Intracranial hemorrhage caused by dabrafenib and trametinib therapy for metastatic melanoma.

Although generally well tolerated compared with chemotherapy, molecular targeted therapy used in metastatic melanoma may be associated with life-threatening toxicity. We report the case of a patient with metastatic melanoma treated by dabrafenib plus trametinib who developed intracranial hemorrhage. Physicians should be aware of this rare but life-threatening adverse event of B-rapidly accelerated fibrosarcoma (BRAF) and mitogen-activated protein kinase kinase (MEK) inhibitors. However, they should be also careful about the bleeding origin, which can prove to be a new onset of melanoma metastasis or anticoagulation overdose, or even an uncontrolled arterial hypertension.

BRAF/MEK-targeted therapy in BRAF ex15 p.T599dup mutation-driven NSCLC: a case report.

BRAF mutations are found in 1-5% of non-small-cell lung cancer (NSCLC), with V600 and non-V600 accounting for approximately 50% each. It has been confirmed that targeted therapy with dabrafenib + trametinib is effective in patients with metastatic NSCLC carrying BRAF V600E mutations. Preclinical studies have shown that dabrafenib + trametinib may also have inhibitory effects on some types of non-V600E mutations, especially some class II BRAF mutations. However, the efficacy of dabrafenib + trametinib on non-V600E mutant NSCLC in clinical practice only exists in some case reports. Here, we report a case of NSCLC patient carrying BRAF ex15 p.T599dup, who showed a clinical response to the combined therapy of dabrafenib + trametinib.

Response to Dabrafenib Plus Trametinib in a Patient With an Uncommon Activating BRAF Mutation: A First in Non-Small Cell Lung Cancer.

Mutations in BRAF are present in 4% of non-small cell lung cancer (NSCLC), of which half are well-characterized activating variants affecting codon 600 (classified as class I). These mutations, most commonly BRAF V600E, have been associated with response to BRAF/MEK-directed small molecule kinase inhibitors. NSCLC with kinase-activating BRAF mutations occurring at other codons (class II variants) represent a substantial portion of BRAF-mutated NSCLC, but use of targeted therapy in these tumors is still under investigation. Class II mutations have been described in other tumor types and have been associated with response to BRAF/MEK-targeted agents, although optimal treatment strategies for these patients are lacking. This report presents a case of a woman with metastatic NSCLC harboring a class II BRAF p.N486_P490del variant who had a sustained clinical response to combination therapy with dabrafenib and trametinib. This first report of the use of BRAF/MEK-targeted therapy for this variant in NSCLC supports consideration of such treatment for tumors with class II BRAF variants.

No-observed-adverse-effect-level (NOAEL) assessment as an optimized dose of cholinesterase reactivators for the treatment of exposure to warfare nerve agents in mice.

Despite the international convention on the prohibition of chemical weapons ratified in 1997, the threat of conflicts and terrorist attacks involving such weapons still exists. Among these, organophosphorus-nerve agents (OPs) inhibit cholinesterases (ChE) causing cholinergic syndrome. The reactivation of these enzymes is therefore essential to protect the poisoned people. However, these reactivating molecules, mainly named oximes, have major drawbacks with limited efficacy against some OPs and a non-negligible ChE inhibitor potential if administered at an inadequate dose, an effect that they are precisely supposed to mitigate. As a result, this project focused on assessing therapeutic efficacy, in mice, up to the NOAEL dose, the maximum dose of oxime that does not induce any observable toxic effect. NOAEL doses of HI-6 DMS, a reference oxime, and JDS364. HCl, a candidate reactivator, were assessed using dual-chamber plethysmography, with respiratory ventilation impairment as a toxicity criterion. Time-course modeling parameters and pharmacodynamic profiles, reflecting the interaction between the oxime and circulating ChE, were evaluated for treatments at their NOAEL and higher doses. Finally, the therapeutic potential against OPs poisoning was determined through the assessment of protective indices. For JDS364. HCl, the NOAEL dose corresponds to the smallest dose inducing the most significant therapeutic effect without causing any abnormality in ChE activity. In contrast, for HI-6 DMS, its therapeutic benefit was observed at doses higher than its NOAEL, leading to alterations in respiratory function. These alterations could not be directly correlated with ChE inhibition and had no adverse effects on survival. They are potentially attributed to the stimulation of non-enzymatic cholinergic targets by HI-6 DMS. Thus, the NOAEL appears to be an optimal dose for evaluating the efficacy of oximes, particularly when it can be linked to respiratory alterations effectively resulting from ChE inhibition.

Restoration of nerve agent impaired neuromuscular transmission in rat diaphragm by bispyridinium non-oximes - Structure-activity relationships.

Organophosphate (OP) poisoning is currently treated with atropine, oximes and benzodiazepines. The nicotinic signs, i.e., respiratory impairment, can only be targeted indirectly via the use of oximes as reactivators of OP-inhibited acetylcholinesterase. Hence, compounds selectively targeting nicotinic acetylcholine receptors (nAChRs) might fundamentally improve current treatment options. The bispyridinium compound MB327 has previously shown some therapeutic effect against nerve agents in vitro and in vivo. Nevertheless, compound optimization was deemed necessary, due to limitations (e.g., toxicity and efficacy). The current study investigated a series of 4-tert-butyl bispyridinium compounds and of corresponding bispyridinium compounds without substituents in a rat diaphragm model using an indirect field stimulation technique. The length of the respective linker influenced the ability of the bispyridinium compounds to restore muscle function in rat hemidiaphragms. The current data show structure-activity relationships for a series of bispyridinium compounds and provide insight for future structure-based molecular modeling.

Oxime-Linked Peptide-Daunomycin Conjugates as Good Tools for Selection of Suitable Homing Devices in Targeted Tumor Therapy: An Overview.

Chemotherapy is still one of the main therapeutic approaches in cancer therapy. Nevertheless, its poor selectivity causes severe toxic side effects that, together with the development of drug resistance in tumor cells, results in a limitation for its application. Tumor-targeted drug delivery is a possible choice to overcome these drawbacks. As well as monoclonal antibodies, peptides are promising targeting moieties for drug delivery. However, the development of peptide-drug conjugates (PDCs) is still a big challenge. The main reason is that the conjugates have to be stable in circulation, but the drug or its active metabolite should be released efficiently in the tumor cells. For this purpose, suitable linker systems are needed that connect the drug molecule with the homing peptide. The applied linker systems are commonly categorized as cleavable and non-cleavable linkers. Both the groups possess advantages and disadvantages that are summarized briefly in this manuscript. Moreover, in this review paper, we highlight the benefit of oxime-linked anthracycline-peptide conjugates in the development of PDCs. For instance, straightforward synthesis as well as a conjugation reaction proceed in excellent yields, and the autofluorescence of anthracyclines provides a good tool to select the appropriate homing peptides. Furthermore, we demonstrate that these conjugates can be used properly in in vivo studies. The results indicate that the oxime-linked PDCs are potential candidates for targeted tumor therapy.

Characterization of dabrafenib-induced drug insensitivity via cellular barcoding and collateral sensitivity to second-line therapeutics.

Drug insensitivity is arguably one of the biggest challenges in cancer therapeutics. Although effective therapeutic solutions in cancer are limited due to the emergence of drug insensitivity, exploiting evolutionary understanding in this context can provide potential second-line therapeutics sensitizing the drug insensitive populations. Targeted therapeutic agent dabrafenib is used to treat CRC patients with BRAF V600E genotype and insensitivity to dabrafenib is often observed. Understanding underlying clonal architecture of dabrafenib-induced drug insensitivity and identification of potential second-line therapeutics that could sensitize dabrafenib insensitive populations remain to be elucidated. For this purpose, we utilized cellular barcoding technology to decipher dabrafenib-induced clonal evolution in BRAF V600E mutant HT-29 cells. This approach revealed the detection of both pre-existing and de novo barcodes with increased frequencies as a result of dabrafenib insensitivity. Furthermore, our longitudinal monitoring of drug insensitivity based on barcode detection from floating DNA within used medium enabled to identify temporal dynamics of pre-existing and de novo barcodes in relation to dabrafenib insensitivity in HT-29 cells. Moreover, whole-exome sequencing analysis exhibited possible somatic CNVs and SNVs contributing to dabrafenib insensitivity in HT-29 cells. Last, collateral drug sensitivity testing demonstrated oxaliplatin and capecitabine, alone or in combination, as successful second-like therapeutics in inducing collateral sensitivity in dabrafenib-insensitive HT-29 cells. Overall, our findings demonstrate clonal dynamics of dabrafenib-insensitivity in HT-29 cells. In addition, oxaliplatin and capecitabine, alone or in combination, were successful second-line therapeutics in inducing collateral sensitivity in dabrafenib-insensitive HT-29 cells.

Efficacy of the oxime HI-6 dimethanesulphonate in the treatment of guinea-pigs exposed to the nerve agents GB and GD.

The bispyridinium oxime HI-6 DMS is in development as an improved therapy for the treatment of patients exposed to organophosphorus nerve agents. The aim of the work described in this paper was to provide non-clinical data to support regulatory approval of HI-6 DMS, by demonstrating efficacy against an oxime-sensitive agent, GB and an oxime-resistant agent, GD. We investigated the dose-dependent protection afforded by therapy including atropine, avizafone and HI-6 DMS in guinea-pigs challenged with GB or GD. We also compared the efficacy of 30 mg.kg-1 of HI-6 DMS to an equimolar dose of the current in-service oxime P2S and the dichloride salt of HI-6 (HI-6 Cl2). In the treatment of GB or GD poisoning there was no significant difference between the salt forms. The most effective dose of HI-6 DMS in preventing lethality following challenge with GB was 100 mg.kg-1; though protection ratios of at least 25 were obtained at 10 mg.kg-1. Protection against GD was lower, and there was no significant increase in effectiveness of HI-6 DMS doses of 30 or 100 mg.kg-1. For GD, the outcome was improved by the addition of pyridostigmine pre-treatment. These data demonstrate the benefits of HI-6 DMS as a component of nerve agent therapy. © Crown copyright (2023), Dstl.

AChE reactivation in precision-cut lung slices following organophosphorus compound poisoning.

Precision-cut lung slices (PCLS) are a suitable model for analyzing the acetylcholinesterase (AChE) activity and subsequent effects after exposure to organophosphorus (OP) compounds. In this study, the AChE activity was determined in intact PCLS for the first time. Since the current standard therapy for OP poisoning (atropine + oxime + benzodiazepine) lacks efficiency, reliable models to study novel therapeutic substances are needed. Models should depict pathophysiological mechanisms and help to evaluate the beneficial effects of new therapeutics. Here PCLS were exposed to three organophosphorus nerve agents (OPNAs): sarin (GB), cyclosarin (GF), and VX. They were then treated with three reactivators: HI-6, obidoxime (OBI), and a non-oxime (NOX-6). The endpoints investigated in this study were the AChE activity and the airway area (AA) change. OPNA exposure led to very low residual AChE activities. Depending on the reactivator properties different AChE reactivation results were measured. GB-inhibited PCLS-AChE was reactivated best, followed by VX and GF. To substantiate these findings and to understand the connection between the molecular and the functional levels in a more profound way the results were correlated to the AA changes. These investigations underline the importance of reactivator use and point to the possibilities for future improvements in the treatment of OPNA-exposed victims.

Molecular Modeling Unveils the Effective Interaction of B-RAF Inhibitors with Rare B-RAF Insertion Variants.

The Food and Drug Administration (FDA) has approved MAPK inhibitors as a treatment for melanoma patients carrying a mutation in codon V600 of the BRAF gene exclusively. However, BRAF mutations outside the V600 codon may occur in a small percentage of melanomas. Although these rare variants may cause B-RAF activation, their predictive response to B-RAF inhibitor treatments is still poorly understood. We exploited an integrated approach for mutation detection, tumor evolution tracking, and assessment of response to treatment in a metastatic melanoma patient carrying the rare p.T599dup B-RAF mutation. He was addressed to Dabrafenib/Trametinib targeted therapy, showing an initial dramatic response. In parallel, in-silico ligand-based homology modeling was set up and performed on this and an additional B-RAF rare variant (p.A598_T599insV) to unveil and justify the success of the B-RAF inhibitory activity of Dabrafenib, showing that it could adeptly bind both these variants in a similar manner to how it binds and inhibits the V600E mutant. These findings open up the possibility of broadening the spectrum of BRAF inhibitor-sensitive mutations beyond mutations at codon V600, suggesting that B-RAF V600 WT melanomas should undergo more specific investigations before ruling out the possibility of targeted therapy.

Outcomes in patients with BRAFV600-mutated melanoma and brain metastases at baseline treated with dabrafenib plus trametinib.

BACKGROUND: Brain metastases (BM) and lactate dehydrogenase (LDH) levels above the upper limit of normal (ULN) are associated with poor prognosis in patients with melanoma. Although treatment with the BRAF inhibitor dabrafenib and the MEK inhibitor trametinib have demonstrated long-term clinical benefit in patients with melanoma, data on their efficacy in patients with BM are limited. METHODS: DESCRIBE Italy is an observational, retrospective, real-world study evaluating dabrafenib plus trametinib in 499 patients with BRAFV600-mutant stage III unresectable or stage IV melanoma from various sites across Italy. Here, we analyzed the clinical outcomes for the subgroup of patients receiving first-line treatment and presenting with BM at diagnosis and assessed the impact of predictive factors such as LDH levels and the presence of other metastases on median progression-free survival (mPFS). RESULTS: Overall, 325 evaluable patients were on first-line therapy and are the focus of this analysis; of these, 76 patients (23.4%) had BM at baseline. mPFS was lower for patients with BM at baseline compared with overall patients (8.7 months vs 9.3 months, respectively). Patients with BM at diagnosis and LDH >ULN had a considerably shorter mPFS compared with patients with LDH ⩽ULN (5.3 months vs 9.9 months, respectively). mPFS was noticeably longer for patients with cerebral metastases only compared with patients with cerebral and other metastases (15.0 months vs 8.7 months, respectively). CONCLUSIONS: Dabrafenib plus trametinib showed effectiveness in a real-world population of patients with advanced BRAFV600-mutated melanoma and BM at baseline, supporting its use in this population with poor outcomes.

Extemporaneous compounding of dabrafenib and trametinib for cancer patients with feeding tubes.

INTRODUCTION: Dabrafenib and trametinib are oral targeted agents indicated for BRAF mutated non-small cell lung cancer and melanoma. There is little data to support the administration of these two agents via enteral feeding tube. This case series describes three patients who received compounded dabrafenib and trametinib suspensions through enteral feeding tubes. CASE REPORT: We present three patients who required dabrafenib and trametinib to be prepared as a non-standard compound for the medications to be administered via feeding tube. The patients were diagnosed with with BRAF mutated cancers including melanoma, non-small-cell lung carcinoma, and anaplastic thyroid cancer. In all three cases, there was evidence of initial disease response on imaging, and there were no unexpected toxicities secondary to dabrafenib and trametinib. DISCUSSION: There are patients that are unable to tolerate medications by mouth due to dysphagia, anatomical malfunctions, or other digestive disorders. There is limited literature that describes preparation of trametinib and dabrafenib into an enteral suspension. Identifying a safe and efficacious method of administering these two medications via feeding tube ensures that these patients continue to be able to receive them as part of their anti-cancer therapy. CONCLUSION: Despite the lack of available data, compounding of dabrafenib and trametinib may be clinically appropriate when benefits outweigh the risk of unconventional administration. Further studies are warranted to assess for the pharmacokinetics, pharmacodynamics, stability, and storage for these liquid medications.

Combination of acetylcholinesterase inhibitors and NMDA receptor antagonists increases survival rate in soman-poisoned mice.

Organophosphorus nerve agents pose a global threat to both military personnel and civilian population, because of their high acute toxicity and insufficient medical countermeasures. Commonly used drugs could ameliorate the intoxication and overall medical outcomes. In this study, we tested the drugs able to alleviate the symptoms of Alzheimer's disease (donepezil, huperzine A, memantine) or Parkinson's disease (procyclidine). They were administered to mice before soman intoxication in terms of their: i) protection potential against soman toxicity and ii) influence on post-exposure therapy consisting of atropine and asoxime (also known as oxime HI-6). Their pretreatment effect was not significant, when administered alone, but in combination (acetylcholinesterase inhibitor such as denepezil or huperzine A with NMDA antagonist such as memantine or procyclidine) they lowered the soman toxicity more than twice. These combinations also positively influenced the efficacy of post-exposure treatment in a similar fashion; the combinations increased the therapeutic effectiveness of antidotal treatment. In conclusion, the most effective combination - huperzine A and procyclidine - lowered the toxicity three times and improved the post-exposure therapy efficacy more than six times. These results are unprecedented in the published literature.

PPRX-1701, a nanoparticle formulation of 6'-bromoindirubin acetoxime, improves delivery and shows efficacy in preclinical GBM models.

Derivatives of the Chinese traditional medicine indirubin have shown potential for the treatment of cancer through a range of mechanisms. This study investigates the impact of 6'-bromoindirubin-3'-acetoxime (BiA) on immunosuppressive mechanisms in glioblastoma (GBM) and evaluates the efficacy of a BiA nanoparticle formulation, PPRX-1701, in immunocompetent mouse GBM models. Transcriptomic studies reveal that BiA downregulates immune-related genes, including indoleamine 2,3-dioxygenase 1 (IDO1), a critical enzyme in the tryptophan-kynurenine-aryl hydrocarbon receptor (Trp-Kyn-AhR) immunosuppressive pathway in tumor cells. BiA blocks interferon-γ (IFNγ)-induced IDO1 protein expression in vitro and enhances T cell-mediated tumor cell killing in GBM stem-like cell co-culture models. PPRX-1701 reaches intracranial murine GBM and significantly improves survival in immunocompetent GBM models in vivo. Our results indicate that BiA improves survival in murine GBM models via effects on important immunotherapeutic targets in GBM and that it can be delivered efficiently via PPRX-1701, a nanoparticle injectable formulation of BiA.