Tumor-Infiltrating Lymphocyte Therapy or Ipilimumab in Advanced Melanoma.

BACKGROUND: Immune checkpoint inhibitors and targeted therapies have dramatically improved outcomes in patients with advanced melanoma, but approximately half these patients will not have a durable benefit. Phase 1-2 trials of adoptive cell therapy with tumor-infiltrating lymphocytes (TILs) have shown promising responses, but data from phase 3 trials are lacking to determine the role of TILs in treating advanced melanoma. METHODS: In this phase 3, multicenter, open-label trial, we randomly assigned patients with unresectable stage IIIC or IV melanoma in a 1:1 ratio to receive TIL or anti-cytotoxic T-lymphocyte antigen 4 therapy (ipilimumab at 3 mg per kilogram of body weight). Infusion of at least 5×109 TILs was preceded by nonmyeloablative, lymphodepleting chemotherapy (cyclophosphamide plus fludarabine) and followed by high-dose interleukin-2. The primary end point was progression-free survival. RESULTS: A total of 168 patients (86% with disease refractory to anti-programmed death 1 treatment) were assigned to receive TILs (84 patients) or ipilimumab (84 patients). In the intention-to-treat population, median progression-free survival was 7.2 months (95% confidence interval [CI], 4.2 to 13.1) in the TIL group and 3.1 months (95% CI, 3.0 to 4.3) in the ipilimumab group (hazard ratio for progression or death, 0.50; 95% CI, 0.35 to 0.72; P<0.001); 49% (95% CI, 38 to 60) and 21% (95% CI, 13 to 32) of the patients, respectively, had an objective response. Median overall survival was 25.8 months (95% CI, 18.2 to not reached) in the TIL group and 18.9 months (95% CI, 13.8 to 32.6) in the ipilimumab group. Treatment-related adverse events of grade 3 or higher occurred in all patients who received TILs and in 57% of those who received ipilimumab; in the TIL group, these events were mainly chemotherapy-related myelosuppression. CONCLUSIONS: In patients with advanced melanoma, progression-free survival was significantly longer among those who received TIL therapy than among those who received ipilimumab. (Funded by the Dutch Cancer Society and others; ClinicalTrials.gov number, NCT02278887.).

A prediction model for response to immune checkpoint inhibition in advanced melanoma.

Predicting who will benefit from treatment with immune checkpoint inhibition (ICI) in patients with advanced melanoma is challenging. We developed a multivariable prediction model for response to ICI, using routinely available clinical data including primary melanoma characteristics. We used a population-based cohort of 3525 patients with advanced cutaneous melanoma treated with anti-PD-1-based therapy. Our prediction model for predicting response within 6 months after ICI initiation was internally validated with bootstrap resampling. Performance evaluation included calibration, discrimination and internal-external cross-validation. Included patients received anti-PD-1 monotherapy (n = 2366) or ipilimumab plus nivolumab (n = 1159) in any treatment line. The model included serum lactate dehydrogenase, World Health Organization performance score, type and line of ICI, disease stage and time to first distant recurrence-all at start of ICI-, and location and type of primary melanoma, the presence of satellites and/or in-transit metastases at primary diagnosis and sex. The over-optimism adjusted area under the receiver operating characteristic was 0.66 (95% CI: 0.64-0.66). The range of predicted response probabilities was 7%-81%. Based on these probabilities, patients were categorized into quartiles. Compared to the lowest response quartile, patients in the highest quartile had a significantly longer median progression-free survival (20.0 vs 2.8 months; P < .001) and median overall survival (62.0 vs 8.0 months; P < .001). Our prediction model, based on routinely available clinical variables and primary melanoma characteristics, predicts response to ICI in patients with advanced melanoma and discriminates well between treated patients with a very good and very poor prognosis.

Adjuvant treatment with anti-PD-1 in acral melanoma: A nationwide study.

Previous studies demonstrated limited efficacy of immune checkpoint inhibitors in unresectable acral melanoma (AM); it remains unclear how this translates to the adjuvant setting. This study investigates clinical outcomes of acral compared to cutaneous melanoma (CM) patients treated with adjuvant anti-PD-1 after complete resection. All stages III-IV AM and CM patients receiving adjuvant anti-PD-1 after complete resection between 2018 and 2022 were included from the prospective nationwide Dutch Melanoma Treatment Registry. We analyzed recurrence-free survival (RFS), distant metastasis-free survival (DMFS), and overall survival (OS). A multivariable Cox regression analysis of RFS was performed to adjust for potential confounders. We included 1958 (86 AM and 1872 CM) patients. At baseline, AM patients more frequently had KIT mutations, higher disease stages, and Eastern Cooperative Oncology Group Performance Status, and fewer BRAF and NRAS mutations. Median RFS was 14.8 months (95% confidence interval [CI]: 11.5-29.3) in AM and 37.4 months (95% CI: 34.6 to not reached) in CM (p = .002). After correcting for potential confounders, AM remained associated with a higher risk of recurrence (HRadj 1.53; 95% CI: 1.07-2.17; p = .019). Two-year DMFS tended to be worse for AM than for CM: 64.5% versus 79.7% (p = .050). Two-year OS was significantly lower in AM (71.5% vs. 84.3%; p = .027). The results of this study suggest a poorer outcome of adjuvant-treated AM compared to CM. Studies assessing the added value of adjuvant treatment in AM are needed. Future research should investigate alternative treatment strategies to improve outcomes of high-risk AM.

BRAF/MEK inhibitor rechallenge in advanced melanoma patients.

BACKGROUND: Effectivity of BRAF(/MEK) inhibitor rechallenge has been described in prior studies. However, structured data are largely lacking. METHODS: Data from all advanced melanoma patients treated with BRAFi(/MEKi) rechallenge were retrieved from the Dutch Melanoma Treatment Registry. The authors analyzed objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) for both first treatment and rechallenge. They performed a multivariable logistic regression and a multivariable Cox proportional hazards model to assess factors associated with response and survival. RESULTS: The authors included 468 patients in the largest cohort to date who underwent at least two treatment episodes of BRAFi(/MEKi). Following rechallenge, ORR was 43%, median PFS was 4.6 months (95% confidence interval [CI], 4.1-5.2), and median OS was 8.2 months (95% CI, 7.2-9.4). Median PFS after rechallenge for patients who discontinued first BRAFi(/MEKi) treatment due to progression was 3.1 months (95% CI, 2.7-4.0) versus 5.2 months (95% CI, 4.5-5.9) for patients who discontinued treatment for other reasons. Discontinuing first treatment due to progression and lactate dehydrogenase (LDH) levels greater than two times the upper limit of normal were associated with lower odds of response and worse PFS and OS. Symptomatic brain metastases were associated with worse survival, whereas a longer treatment interval between first treatment and rechallenge was associated with better survival. Responding to the first BRAFi(/MEKi) treatment was not associated with response or survival. CONCLUSIONS: This study confirms that patients benefit from rechallenge. Elevated LDH levels, symptomatic brain metastases, and discontinuing first BRAFi(/MEKi) treatment due to progression are associated with less benefit from rechallenge. A prolonged treatment interval is associated with more benefit from rechallenge.

Adjuvant treatment of in-transit melanoma: Narrowing the knowledge gap left by clinical trials.

Few clinical trials address efficacy of adjuvant systemic treatment in patients with in-transit melanoma (ITM). This study describes adjuvant systemic therapy of ITM patients beyond clinical trials. In this study, we included stage III adjuvant-treated melanoma patients registered in the nationwide Dutch Melanoma Treatment Registry between July 2018 and December 2020. Patients were divided into three groups: nodal disease only, ITM only and ITM and nodal disease. Recurrence patterns, recurrence-free survival (RFS) and overall survival (OS) at 12-months were analyzed. In our study population of 1037 patients, 66.8% had nodal disease only, 16.7% had ITM only and 16.2% had ITM with nodal disease. RFS at 12-months was comparable in the nodal only and ITM only group (72.2% vs70.1%, P = .97) but lower in ITM and nodal disease patients (57.8%; P = .01, P < .01). Locoregional metastases occurred as first recurrence in 38.9% nodal disease only, 71.9% of ITM-only and 44.0% of ITM and nodal disease patients. Distant recurrences occurred in 42.3%, 18.8% and 36.0%, respectively (P = .02). 12-months OS was not significantly different for nodal disease only patients compared with ITM-only (94.4% vs 97.6%, P = .06) but was significantly higher for ITM-only compared with ITM and nodal disease patients (97.6% vs 91.0%, P < .01). In conclusion, we showed that in the adjuvant setting, RFS rates in ITM-only patients are similar to non-ITM, though better than in ITM and nodal disease patients. Adjuvant-treated ITM-only patients less often experience distant recurrences and have a superior OS compared with ITM and nodal disease patients.

Time interval from primary melanoma to first distant recurrence in relation to patient outcomes in advanced melanoma.

Since the introduction of BRAF(/MEK) inhibition and immune checkpoint inhibition (ICI), the prognosis of advanced melanoma has greatly improved. Melanoma is known for its remarkably long time to first distant recurrence (TFDR), which can be decades in some patients and is partly attributed to immune-surveillance. We investigated the relationship between TFDR and patient outcomes after systemic treatment for advanced melanoma. We selected patients undergoing first-line systemic therapy for advanced melanoma from the nationwide Dutch Melanoma Treatment Registry. The association between TFDR and progression-free survival (PFS) and overall survival (OS) was assessed by Cox proportional hazard regression models. The TFDR was modeled categorically, linearly, and flexibly using restricted cubic splines. Patients received anti-PD-1-based treatment (n = 1844) or BRAF(/MEK) inhibition (n = 1618). For ICI-treated patients with a TFDR <2 years, median OS was 25.0 months, compared to 37.3 months for a TFDR >5 years (P = .014). Patients treated with BRAF(/MEK) inhibition with a longer TFDR also had a significantly longer median OS (8.6 months for TFDR <2 years compared to 11.1 months for >5 years, P = .004). The hazard of dying rapidly decreased with increasing TFDR until approximately 5 years (HR 0.87), after which the hazard of dying further decreased with increasing TFDR, but less strongly (HR 0.82 for a TFDR of 10 years and HR 0.79 for a TFDR of 15 years). Results were similar when stratifying for type of treatment. Advanced melanoma patients with longer TFDR have a prolonged PFS and OS, irrespective of being treated with first-line ICI or targeted therapy.

Is a History of Optimal Staging by Sentinel Lymph Node Biopsy in the Era Prior to Adjuvant Therapy Associated with Improved Outcome Once Melanoma Patients have Progressed to Advanced Disease?

INTRODUCTION: Sentinel lymph node biopsy (SLNB) is important for staging in patients with primary cutaneous melanoma. Did having previously undergone SLNB also affect outcomes in patients once they have progressed to metastatic melanoma in the era prior to adjuvant therapy? METHODS: Data were retrieved from the Dutch Melanoma Treatment Registry, a prospectively collected, nationwide database of patients with unresectable stage IIIC or IV (advanced) melanoma between 2012 and 2018. Melanoma-specific survival (MSS) was compared between patients with advanced cutaneous melanoma, previously treated with a wide local excision (WLE) or WLE combined with SLNB as initial treatment of their primary tumor. Cox regression analyses were used to analyze the influence of different variables on MSS. RESULTS: In total, 2581 patients were included, of whom 1412 were treated with a WLE of the primary tumor alone and 1169 in whom this was combined with SLNB. At a median follow-up of 44 months from diagnosis of advanced melanoma, MSS was significantly longer in patients who had previously undergone SLNB {median 23 months (95% confidence interval [CI] 19-29) vs. 18 months (95% CI 15-20) for patients treated with WLE alone; p = 0.002}. However, multivariate Cox regression did not identify SLNB as an independent favorable prognostic factor for MSS after diagnosis of advanced melanoma. CONCLUSION: Prior to the availability of adjuvant systemic therapy, once patients have unresectable stage IIIC or IV (advanced) melanoma, there was no difference in disease outcome for patients who were or were not previously staged with SLNB.

The unfavorable effects of COVID-19 on Dutch advanced melanoma care.

The COVID-19 pandemic had a severe impact on medical care. Our study aims to investigate the impact of COVID-19 on advanced melanoma care in the Netherlands. We selected patients diagnosed with irresectable stage IIIc and IV melanoma during the first and second COVID-19 wave and compared them with patients diagnosed within the same time frame in 2018 and 2019. Patients were divided into three geographical regions. We investigated baseline characteristics, time from diagnosis until start of systemic therapy and postponement of anti-PD-1 courses. During both waves, fewer patients were diagnosed compared to the control groups. During the first wave, time between diagnosis and start of treatment was significantly longer in the southern region compared to other regions (33 vs 9 and 15 days, P-value <.05). Anti-PD-1 courses were postponed in 20.0% vs 3.0% of patients in the first wave compared to the control period. Significantly more patients had courses postponed in the south during the first wave compared to other regions (34.8% vs 11.5% vs 22.3%, P-value <.001). Significantly more patients diagnosed during the second wave had brain metastases and worse performance status compared to the control period. In conclusion, advanced melanoma care in the Netherlands was severely affected by the COVID-19 pandemic. In the south, the start of systemic treatment for advanced melanoma was more often delayed, and treatment courses were more frequently postponed. During the second wave, patients were diagnosed with poorer patient and tumor characteristics. Longer follow-up is needed to establish the impact on patient outcomes.

Safety and Efficacy of Checkpoint Inhibition in Patients With Melanoma and Preexisting Autoimmune Disease : A Cohort Study.

BACKGROUND: Because immune checkpoint inhibition (ICI) can cause immune-related adverse events (irAEs) mimicking immunologic diseases, patients with preexisting autoimmune disease (AID) have been excluded from clinical trials. OBJECTIVE: To evaluate the safety and efficacy of ICI in patients with advanced melanoma with and without AID. DESIGN: Nationwide cohort study. SETTING: The Netherlands. PATIENTS: 4367 patients with advanced melanoma enrolled in the Dutch Melanoma Treatment Registry (DMTR) between July 2013 and July 2018 and followed through February 2019. MEASUREMENTS: Patient, clinical, and treatment characteristics; irAEs of grade 3 or higher; treatment response; and survival. RESULTS: A total of 415 patients (9.5%) had AID, categorized as rheumatologic AID (n = 227), endocrine AID (n = 143), inflammatory bowel disease (IBD) (n = 55), or "other" (n = 8). Of these, 228 patients (55%) were treated with ICI (vs. 2546 [58%] without AID); 87 were treated with anti-cytotoxic T lymphocyte-associated protein 4 (CTLA-4), 187 with anti-programmed cell death 1 (PD-1), and 34 with the combination. The incidences of irAEs of grade 3 or higher in patients with AID were 30% (95% CI, 21% to 41%) with anti-CTLA-4, 17% (CI, 12% to 23%) with anti-PD-1, and 44% (CI, 27% to 62%) with combination therapy; for patients without AID, the incidences were 30% (CI, 27% to 33%) (n = 916), 13% (CI, 12% to 15%) (n = 1540), and 48% (CI, 43% to 53%) (n = 388), respectively. Patients with AID more often discontinued anti-PD-1 treatment because of toxicity than patients without AID (17% [CI, 12% to 23%] vs. 9% [CI, 8% to 11%]). Patients with IBD were more prone to anti-PD-1-induced colitis (6/31 = 19% [CI, 7% to 37%]) than patients with other AIDs (3% [CI, 0% to 6%]) and patients without AID (2% [CI, 2% to 3%]).The objective response rate was similar in patients with versus without AID who were treated with anti-CTLA-4 (10% [CI, 5% to 19%] vs. 16% [CI, 14% to 19%]), anti-PD-1 (40% [CI, 33% to 47%] vs. 44% [CI, 41% to 46%]), or the combination (39% [CI, 20% to 59%] vs. 43% [CI, 38% to 49%]). Survival did not differ between patients with and those without AID (median, 13 months [CI, 10 to 16 months] vs. 14 months [CI, 13 to 15 months]). LIMITATION: Information was limited on AID severity and immunosuppressive treatment. CONCLUSION: Response to ICI with anti-CTLA-4, anti-PD-1, or their combination for advanced melanoma and overall incidence of any irAEs of grade 3 or higher were similar in patients with and without preexisting AID. However, severe colitis and toxicity requiring early discontinuation of treatment occurred more frequently among patients with preexisting IBD, warranting close follow-up. PRIMARY FUNDING SOURCE: The Netherlands Organization for Health Research and Development.

First-line BRAF/MEK inhibitors versus anti-PD-1 monotherapy in BRAFV600-mutant advanced melanoma patients: a propensity-matched survival analysis.

BACKGROUND: Anti-PD-1 antibodies and BRAF/MEK inhibitors are the two main groups of systemic therapy in the treatment of BRAFV600-mutant advanced melanoma. Until now, data are inconclusive on which therapy to use as first-line treatment. The aim of this study was to use propensity score matching to compare first-line anti-PD-1 monotherapy vs. BRAF/MEK inhibitors in advanced BRAFV600-mutant melanoma patients. METHODS: We selected patients diagnosed between 2014 and 2017 with advanced melanoma and a known BRAFV600-mutation treated with first-line BRAF/MEK inhibitors or anti-PD-1 antibodies, registered in the Dutch Melanoma Treatment Registry. Patients were matched based on their propensity scores using the nearest neighbour and the optimal matching method. RESULTS: Between 2014 and 2017, a total of 330 and 254 advanced melanoma patients received BRAF/MEK inhibitors and anti-PD-1 monotherapy as first-line systemic therapy. In the matched cohort, patients receiving anti-PD-1 antibodies as a first-line treatment had a higher median and 2-year overall survival compared to patients treated with first-line BRAF/MEK inhibitors, 42.3 months (95% CI: 37.3-NE) vs. 19.8 months (95% CI: 16.7-24.3) and 65.4% (95% CI: 58.1-73.6) vs. 41.7% (95% CI: 34.2-51.0). CONCLUSIONS: Our data suggest that in the matched BRAFV600-mutant advanced melanoma patients, anti-PD-1 monotherapy is the preferred first-line treatment in patients with relatively favourable patient and tumour characteristics.

Clinical outcome of patients with metastatic melanoma of unknown primary in the era of novel therapy.

Melanoma of unknown primary (MUP) is considered different from melanoma of known primary (MKP), and it is unclear whether these patients benefit equally from novel therapies. In the current study, characteristics and overall survival (OS) of patients with advanced and metastatic MUP and MKP were compared in the era of novel therapy. Patients were selected from the prospective nation-wide Dutch Melanoma Treatment Registry (DMTR). The following criteria were applied: diagnosis of stage IIIc unresectable or IV cutaneous MKP (cMKP) or MUP between July 2012 and July 2017 and treatment with immune checkpoint inhibition and/or targeted therapy. OS was estimated using the Kaplan-Meier method. The stratified multivariable Cox regression model was used for adjusted analysis. A total of 2706 patients were eligible including 2321 (85.8%) patients with cMKP and 385 (14.2%) with MUP. In comparative analysis, MUP patients more often presented with advanced and metastatic disease at primary diagnosis with poorer performance status, higher LDH, and central nervous system metastases. In crude analysis, median OS of cMKP or MUP patients was 12 months (interquartile range [IQR] 5 - 44) and 14 months (IQR 5 - not reached), respectively (P = 0.278). In adjusted analysis, OS in MUP patients was superior (hazard rate 0.70, 95% confidence interval 0.58-0.85; P < 0.001). As compared to patients with advanced and metastatic cMKP, MUP patients have superior survival in adjusted analysis, but usually present with poorer prognostic characteristics. In crude analysis, OS was comparable indicating that patients with MUP benefit at least equally from treatment with novel therapies.

Real-world outcomes of advanced melanoma patients not represented in phase III trials.

The aim was to provide evidence on systemically treated patients with advanced melanoma not represented in phase III trials to support clinical decision-making. Analysis were performed on advanced melanoma patients diagnosed between 2014 and 2017 in the Netherlands, treated with immune- or targeted therapy, who met ≥1 trial exclusion criteria. These criteria were derived from the KEYNOTE-006 and CHECKMATE-067/-066 phase III trials. Prognostic importance of factors associated with overall survival (OS) was assessed with the Kaplan-Meier method, Cox models, predicted OS probabilities of prognostic subgroups and a conditional inference survival tree (CIST). A nationwide population-based registry was used as data source. Of 2536 systemically treated patients with advanced melanoma, 1004 (40%) patients were ineligible for phase IIII trials. Ineligible patients had a poorer median OS (mOS) compared to eligible patients (8.8 vs 23 months). Eligibility criteria strongly associated with OS in systemically treated ineligible patients were Eastern Cooperative Oncology Group Performance Score (ECOG PS) ≥2, brain metastases (BM) and lactate dehydrogenase (LDH) of >500 U/L. Patients with ECOG PS of ≥2 with or without symptomatic BM had a predicted mOS of 6.5 and 11.3 months and a 3-year survival probability of 9.3% and 23.6%, respectively. The CIST showed the strongest prognostic covariate for survival was LDH, followed by ECOG PS. The prognosis of patients with LDH of >500 U/L is poor, but long-term survival is possible. The prognosis of ineligible patients with advanced melanoma in real-world was very heterogeneous and highly dependent on LDH value, ECOG PS and symptomatic BM.

Early Recurrence in Completely Resected IIIB and IIIC Melanoma Warrants Restaging Prior to Adjuvant Therapy.

PURPOSE: To evaluate the results of restaging completely resected stage IIIB/C melanoma prior to start of adjuvant therapy. PATIENTS AND METHODS: One hundred twenty patients with stage IIIB or IIIC (AJCC 2009) melanoma who underwent complete surgical resection were screened for inclusion in our trial investigating adjuvant dendritic cell therapy (NCT02993315). All patients underwent imaging to exclude local relapse or metastasis before entering the trial. The frequency of recurrent disease within 12 weeks after resection and the method of detection were investigated. RESULTS: Sixty-nine (58%) stage IIIB and 51 (43%) stage IIIC melanoma patients were screened. Median age was 54 (range 27-79) years. Twenty-two (18%) of 120 patients with completely resected stage IIIB/C melanoma had evidence of early recurrent disease, despite exclusion thereof by prior imaging. Median interval between resection and detection of relapse was 7.4 (range 4.3-10.7) weeks. Recurrence was asymptomatic in 17 (77%) patients, but metastasis was noticed by the patient or physician in 5 (23%). Eight patients with local relapse received local treatment with curative intent, and one was treated with systemic therapy. The remaining patients had distant metastasis, 1 of whom underwent resection of a solitary liver metastasis while 12 patients received systemic treatment. CONCLUSIONS: Patients with completely resected stage IIIB/C melanoma have high risk of early recurrence before start of adjuvant therapy. Restaging should be considered for high-risk melanoma patients before start of adjuvant therapy.

Endoscopy in patients with diarrhea during treatment with vascular endothelial growth factor receptor tyrosine kinase inhibitors: Is the cause in the mucosa?

BACKGROUND: Diarrhea is a frequently occurring adverse event during treatment with vascular endothelial growth factor receptor tyrosine kinase inhibitors (VEGFR TKIs) and is mostly accompanied by abdominal cramps, flatulence and pyrosis. These complaints impair quality of life and lead to dose reductions and treatment interruptions. It is hypothesized that the diarrhea might be due to ischemia in bowel mucosa or inflammation, but the exact underlying pathophysiological mechanism of the diarrhea is still unknown. We aimed at exploring the mechanism for diarrhea in these patients by thorough endoscopic and histological assessment. MATERIALS AND METHODS: Endoscopies of the upper and lower gastrointestinal (GI) tract in 10 patients with metastatic renal cell carcinoma (mRCC) who developed diarrhea during treatment with VEGFR TKIs were performed. RESULTS: Ten patients were included. The results showed endoscopically normal mucosa in the lower GI tract in seven patients without signs of ischemic colitis or inflammation. Gastroduodenoscopy revealed gastro-esophageal reflux disease, bulbitis and/or duodenitis with ulcers in eight patients. In three selected patients with bulbitis/duodenitis additional video capsule endoscopy was performed but revealed no additional intestinal abnormalities. CONCLUSION: We observed frequent mucosal abnormalities in the upper GI tract in VEGFR TKI-treated mRCC patients with diarrhea. Although these abnormalities provide insufficient explanation for the occurrence of diarrhea, we suggest to perform routine upper GI endoscopy in VEGFR TKI-treated patients with GI complaints.

Baseline and on Treatment Biodistribution Variability of 18 F-FLT Uptake in Patients With Advanced Melanoma: Brief Communication.

PURPOSE: This prospective study evaluates the biodistribution of 18 F-FLT PET in patients with advanced melanoma before and after treatment with BRAF/MEK inhibitors. PATIENTS AND METHODS: Eighteen BRAF-positive unresectable stage IIIc or IV melanoma patients referred for 18 F-FLT PET/CT before (BL) and during (D14) BRAF/MEK inhibition were included. 18 F-FLT accumulation in the liver, bone marrow, blood, and muscle was quantified. RESULTS: Baseline interpatient 18 F-FLT uptake had a coefficient-of-variation between 17.5% and 21.5%. During treatment, liver uptake increased (SUV meanBL = 4.86 ± 0.98, SUV meanD14 = 6.31 ± 1.36, P < 0.001) and bone marrow uptake decreased (SUV meanBL = 7.67 ± 1.65, SUV meanD14 = 6.78 ± 1.19, P < 0.025). Both changes were unrelated to baseline metabolic tumor volume or tumor response. CONCLUSIONS: To assess 18 F-FLT PET, both liver and bone marrow uptake may be used as normal tissue references at baseline, but 18 F-FLT biodistribution significantly changes in longitudinal response studies when treated with BRAF/MEK inhibitors.

The Predictive Value of FDG PET/CT for Determining Progression-Free Survival in Advanced Stage III-IV BRAF -Mutated Melanoma Patients Treated With Targeted Therapy-What Can Be Learned From Progression?

PURPOSE: The aims of this study were to investigate whether (early) PERCIST response monitoring with 18 F-FDG PET/CT is predictive for progression-free survival (PFS) in unresectable stage III or IV melanoma patients treated with BRAF/MEK inhibitor (MEKi) and to define dissemination patterns at progression with a lesion-based evaluation in direct comparison to baseline to improve our understanding of 18 F-FDG PET/CT during BRAF/MEKi. PATIENTS AND METHODS: This prospective multicenter single-arm study included 70 patients with unresectable stage III/IV BRAF -mutated melanoma who underwent contrast-enhanced CT and 18 F-FDG PET/CT at baseline and 2 and 7 weeks during treatment with vemurafenib plus cobimetinib and at progression if possible. Tumor response assessment was done with RECIST1.1 and PERCIST. Follow-up PET/CT scans were visually compared with baseline to assess dissemination patterns. RESULTS: Using RECIST1.1, PFS was not significantly different between the response groups ( P = 0.26). At 2 weeks, PERCIST median PFS was 15.7 months for patients with complete metabolic response (CMR) versus 8.3 months for non-CMR ( P = 0.035). The hazards ratio (HR) for progression/death in non-CMR versus CMR was 1.99 (95% confidence interval [CI], 1.03-3.84; P = 0.040) and 1.77 (95% CI, 0.91-3.43; P = 0.0935) when adjusting for lactate dehydrogenase (LDH). At 7 weeks, median PFS for PERCIST CMR was 16.7 months versus 8.5 months for non-CMR ( P = 0.0003). The HR for progression/death in the non-CMR group was significantly increased (HR, 2.94; 95% CI, 1.60-5.40; P = 0.0005), even when adjusting for LDH (HR, 2.65; 95% CI, 1.43-4.91; P = 0.0020). At week 7, 18 F-FDG PET/CT was false-positive in all 4 (6%) patients with new FDG-avid lesions but CMR of known metastases. When 18 F-FDG PET/CT was performed at progressive disease, 18/22 (82%) patients had progression of known metastases with or without new 18 F-FDG-avid lesions. CONCLUSIONS: This study shows that PERCIST response assessment at week 7 is predictive for PFS, regardless of LDH. At 2 weeks, patients with CMR have longer PFS than patients with non-CMR, but different PET parameters should be investigated to further evaluate the added value of early 18 F-FDG PET/CT. Disease progression on PET/CT is predominated by progression of known metastases, and new 18 F-FDG-avid lesions during BRAF/MEKi are not automatically a sign of recurrent disease.