Knowledge of community pharmacists on infantile haemangioma: Gaps and lack confidence to deliver propranolol still need to be filled

AIM

To evaluate the knowledge, practices and self-confidence of community pharmacists, pharmacy technicians and pharmacy students about infantile haemangioma (IH) and propranolol treatment.

METHODS

A national survey was conducted in France from May 2022 to October 2022. A 42-item online questionnaire was used to assess pharmacists' knowledge of the epidemiology, clinical features and management of IH and propranolol treatment.

RESULTS

The survey included 255 participants. The mean age was 34.9 years (±9.0); 225 (88%) were women. In all, 193 (76%) practised in urban pharmacies. Altogether, 83 participants (33%) had delivered oral propranolol solution for IH in the last 6 months. Participants' median score for self-confidence regarding propranolol dispensing was five (interquartile range, 2.5-6) on a scale of 1 to 10. Overall, 96 (38%) had more than 50% correct answers on the questionnaire. Multinomial regression models showed high scores on the questionnaire associated with high self-confidence when delivering oral propranolol solution, low number of years since graduation and having already delivered propranolol treatment.

CONCLUSION

This study highlights a lack of knowledge of IH and modalities of propranolol treatment by community pharmacists and slight self-confidence when delivering propranolol. Greater cooperation between healthcare professionals could improve the proper use of medicine.

Branched pegylated linker-auristatin to control hydrophobicity for the production of homogeneous minibody-drug conjugate against HER2-positive breast cancer

Trastuzumab emtansine (Kadcyla®) was the first antibody-drug conjugate (ADC) approved by the Food and Drug Administration in 2013 against a solid tumor, and the first ADC to treat human epidermal growth factor receptor 2 positive (HER2+) breast cancer. However, this second generation ADC is burden by several limitations included heterogeneity, limited activity against heterogeneous tumor (regarding antigen expression) and suboptimal tumor penetration. To address this, different development strategies are oriented towards homogeneous conjugation, new drugs, optimized linkers and/or smaller antibody formats. To reach better developed next generation ADCs, a key parameter to consider is the management of the hydrophobicity associated with the linker-drug, increasing with and limiting the drug-to-antibody ratio (DAR) of the ADC. Here, an innovative branched pegylated linker was developed, to control the hydrophobicity of the monomethyl auristatin E (MMAE) and its cathepsin B-sensitive trigger. This branched pegylated linker-MMAE was then used for the efficient generation of internalizing homogeneous ADC of DAR 8 and minibody-drug conjugate of DAR 4, targeting HER2. Both immunoconjugates were then evaluated in vitro and in vivo on breast cancer models. Interestingly, this study highlighted that the minibody-MMAE conjugate of DAR 4 was the best immunoconjugate regarding in vitro cellular internalization and cytotoxicity, gamma imaging, ex vivo biodistribution profile in mice and efficient reduction of tumor size in vivo. These results are very promising and encourage us to explore further fragment-drug conjugate development.

Synthesis and In Vitro Comparison of DOTA, NODAGA and 15-5 Macrocycles as Chelators for the 64Cu-Labelling of Immunoconjugates

The development of ⁶⁴Cu-based immuno-PET radiotracers requires the use of copper-specific bifunctional chelators (BFCs) that contain functional groups allowing both convenient bioconjugation and stable copper complexes to limit in vivo bioreduction, transmetallation and/or transchelation. The excellent in vivo kinetic inertness of the pentaazamacrocyclic [⁶⁴Cu]Cu-15-5 complex prompted us to investigate its potential for the ⁶⁴Cu-labelling of monoclonal antibodies (mAbs), compared with the well-known NODAGA and DOTA chelators. To this end, three NODAGA, DOTA and 15-5-derived BFCs, containing a pendant azadibenzocyclooctyne moiety, were synthesised and a robust methodology was determined to form covalent bonds between them and azide-functionalised trastuzumab, an anti-HER2 mAb, using strain-promoted azide-alkyne cycloaddition. Unlike the DOTA derivative, the NODAGA- and 15-5-mAb conjugates were radiolabelled with ⁶⁴Cu, obtaining excellent radiochemical yields, under mild conditions. Although all the radioimmunoconjugates showed excellent stability in PBS or mouse serum, [⁶⁴Cu]Cu-15-5- and [⁶⁴Cu]Cu-NODAGA-trastuzumab presented higher resistance to transchelation when challenged by EDTA. Finally, the immunoreactive fraction of the radioimmunoconjugates (88-94%) was determined in HER-2 positive BT474 human breast cancer cells, confirming that the bioconjugation and radiolabelling processes implemented had no significant impact on antigen recognition.

Dual intra- and extracellular release of monomethyl auristatin E from a neutrophil elastase-sensitive antibody-drug conjugate

Antibody-drug conjugates (ADCs) are targeted therapies, mainly used in oncology, consisting in a three-component molecular architecture combining a highly potent drug conjugated via a linker onto a monoclonal antibody (mAb), designed for the selective delivery of the drug to the tumor site. The linker is a key component, defining the ADC stability and mechanism of action, and particularly the drug release strategy. In this study, we have developed and synthesized a cleavable linker, which possesses an Asn-Pro-Val (NPV) sequence sensitive to the human neutrophil elastase (HNE), overexpressed in the tumor microenvironment. This linker permitted the site-specific conjugation of the cell-permeable drug, monomethyl auristatin E (MMAE), onto trastuzumab, using a disulfide re-bridging technology. The resulting ADC was then evaluated in vitro. This conjugate demonstrated retained antigen (Ag) binding affinity and exhibited high subnanomolar potency against Ag-positive tumor cells after internalization, suggesting an intracellular mechanism of linker cleavage. While no internalization and cytotoxic activity of this ADC was observed on Ag-negative cells in classical conditions, the supplementation of exogenous HNE permitted to restore a nanomolar activity on these cells, suggesting an extracellular mechanism of drug release in these conditions. This in vitro proof of concept tends to prove that the NPV sequence could allow a dual intra- and extracellular mechanism of drug release. This work represents a first step in the design of original ADCs with a new dual intra- and extracellular drug delivery system and opens the way to further experimentations to evaluate their full potential in vivo.

Therapeutic antibodies - natural and pathological barriers and strategies to overcome them

Antibody-based therapeutics have become a major class of therapeutics with over 120 recombinant antibodies approved or under review in the EU or US. This therapeutic class has experienced a remarkable expansion with an expected acceleration in 2021-2022 due to the extraordinary global response to SARS-CoV2 pandemic and the public disclosure of over a hundred anti-SARS-CoV2 antibodies. Mainly delivered intravenously, alternative delivery routes have emerged to improve antibody therapeutic index and patient comfort. A major hurdle for antibody delivery and efficacy as well as the development of alternative administration routes, is to understand the different natural and pathological barriers that antibodies face as soon as they enter the body up to the moment they bind to their target antigen. In this review, we discuss the well-known and more under-investigated extracellular and cellular barriers faced by antibodies. We also discuss some of the strategies developed in the recent years to overcome these barriers and increase antibody delivery to its site of action. A better understanding of the biological barriers that antibodies have to face will allow the optimization of antibody delivery near its target. This opens the way to the development of improved therapy with less systemic side effects and increased patients' adherence to the treatment.

Internalization of Foldamer-Based DNA Mimics through a Site-Specific Antibody Conjugate to Target HER2-Positive Cancer Cells

Inhibition of protein-DNA interactions represents an attractive strategy to modulate essential cellular functions. We reported the synthesis of unique oligoamide-based foldamers that adopt single helical conformations and mimic the negatively charged phosphate moieties of B-DNA. These mimics alter the activity of DNA interacting enzymes used as targets for cancer treatment, such as DNA topoisomerase I, and they are cytotoxic only in the presence of a transfection agent. The aim of our study was to improve internalization and selective delivery of these highly charged molecules to cancer cells. For this purpose, we synthesized an antibody-drug conjugate (ADC) using a DNA mimic as a payload to specifically target cancer cells overexpressing HER2. We report the bioconjugation of a 16-mer DNA mimic with trastuzumab and its functional validation in breast and ovarian cancer cells expressing various levels of HER2. Binding of the ADC to HER2 increased with the expression of the receptor. The ADC was internalized into cells and was more efficient than trastuzumab at inhibiting their growth in vitro. These results provide proof of concept that it is possible to site-specifically graft high molecular weight payloads such as DNA mimics onto monoclonal antibodies to improve their selective internalization and delivery in cancer cells.

Design, synthesis, and antiproliferative effect of 2,9-bis[4-(pyridinylalkylaminomethyl)phenyl]-1,10-phenanthroline derivatives on human leukemic cells by targeting G-quadruplex

Current multiagent chemotherapy regimens have improved the cure rate in acute leukemia patients, but they are highly toxic and poorly efficient in relapsed patients. To improve the treatment approaches, new specific molecules are needed. The G-quadruplexes (G4s), which are noncanonical nucleic acid structures found in specific guanine-rich DNA or RNA, are involved in many cellular events, including control of gene expression. G4s are considered as targets for the development of anticancer agents. Heterocyclic molecules are well known to target and stabilize G4 structures. Thus, a new series of 2,9-bis[(substituted-aminomethyl)phenyl]-1,10-phenanthroline derivatives (1a-i) was designed, synthesized, and evaluated against five human myeloid leukemia cell lines (K562, KU812, MV4-11, HL60, and U937). Their ability to stabilize various oncogene promoter G4 structures (c-MYC, BCL-2, and K-RAS) as well as the telomeric G4 was also determined through the fluorescence resonance energy transfer melting assay and native mass spectrometry. In addition, the more bioactive ligands 1g-i were tested for telomerase activity in HuT78 and MV4-11 protein extracts.

Antibody-Drug Conjugates: The Last Decade

An armed antibody (antibody–drug conjugate or ADC) is a vectorized chemotherapy, which results from the grafting of a cytotoxic agent onto a monoclonal antibody via a judiciously constructed spacer arm. ADCs have made considerable progress in 10 years. While in 2009 only gemtuzumab ozogamicin (Mylotarg^®) was used clinically, in 2020, 9 Food and Drug Administration (FDA)-approved ADCs are available, and more than 80 others are in active clinical studies. This review will focus on FDA-approved and late-stage ADCs, their limitations including their toxicity and associated resistance mechanisms, as well as new emerging strategies to address these issues and attempt to widen their therapeutic window. Finally, we will discuss their combination with conventional chemotherapy or checkpoint inhibitors, and their design for applications beyond oncology, to make ADCs the magic bullet that Paul Ehrlich dreamed of.

Structure-based design of novel quinoxaline-2-carboxylic acids and analogues as Pim-1 inhibitors

We identified a new series of quinoxaline-2-carboxylic acid derivatives, targeting the human proviral integration site for Moloney murine leukemia virus-1 (HsPim-1) kinase. Seventeen analogues were synthesized providing useful insight into structure-activity relationships studied. Docking studies realized in the ATP pocket of HsPim-1 are consistent with an unclassical binding mode of these inhibitors. The lead compound 1 was able to block HsPim-1 enzymatic activity at nanomolar concentrations (IC₅₀ of 74 nM), with a good selectivity profile against a panel of mammalian protein kinases. In vitro studies on the human chronic myeloid leukemia cell line KU812 showed an antitumor activity at micromolar concentrations. As a result, compound 1 represents a promising lead for the design of novel anticancer targeted therapies.

Imidazo[1,2-b]pyridazines targeting Toxoplasma gondii calcium-dependent protein kinase 1 decrease the parasite burden in mice with acute toxoplasmosis

The current therapeutic arsenal for toxoplasmosis is restricted to drugs non-specific to the parasite which cause important side effects. Development of more efficient and specific anti-Toxoplasma compounds is urgently needed. Imidazo[1,2-b]pyridazines designed to inhibit the calcium-dependent protein kinase 1 of Toxoplasma gondii (TgCDPK1) and effective against tachyzoite growth in vitro at submicromolar ranges were modified into hydrochloride salts to be administered in vivo in a mouse model of acute toxoplasmosis. All protonated imidazo[1,2-b]pyridazine salts (SP230, SP231 and SP232) maintained their activity on TgCDPK1 and T. gondii tachyzoites. Rat and mouse liver microsomes were used to predict half-life and intrinsic clearance, and the pharmacokinetic profile of the most rapidly degraded imidazo[1,2b]pyridazine salt (SP230) was determined in serum, brain and lungs of mice after a single administration of 50 mg/kg. Compounds were then tested in vivo in a murine model of acute toxoplasmosis. Mice infected with tachyzoites of the ME49 strain of T. gondii were treated for 4, 7 or 8 days with 25 or 50 mg/kg/day of SP230, SP231 or SP232. The parasite burdens were strongly diminished (>90% reduction under some conditions) in the spleen and the lungs of mice treated with imidazo[1,2-b]pyridazine salts compared with untreated mice, without the need for pre-treatment. Moreover, no increases in the levels of hepatic and renal toxicity markers were observed, demonstrating no significant signs of short-term toxicity. To conclude, imidazo[1,2-b]pyridazine salts have strong efficacy in vivo on acute toxoplasmosis and should be further tested in a model of mouse congenital toxoplasmosis.

Development of new highly potent imidazo[1,2-b]pyridazines targeting Toxoplasma gondii calcium-dependent protein kinase 1

Using a structure-based design approach, we have developed a new series of imidazo[1,2-b]pyridazines, targeting the calcium-dependent protein kinase-1 (CDPK1) from Toxoplasma gondii. Twenty derivatives were thus synthesized. Structure-activity relationships and docking studies confirmed the binding mode of these inhibitors within the ATP binding pocket of TgCDPK1. Two lead compounds (16a and 16f) were then identified, which were able to block TgCDPK1 enzymatic activity at low nanomolar concentrations, with a good selectivity profile against a panel of mammalian kinases. The potential of these inhibitors was confirmed in vitro on T. gondii growth, with EC50 values of 100 nM and 70 nM, respectively. These best candidates also displayed low toxicity to mammalian cells and were selected for further in vivo investigations on murine model of acute toxoplasmosis.

A small-molecule cell-based screen led to the identification of biphenylimidazoazines with highly potent and broad-spectrum anti-apicomplexan activity

An in vitro screening of the anti-apicomplexan activity of 51 compounds, stemming from our chemical library and from chemical synthesis, was performed. As a study model, we used Toxoplasma gondii (T. gondii), expressing β-galactosidase for the colorimetric assessment of drug activity on parasites cultivated in vitro. This approach allowed the validation of a new series of molecules with a biphenylimidazoazine scaffold as inhibitors of T. gondii growth in vitro. Hence, 8 molecules significantly inhibited intracellular replication of T. gondii in vitro, with EC50 < 1 μM, while being non-toxic for human fibroblasts at these concentrations. Most attractive candidates were then selected for further biological investigations on other apicomplexan parasites (Neospora caninum, Besnoitia besnoiti, Eimeria tenella and Plasmodium falciparum). Finally, two compounds were able to inhibit growth of four different apicomplexans with EC50 in the submicromolar to nanomolar range, for each parasite. These data, including the broad anti-parasite spectrum of these inhibitors, define a new generation of potential anti-parasite compounds of wide interest, including for veterinary application. Studies realized on E. tenella suggest that these molecules act during the intracellular development steps of the parasite. Further experiments should be done to identify the molecular target(s) of these compounds.