A novel anti-CD146 antibody specifically targets cancer cells by internalizing the molecule

CD146 is an adhesion molecule present on many tumors (melanoma, kidney, pancreas, breast, ...). In addition, it has been shown to be expressed on vascular endothelial and smooth muscle cells. Generating an antibody able to specifically recognize CD146 in cancer cells (designated as tumor CD146), but not in normal cells, would thus be of major interest for targeting tumor CD146 without affecting the vascular system.

We thus generated antibodies against the extracellular domain of the molecule produced in cancer cells and selected an antibody that specifically recognizes tumor CD146. This antibody (TsCD146 mAb) was able to detect CD146-positive tumors in human biopsies and in vivo, by PET imaging, in a murine xenograft model. In addition, TsCD146 mAb antibody was able to specifically detect CD146-positive cancer microparticles in the plasma of patients. TsCD146 mAb displayed also therapeutic effects since it was able to reduce the growth of human CD146-positive cancer cells xenografted in nude mice. This effect was due to a decrease in the proliferation and an increase in the apoptosis of CD146-positive cancer cells after TsCD146-mediated internalization of the cell surface CD146.

Thus, TsCD146 mAb could be of major interest for diagnostic and therapeutic strategies against CD146-positive tumors in a context of personalized medicine.

Survival of melanoma patients treated with targeted therapy and immunotherapy after systematic upfront control of brain metastases by radiosurgery

BACKGROUND

Targeted therapy (TT) and immunotherapies (ITs) have dramatically improved survival in metastatic melanoma (MM). However, their efficacy on brain metastasis (BM) remains limited and poorly documented.

PATIENTS AND METHODS

Retrospective cohort of consecutive MM patients (pts) with BMs, all systematically upfront treated by Gamma-Knife (GK) at first BM and retreated in case of new BMs, from 2010 to 2015 at the time when ipilimumab BRAF ± MEK inhibitors and anti-PD1 were introduced in practice. Survival after 1st GK (OS_GK1) according to prognostic factors and treatment.

RESULTS

Among 179 consecutive pts treated by GK, 109 received IT and/or TT after the 1st GK. Median OS_GK1 was 10.95 months and 1- and 2-year survival rates were 49.5% and 27.4%, respectively, versus a median overall survival (OS) of 2.29 months (p < .001) in those who did not receive IT or TT. In pts who initially had a single BM, median OS and 1- and 2-year survival rates were 14.46 months, 66.7% and 43.4%, respectively; in pts with 2-3 BMs: 8.85 months, 46.4% and 31%, respectively; in pts with >3 BMs: 7.25 months, 37.2% and 11.9%, respectively. Multivariate analysis for OS_GK1 confirmed that IT and TT were significantly and highly protective. Best OS_GK1 was observed in BRAF-wild-type pts receiving anti-PD1 or in BRAF-mutated pts receiving BRAF-inhibitors and anti-PD1 (12.26 and 14.82 months, respectively).

CONCLUSION

In real-life MM pts with BMs, a strategy aiming at controlling BM with GK together with TT and/or TT seems to achieve unprecedented survival rates.

Risk factors of fast growing melanomas in a French prospective cohort

e21042

Background: Rate of growth (ROG) of the primary tumor is a known prognostic factor in melanoma (MM). Fast growing melanomas (FGMM) could account for an important part of the thick tumors which still exist despite earlier and earlier detection. Methods: All patients referred for a primary mm to two French Dermatology Department from the period 2012-2016 were prospectively enrolled in an observational case control study. ROG was calculated as the ratio of Breslow thickness to time to mm development according to patient, following a well-established process. FGMM were defined as those with a ROG > 0.5 mm/month and MMs with a ROG ≤05mm/month were used as controls. Differences in epidemiological, clinical and pathological features were evaluated with univariate and multivariate analysis. Results: 464 patients were enrolled. 149 mm (32.1%) were FGMM. Factors associated with FGMM in univariate analysis were age > 70 years (p = 0.006), tumor location (p = 0.032), histological subtype (p = 0.021), median thickness (p < 0.001), ulceration (p < 0.001), high mitotic rate ( > 1/mm2 )(p = 0.002), sentinel node involvement (p = 0.008), hair color at the age of 20 (p = 0.011), lower NSAIDS consumption (p = 0.012) and lower number of sunburns (p = 0.002). Age > 70 years (OR 1.88 95%CI 1.19-2.98, p = 0.007), ulceration (OR 3.70 95%CI 2.05-6.61) p < 0.001), sentinel node involvement (OR 1.93 95%CI 1.01-3.69 p = 0.046), regression (OR 0.37 95%CI 0.15-0.94) p = 0.037) and NSAIDS exposure (OR 0.29 95%CI 0.11-0.78, p = 0.014) remained associated with FGMM in multivariate analysis. OS and PFS were significantly lower in the FGMM group (HR 1.98 (95%CI 1.11-3.54, p = 0.02) and HR 1.79 (95%CI 1.17-2.73, p = 0.007), respectively). Conclusions: Fast growth characterizes a subset of primary mm which are intrinsically more aggressive and have different risk factors than other MM, namely more frequent in the elderly and with no association with skin type, nevus count or sun exposure. Association with ulceration could reflect a specific immune context. Negative association with NSAIDS exposure warrants more investigation, since it may have therapeutic implications.

Glycemic disorders in melanoma patients treated with anti-PD1

9525

Background: Anti-PD1 are now the backbone of immunotherapy (IT) of metastatic melanoma (MM). Although they are overall well- tolerated, a number of severe immune-related adverse events (IRAE) have been described, among which type 1 diabetes. We observed 3 cases of fulminant diabetes (FD) in our center, and also had the impression that diabetics patients became more difficult to manage when receiving anti-PD1. Methods: Retrospective analysis of blood glucose samples collected before, during and after anti-PD1 treatment (trt ) in all mm patients (pts) receiving anti-PD1 in our department over a 36-month period. Study of FD cases observed. Results: A total of 163 pts were treated with 1920 cures of anti-PD1 including 27 treated within clinical trials. Anti-PD1 was the 1st line of IT in 70% of cases. As a whole, 1470 glycaemia were available. There was no significant difference between the median pre and post-trt glycaemia (5.37 +/-1.6 vs 5.6 +/-1.3 mmol/L (p = 0.033)). In the 28 pts with a type I (n = 0) or II (n = 28) diabetes prior to trt, there was very slight drift toward an increase of glycaemia along with the successive trt infusions (+0.05mmol/L/Cure, p = 0.004 with linear regression tendency test) .Three pts (1.84%) developed a FD revealed by a severe episode of ketosis with acute polyuria polydipsia, hyperglycaemia until 50mmol/L and weight loss. Two additional cases of FD were observed in pts treated within clinical trial comparing anti-PD1 with anti-CTLA4 in adjuvant and metastatic situation (imputability of anti-PD1 likely but uncertain until unblinding). None of these pts had any glucose increase in weeks prior to FD diagnosis. Four out of 5 FD cases had an HLA group at risk for type 1 diabetes development (HLA DRB3/4), a rare group in general population (1%). Conclusions: We could not document any systematic tendency to glycemic disorder in mm pts treated by anti-PD1. In diabetic pts prior to trt, a slight drift toward increase of glycaemia may be explained by other interfering factors (diet, metastatic disease itself, corticosteroids, anxiety etc). FD is not exceptional (2% of patients in our series) and does not seem to be announced by any minor preliminary glycemic disorder. Despite apparently stochastic onset, FD may be associated with HLA DRB3/4 subgroup.

HVEM: A novel cosignaling molecule of major interest in melanoma

e14591

Background: Herpes Virus Entry Mediator (HVEM) is a member of the TNF superfamily, its ligation of the immunoglobulin family member B-lymphocyte and T-lymphocyte attenuator (BTLA) activates inhibitory signaling in T-cells and could play a role in evading host anti-tumor immunity. Ectopic overexpression of HVEM is associated with poor survival in some solid tumors. Our objectives were: -to evaluate HVEM expression in melanoma (MM) -to explore potential link of its overexpression with clinical outcomes -to understand the mechanisms by which HVEM was ectopically expressed in MM, and how HVEM-BTLA may play a role in MM. Methods: HVEM expression was analyzed by IHC in formalin-fixed samples of mm metastases and was correlated with OS in 130 patients. To better understand how HVEM could interfere with prognosis, relation of HVEM with its ligand BTLA was studied in the tumor and tumor microenvironment on 15 fresh metastases by flow cytometry after tumor dissociation. Bioinformatic studies based on TCGA and CCLE data combined to targeting of candidate genes by siRNA were used to investigate HVEM regulation on MM. Results: Patients with high HVEM expression on mm cells in their metastases have a significantly (p = 0.0142) poorer overall survival than those with a low expression. TCGA transcriptomic data support these results. From the mechanistic point of view, we could show that 1-HVEM expressed at the tumor cell surface interacts with BTLA expressed by tumor-infiltrated lymphocytes. 2-HVEM expression is neither linked to the mm mutational status nor inducible by IFN 3-Genes co-regulated with HVEM are associated with an aggressive gene signature 4- HVEM strongly correlate with MITF expression, MITF binds HVEM promoter, and its downregulation by siRNA results in a decrease in HVEM expression. Conclusions: A high expression of HVEM by mm metastases seems to be a pejorative prognostic marker. HVEM-BTLA interaction is a co-signaling system similar to the PD1-PDL1 one, but seem to be constitutive rather than inducible. HVEM and its co-regulated genes may constitute a signature of aggressiveness associated to MITF. High HVEM expression on mm cells may dampen anti-tumor immune responses, making HVEM and BTLA potential new targets for “checkpoint blockade” therapy.

Safety and results of anti-PD1 combined with radiosurgery for the treatment of melanoma brain metastases

9552

Background: Anti-PD1 are now pivotal in the treatment of metastatic melanoma (MM). Some concerns have emerged regarding the risk/benefit ratio of their combination with stereotactic radiosurgery. Methods: Retrospective assessment of the interaction between Gamma-Knife radiosurgery (GKRS) and anti-PD1 in terms of toxicity and OS in mm patients (pts) with BM. Patients were included if they were under anti-PD1 (PRE) at time of GKRS, or if they had started anti-PD1 concomitantly with GKRS (CO), or had received anti-PD1 within 3 months after GKRS (POST). Results: Among 47 pts who received GKRS and anti-PD1 during their disease course, 35 fulfilled PRE or CO or POST criteria (anti PD1 1st line therapy in 10 pts and 2d or more in 25 pts). One pt died before radiological evaluation. GKRS targeted a single BM in 10 pts and multiple BMs in 24 (max 19 BMs). Out of the 128 BMs treated, 6 cases of increase of preexisting edema (4.7%) and 8 hemorrhages (6.25%) occurred in 12 pts, but only 5 events (5%) were regarded as Adverse Radiation effects (ARE), being symptomatic in 3 pts (8% of pts). One BM had to be resected because of the occurrence of a symptomatic hemorrhage with hemiparesis 9 month after treatment. Median follow- up from GKRS was 13.7 mths. Median overall survival (OS) from GKRS and 1st BM were 14.8 and 26.5 mths respectively, with 6 and 12 mths 0S rates from GKRS of 65.7% and 57%, respectively. Local failure was observed in 5 pt. Median time to new BM was 12.6 mths. There was no significant difference in outcomes in pts, depending on PRE, CO and POST conditions. Conclusions: In this series, the largest to date of pts with BMs treated by GKRS and anti-PD1,ARE were within the expected range and survival rates appear promising. Given the natural propensity of MM-BMs for bleeding and edema our data do not support an increased risk with the combination of GKRS and anti-PD1. Regarding the timing between anti-PD1 administration and GKRS our data do not support a higher efficacy or higher toxicity among the 3 following potential mechanisms: immuno- sensitization to radiation (PRE), immuno-radio direct synergy (CO) or radiosensitization to immunotherapy (POST).

Long-term treatment of cutaneous manifestations of tuberous sclerosis complex with topical 1% sirolimus cream: A prospective study of 25 patients

BACKGROUND

Data on long-term topical sirolimus treatment of the cutaneous manifestations of tuberous sclerosis complex are rare.

OBJECTIVE

To evaluate the long-term benefit and tolerance of topical 1% sirolimus in tuberous sclerosis complex.

METHODS

In this 18-month prospective single-center study, 1% sirolimus cream was applied daily to facial angiofibromas (FAs), fibrous cephalic plaques (FCPs), shagreen patches, hypomelanotic macules, and ungual fibromas. After complete clearance (CC) of FAs, we evaluated a maintenance protocol of 3 applications weekly.

RESULTS

Twenty-five patients were enrolled. Fifty percent obtained CC of FAs within 9 months. Of 7 patients with CC (58%) who were following the maintenance protocol, 6 relapsed within 7 months and 1 was still responding at 1 year. Of 16 patients with FCPs, 7 (44%) remained stable at 12 months and 9 (56%) improved after 3 to 9 months of treatment. Only 1 of 5 patients treated for shagreen patches showed improvement at 12 months. Treatment was well tolerated with no serious adverse events.

LIMITATIONS

The small number of patients was a limitation.

CONCLUSIONS

Topical 1% sirolimus applied daily produced positive responses in treatment of FAs, FCPs, and facial hypomelanotic macules and was well tolerated. A 3-times-weekly maintenance protocol did not prevent FA relapses.

Study of metastatic kinetics in metastatic melanoma treated with B-RAF inhibitors: Introducing mathematical modelling of kinetics into the therapeutic decision

Background

Evolution of metastatic melanoma (MM) under B-RAF inhibitors (BRAFi) is unpredictable, but anticipation is crucial for therapeutic decision. Kinetics changes in metastatic growth are driven by molecular and immune events, and thus we hypothesized that they convey relevant information for decision making.

Patients and methods

We used a retrospective cohort of 37 MM patients treated by BRAFi only with at least 2 close CT-scans available before BRAFi, as a model to study kinetics of metastatic growth before, under and after BRAFi. All metastases (mets) were individually measured at each CT-scan. From these measurements, different measures of growth kinetics of each met and total tumor volume were computed at different time points. A historical cohort permitted to build a reference model for the expected spontaneous disease kinetics without BRAFi. All variables were included in Cox and multistate regression models for survival, to select best candidates for predicting overall survival.

Results

Before starting BRAFi, fast kinetics and moreover a wide range of kinetics (fast and slow growing mets in a same patient) were pejorative markers. At the first assessment after BRAFi introduction, high heterogeneity of kinetics predicted short survival, and added independent information over RECIST progression in multivariate analysis. Metastatic growth rates after BRAFi discontinuation was usually not faster than before BRAFi introduction, but they were often more heterogeneous than before.

Conclusions

Monitoring kinetics of different mets before and under BRAFi by repeated CT-scan provides information for predictive mathematical modelling. Disease kinetics deserves more interest

The scalp hair collar and tuft signs: A retrospective multicenter study of 78 patients with a systematic review of the literature

BACKGROUND

Hair collar sign (HCS) and hair tuft of the scalp (HTS) are cutaneous signs of an underlying neuroectodermal defect, but most available data are based on case reports.

OBJECTIVE

We sought to define the clinical spectrum of HCS and HTS, clarify the risk for underlying neurovascular anomalies, and provide imaging recommendations.

METHODS

A 10-year multicenter retrospective and prospective analysis of clinical, radiologic, and histopathologic features of HCS and HTS in pediatric patients was performed.

RESULTS

Of the 78 patients included in the study, 56 underwent cranial and brain imaging. Twenty-three of the 56 patients (41%) had abnormal findings, including the following: (1) cranial/bone defect (30.4%), with direct communication with the central nervous system in 28.6%; (2) venous malformations (25%); or (3) central nervous system abnormalities (12.5%). Meningeal heterotopia in 34.6% (9/26) was the most common neuroectodermal association. Sinus pericranii, paraganglioma, and combined nevus were also identified.

LIMITATIONS

The partial retrospective design and predominant recruitment from the dermatology department are limitations of this study.

CONCLUSIONS

Infants with HCS or HTS are at high risk for underlying neurovascular anomalies. Magnetic resonance imaging scans should be performed in order to refer the infant to the appropriate specialist for management.