BRAF/MEK Inhibition as a Bridge to Immunotherapy for Symptomatic BRAF V600 Melanoma Brain Metastases: A Case Series.

Targeted and immune therapies have changed the paradigm of treatment for patients with metastatic melanoma. Treatment of patients with symptomatic melanoma brain metastases, however, is complicated by the frequent use of immune suppression for the management of vasogenic edema and the urgency in addressing disease burden. Use of BRAF/MEK inhibitors in patients with a corresponding BRAF V600 mutation often results in rapid response but is hindered by high rates of disease relapse and progression. Immunotherapy has higher durability of response, but the rate of response is slower and responses can be significantly diminished for patients on concurrent steroid therapy. Considering this gap in evidence-based guidance for optimal adjuvant therapy sequence in immunosuppressed patients with BRAF V600-mutant melanoma brain metastases, we report on 4 cases utilizing BRAF/MEK inhibitors as a bridging therapy for brain metastases management before initiation of immune checkpoint inhibitor therapy. Future prospective studies will be required to determine the optimal treatment sequencing for patients in this population with high unmet medical need.

Phosphatidylinositol-(4,5)-Bisphosphate Regulates Plasma Cholesterol Through LDL (Low-Density Lipoprotein) Receptor Lysosomal Degradation.

OBJECTIVE: TMEM55B (transmembrane protein 55B) is a phosphatidylinositol-(4,5)-bisphosphate (PI[4,5]P2) phosphatase that regulates cellular cholesterol, modulates LDLR (low-density lipoprotein receptor) decay, and lysosome function. We tested the effects of Tmem55b knockdown on plasma lipids in mice and assessed the roles of LDLR lysosomal degradation and change in (PI[4,5]P2) in mediating these effects. Approach and Results: Western diet-fed C57BL/6J mice were treated with antisense oligonucleotides against Tmem55b or a nontargeting control for 3 to 4 weeks. Hepatic Tmem55b transcript and protein levels were reduced by ≈70%, and plasma non-HDL (high-density lipoprotein) cholesterol was increased ≈1.8-fold (P<0.0001). Immunoblot analysis of fast protein liquid chromatography (FPLC) fractions revealed enrichment of ApoE-containing particles in the LDL size range. In contrast, Tmem55b knockdown had no effect on plasma cholesterol in Ldlr-/- mice. In primary hepatocytes and liver tissues from Tmem55b knockdown mice, there was decreased LDLR protein. In the hepatocytes, there was increased lysosome staining and increased LDLR-lysosome colocalization. Impairment of lysosome function (incubation with NH4Cl or knockdown of the lysosomal proteins LAMP1 or RAB7) abolished the effect of TMEM55B knockdown on LDLR in HepG2 (human hepatoma) cells. Colocalization of the recycling endosome marker RAB11 (Ras-related protein 11) with LDLR in HepG2 cells was reduced by 50% upon TMEM55B knockdown. Finally, knockdown increased hepatic PI(4,5)P2 levels in vivo and in HepG2 cells, while TMEM55B overexpression in vitro decreased PI(4,5)P2. TMEM55B knockdown decreased, whereas overexpression increased, LDL uptake in HepG2 cells. Notably, the TMEM55B overexpression effect was reversed by incubation with PI(4,5)P2. Conclusions: These findings indicate a role for TMEM55B in regulating plasma cholesterol levels by affecting PI(4,5)P2-mediated LDLR lysosomal degradation.

Retinopathy of prematurity screening: prevalence and risk factors of ophthalmic complications in non-treated preterm infants.

INTRODUCTION: Retinopathy of prematurity (ROP) is a vision-threatening disease of premature infants. Practice guidelines recommend that all infants screened for ROP receive follow-up eye examinations to screen for ophthalmic complications.1 The purpose of this study was to identify risk factors for the development of strabismus, amblyopia, high refractive error, and cataracts among ROP-screened, non-treated infants. METHODS: Retrospective single-centre study of ROP-screened, non-treated premature infants with ophthalmic follow-up. Clinical variables were screened for association with ocular findings at follow-up. Multivariable logistic regression was used to determine the risk factors associated with ocular findings. RESULTS: 309 patients were seen for follow-up at 0.97 (0.69) [mean (SD)] years after neonatal intensive care unit (NICU) discharge. Strabismus was predicted by occipitofrontal circumference (OFC) z-score at NICU discharge (OR 0.61; 95% CI [0.42, 0.88]; p = 0.008), intraventricular haemorrhage (IVH) grade III or IV (OR 3.18; 95% CI [1.18, 8.54]; p = 0.02), and exclusive formula feeding at NICU discharge (OR 2.20; 95% CI [1.07, 4.53]; p = 0.03). Significant predictors of amblyopia were OFC z-score at discharge (OR 0.55; 95% CI [0.31, 0.96]; p = 0.03) and necrotising enterocolitis (NEC) (OR 6.94; 95% CI [1.38, 35.00]; p = 0.02). NEC was a significant risk factor for high refractive error (OR 7.27; 95% CI [1.39, 37.94]; p = 0.02). CONCLUSIONS: Among premature infants screened but not treated for ROP, severe IVH, NEC, low OFC z-score, and exclusive formula feeding at NICU discharge were risk factors for ocular morbidity. These findings affirm the value of ophthalmic follow-up for all ROP-screened infants, particularly those with the identified risk factors.