Vemurafenib Research Articles

Into the Groove: A Multitechnique Insight into the DNA–Vemurafenib Interaction

This study explores the interaction between Vemurafenib (VEM), a potent BRAF inhibitor, and calf thymus DNA (ctDNA) using a comprehensive array of biophysical and computational techniques. The primary objective is to understand the potential off-target effects of VEM on DNA, given its established role in melanoma therapy targeting the BRAF V600E mutation. The investigation employed methods such as ultraviolet–visible absorption spectroscopy, steady-state fluorescence, circular dichroism, isothermal titration calorimetry, and advanced molecular dynamics simulations. The results indicate that VEM interacts with DNA primarily through a minor groove-binding mechanism, causing minimal structural disruption to the DNA double helix. Viscosity measurements and melting temperature analyses further confirmed this non-intercalative mode of binding. Calorimetry data revealed an exothermic, thermodynamically favorable interaction between VEM and ctDNA, driven by both enthalpic and entropic factors. Finally, computer simulations identified the most probable binding site and mode of VEM within the minor groove of the nucleic acid, providing a molecular basis for the experimental findings.

Dual Chemotherapeutic Loading in Oxalate Transferrin-Conjugated Polymersomes Incorporated into Chitosan Hydrogels for Site-Specific Targeting of Melanoma Cells.

In this work, we developed a smart drug delivery system composed of poly (ethylene glycol)-block-poly (ε-caprolactone) (PEG-PCL)-based polymersomes (Ps) loaded with doxorubicin (DOX) and vemurafenib (VEM). To enhance targeted delivery to malignant melanoma cells, these drug-loaded nanovesicles were conjugated to the oxalate transferrin variant (oxalate Tf) and incorporated into three-dimensional chitosan hydrogels. This innovative approach represents the first application of oxalate Tf for the precision delivery of drug-loaded polymersomes within a semi-solid dosage form based on chitosan hydrogels. These resulting semi-solids exhibited a sustained release profile for both encapsulated drugs. To evaluate their potency, we compared the cytotoxicity of native Tf-Ps with oxalate Tf-Ps. Notably, the oxalate Tf-Ps demonstrated a 3-fold decrease in cell viability against melanoma cells compared to normal cells and were 1.6-fold more potent than native Tf-Ps, indicating the greater potency of this nanoformulation. These findings suggest that dual-drug delivery using an oxalate-Tf-targeting ligand significantly enhances the drug delivery efficiency of Tf-conjugated nanovesicles and offers a promising strategy to overcome the challenge of multidrug resistance in melanoma therapy.

623P Phase II trial of vemurafenib (VEM) and cobimetinib (COB) in BRAF V600-mutated solid tumours and first-line (1L) non-small cell lung cancer (NSCLC): Australian molecular screening and therapeutics (MoST) substudy 12

623P Phase II trial of vemurafenib (VEM) and cobimetinib (COB) in BRAF V600-mutated solid tumours and first-line (1L) non-small cell lung cancer (NSCLC): Australian molecular screening and therapeutics (MoST) substudy 12

Novel gene therapy for drug-resistant melanoma: Synergistic combination of PTEN plasmid and BRD4 PROTAC-loaded lipid nanocarriers

Patients suffering from BRAF mutant melanoma have tumor recurrence within merely 7 months of treatment with a potent BRAF inhibitor (BRAFi) like vemurafenib (VEM). It has been proven that diverse molecular pathways driving BRAFi resistance converge to activation of c-Myc in melanoma. Therefore, we identified a novel combinatorial therapeutic strategy by targeting loss of PTEN tumor suppressor gene and upregulated BRD4 oncoprotein as Myc-dependent vulnerabilities of drug-resistant melanoma. Being promising therapeutic targets, we decided to concomitantly deliver PTEN plasmid and BRD4 targeted PROteolysis-TArgeting Chimera (ARV) to drug the “undruggable” c-Myc in BRAFi-resistant melanoma. Since PTEN plasmid and ARV are distinct in their physicochemical properties, we fabricated PTEN-plasmid loaded LNPs (PL-NANO) and ARV-825 loaded nanoliposomes (AL-NANO) to yield mean particle size of <100 nm and >99% encapsulation efficiency for each therapeutic payload. Combination of PL-NANO and AL-NANO displayed synergistic tumor growth inhibition and substantial apoptosis in in vitro 2D and 3D models. Importantly, simultaneous delivery of PL-NANO and AL-NANO achieved significant upregulation of PTEN expression levels and degradation of BRD4 protein to ultimately downregulate c-Myc levels in BRAFi-resistant melanoma cells. Altogether, lipid nanocarriers delivering this novel lethal cocktail stands as “one-of-a-kind” gene therapy to target “undruggable” c-Myc oncogene in BRAFi-resistant melanoma.

A Quality by Design Approach for Developing SNEDDS Loaded with Vemurafenib for Enhanced Oral Bioavailability.

Vemurafenib (VMF) is a practically insoluble (< 0.1μg/mL) and least bioavailable (1%) drug. To enhance its oral bioavailability and solubility, we formulated a reliable self-nano emulsifying drug delivery system (SNEDDS). A Quality by Design (QbD) approach was used to optimize the ratio of Capryol 90, Tween 80, and Transcutol HP. VMF-loaded SNEDDS was characterized for its size, polydispersity index (PDI), zeta potential, drug content, and transmittance. The in vitro release profile of the drug loaded in SNEDDS was compared to the free drug in two media, pH 6.8 and 1.2, and the data obtained were analyzed with different mathematical models. A reverse-phase ultra-pressure liquid chromatography (UPLC) technique with high sensitivity and selectivity was developed and validated for the quantification of VMF in analytical and bioanalytical samples. Dissolution efficiency for SNEDDS was estimated using different models, which proved that the developed novel SNEDDS formulation had a better in vitro dissolution profile than the free drug. A 2.13-fold enhanced oral bioavailability of VMF-loaded SNEDDS compared to the free drug demonstrates the superiority of the developed formulation. This work thus presents an overview of VMF-loaded SNEDDS as a promising alternative to improve the oral bioavailability of the drug.

Oral lipid nanocomplex of BRD4 PROteolysis TArgeting Chimera and vemurafenib for drug-resistant malignant melanoma

BRAF inhibitors (BRAFi) like vemurafenib (VEM) provide initial regression in mutated melanoma but rapidly develop resistance. Molecular pathways responsible for development of resistance against VEM finally converge towards the activation of oncogenic c-Myc. We identified an epigenetic approach to inhibit the c-Myc expression and resensitize BRAFi-resistant melanoma cells. ARV-825 (ARV) was employed as a BRD4 targeted PROteolysis TArgeting Chimera that selectively degrades the BRD4 to downregulate c-Myc. ARV synergistically enhanced the cytotoxicity of VEM in vitro to overcome its resistance in melanoma. Development of ARV and VEM-loaded lipid nanocomplex (NANOVB) significantly improved their physicochemical properties for oral delivery. Most importantly, oral administration of NANOVB substantially inhibited tumor growth at rate of 41.07 mm3/day in nude athymic mice. NANOVB treatment resulted in prolonged survival with 50% of mice surviving until the experimental endpoint. Histopathological analysis revealed significant tumor necrosis and downregulation of Ki-67 and BRD4 protein in vivo. Promising in vivo antitumor activity and prolonged survival demonstrated by NANOVB signifies its clinical translational potential for BRAFi-resistant melanoma.

Reversing vemurafenib-resistance in primary melanoma cells by combined romidepsin and type I IFN treatment through blocking of tumorigenic signals and induction of immunogenic effects.

BRAFV600 mutations are the most common oncogenic alterations in melanoma cells, supporting proliferation, invasion, metastasis and immune evasion. In patients, these aberrantly activated cellular pathways are inhibited by BRAFi whose potent antitumor effect and therapeutic potential are dampened by the development of resistance. Here, by using primary melanoma cell lines, generated from lymph node lesions of metastatic patients, we show that the combination of two FDA-approved drugs, the histone deacetylate inhibitor (HDCAi) romidepsin and the immunomodulatory agent IFN-α2b, reduces melanoma proliferation, long-term survival and invasiveness and overcomes acquired resistance to the BRAFi vemurafenib (VEM). Targeted resequencing revealed that each VEM-resistant melanoma cell line and the parental counterpart are characterized by a distinctive and similar genetic fingerprint, shaping the differential and specific antitumor modulation of MAPK/AKT pathways by combined drug treatment. By using RNA-sequencing and functional in vitro assays, we further report that romidepsin-IFN-α2b treatment restores epigenetically silenced immune signals, modulates MITF and AXL expression and induces both apoptosis and necroptosis in sensitive and VEM-resistant primary melanoma cells. Moreover, the immunogenic potential of drug-treated VEM-resistant melanoma cells results significantly enhanced, given the increased phagocytosis rate of these cells by dendritic cells, which in turn exhibit also a selective down-modulation of the immune checkpoint TIM-3. Overall, our results provide evidence that combined epigenetic-immune drugs can overcome VEM resistance of primary melanoma cells by oncogenic and immune pathways reprogramming, and pave the way for rapidly exploiting this combination to improve BRAFi-resistant metastatic melanoma treatment, also via reinforcement of immune checkpoint inhibitor therapy.

Direct structure determination of vemurafenib polymorphism from compact spherulites using 3D electron diffraction

The spherulitic morphology is considered to be the most common morphology of crystalline materials and is particularly apparent in melt-crystallized products. Yet, historically, the polycrystalline nature of spherulites has hindered successful crystal structure determination. Here, we report the direct structure determination of a clinical drug, vemurafenib (VMN), in compact spherulite form using 3D electron diffraction (3D ED). VMN has four known polymorphs. We first solved the crystal structures of α-, β-, and γ-VMN from compact spherulites using 3D ED, and the resulting structures were highly consistent with those obtained by single-crystal X-ray diffraction. We then determined the crystal structure of δ-VMN—the least stable polymorph which cannot be cultivated as a single crystal—directly from the compact spherulite sample. We unexpectedly discovered a new polymorph during our studies, denoted as ε-VMN. Single crystals of ε-VMN are extremely thin and not suitable for study by X-ray diffraction. Again, we determined the structure of ε-VMN in a compact spherulite form. This successful structure elucidation of all five VMN polymorphs demonstrates the possibility of directly determining structures from melt-grown compact spherulite samples. Thereby, this discovery will improve the efficiency and broaden the scope of polymorphism research, especially within the field of melt crystallization.

Photosensitization of human skin fibroblasts by vemurafenib promotes pleiotropic effects on membrane-enclosed organelles and apoptosis.

Vemurafenib (VB), a BRAF inhibitor and a first-line treatment for unresectable or metastatic melanoma, is strongly phototoxic towards normal skin cells. Herein, we show that in cultured HS 68 human diploid dermal fibroblasts, low concentrations of VB suffice to promote photosensitization to low doses of UVA (∼ 5J/cm2), as evidenced by a significant decrease in cell viability. In contrast to data obtained in chemico our results support a role for ROS (reactive oxygen species). Indeed, peroxidation of cellular lipids was observed which could be alleviated by the lipophilic antioxidant BHT (2,6-di-tert-butyl-4-methylphenol). Using in vivo confocal laser scanning microscopy and vital fluorescent probes it was shown at the single cell level that the plasma membrane and lipid-rich organelles, namely mitochondria, endoplasmic reticulum, and lysosomes, as well as actin filaments, were severely damaged by the UVA-induced VB-photosensitization. Finally, we showed that mitochondrial impairment was concurrent with caspase 3/7 activation and cell death by apoptosis.

Self-assembling micelles of lipopolysaccharides (LPS) for loading hydrophobic (bio)molecules

Lipopolysaccharide (LPS) endotoxins are the most common pyrogenic biomolecules naturally present in Gram-negative bacteria membranes. Although LPS pathophysiological features are widely reported, a number of nanobiotechnological aspects perceive importance. Therefore, herein this study reports the physicochemical properties of LPS-based micelles from Escherichia coli O113, specifically focusing on their self-assembling distribution and aptitude to interact with four different (bio)molecules [i.e., chloroquine (CQ), curcumin (CCM), vemurafenib (VEM), and doxorubicin (DOX)]. The critical micelle concentration of LPS (CMCLPS) in an aqueous environment was determined to be 0.020 mg/mL, using a pyrene fluorescence emission spectra technique. The interaction of LPS and hydrophobic (bio)molecules was evaluated as a function of encapsulation parameters at the highest LPS concentration (CLPS of 0.043 mg/mL, i.e. >CMCLPS) for namely drug loading (DL) and encapsulation efficiency (EE). The DL results for CQ, CCM, VEM, and DOX were 28, 26, 22, and 20%, with 83, 80, 76, and 74% for their EE parameter, respectively. A straightforward relationship was observed for CLPS that increased jointly with micelle size (DH at 0.043 mg/mL > DH at 0.020 mg/mL). The presence of the (bio)molecules also affected LPS micelle size where DH was 51 nm (control micelles), which increased to 58, 58, 55, and 55 nm for CQ, CCM, VEM, and DOX, respectively, at a CLPS of 0.043 mg/mL. This trend demonstrates that increasing LPS micelle size (>CMCLPS) enhances the encapsulation capacity of the hydrophobic (bio)molecules. The understanding and characterization of the LPS-based micelles and their interaction with (bio)molecules could lead to novel applications in nanobiotechnology, such as the potential use of LPS, e.g., as drug/vaccine nanocarriers in the near future.

484 Melatonin induces melanoma cell death and synergizes with BRAF/MEK inhibitors by altering cell bioenergetics

Melanoma is a leading cause of cancer deaths worldwide. Although targeted therapy and immunotherapy have improved the outcome of patients with metastatic disease, unwanted side effects are a problem. Herein, by using human melanoma cell lines in vitro, we explore that melatonin enhances anti-tumor activity of commonly used BRAF/MEK inhibitors, i.e. vemurafenib (VF) and cobimetinib (CB), respectively. Our results have demonstrated that compared with VF/CB alone, melatonin significantly reduced proliferation read-outs (colony assay, drop assay) and induced of apoptosis (cleaved Casp-3, PARP) in melanoma cells.

Some things old, new and borrowed: Delivery of dabrafenib and vemurafenib to melanoma cells via self-assembled nanomicelles based on an amphiphilic dendrimer

Two clinically approved anticancer drugs targeting BRAF in melanoma patients – dabrafenib (DAB) and vemurafenib (VEM) – have been successfully encapsulated into nanomicelles formed upon self-assembly of an amphiphilic dendrimer AD based on two C18 aliphatic chains and a G2 PAMAM head. The process resulted in the formation of well-defined (∼10 nm) core-shell nanomicelles (NMs) with excellent encapsulation efficiency (∼70% for DAB and ∼60% for VEM) and good drug loading capacity (∼27% and ∼24% for DAB and VEM, respectively). Dynamic light scattering (DLS), transmission electron microscopy (TEM), small-angle x-ray scattering (SAXS), nuclear magnetic resonance (NMR), isothermal titration calorimetry (ITC), and molecular simulation (MS) experiments were used, respectively, to determine the size and structure of the empty and drug-loaded nanomicelles (DLNMs), along with the interactions between the NMs and their cargoes. The in vitro release data revealed profiles governed by Fickian diffusion; moreover, for both anticancer molecules, an acidic environment (pH = 5.0) facilitated drug release with respect to physiological pH conditions (pH = 7.4). Finally, both DAB- and VEM-loaded NMs elicited enhanced response with respect to free drug treatments in 4 different melanoma cell lines.

Modified solid in oil nanodispersion containing vemurafenib-lipid complex- in vitro/ in vivo study.

Background: Vemurafenib (VEM) was a licensed drug for the treatment of skin melanoma and is available only in the market as oral tablets prescribed in huge doses (1920 mg/day). One reason for the high dose is vemurafenib's low oral bioavailability. Methods: VEM-lipid complex (DLC) was predicted based on Conquest and Mercury programs and prepared using the solvent evaporation method using the lipid (phosphatidylethanolamine). DLC was subjected to characterization (FT-IR, Raman spectroscopy, DSC, TGA, P-XRD, and FESEM) to confirm complexation. DLC was used to prepare solid in oil nanodispersion (DLC-SON) and subjected to in vitro, ex vivo, and in vivo evaluation in comparison to our recently prepared conventional SON (VEM-SON) and DLC-control. Results: Conquest and Mercury predict the availability of intermolecular hydrogen bonding between VEM and phosphatidylethanolamine (PE). All characterization tests of DLC ensure the complexation of the drug with PE. Ex vivo studies showed that the drug in DLC-SON has significantly (P<0.05) higher skin permeation than DLC-control but lower drug permeation than conventional SON but it has a higher % skin deposition (P<0.05) than others. The half-maximal inhibitory concentration (IC50) of the prepared DLC-SON is significantly high (P<0.05) in comparison to the conventional SON and pure VEM. In vivo permeation using confocal laser scanning microscopy (on the rat) results indicated that both conventional SON and DLC-SON can cross the SC and infiltrate the dermis and epidermis but DLC-SON has a higher luminance/gray value after 24 h in the dermis in comparison to the conventional SON. Conclusion: The novel lipid complex for VEM prepared using PE as a lipid and enclosed in SON showed higher anticancer activity and topical permeation as well as sustained delivery and good retention time in the dermis that localize the drug in a sufficient concentration to eliminate early diagnosed skin melanoma.

Nuclear AREG affects a low-proliferative phenotype and contributes to drug resistance of melanoma.

AMPHIREGULIN (AREG) is a multifaceted molecule, which acts not only as an extracellular ligand for EGF receptor (EGFR), but also as an intracellular signaling molecule. It remains elusive, however, whether AREG has a tumor suppressive or oncogenic role in melanoma. Here, we found that several melanoma cell lines express AREG, but the expression does not correlate with that of EGFR. Recombinant AREG and the neutralizing antibody experiments showed that intracellular AREG plays an important role in melanoma, implying a divergent function of AREG in addition to the role as a ligand for EGFR. Further investigation of this mechanism revealed that particularly nuclear-localized AREG regulates IGF-1R, P21 (Cip1/Waf1), TP53 and JARID1B protein accumulation in the nucleus. Furthermore, manipulation of nuclear AREG levels has influence on heterochromatin condensation (HP1beta, SETDB1) and trimethylation of histones H3K9 and H3K4. As these molecules correspond to previously identified markers for slow-cycling drug resistant cells, we speculate that nuclear AREG predisposes cells to resistance to therapy. According to the hypothesis, we detected the accumulation of AREG in the nucleus of SK-Mel-28-VR, which was cultured under Vemurafenib (VR) selection pressure, and this correlates with JARID1B expression. Here, knockdown of AREG makes the previously resistant cells more sensitive to VR treatment, resulting in inhibited proliferation. Taken together, we suggest that nuclear AREG affects a slow-cycling phenotype and increases resistance to VR, raising a possibility that AREG might be a potential therapeutic target for resistance in melanoma.

Modified solid in oil nanodispersion containing vemurafenib-lipid complex- in vitro/ in vivo study.

Background: Vemurafenib (VEM) was a licensed drug for the treatment of skin melanoma and is available only in the market as oral tablets prescribed in huge doses (1920 mg/day). One reason for the high dose is vemurafenib's low oral bioavailability. Methods: VEM-lipid complex (DLC) was predicted based on Conquest and Mercury programs and prepared using the solvent evaporation method using the lipid (phosphatidylethanolamine). DLC was subjected to characterization (FT-IR, Raman spectroscopy, DSC, TGA, P-XRD, and FESEM) to confirm complexation. DLC was used to prepare solid in oil nanodispersion (DLC-SON) and subjected to in vitro, ex vivo, and in vivo evaluation in comparison to our recently prepared conventional SON (VEM-SON) and DLC-control. Results: Conquest and Mercury predict the availability of intermolecular hydrogen bonding between VEM and phosphatidylethanolamine (PE). All characterization tests of DLC ensure the complexation of the drug with PE. Ex vivo studies showed that the drug in DLC-SON has significantly (P<0.05) higher skin permeation than DLC-control but lower drug permeation than conventional SON but it has a higher % skin deposition (P<0.05) than others. The half-maximal inhibitory concentration (IC50) of the prepared DLC-SON is significantly high (P<0.05) in comparison to the conventional SON and pure VEM. In vivo permeation using confocal laser scanning microscopy (on the rat) results indicated that both conventional SON and DLC-SON can cross the SC and infiltrate the dermis and epidermis but DLC-SON has a higher luminance/gray value after 24 h in the dermis in comparison to the conventional SON. Conclusion: The novel lipid complex for VEM prepared using PE as a lipid and enclosed in SON showed higher anticancer activity and topical permeation as well as sustained delivery and good retention time in the dermis that localize the drug in a sufficient concentration to eliminate early diagnosed skin melanoma.

Simultaneously improving the physicochemical and pharmacokinetic properties of vemurafenib through cocrystallization strategy

Vemurafenib (VEM) is a first-line drug for the treatment of metastatic melanoma with BRAFV600 mutation, which was developed in the form of amorphous solid dispersion to overcome the defects of poor aqueous solubility and oral absorption. However, the oral dose of VEM is still very high; besides, the poor stability of amorphous form may increase the risks in drug effectiveness and safety. Herein, we attempted to provide a solution to these issues based on cocrystallization strategy. Three cocrystalline forms involving VEM and D/L/dl-camphorsulfonic acid with stoichiometric ratio of 1:1 were synthesized and characterized by powder X-ray diffraction analysis, 1H nuclear magnetic resonance, thermal analyses and Fourier transform infrared spectroscopy. The in vitro evaluations show that all of the cocrystalline forms demonstrate improved hygroscopicity and stability compared to amorphous VEM; especially, the cocrystalline form with dl-camphorsulfonic acid exhibits much better tabletability and apparent solubility than all of other forms. Pharmacokinetic tests reveal that all the cocrystallized products show significantly enhanced Cmax and AUC0-t values compared to the amorphous form. Therefore, the newly discovered cocrystalline forms of VEM are expected to overcome the issues of poor solubility and oral absorption and provide great potential for the development of improved preparations of the drug.

Development of PEG-PCL-based polymersomes through design of experiments for co-encapsulation of vemurafenib and doxorubicin as chemotherapeutic drugs

Nanostructures for co-encapsulation of chemotherapeutic drugs have been widely studied for the last years due to its important advantages, e.g. improved bioavailability and cellular uptake, increased solubility of drugs, and lower chances of multidrug resistance (MDR). In this context, this work describes essential parameters of production and characterization of poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-PCL)-based polymersomes (Ps) for the co-encapsulation of two chemotherapeutic drugs, doxorubicin (DOX) and vemurafenib (VEM). Three PEG-PCL copolymers were studied, namely PEG45PCL44, PEG114PCL98, and PEG114PCL114. We evaluated the effect of conditions such as stirring speed, stirring time, hydration volume, and ultrasound time in particle size (DH) and polydispersity index (PDI) by two statistical designs (23) to achieve improved (smaller) DH and PDI of PEG-PCL-based Ps. According to our results, the best condition to generate PEG-PCL-based Ps was to employ 1050 rpm of stirring speed by 42 h, a hydration volume of 15 mL (0.05% m/v), and ultrasound by 35 min, resulting in a DH and PDI range of 210 to 245 nm and 0.117 to 0.148, respectively. Moreover, co-encapsulation of DOX and VEM resulted in drug loading ranges of 12 to 18% and 16 to 26% and encapsulation efficiency of 35 to 39% and 43 to 55%, for DOX and VEM, respectively, together with an increase in the DH (i.e., 254 to 282 nm). The Ps nanoformulations were stable at 4, 25, and 37 °C and the release of drugs was faster with the smaller PEG-PCL blocks (i.e., PEG45PCL44 > PEG114PCL98 > PEG114PCL114). The PEG-PCL-based Ps also demonstrated higher drugs release in an acidic environment (i.e., pH 5.0 at 37 °C, found in tumor cells) compared to physiological conditions (pH 7.4 at 37 °C). In conclusion, the DOX/VEM-PEG-PCL-based Ps may be a promising approach to cancer therapy with potential synergic effect, lower dosage, and lower risk of causing MDR.

Cutaneous adverse events in children treated with vemurafenib for refractory BRAFV600E mutated Langerhans cell histiocytosis.

The somatic BRAFV600E mutation occurs in 38-64% of pediatric cases of Langerhans cell histiocytosis (LCH). Vemurafenib (VMF), a BRAF inhibitor, was approved for refractory BRAFV600E mutated LCH. In adults, VMF causes frequent cutaneous adverse events (CAE) including skin tumors (squamous cell carcinomas, melanomas), but little is known in children. The objective of this study was to evaluate the frequency, clinical spectrum, and severity of CAEs in children treated with VMF for LCH. In addition, a correlation between CAE occurrence and VMF dose, residual plasma levels (RPLs), and efficacy was searched for. Multicentric retrospective observational study including patients <18years treated with VMF alone for refractory BRAFV600E mutated LCH in 13 countries between October 1, 2013 and December 31, 2018. Fifty-seven patients: 56% female, median age 2.1years (0.2-14.6), median treatment duration 4.1months (1.4-29.7). Forty-one patients (72%) had at least one CAE: photosensitivity (40%), keratosis pilaris (32%), rash (26%), xerosis (21%), and neutrophilic panniculitis (16%). No skin tumor was observed. Five percent of CAEs were grade 3. None were grade 4 or led to permanent VMF discontinuation. Dose reduction was necessary for 12% of patients, temporary treatment discontinuation for 16%, none leading to loss of efficacy. VMF dose, median RPL, and efficacy were not correlated with CAE occurrence. At doses used for pediatric LCH, CAEs are frequent but rarely severe and have little impact on the continuation of treatment when managed appropriately. Regular dermatological follow-up is essential to manage CAEs and screen for possible induced skin tumors.

Early Exanthema Upon Vemurafenib Plus Cobimetinib Is Associated With a Favorable Treatment Outcome in Metastatic Melanoma: A Retrospective Multicenter DeCOG Study

BackgroundThe combination of BRAF and MEK inhibitors has become standard of care in the treatment of metastatic BRAF V600-mutated melanoma. Clinical factors for an early prediction of tumor response are rare. The present study investigated the association between the development of an early exanthema induced by vemurafenib or vemurafenib plus cobimetinib and therapy outcome.MethodsThis multicenter retrospective study included patients with BRAF V600-mutated irresectable AJCC-v8 stage IIIC/D to IV metastatic melanoma who received treatment with vemurafenib (VEM) or vemurafenib plus cobimetinib (COBIVEM). The development of an early exanthema within six weeks after therapy start and its grading according to CTCAEv4.0 criteria was correlated to therapy outcome in terms of best overall response, progression-free (PFS), and overall survival (OS).ResultsA total of 422 patients from 16 centers were included (VEM, n=299; COBIVEM, n=123). 20.4% of VEM and 43.1% of COBIVEM patients developed an early exanthema. In the VEM cohort, objective responders (CR/PR) more frequently presented with an early exanthema than non-responders (SD/PD); 59.0% versus 38.7%; p=0.0027. However, median PFS and OS did not differ between VEM patients with or without an early exanthema (PFS, 6.9 versus 6.0 months, p=0.65; OS, 11.0 versus 12.4 months, p=0.69). In the COBIVEM cohort, 66.0% of objective responders had an early exanthema compared to 54.3% of non-responders (p=0.031). Median survival times were significantly longer for patients who developed an early exanthema compared to patients who did not (PFS, 9.7 versus 5.6 months, p=0.013; OS, not reached versus 11.6 months, p=0.0061). COBIVEM patients with a mild early exanthema (CTCAEv4.0 grade 1-2) had a superior survival outcome as compared to COBIVEM patients with a severe (CTCAEv4.0 grade 3-4) or non early exanthema, respectively (p=0.047). This might be caused by the fact that 23.6% of patients with severe exanthema underwent a dose reduction or discontinuation of COBIVEM compared to only 8.9% of patients with mild exanthema.ConclusionsThe development of an early exanthema within 6 weeks after treatment start indicates a favorable therapy outcome upon vemurafenib plus cobimetinib. Patients presenting with an early exanthema should therefore be treated with adequate supportive measures to provide that patients can stay on treatment.

Computational Study on the Mechanism of the Photouncaging Reaction of Vemurafenib: Toward an Enhanced Photoprotection Approach for Photosensitive Drugs.

The photochemical behavior of the photosensitive first-line anticancer drug vemurafenib (VFB) is of great interest due to the impact of such behavior on its pharmacological activity. In this work, we computationally elucidated the mechanism of the photoinduced release of VFB from the 4,5-dimethoxy-2-nitrobenzene (DMNB) photoprotecting group by employing various density functional theory (DFT)/time-dependent DFT (TD-DFT) approaches. The computational investigations included a comparative assessment of the influence of the position of the photoprotecting group as a substituent on the thermodynamics and kinetics of the photouncaging reactions of two VFB-DMNB prodrugs, namely pyrrole (NP) and sulfonamide (NS). With the aid of the DFT calculations concerning the activation energy barrier (∆G‡), the obtained results suggest that the step of the photoinduced intramolecular proton transfer of the DMNB moiety is not detrimental concerning the overall reaction profile of the photouncaging reaction of both prodrugs. However, the obtained results suggested that the position of the substitution position of the DMNB photoprotecting group within the prodrug structure has a substantial impact on the photouncaging reaction. In particular, the DMNB-Ns-VFB prodrug exhibited a notable increase in ∆G‡ for the key step of ring opining within the DMNB moiety indicative of potentially hindered kinetics of the photouncaging process compared with DMNB-Np-VFB. Such an increase in ∆G‡ may be attributed to the electronic influence of the NP fragment of the prodrug. The results reported herein elaborate on the mechanism of the photoinduced release of an important anticancer drug from photoprotecting groups with the aim of enhancing our understanding of the photochemical behavior of such photosensitive pharmaceutical materials at the molecular level.