early stages. Palliative chemotherapy is recommended in the metastatic or recurrent setting, with carboplatin/paclitaxel doublet being the first-line regimen. Although the introduction of immunotherapy plus/minus a tyrosine kinase inhibitor shifted the paradigm of treatment of patients with recurrent endometrial cancer, patients with endometrial carcinosarcoma were excluded from most studies evaluating single-agent immunotherapy or the combination. However, the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) approved the use of pembrolizumab and lenvatinib in endometrial cancer (all histotypes) after progression on chemotherapy and single-agent immunotherapy in MSI-H cancers. In the era of precision medicine, emerging knowledge on molecular endometrial carcinosarcoma is opening new promising therapeutic options for more personalized treatment. The present review outlines state-of-the-art knowledge and future directions for patients with endometrial carcinosarcoma.

A Ten-Year Real-Life Experience with Pazopanib in Uterine Leyomiosarcoma in Two High-Specialized Centers in Italy: Effectiveness and Safety.

BACKGROUND: Uterine leiomyosarcoma (uLMS) is characterized by aggressive behavior associated with a high risk of relapse and mortality. Several therapeutic agents have been employed in the treatment of metastatic disease, with a poor objective response rate. Pazopanib, approved in 2012, is a multi-targeted, orally active small molecule that exerts its effects by inhibiting several tyrosine kinases. To date, poor research on real-life data has been conducted. We aimed to assess the effectiveness and safety of the drug in everyday clinical practice. METHODS: We present results of multicenter retrospective data on 38 patients with heavily pretreated metastatic uLMS who underwent oral pazopanib during their therapeutic journey. RESULTS: At a median follow-up of 8.6 months, the disease control rate was 55.2%, with 17% partial responses and 15 patients (39.5%) with stable disease. At a median follow-up of 8.6 months, median progression-free survival was 4 months, and median overall survival was 19.8 months. The most common grade 3 adverse events (AEs) drug-related were hepatic toxicities, diarrhea, hypertension, nausea, and vomiting (all of them with an incidence of 5% considering the whole study cohort). No grade 4 AEs occurred. CONCLUSIONS: Pazopanib in everyday clinical practice is safe and shows a good disease control rate with prolonged survival.

Moving HER2-low breast cancer predictive and prognostic data from clinical trials into the real world.

Background: Previous data, mostly from clinical trials, reported that HER2-low status is associated with low pathological complete response (pCR), and favourable prognosis. Since these findings suggest the existence of an additional breast cancer subtype, we questioned if the predictive/prognostic value of HER2-low was also relevant in the real world. Methods: Data from non-metastatic breast cancer patients treated with neoadjuvant chemotherapy and surgery (2009-2020) were retrieved from our institutional prospectively-maintained registry. Univariable and multivariable logistic models were implemented to study the association between pCR and baseline HER2 status. Univariable analysis of disease-free survival (DFS) was performed through Kaplan-Meier survival curves and log-rank tests. Results: Starting from a total of 790 consecutive cases, we identified 444 newly-diagnosed breast cancer patients featuring HER2 immunohistochemistry (IHC) 0 (HER2-0, n = 109), and 1 + or IHC 2+/in situ hybridization negative (HER2-low, n = 335) receiving anthracycline and taxane-based regimens in 88.9% of cases. Most of the patients were diagnosed with stage II (67.3%) and there was no difference of disease presentation according to HER2-status. pCR was attained by 71 (16.0%) patients and was significantly associated with increased DFS (p = 0.031). Compared to HER2-0, HER2-low cases were more likely hormone receptor-positive (81.2% vs. 43.1%, p < 0.001), well-differentiated (47.5% vs. 26.6%, p = 0.001), less proliferative (21.5% vs. 8.3%, p = 0.001) and less responsive to treatment (pCR 11.6% vs. 29.4%, p < 0.0001). There was no difference in DFS according to HER2 status, though hormone-receptor (HR) negative/HER2-low cases tended to have a worse prognosis compared to HR-negative/HER2-0. By pCR achievement, 3-years DFS was 87.5.% (75.1-100%) vs. 71.6% (65.9-77.8%) (p = 0.161) in HER2-low and 89.1% (75.8-100%) vs. 72.1% (59.7-87.0%) (p = 0.092) in HER2-0. Conclusion: Our real-world data show that HER2-low breast cancer patients represent roughly a half of the cases treated with neoadjuvant therapy, and have poor treatment response. In absence of pCR, HER2-low breast cancer patients have a dismal prognosis, especially when primary tumor hormone receptor status is negative. Studies are therefore needed to define the biology of these tumors for new therapeutic targets and to incorporate HER2-targeting agents in early-stage treatment.

Real-World Data on Newly Diagnosed BRCA-Mutated High-Grade Epithelial Ovarian Cancers: The French National Multicenter ESME Database.

BACKGROUND: In spite of the frequency and clinical impact of BRCA1/2 alterations in high-grade epithelial ovarian cancer (HGEOC), real-world information based on robust data warehouse has been scarce to date. METHODS: Consecutive patients with BRCA-mutated HGEOC treated between 2011 and 2016 within French comprehensive cancer centers from the Unicancer network were extracted from the ESME database. The main objective of the study was the assessment of clinicopathological and treatments parameters. RESULTS: Out of the 8021 patients included in the ESME database, 266 patients matching the selection criteria were included. BRCA1 mutation was found in 191 (71.8%) patients, while 75 (28.2%) had a BRCA2 mutation only; 95.5% of patients received a cytoreductive surgery. All patients received a taxane/platinum-based chemotherapy (median = six cycles). Complete and partial response were obtained in 53.3% and 20.4% of the cases, respectively. Maintenance therapy was administered in 55.3% of the cases, bevacizumab being the most common agent. After a median follow up of 51.7 months, a median progression-free survival of 28.6 months (95% confidence interval (CI) [26.5; 32.7]) and an estimated 5-year median overall survival of 69.2% (95% CI [61.6; 70.3]) were reported. Notably, BRCA1- and BRCA2-mutated cases exhibited a trend towards different median progression-free survivals, with 28.0 (95% CI [24.4; 32.3]) and 33.3 months (95% CI [26.7; 46.1]), respectively (p-value = 0.053). Furthermore, five-year OS for BRCA1-mutated patients was 64.5% (95% CI [59.7; 69.2]), while it was 82.5% (95% CI [76.6; 88.5]) for BRCA2-mutated ones (p-value = 0.029). CONCLUSIONS: This study reports the largest French multicenter cohort of BRCA-mutated HGEOCs based on robust data from the ESME, exhibiting relevant real-world data regarding this specific population.

Platinum sensitivity in patients with IDH1/2 mutated vs wild-type intrahepatic cholangiocarcinoma: A propensity score-based study.

Isocitrate dehydrogenase (IDH)1/2 mutations are the most frequent druggable alterations in intrahepatic cholangiocarcinoma (iCCA), reported in ~20% of cases. Preclinical evidence indicates that these mutations are associated with homologous recombination deficiency (HRD), which could be exploited as a target for platinum chemotherapy (ChT) and PARP inhibitors. However, the role of IDH1/2 mutations as surrogate biomarkers for platinum efficacy is unknown. We conducted a multicenter, propensity score-matched analysis to investigate the impact of IDH1/2 mutations on progression-free survival (PFS), overall response rate (ORR) and disease control rate (DCR) in patients with iCCA treated with platinum-based ChT. An exploratory comparison of complex HRD estimates between IDH1/2 mutated and wild-type tumors from TCGA was also performed. A total of 120 cases were matched in a 1:1 ratio (60 IDH1/2 mutant and 60 wild-type). No differences were observed for platinum-based PFS (7.7 vs 7.3 months, P = .970), DCR (66.1% vs 74.1%, P = .361) and ORR (27.8% vs 25.0%, P = .741). IDH1/2 mutations showed mutual exclusivity with genomic alterations in ATM, BRCA2, MST1R, NF1, FGFR2 and CDKN2A/B losses, respectively, with no clear survival and response differences. Among TCGA tumors, IDH1/2 mutated CCA did not show higher HRD compared to wild-type cases. IDH1/2 mutations are not associated with increased sensitivity to platinum-based ChT in iCCA patients. Deeper genomic sequencing is needed to elucidate the HRD phenotype in IDH1/2 mutant iCCA and exploit its therapeutic vulnerabilities.

MGMT inactivation as a new biomarker in patients with advanced biliary tract cancers.

Biliary tract cancers (BTCs) have poor prognosis and limited therapeutic options. The impact of O6 -methylguanine-DNA methyltransferase (MGMT) inactivation in advanced BTC patients is not established. We investigated the prevalence, prognostic, and predictive impact of MGMT inactivation in two multicenter cohorts. MGMT inactivation was assessed through PCR and immunohistochemistry (IHC) in an Italian cohort; the results were then externally validated using RNA sequencing (RNA-seq) data from the BTC subcohort of the Molecularly Aided Stratification for Tumor Eradication Research (MASTER) precision oncology program of the National Center for Tumor Diseases Heidelberg and the German Cancer Consortium. Among 164 Italian cases, 18% presented MGMT promoter hypermethylation (> 14%) and 73% had negative MGMT protein expression. Both were associated with worse overall survival (OS; HR 2.31; P < 0.001 and HR 1.99, P = 0.012, respectively). In the MASTER cohort, patients with lower MGMT mRNA expression showed significantly poorer OS (median OS [mOS] 20.4 vs 31.7 months, unadjusted HR 1.89; P = 0.043). Our results suggest that MGMT inactivation is a frequent epigenetic alteration in BTC, with a significant prognostic impact, and provide the rationale to explore DNA-damaging agents in MGMT-inactivated BTCs.

Clear cell carcinoma of the endometrium.

Clear cell endometrial carcinoma represents an uncommon and poorly understood entity. Data from molecular/genomic profiling highlighted the importance of various signatures in assessing the prognosis of endometrial cancer according to four classes of risk (POLE mutated, MMRd, NSMP, and p53 abnormal). Unfortunately, data specific to clear cell histological subtype endometrial cancer are lacking. More recently, data has emerged to suggest that most of the patients (more than 80%) with clear cell endometrial carcinoma are characterized by p53 abnormality or NSMP type. This classification has important therapeutic implications. Although it is an uncommon entity, clear cell endometrial cancer patients with POLE mutation seem characterized by a good prognosis. Chemotherapy is effective in patients with NSMP (especially in stage III and IV) and patients with p53 abnormal disease (all stages). While, preliminary data suggested that patients with MMRd are less likely to benefit from chemotherapy. The latter group appears to benefit much more from immune checkpoint inhibitors: recent data from clinical trials on pembrolizumab plus lenvatinib and nivolumab plus cabozantinib supported that immunotherapy plus tyrosine kinase inhibitors (TKI) would be the most appropriate treatment for recurrent non-endometrioid endometrial cancer (including clear cell carcinoma) after the failure of platinum-based chemotherapy. Moreover, ongoing clinical trials testing the anti-tumor activity of innovative products will clarify the better strategies for advanced/recurrent clear cell endometrial carcinoma. Further prospective evidence is urgently needed to better characterize clear cell endometrial carcinoma.

Immune-Checkpoint Inhibitors in Advanced Non-Small Cell Lung Cancer With Uncommon Histology.

BACKGROUND: Immune-checkpoint inhibitors (ICIs) have significantly improved outcome of advanced non-small cell lung cancer (aNSCLC) patients. However, their efficacy remains uncertain in uncommon histologies (UH). MATERIALS AND METHODS: Data from ICI treated aNSCLC patients (April,2013-January,2021) in one Institution were retrospectively collected. Univariate and multivariate survival analyses were estimated by Kaplan-Meier and Cox proportional hazards regression model, respectively. Objective response rate (ORR) and disease control rate (DCR) were assessed. RESULTS: Of 375 patients, 79 (21.1%) had UH: 19 (24.1%) sarcomatoid carcinoma, 15 (19.0%) mucinous adenocarcinoma, 10 (12.6%) enteric adenocarcinoma, 8 (10.1%) adenocarcinoma not otherwise specified, 7 (8.9%) large-cell neuroendocrine carcinoma, 6 (7.6%) mixed histology non-adenosquamous, 5 (6.3%) adenosquamous carcinoma, 9 (11.4%) other UH. In UH group, programmed death-ligand 1 (PD-L1) <1%, 1-49%, ≥50% and unknown expression were reported in 27.8%, 22.8%, 31.7% and 17.7% patients respectively and ICI was the second/further-line in the majority of patients. After a median follow-up of 35.64 months (m), median progression-free survival (mPFS) was 2.5 m in UH [95% CI 2.2-2.9 m] versus (vs.) 2.7 m in CH [95% CI 2.3-3.2 m, P-value = .584]; median overall survival (mOS) was 8.8 m [95% CI 4.9-12.6 m] vs. 9.7 m [95% CI 8.0-11.3 m, P-value = .653]. At multivariate analyses only ECOG PS was a confirmed prognostic factor in UH. ORR and DCR were 25.3% and 40.5% in UH vs. 21.6% and 49.5% in CH [P-value = .493 and .155 respectively]. CONCLUSIONS: No significant differences were detected between UH and CH groups. Prospective trials are needed to understand ICIs role in UH population.

Blood Bacterial DNA Load and Profiling Differ in Colorectal Cancer Patients Compared to Tumor-Free Controls.

Inflammation and immunity are linked to intestinal adenoma (IA) and colorectal cancer (CRC) development. The gut microbiota is associated with CRC risk. Epithelial barrier dysfunction can occur, possibly leading to increased intestinal permeability in CRC patients. We conducted a case-control study including 100 incident histologically confirmed CRC cases, and 100 IA and 100 healthy subjects, matched to cases by center, sex and age. We performed 16S rRNA gene analysis of blood and applied conditional logistic regression. Further analyses were based on negative binomial distribution normalization and Random Forest algorithm. We found an overrepresentation of blood 16S rRNA gene copies in colon cancer as compared to tumor-free controls. For high levels of gene copies, community diversity was higher in colon cancer cases than controls. Bacterial taxa and operational taxonomic unit abundances were different between groups and were able to predict CRC with an accuracy of 0.70. Our data support the hypothesis of a higher passage of bacteria from gastrointestinal tract to bloodstream in colon cancer. This result can be applied on non-invasive diagnostic tests for colon cancer control.

Nanodispersions of TiO2 in Water for Removing Acrylic Films Used in Conservation.

The influence of a nanodispersion of TiO2 in water (nanoparticle size: 40 nm, polydispersity index: 0.25), brushed on a Paraloid film and subjected to UV-Vis irradiation was evaluated. The TiO2 nanodispersions showed a tendency to reduce the molecular weight of Paraloid due to its photocatalytic properties. FTIR and GPC analyses and SEM images suggested the degradation of the polymer, while chromatic variations of the films were scarcely detected. This study is very remarkable in the perspective of using this material for the removal of polymeric films used in conservation.

Liquid Biopsy and Radiological Response Predict Outcomes Following Discontinuation of Targeted Therapy in Patients with BRAF Mutated Melanoma.

BACKGROUND: Outcomes of patients with metastatic melanoma discontinuing BRAF-targeted therapy for cumulative toxicity after sustained response are unknown. MATERIALS AND METHODS: This retrospective case series analysis conducted at a single Cancer Center in Italy included patients with BRAF mutated metastatic melanoma treated with a BRAF inhibitor as a single agent or in combination with a MEK inhibitor between June 1, 2011 and January 1, 2020 and interrupted treatment due to cumulative toxicity after achieving complete response (CR) or long-lasting partial response (PR; i.e. >12 months). RESULTS: We included 24 patients with a median treatment duration of 59.4 months (95% confidence interval [CI], 55.4-63.4; range, 12-88). CR and PR were achieved in 71% and 29% of patients, respectively. At a median follow-up after treatment discontinuation of 37.8 months (95% CI, 33.7-41.9), the 12-month progression-free survival after discontinuation (dPFS) rate was 70.8% (95% CI 54.8-91.6) and 24-month dPFS rate was 58.3% (95% CI, 41.6-81.8). Baseline patient and tumor characteristics as well as treatment duration and best response did not significantly impact on dPFS. Patients with CR and negative circulating tumor DNA (ctDNA) at time of discontinuation had a significantly improved dPFS compared with patients with either radiological residual disease or ctDNA positivity (p = .007). No patient in CR with undetectable ctDNA experienced progression. CONCLUSION: The risk of progression is high even in patients with sustained sensitivity to BRAF/MEK inhibitors. Integration of liquid biopsy in clinical trials investigating the optimal management of patients with sustained sensitivity to BRAF/MEK inhibitors is warranted. IMPLICATIONS FOR PRACTICE: Outcomes of patients with metastatic melanoma discontinuing BRAF-targeted therapy for cumulative toxicity are unknown. This study analyzed patients with sustained responses (median treatment duration 59.4 months). Twelve- and 24-month progression-free survival following discontinuation were 70.8% and 58.3%, respectively. Complete response and negative circulating tumor DNA at time of discontinuation are promising prognostic biomarkers in this setting.