Anaplastic lymphoma kinase (ALK) inhibitors in the treatment of ALK-driven lung cancers

Population pharmacokinetics and exposure-response analyses of SAF-189s in Chinese patients with ALK+/ROS1+ non-small cell lung cancer

Objective

SAF-189s is a potent ALK/ROS1 inhibitor that is currently in clinical development for treating advanced ALK+/ROS1+ non-small cell lung cancer (NSCLC). Comprehensive population pharmacokinetics (PopPK) and exposure-response models were developed to evaluate the efficacy and safety of SAF-189s by integrating data from two clinical studies.

Methods

The PopPK model was developed using plasma concentration data collected from patients with ALK+/ROS1+ advanced NSCLC (n = 299) and healthy subjects (n = 24). The covariates (demographics, laboratory values, subject types, and concomitant medications) were evaluated to determine their potential influence on the between-patient variability in the pharmacokinetics of SAF-189s. Individual exposure values were then used to investigate the relationships with the efficacy endpoints (overall response rate (ORR), progression-free survival (PFS), and duration of response (DOR)) and key safety endpoints (adverse events of interest).

Results

The final PopPK model of SAF-189s was described by a one-compartment model with delayed first-order absorption and time-dependent elimination by allowing the clearance to decrease stepwise over time. Age was included as a covariate for apparent clearance (CL/F), while prior anti-cancer therapy in ALK+ patients (ALKPOT) was included for apparent volume of distribution (V/F). There were no apparent exposure-response relationships for any of the efficacy endpoints at doses of 80-210 mg. The relationship between exposure and safety suggested that a higher steady-state exposure was associated with more frequent incidences of hyperglycemia and proteinuria; the 210-mg dose group was also less tolerated than the other low-dose groups.

Conclusion

PopPK and exposure-response models were developed for SAF-189s, and their results demonstrate that SAF-189s exposures are at the plateau of exposure-response for efficacy. The 210-mg dose group had a significantly higher safety risk, while the 160-mg dose group was well-tolerated. Thus, 160 mg of SAF-189s once daily was selected as the recommended phase III dose for the ALK+/ROS1+ or ROS1+ NSCLC patients.

Establishment and characterization of TK-ALCL1: a novel NPM-ALK-positive anaplastic large-cell lymphoma cell line

TK-ALCL1, a novel anaplastic lymphoma kinase (ALK)-positive anaplastic large-cell lymphoma (ALK+ ALCL) cell line, was established from the primary tumor site of a 59-year-old Japanese male patient. The immune profile of TK-ALCL1 corresponds to that seen typically in primary ALCL cells, i.e., positive for ALK, CD30, EMA, and CD4, but negative for CD2, CD3, CD5, CD8a, and EBV-related antigens. The rearrangement of the T cell receptor-gamma locus shows that TK-ALCL1 is clonally derived from T-lineage lymphoid cells. FISH and RT-PCR analysis revealed that TK-ALCL1 has the nucleophosmin (NPM)-ALK fusion transcript, which is typical for ALK+ ALCL cell lines. When TK-ALCL1 was subcutaneously inoculated into 6-week-old BALB/c Rag2-/-/Jak3-/- (BRJ) mice, it formed tumor masses within 4-6 weeks. Morphological, immunohistochemical, and molecular genetic investigations confirmed that the xenograft and the original ALCL tumor were identical. The ALK inhibitors Alectinib and Lorlatinib suppressed proliferation in a dose-dependent manner. Thus, TK-ALCL1 provides a useful in vitro and in vivo model for investigation of the biology of ALK+ ALCL and of novel therapeutic approaches targeting ALK.

ALK-Rearranged Renal Cell Carcinoma: A Multi-Institutional Study of 9 Cases With Expanding the Morphologic and Molecular Genetic Spectrum

ALK-rearranged renal cell carcinoma (ALK-RCC) is rare, molecularly defined RCC subtype in the recently published fifth edition of World Health Organization classification of tumors. In this study, we described 9 ALK-RCCs from a clinicopathologic, immunohistochemical, and molecular genetic aspect, supporting and extending upon the observations by previous studies regarding this rare subgroup of RCC. There were 6 male and 3 female patients with ages ranging from 14 to 59 years (mean, 34.4 years). None of the patients had sickle cell trait. The diagnosis was based on radical or partial nephrectomy specimen for 8 patients and on biopsy specimen for 1. Tumor size ranged from 2.5 to 7.2 cm (mean, 2.8 cm). Follow-up was available for 6 of 9 patients (6-36 months); 5 had no tumor recurrence or metastasis and 1 developed lung metastasis at 24 months. The patient was subsequently treated with resection of the metastatic tumor followed by crizotinib-targeted therapy, and he was alive without tumor 12 months later. Histologically, the tumors showed a mixed growth of multiple patterns, including papillary, solid, tubular, tubulocystic, cribriform, and corded, often set in a mucinous background. The neoplastic cells had predominantly eosinophilic cytoplasm. Focally, clear cytoplasm with polarized nuclei and subnuclear vacuoles (n = 1), and pale foamy cytoplasm (n = 1) were observed on the tumor cells. The biopsied tumor showed solid growth of elongated tubules merging with bland spindle cells. Other common and uncommon features included psammomatous microcalcifications (n = 5), rhabdoid cells (n = 4), prominent intracytoplasmic vacuoles (n = 4), prominent chronic inflammatory infiltrate (n = 3), signet ring cell morphology (n = 2), and pleomorphic cells (n = 2). By immunohistochemistry, all 9 tumors were diffusely positive for ALK(5A4) and 4 of 8 tested cases showed reactivity for TFE3 protein. By fluorescence in situ hybridization analysis, ALK rearrangement was identified in all the 9 tumors; none of the tested tumors harbored TFE3 rearrangement (0/4) or gains of chromosomes 7 and 17 (0/3). ALK fusion partners were identified by RNA-sequencing in all 8 cases analyzed, including EML4 (n = 2), STRN (n = 1), TPM3 (n = 1), KIF5B (n = 1), HOOK1 (n = 1), SLIT1 (n = 1), and TPM1(3'UTR) (n = 1). Our study further expands the morphologic and molecular genetic spectrum of ALK-RCC.

Recent advances in c-Met-based dual inhibitors in the treatment of cancers

The cellular-mesenchymal epithelial transition factor (c-Met) is a receptor tyrosine kinase (RTK) located on the 7q31 locus encoding the Met proto-oncogene and plays a critical role in regulating cell proliferation, metastasis, differentiation, and apoptosis through various signaling pathways. However, its aberrant activation and overexpression have been implicated in many human cancers. Therefore, c-Met is a promising target for cancer treatment. However, the anticancer effect of selective single-targeted drugs is limited due to the complexity of the signaling system and the involvement of different proteins and enzymes. After inhibiting one pathway, signal molecules can be transmitted through other pathways, resulting in poor efficacy of single-targeted drug therapy. Dual inhibitors that simultaneously block c-Met and another factor can significantly improve efficacy and overcome some of the shortcomings of single-target inhibitors, including drug resistance. In this review, We introduced c-Met kinase and the synergism between c-Met and other anti-tumor targets, then dual-target inhibitors based on c-Met for the treatment of cancers were summarized and their design concepts and structure-activity relationships (SARs) were discussed elaborately, providing a valuable insight for the further development of novel c-Met-based dual inhibitors.

ALK-rearranged mesenchymal neoplasms: a clinicopathological and molecular study of eight additional cases of an emerging group of tyrosine kinase fusion mesenchymal tumours

AIMS

Mesenchymal neoplasms characterised by ALK fusions mainly include inflammatory myofibroblastic tumour (IMT) and epithelioid fibrous histiocytoma (EFH). Most recently, ALK-rearranged mesenchymal tumours that are not IMT or EFH have been reported. Our aim is to further characterise eight such neoplasms, with a detailed clinicopathological, immunohistochemical and molecular analysis.

METHODS

Clinicopathological features were assessed and partner agnostic targeted RNA-sequencing on clinically validated platforms was performed.

RESULTS

The patients consisted of seven males and one female with a median age of 47 years (28 -59 years). The tumours ranged in size from 2.0 to 10.0 cm (mean=3.0 cm) and involved superficial and deep soft tissue (n=6) and visceral locations (n=2). Of the seven patients with follow-up (9-130 months), two developed distant metastases and five had no disease recurrence or metastasis. The tumours demonstrated diverse architectures and variable cellularity and cellular morphologies. The main constitutive cells appeared in elongated spindled in three, primitive to ovoid in two and round to epithelioid in three cases. We expanded the histopathological spectrum to include mildly to moderately cellular spindled to stellate cells in a multinodular growth in a prominent myxoid and vascularised stroma (n=2). All tumours expressed ALK(D5F3); seven were positive for S100 protein and six were positive for CD34. By fluorescence in situ hybridisation, ALK rearrangement was identified in all eight tumours. ALK fusion partners were identified by RNA-sequencing in all cases, including previously reported: EML4 (n=3), DCTN (n=1), CLIP1 (n=1) and PLEKHH2 (n=1), and also two novel fusion partners: TKT (n=1) and MMP2 (n=1).

CONCLUSIONS

Our study expands the clinicopathological and molecular spectrum of ALK-rearranged mesenchymal neoplasms.

Inhibition of human UDP-glucuronosyltransferase enzyme by entrectinib: Implications for drug-drug interactions

As a new type of oral tyrosine kinase inhibitor, entrectinib can act on multiple targets and exert efficacy and has been approved for the treatment of non-small cell lung cancer (NSCLC) and solid tumors. However, whether entrectinib affects the activities of recombinant human UDP-glucuronosyltransferases (UGTs) remains unclear. Herein, we aimed to investigate the inhibitory effects of entrectinib on human UGTs and to assess the potential risk of causing drug-drug interactions (DDIs) based on the inhibition against UGTs. High-performance liquid chromatography (HPLC) was used to evaluate the inhibitory effects of entrectinib on UGTs according to the product formation rate of UGT substrate with or without entrectinib, and the inhibition kinetics experiment was conducted to assess the inhibitory type of entrectinib on UGTs. Our results showed that entrectinib exhibited extensive inhibitory effects on most human UGTs, and especially inhibited the activities of UGT1A7, UGT1A8, and UGT2B15 with Ki (Inhibition constant) of lower than 5 μM (0.95-4.38 μM). Furthermore, the results from quantitative prediction research suggested that the combination of entrectinib at 600 mg/day with substrates primarily metabolized by hepatic UGT2B15 or intestinal UGT1A7 and UGT1A8 might cause clinical DDIs. Thus, special attention should be paid to avoid adverse reactions induced by DDIs when co-administration of entrectinib and drugs metabolized by UGTs.

Kinase inhibitor macrocycles: a perspective on limiting conformational flexibility when targeting the kinome with small molecules

Methods utilized for drug discovery and development within the kinome have rapidly evolved since the approval of imatinib, the first small molecule kinase inhibitor. Macrocycles have received increasing interest as a technique to improve kinase inhibitor drug properties evident by the FDA approvals of lorlatinib, pacritinib, and repotrectinib. Compared to their acyclic counterparts, macrocycles can possess improved pharmacodynamic and pharmacokinetic properties. This review highlights clinical success stories when implementing macrocycles in kinase-based drug discovery and showcases that macrocyclization is a clinically validated drug discovery strategy when targeting the kinome.

Properties of FDA-approved small molecule protein kinase inhibitors: A 2024 update

Owing to the dysregulation of protein kinase activity in many diseases including cancer, this enzyme family has become one of the most important drug targets in the 21st century. There are 80 FDA-approved therapeutic agents that target about two dozen different protein kinases and seven of these drugs were approved in 2023. Of the approved drugs, thirteen target protein-serine/threonine protein kinases, four are directed against dual specificity protein kinases (MEK1/2), twenty block nonreceptor protein-tyrosine kinases, and 43 inhibit receptor protein-tyrosine kinases. The data indicate that 69 of these drugs are prescribed for the treatment of neoplasms. Six drugs (abrocitinib, baricitinib, deucravacitinib, ritlecitinib, tofacitinib, upadacitinib) are used for the treatment of inflammatory diseases (atopic dermatitis, rheumatoid arthritis, psoriasis, alopecia areata, and ulcerative colitis). Of the 80 approved drugs, nearly two dozen are used in the treatment of multiple diseases. The following seven drugs received FDA approval in 2023: capivasertib (HER2-positive breast cancer), fruquintinib (metastatic colorectal cancer), momelotinib (myelofibrosis), pirtobrutinib (mantle cell lymphoma, chronic lymphocytic leukemia, small lymphocytic lymphoma), quizartinib (Flt3-mutant acute myelogenous leukemia), repotrectinib (ROS1-positive lung cancer), and ritlecitinib (alopecia areata). All of the FDA-approved drugs are orally effective with the exception of netarsudil, temsirolimus, and trilaciclib. This review summarizes the physicochemical properties of all 80 FDA-approved small molecule protein kinase inhibitors including the molecular weight, number of hydrogen bond donors/acceptors, polar surface area, potency, solubility, lipophilic efficiency, and ligand efficiency.

Cost in the United States of FDA-approved small molecule protein kinase inhibitors used in the treatment of neoplastic and non-neoplastic diseases

Because genetic alterations including mutations, overexpression, translocations, and dysregulation of protein kinases are involved in the pathogenesis of many illnesses, this enzyme family is the target of many drug discovery programs worldwide. The FDA has approved 80 small molecule protein kinase inhibitors with 77 drugs orally bioavailable. The data indicate that 69 of these medicinals are approved for the management of neoplasms including solid tumors such as breast and lung cancer as well as non-solid tumors such as leukemia. Moreover, the remaining 11 drugs target non-neoplastic diseases including psoriasis, rheumatoid arthritis, and ulcerative colitis. The cost of drugs was obtained from www.pharmacychecker.com using the FDA label to determine the dosage and number of tablets required per day. This methodology excludes any private or governmental insurance coverage, which would cover the entire cost or more likely a fraction of the stated price. The average monthly cost for the treatment of neoplastic diseases was $17,900 with a price of $44,000 for futibatinib (used to treat cholangiocarcinomas with FGFR2 fusions) and minimum of $5100 for binimetinib (melanoma). The average monthly cost for the treatment of non-neoplastic diseases was $6800 with a maximum of $17,000 for belumosudil (graft vs. host disease) and a minimum of $200 for netarsudil eye drops (glaucoma). There is a negative correlation of the cost of the drugs and the incidence of the targeted disease. Many of these agents are or were designated as orphan drugs meaning that there are fewer than 200,000 potential patients in the United States.

Ocular complications of antineoplastic therapies

Ocular complications of antineoplastic agents can have a profound effect on the quality of life of cancer patients. New oncologic treatments like monoclonal antibodies, immunotherapies, antibody-drug conjugates, checkpoint inhibitors and growth factor receptors have resulted in increased ocular complications. These ocular complications differs in respect to distinct mechanisms of actions and lead to significant challenges in the management of cancer patients. In this review, we reviewed literature, clinical studies and cases detailing ocular complications due to administration of antineoplastic agents and emphasized the need for communication between oncologists and ophthalmologists toward early detection and management of ocular complications.

Rule of five violations among the FDA-approved small molecule protein kinase inhibitors

Because genetic alterations including mutations, overexpression, translocations, and dysregulation of protein kinases are involved in the pathogenesis of many illnesses, this enzyme family is the target of many drug discovery programs in the pharmaceutical industry. Overall, the US FDA has approved 74 small molecule protein kinase inhibitors, nearly all of which are orally effective. Of the 74 approved drugs, forty block receptor protein-tyrosine kinases, eighteen target nonreceptor protein-tyrosine kinases, twelve are directed against protein-serine/threonine protein kinases, and four target dual specificity protein kinases. The data indicate that 63 of these medicinals are approved for the management of neoplasms (51 against solid tumors such as breast, colon, and lung cancers, eight against nonsolid tumors such as leukemia, and four against both types of tumors). Seven of the FDA-approved kinase inhibitors form covalent bonds with their target enzymes and they are accordingly classified as TCIs (targeted covalent inhibitors). Medicinal chemists have examined the physicochemical properties of drugs that are orally effective. Lipinski's rule of five (Ro5) is a computational procedure that is used to estimate solubility, membrane permeability, and pharmacological effectiveness in the drug-discovery setting. It relies on four parameters including molecular weight, number of hydrogen bond donors and acceptors, and the Log of the partition coefficient. Other important descriptors include the lipophilic efficiency, the polar surface area, and the number of rotatable bonds and aromatic rings. We tabulated these and other properties of the FDA-approved kinase inhibitors. Of the 74 approved drugs, 30 fail to comply with the rule of five.

Deucravacitinib is an allosteric TYK2 protein kinase inhibitor FDA-approved for the treatment of psoriasis

Psoriasis is a heterogeneous, inflammatory, autoimmune skin disease that affects up to 2% of the world's population. There are many treatment modalities including topical medicines, ultraviolet light therapy, monoclonal antibodies, and several oral medications. Cytokines play a central role in the pathogenesis of this disorder including TNF-α, (tumor necrosis factor-α) IL-17A (interleukin-17A), IL-17F, IL-22, and IL-23. Cytokine signaling involves transduction mediated by the JAK-STAT pathway. There are four JAKS (JAK1/2/3 and TYK2) and six STATS (signal transducer and activators of transcription). Janus kinases contain an inactive JH2 domain that is aminoterminal to the active JH1 domain. Under basal conditions, the JH2 domain inhibits the activity of the JH1 domain. Deucravacitinib is an orally effective N-trideuteromethyl-pyridazine derivative that targets and stabilizes the TYK2 JH2 domain and thereby blocks TYK2 JH1 activity. Seven other JAK inhibitors, which target the JAK family JH1 domain, are prescribed for the treatment of neoplastic and other inflammatory diseases. The use of deuterium in the trimethylamide decreases the rate of demethylation and slows the production of a metabolite that is active against a variety of targets in addition to TYK2. A second unique aspect in the development of deucravacitinib is the targeting of a pseudokinase domain. Deucravacitinib is rather specific for TYK2 and its toxic effects are much less than those of the other FDA-approved JAK inhibitors. The successful development of deucravacitinib may stimulate the development of additional pseudokinase ligands for the JAK family and for other kinase families as well.

Properties of FDA-approved small molecule protein kinase inhibitors: A 2023 update

Owing to the dysregulation of protein kinase activity in many diseases including cancer, this enzyme family has become one of the most important drug targets in the 21st century. There are 72 FDA-approved therapeutic agents that target about two dozen different protein kinases and three of these drugs were approved in 2022. Of the approved drugs, twelve target protein-serine/threonine protein kinases, four are directed against dual specificity protein kinases (MEK1/2), sixteen block nonreceptor protein-tyrosine kinases, and 40 target receptor protein-tyrosine kinases. The data indicate that 62 of these drugs are prescribed for the treatment of neoplasms (57 against solid tumors including breast, lung, and colon, ten against nonsolid tumors such as leukemia, and four against both solid and nonsolid tumors: acalabrutinib, ibrutinib, imatinib, and midostaurin). Four drugs (abrocitinib, baricitinib, tofacitinib, upadacitinib) are used for the treatment of inflammatory diseases (atopic dermatitis, psoriatic arthritis, rheumatoid arthritis, Crohn disease, and ulcerative colitis). Of the 72 approved drugs, eighteen are used in the treatment of multiple diseases. The following three drugs received FDA approval in 2022 for the treatment of these specified diseases: abrocitinib (atopic dermatitis), futibatinib (cholangiocarcinomas), pacritinib (myelofibrosis). All of the FDA-approved drugs are orally effective with the exception of netarsudil, temsirolimus, and trilaciclib. This review summarizes the physicochemical properties of all 72 FDA-approved small molecule protein kinase inhibitors including lipophilic efficiency and ligand efficiency.

Current Landscape of Therapeutic Resistance in Lung Cancer and Promising Strategies to Overcome Resistance

Simple Summary

Despite an initial response to therapy, many lung cancer patients inevitably develop resistance to therapy leading to decreased duration of response and success of treatment. Recent research aims to elucidate mechanisms of resistance in order to improve drug response and treatment outcomes. By utilizing multidisciplinary approaches that target various resistance mechanism, it may be possible to delay development of treatment resistance or even resensitize cancers. This review aims to discuss novel approaches to improve clinical outcomes, delay the occurrence of resistance, and overcome resistance.

Abstract

Lung cancer is one of the leading causes of cancer-related deaths worldwide with a 5-year survival rate of less than 18%. Current treatment modalities include surgery, chemotherapy, radiation therapy, targeted therapy, and immunotherapy. Despite advances in therapeutic options, resistance to therapy remains a major obstacle to the effectiveness of long-term treatment, eventually leading to therapeutic insensitivity, poor progression-free survival, and disease relapse. Resistance mechanisms stem from genetic mutations and/or epigenetic changes, unregulated drug efflux, tumor hypoxia, alterations in the tumor microenvironment, and several other cellular and molecular alterations. A better understanding of these mechanisms is crucial for targeting factors involved in therapeutic resistance, establishing novel antitumor targets, and developing therapeutic strategies to resensitize cancer cells towards treatment. In this review, we summarize diverse mechanisms driving resistance to chemotherapy, radiotherapy, targeted therapy, and immunotherapy, and promising strategies to help overcome this therapeutic resistance.

Janus kinase (JAK) inhibitors in the treatment of neoplastic and inflammatory disorders

The Janus kinase (JAK) family of nonreceptor protein-tyrosine kinases consists of JAK1, JAK2, JAK3, and TYK2 (Tyrosine Kinase 2). Each of these proteins contains a JAK homology pseudokinase (JH2) domain that interacts with and regulates the activity of the adjacent protein kinase domain (JH1). The Janus kinase family is regulated by numerous cytokines including interferons, interleukins, and hormones such as erythropoietin and thrombopoietin. Ligand binding to cytokine receptors leads to the activation of associated Janus kinases, which then catalyze the phosphorylation of the receptors. The SH2 domain of signal transducers and activators of transcription (STAT) binds to the cytokine receptor phosphotyrosines thereby promoting STAT phosphorylation and activation by the Janus kinases. STAT dimers are then translocated into the nucleus where they participate in the regulation and expression of dozens of proteins. JAK1/3 signaling participates in the pathogenesis of inflammatory disorders while JAK1/2 signaling contributes to the development of myeloproliferative neoplasms as well as several malignancies including leukemias and lymphomas. An activating JAK2 V617F mutation occurs in 95% of people with polycythemia vera and about 50% of cases of myelofibrosis and essential thrombocythemia. Abrocitinib, ruxolitinib, and upadacitinib are JAK inhibitors that are FDA-approved for the treatment of atopic dermatitis. Baricitinib is used for the treatment of rheumatoid arthritis and covid 19. Tofacitinib and upadacitinib are JAK antagonists that are used for the treatment of rheumatoid arthritis and ulcerative colitis. Additionally, ruxolitinib is approved for the treatment of polycythemia vera while fedratinib, pacritinib, and ruxolitinib are approved for the treatment of myelofibrosis.

Lorlatinib as a treatment for ALK-positive lung cancer

Lorlatinib, a third-generation ALK tyrosine kinase inhibitor, has been approved as a treatment for ALK-positive lung cancer. This review provides information regarding the pharmacology and clinical features of lorlatinib, including its efficacy and associated adverse events. Pivotal clinical trials are discussed along with the current status of lorlatinib as a treatment for ALK-positive lung cancer and future therapeutic challenges.

Metastatic pheochromocytomas and paragangliomas: where are we?

Pheochromocytomas and paragangliomas (PPGLs) can metastasize in approximately 15-20% of cases. This review discusses the available evidence on the biology and treatment of metastatic PPGLs. Chemotherapy is the first-line treatment option for this evolving and symptomatic disease. In patients with high MIBG uptake and positive PETGa-68, radiometabolic treatment may be considered. The efficacy of sunitinib has been shown in observational studies, and pembrolizumab has been evaluated in phase II clinical studies, while other agents investigated in this setting are anti-angiogenic drugs cabozantinib, dovitinib, axitinib and lenvatinib. As these agents' efficacy and safety data, alone or in combination, are scant and based on few treated patients, enrollment in clinical trials is mandatory. Future therapeutic options may be represented by DNA repair system inhibitors (such as olaparib), HIF2 inhibitors and immunotherapy.

Inhibition of human lung cancer cells by anti-p21Ras scFv mediated by the activatable cell-penetrating peptide

Activatable cell-penetrating peptide (ACPP) is a tumour-targeting cell-penetrating peptide. Here, we used ACPP to carry anti-p21Ras scFv for Ras-driven cancer therapy. The ACPP-p21Ras scFv fusion protein was prepared by a prokaryotic expression system and Ni-NTA column purification. The human tumour cell lines A549, SW480, U251 and Huh7 and the normal cell line BEAS 2B were used to study the tumor-targeting and membrane-penetrating ability of ACPP-p21Ras scFv. The antitumour activity of ACPP-p21Ras scFv on A549 cells and H1299 cells in vitro was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, scratch wound healing, plate cloning and apoptosis assays. The penetration pathway of ACPP was determined by enhanced green fluorescent protein. The ACPP-p21Ras scFv fusion protein was successfully obtained at a concentration of 1.8 mg/ml. We found that ACPP-p21Ras scFv could penetrate tumour cell membranes with high expression of matrix metalloproteinase-2 (MMP-2), effectively inhibit the migration and proliferation of A549 cells and H1299 cells, and promote the apoptosis of A549 cells and H1299 cells. The membrane penetration experiment demonstrated that ACPP could enter A549 cells by direct penetration. The ability of ACPP to penetrate the membrane was affected by the addition of a membrane affinity inhibitor and a change in the potential difference across the cell membrane but not by the addition of endocytosis inhibitors and a change in temperature. The ACPP-p21Ras scFv fusion protein can penetrate tumour cells with MMP-2 expression and has antitumour activity against A549 cells and H1299 cells in vitro. This molecule is expected to become a potential antitumour drug for Ras gene-driven lung cancer.

Deciphering the Mechanism of Gilteritinib Overcoming Lorlatinib Resistance to the Double Mutant I1171N/F1174I in Anaplastic Lymphoma Kinase

Anaplastic lymphoma kinase (ALK) is validated as a therapeutic molecular target in multiple malignancies, such as non-small cell lung cancer (NSCLC). However, the feasibility of targeted therapies exerted by ALK inhibitors is inevitably hindered owing to drug resistance. The emergence of clinically acquired drug mutations has become a major challenge to targeted therapies and personalized medicines. Thus, elucidating the mechanism of resistance to ALK inhibitors is helpful for providing new therapeutic strategies for the design of next-generation drug. Here, we used molecular docking and multiple molecular dynamics simulations combined with correlated and energetical analyses to explore the mechanism of how gilteritinib overcomes lorlatinib resistance to the double mutant ALK I1171N/F1174I. We found that the conformational dynamics of the ALK kinase domain was reduced by the double mutations I1171N/F1174I. Moreover, energetical and structural analyses implied that the double mutations largely disturbed the conserved hydrogen bonding interactions from the hinge residues Glu1197 and Met1199 in the lorlatinib-bound state, whereas they had no discernible adverse impact on the binding affinity and stability of gilteritinib-bound state. These discrepancies created the capacity of the double mutant ALK I1171N/F1174I to confer drug resistance to lorlatinib. Our result anticipates to provide a mechanistic insight into the mechanism of drug resistance induced by ALK I1171N/F1174I that are resistant to lorlatinib treatment in NSCLC.

Properties of FDA-approved small molecule protein kinase inhibitors: A 2022 update

Owing to the dysregulation of protein kinase activity in many diseases including cancer, this enzyme family has become one of the most important drug targets in the 21st century. There are 68 FDA-approved therapeutic agents that target about two dozen different protein kinases and six of these drugs were approved in 2021. Of the approved drugs, twelve target protein-serine/threonine protein kinases, four are directed against dual specificity protein kinases (MEK1/2), thirteen block nonreceptor protein-tyrosine kinases, and 39 target receptor protein-tyrosine kinases. The data indicate that 58 of these drugs are prescribed for the treatment of neoplasms (49 against solid tumors including breast, lung, and colon, five against nonsolid tumors such as leukemias, and four against both solid and nonsolid tumors: acalabrutinib, ibrutinib, imatinib, and midostaurin). Three drugs (baricitinib, tofacitinib, upadacitinib) are used for the treatment of inflammatory diseases including rheumatoid arthritis. Of the 68 approved drugs, eighteen are used in the treatment of multiple diseases. The following six drugs received FDA approval in 2021 for the treatment of these specified diseases: belumosudil (graft vs. host disease), infigratinib (cholangiocarcinomas), mobocertinib and tepotinib (specific forms of non-small cell lung cancer), tivozanib (renal cell carcinoma), and trilaciclib (to decrease chemotherapy-induced myelosuppression). All of the FDA-approved drugs are orally effective with the exception of netarsudil, temsirolimus, and the newly approved trilaciclib. This review summarizes the physicochemical properties of all 68 FDA-approved small molecule protein kinase inhibitors including lipophilic efficiency and ligand efficiency.

Resistance to Targeted Agents Used to Treat Paediatric ALK-Positive ALCL

Simple Summary

In general, the non-Hodgkin lymphoma (NHL), anaplastic large cell lymphoma (ALCL) diagnosed in childhood has a good survival outcome when treated with multi-agent chemotherapy. However, side effects of treatment are common, and outcomes are poorer after relapse, which occurs in up to 30% of cases. New drugs are required that are more effective and have fewer side effects. Targeted therapies are potential solutions to these problems, however, the development of resistance may limit their impact. This review summarises the potential resistance mechanisms to these targeted therapies.

Abstract

Non-Hodgkin lymphoma (NHL) is the third most common malignancy diagnosed in children. The vast majority of paediatric NHL are either Burkitt lymphoma (BL), diffuse large B-cell lymphoma (DLBCL), anaplastic large cell lymphoma (ALCL), or lymphoblastic lymphoma (LL). Multi-agent chemotherapy is used to treat all of these types of NHL, and survival is over 90% but the chemotherapy regimens are intensive, and outcomes are generally poor if relapse occurs. Therefore, targeted therapies are of interest as potential solutions to these problems. However, the major problem with all targeted agents is the development of resistance. Mechanisms of resistance are not well understood, but increased knowledge will facilitate optimal management strategies through improving our understanding of when to select each targeted agent, and when a combinatorial approach may be helpful. This review summarises currently available knowledge regarding resistance to targeted therapies used in paediatric anaplastic lymphoma kinase (ALK)-positive ALCL. Specifically, we outline where gaps in knowledge exist, and further investigation is required in order to find a solution to the clinical problem of drug resistance in ALCL.

Discovery of 2,4-pyrimidinediamine derivatives as potent dual inhibitors of ALK and HDAC

Combination of anaplastic lymphoma kinase (ALK) inhibitor with histone deacetylases (HDAC) inhibitor could exert synergistically anti-proliferative effects on ALK positive non-small cell lung cancer (NSCLC) naïve or resistant cells. In this work, we designed and synthesized a series of 2,4-pyrimidinediamine derivatives as dual ALK and HDAC inhibitors based on pharmacophore merged strategy. Among which, compound 10f displayed the most potent and balanced inhibitory activity against ALK (IC₅₀ = 2.1 nM) and HDAC1 (IC₅₀ = 7.9 nM), respectively. In particular, 10f was also potent against the frequently observed Crizotinib-resistant ALK^L1196M (IC₅₀ = 1.7 nM) as well as the Ceritinib-resistant ALK^G1202R (IC₅₀ = 0.4 nM) mutants. In antiproliferative activity assay, 10f exhibited impressive activity on ALK-addicted cancer cell lines at low micromole concentrations, which was comparable to that of Crizotinib and Ceritinib. Further flow cytometric analysis indicated that 10f could effectively induce cell death via cell apoptosis and cell cycle arrest. Taken together, these results suggested 10f would be a promising lead compound for the ALK-positive NSCLC treatment, especially the Ceritinib- or Crizotinib-resistant NSCLC.

Small molecules in targeted cancer therapy: advances, challenges, and future perspectives

Due to the advantages in efficacy and safety compared with traditional chemotherapy drugs, targeted therapeutic drugs have become mainstream cancer treatments. Since the first tyrosine kinase inhibitor imatinib was approved to enter the market by the US Food and Drug Administration (FDA) in 2001, an increasing number of small-molecule targeted drugs have been developed for the treatment of malignancies. By December 2020, 89 small-molecule targeted antitumor drugs have been approved by the US FDA and the National Medical Products Administration (NMPA) of China. Despite great progress, small-molecule targeted anti-cancer drugs still face many challenges, such as a low response rate and drug resistance. To better promote the development of targeted anti-cancer drugs, we conducted a comprehensive review of small-molecule targeted anti-cancer drugs according to the target classification. We present all the approved drugs as well as important drug candidates in clinical trials for each target, discuss the current challenges, and provide insights and perspectives for the research and development of anti-cancer drugs.

Successful Treatment with Ensartinib After Alectinib-induced Hyperbilirubinemia in ALK-Positive NSCLC

Background

Alectinib is approved for the treatment of advanced non-small-cell lung cancer (NSCLC) harboring ALK rearrangements. Although generally well tolerated, alectinib can cause serious or life-threatening side effects.

Case Presentation

Here, we report a case of a patient with NSCLC with an EML4-ALK fusion and was treated with alectinib but who developed grade 4 hyperbilirubinemia after five months on therapy. Alectinib was discontinued, and an artificial liver support system (ALSS) was used with an impressive decline in bilirubin levels. After two months drug-free, the patient experienced disease progression. Ensartinib was initiated as second-line treatment with a best response of stable disease after three months of therapy with no evidence of hyperbilirubinemia.

Conclusion

This is the first report of ensartinib treatment after alectinib-induced hyperbilirubinemia which was successfully relieved by ALSS treatment and targeted drug cessation.

Hydrophobic and polar interactions of FDA-approved small molecule protein kinase inhibitors with their target enzymes

Dysregulation and mutations of protein kinases play causal roles in many diseases including cancer. The KLIFS (kinase-ligand interaction fingerprint and structure) catalog includes 85 ligand binding-site residues occurring in both the small and large protein kinase lobes. Except for allosteric inhibitors, all FDA-approved drug-target enzyme complexes display hydrophobic interactions involving catalytic spine residue-6 (KLIFS-77), catalytic spine residue-7 (KLIFS-11), and catalytic spine residue-8 (KLIFS-15) within the small lobe and residues within the hinge-linker region (KLIFS-46-52). Except for allosteric antagonists, the approved drugs form hydrogen bonds with the third hinge residue (KLIFS-48) of their target. Most of the approved drugs, including the allosteric inhibitors, interact with the small lobe gatekeeper residue (KLIFS-45). The type IIA inhibitors have the most hydrophobic interactions with their target enzymes. These include interactions with KLIFS-27/31/35/61/66 residues of the back pocket within both the small and large lobes. There is also interaction with KLIFS-68 (regulatory spine residue-1), the conserved histidine of the catalytic loop that is found in the back pocket of type II antagonists, but within the front pocket of the other types of inhibitors. Owing to the participation of protein kinase signaling cascades in a wide variety of physiological and pathological processes, one can foresee the increasing use of targeted inhibitors both as primary and secondary treatments for many illnesses. Further studies of protein kinase signal transduction pathways promise to yield new and actionable information that will serve as a basis for fundamental and applied biomedical breakthroughs.

Molecular Docking, 3D-QSAR, Fingerprint-Based 2D-QSAR, Analysis of Pyrimidine, and Analogs of ALK (Anaplastic Lymphoma Kinase) Inhibitors as an Anticancer Agent

Background:

ALK inhibitors have become a plausible option for anticancer therapy with the availability of several FDA-approved molecules and clinical trial candidates. Hence, the design of new ALK inhibitors using computational molecular docking studies on the existing inhibitors, is an attractive approach for anticancer drug discovery.

Methods:

We generated six types of independent models through structural based molecular docking study, three-dimensional quantitative structure-activity relationship (3D-QSAR) study, and 2DQSAR approaches using different fingerprints, such as dendritic, linear, 2D molprint, and radial.

Results:

Comparison of the generated models showed that the hinge region hydrogen bond interacted with amino acids ASP1206, MET1199, and LYS1150 in docking analysis and the hydrophobic interacted with amino acids GLU1210, ARG1209, SER1206, and LYS1205 residues are responsible for the ALK inhibition. In the 3D-QSAR study, the hydrogen bond donor features of 2,4- diaryl aminopyrimidine substituents, isopropyl phenyl ring groups in hydrophobic features, and electron-withdrawing groups matched the generated contour plots. The 2D-QSAR fingerprint studies indicated that higher potency was associated with the 2-hydroxy-5-isopropyl benzamide functional group and substituted phenylamine at the second position of the pyrimidine group.

Conclusion:

We conclude that the incorporation of these functional groups in the design of new molecules may result in more potent ALK inhibitors.

The Landscape of the Advanced NSCLC Treatment Paradigm: Molecular Testing and Actionable Mutations

At JADPRO Live Virtual 2020, Rasheda Persinger, AGNP-C, explained the current lung cancer treatment landscape, including targeted therapies for EGFR and ALK rearrangements, as well as for BRAF, ROS1, NTRK, RET, MET, and KRAS mutations, and described the different testing modalities for molecular markers.

Properties of FDA-approved small molecule phosphatidylinositol 3-kinase inhibitors prescribed for the treatment of malignancies

The discovery of the phosphatidylinositol 3-kinase (PI 3-kinase) pathway was a major advance in understanding eukaryotic signal transduction. The high frequency of PI 3-kinase pathway mutations in many cancers stimulated the development of drugs targeting these oncogenic mutants. The PI 3-kinases are divided into three classes and Class I PI 3-kinases, which catalyze the phosphorylation of phosphatidylinositol-4,5-bisphosphate (PI-4,5-P2) to generate phosphatidylinositol-3,4,5-trisphosphate (PIP3), are the main subject of this review. The class I PI 3-kinases are made up of p110α, p110β, p110δ, and p110γ catalytic subunits. These catalytic subunits are constitutively bound to regulatory subunits (p85α, p85β, p55γ, p101, and p87 proteins). The p85/p55 regulatory subunits heterodimerize with p110α or p110δ thereby forming complexes that are regulated chiefly by receptor protein-tyrosine kinases. The p101 and p87 subunits heterodimerize with p110γ to form complexes that are regulated mainly by G protein-coupled receptors (GPCRs). Complexes containing the p110β subunit are activated by receptor protein-tyrosine kinases as well as GPCRs. Following the generation of PIP3, the AKT and mTOR protein-serine/threonine kinases are activated leading to cell growth, proliferation, and survival. Like protein kinases, the PI 3-kinase domains consist of a bilobed structure connected by a hinge-linker segment. ATP and most PI 3-kinase and protein kinase inhibitors form hydrogen bonds with hinge residues. The small and large lobes of PI 3-kinases and protein kinases have a very similar three-dimensional structure called the protein kinase fold. Both PI 3-kinases and eukaryotic protein kinases possess an activation segment that begins with a DFG triad (Asp-Phe-Gly); the activation segment of protein kinases usually ends with an APE (Ala-Pro-Glu) signature while that of PI 3-kinases ends with a PFxLT (Pro-Phe-Xxx-Leu-Thr) signature. Dormant PI 3-kinases have a collapsed activation loop and active PI 3-kinases have an extended activation loop. The distance between the α-carbon atom of the DFG-D residue at the beginning of the activation loop and that of the PFxLT-F residue at the end of the activation loop in dormant PI 3-kinases is about 13 Å; this distance in active PI 3-kinases is about 18 Å. The protein kinase catalytic loop has an HRD (His-Arg-Asp) signature while that of the PI 3-kinases reverses the order with a DRH triad. Alpelisib is an orally effective FDA-approved PI 3-kinase-α inhibitor used for the treatment of breast cancer. Copanlisib, duvelisib, idelalisib, and umbralisib are PI 3-kinase-δ inhibitors that are approved for the third-line treatment of follicular lymphomas and other hematological disorders. Copanlisib is also a potent inhibitor of PI 3-kinase-α. Of the five approved drugs, all are orally bioavailable except copanlisib. Idelalisib interacts with the active conformation of PI 3-kinase-δ and is classified as a type I inhibitor. Alpelisib and copanlisib interact with inactive PI 3-kinase-α and PI 3-kinase-γ, respectively, and are classified as a type I½ antagonists. Except for umbralisib with a molecular weight of 571.5, all five drugs conform to the Lipinski rule of five for oral effectiveness. Copanlisib, however, must be given intravenously. Alpelisib and copanlisib inhibit PI 3-kinase-α, which is involved in insulin signaling, and both drugs promote insulin-resistance and produce hyperglycemia. The five FDA-approved PI 3-kinase inhibitors produce significant on-target toxicities, more so than many approved protein kinase antagonists. The development of PI 3-kinase inhibitors with fewer toxicities is an important long-term therapeutic goal.

Orally effective FDA-approved protein kinase targeted covalent inhibitors (TCIs)

Because dysregulation of protein kinases owing to mutations or overexpression plays causal roles in human diseases, this family of enzymes has become one of the most important drug targets of the 21st century. Of the 62 protein kinases inhibitors that are approved by the FDA, seven of them form irreversible covalent adducts with their target enzymes. The clinical success of ibrutinib, an inhibitor of Bruton tyrosine kinase, in the treatment of mantle cell lymphomas following its approval in 2013 helped to overcome a general bias against the development of irreversible drug inhibitors. The other approved covalent drugs include acalabrutinib and zanubrutinib, which also inhibit Bruton tyrosine kinase. Furthermore afatinib, dacomitinib, and osimertinib, inhibitors of members of the epidermal growth factor receptor family (ErbB1/2/3/4), are used in the treatment of non-small cell lung cancers. Neratinib is an inhibitor of ErbB2 and is used in the treatment of ErbB2/HER2-positive breast cancer. The seven drugs considered in this review have a common mechanism of action; this process involves the addition of a protein cysteine thiolate anion (protein‒S:^-) to an acrylamide derivative (CH₂=CHC(=O)N(H)R) where R represents the pharmacophore. Such reactions are commonly referred to as Michael additions and each reaction results in the formation of a covalent bond between carbon and sulfur; the final product is a thioether. This process consists of two discrete steps; the first step involves the reversible association of the drug with its target enzyme so that a weakly electrophilic functionality, a warhead, is bound near an appropriately positioned nucleophilic cysteine. In the second step, a reaction occurs between the warhead and the target enzyme cysteine to form a covalently modified and inactive protein. For this process to work, the warhead must be appropriately juxtaposed in relationship to the cysteinyl thiolate so that the covalent addition can occur. Covalent inhibitors have emerged from the ranks of drugs to be avoided to become an emerging paradigm. Much of this recent success can be attributed to the clinical efficacy of ibrutinib as well as the other antagonists covered in this review. Moreover, the covalent inhibitor methodology is swiftly gaining acceptance as a valuable component of the medicinal chemist's toolbox and is primed to make a significant impact on the development of enzyme antagonists and receptor modulators.

Medicinal Chemistry Strategies for the Development of Kinase Inhibitors Targeting Point Mutations

Clinically acquired resistance to small molecule kinase inhibitors (SMKIs) has become a major "unmet clinical need" in cancer therapy. To date, there are six SMKIs to be approved for the treatment of cancer patients through targeting of clinically acquired resistance caused by on-target mutations. These are mainly focused on the mutant kinases Bcr-Abl T315I, EGFR T790M, and ALK L1196M. Herein, we summarize the major medicinal chemistry strategies employed in the discovery of these representative SMKIs, such as avoiding steric hindrance, making additional interactions with mutated residues, and forming a covalent bond with an active site cysteine to override resistance observed for reversible inhibitors. Additionally, we also briefly describe allosteric kinase inhibitors and proteolysis targeting chimera (PROTAC) as two other potential strategies while addressing future opportunities in this area.

Ceritinib-associated hyperglycemia in the Japanese Adverse Drug Event Report Database

Genetic rearrangements of anaplastic lymphoma kinase contribute to the pathogenesis of non-small-cell lung cancer; the anaplastic lymphoma kinase inhibitor, ceritinib, is widely used, as it is effective even in patients with non-small-cell lung cancer resistant to other anaplastic lymphoma kinase inhibitors. Although a case of possible ceritinib-induced hyperglycemia was reported, the association of ceritinib with hyperglycemia remains to be investigated. Disproportionality analysis was carried out using the Japanese Adverse Drug Event Report database, which contains all pharmacovigilance data based on spontaneous reports of adverse events between April 2004 and November 2018 to the Pharmaceuticals and Medical Devices Agency. The reporting odds ratio of ceritinib for hyperglycemia was 2.25 (95% confidence interval [CI] 1.24-4.08], whereas those of crizotinib and alectinib were 0.07 (95% CI 0.01-0.40) and 0.94 (95% CI 0.30-2.94), respectively. Among reported events without antidiabetes agent use, the reporting odds ratio of ceritinib was still 2.54 (95% CI 1.27-5.12). Thus, the possibility of hyperglycemia should be carefully monitored in patients receiving ceritinib.

Pharmacokinetic-Based Drug-Drug Interactions with Anaplastic Lymphoma Kinase Inhibitors: A Review

Anaplastic lymphoma kinase (ALK) inhibitors are important treatment options for non-small-cell lung cancer (NSCLC), associated with ALK gene rearrangement. Patients with ALK gene rearrangement show sensitivity to and benefit clinically from treatment with ALK tyrosine kinase inhibitors (ALK-TKIs). To date, crizotinib, ceritinib, alectinib, brigatinib, lorlatinib, and entrectinib have received approval from the US Food and Drug Administration and/or the European Medicines Agency for use during the treatment of ALK-gene-rearrangement forms of NSCLC. Although the oral route of administration is convenient and results in good compliance among patients, oral administration can be affected by many factors, such as food, intragastric pH, cytochrome P450 enzymes, transporters, and p-glycoprotein. These factors can result in increased risks for serious adverse events or can lead to reduced therapeutic effects of ALK-TKIs. This review characterizes and summarizes the pharmacokinetic parameters and drug–-drug interactions associated with ALK-TKIs to provide specific recommendations for oncologists and clinical pharmacists when prescribing ALK-TKIs.

Expression of CHPF modulates cell proliferation and invasion in lung cancer

Lung cancer is the most common malignancy worldwide and is characterized by rapid progression, aggressive behavior, frequent recurrence, and poor prognosis. The TCGA database indicates that chondroitin polymerizing factor (CHPF) is overexpressed in human lung cancer tissues compared with normal tissues and this overexpression corresponds to shorter overall survival in lung cancer patients. In this study, to investigate the function of CHPF in lung cancer, lentiviral vectors expressing CHPF shRNA were stably transduced into A549 and H1299 cells. Compared to shCtrl cells, CHPF knockdown cells had significantly reduced proliferation. Furthermore, the silencing of CHPF in A549 and H1299 cells resulted in apoptotic induction, which led to decreased colony formation. Wound healing and transwell invasion assays revealed that CHPF could positively regulate the migration of lung cancer cells. The tumorigenic role of CHPF was also validated in nude mouse xenograft models. Affymetrix gene chip analysis indicated that CHPF regulated the proliferation and invasion of lung cancer cells through CDH1, RRM2, MKI67, and TNFRSF10B. We thus highlight CHPF as a novel target for lung cancer treatment.

Efficacy and safety of ALK inhibitors in ALK-rearranged non-small cell lung cancer: A systematic review and meta-analysis

OBJECTIVES

No overall survival (OS) benefit has been reported from a mature randomized trial with the use of ALK inhibitors. We conducted a systematic review and meta-analysis to assess the efficacy of ALK inhibitors compared to chemotherapy (ALK vs. chemo) and 2nd generation ALK inhibitors compared to 1 st generation ALK inhibitors (ALK-2 G vs. ALK-1 G).

METHODS

The electronic databases Medline (PubMed), EMBASE, and the Cochrane Database of Systematic Reviews were searched for relevant randomized trials. Pooled hazard ratios (HR) for OS and progression free survival (PFS), and pooled risk ratios for objective response rates (ORR) and toxicity were meta-analyzed using the generic inverse variance and the Mantel-Haenszel methods. To account for between-studies heterogeneity, random-effect models were used. Subgroup analyses compared PFS by gender, smoking status, brain metastases, race and age.

RESULTS

Six trials were included in the analysis of ALK vs. chemo and four in the analysis of ALK-2 G vs. ALK-1 G. Treatment with ALK inhibitors improved OS compared to chemotherapy (HR: 0.84, 95 %CI 0.72-0.97) while a trend toward a better OS was seen with ALK-2 G vs. ALK-1 G (HR: 0.66, 95 %CI 0.43-1.02). PFS was improved with ALK vs. chemo and ALK-2 G vs. ALK-1 G (HR: 0.44, 95 %CI 0.35-0.54 and HR: 0.38, 95 %CI-0.29-0.51, respectively). ORR was improved with ALK vs. chemo and ALK-2 G vs. ALK-1 G. No difference in toxicity was observed.

CONCLUSIONS

This meta-analysis is the first, to our knowledge, to report an OS and PFS benefit with the use of ALK inhibitors compared to chemotherapy from randomized trial data. A trend toward a better OS was also seen with ALK-2 G vs. ALK-1 G and this is likely because of crossover effects and limited OS follow-up. Longer follow up and further research are warranted to directly compare ALK inhibitor sequences and to understand the outcomes of second generation ALK inhibitors as initial therapy.

Continual Improvement of the Reliability of EML4-ALK Rearrangement Detection in Non-Small-Cell Lung Cancer: A Long-Term Comparison of ALK Detection in China

The results of EML4-ALK testing are critical to manage ALK tyrosine kinase receptor inhibitor treatment. Thus, the accurate detection of ALK rearrangement is increasingly becoming a matter of serious concern. To address this issue, a long-term EML4-ALK proficiency testing (PT) scheme was launched in China in 2015, serving as an educational tool for assessing and improving the testing quality of EML4-ALK fusion detection. Responses across 20 different PT samples interrogating three different variants and wild-type samples were collected between 2015 and 2019. Performance was analyzed by evaluating the detection methods, kits, and pre-analytic practices used to further display the landscape of changing conditions of the reliability of EML4-ALK testing. During the 5 years, 3224 results reported from 988 laboratories were evaluated, with an overall error rate of 5.36%. Along with an increasing number of participating laboratories, the error rate within each of the different methods showed a significantly downward trend over the years. No obvious differences in the error rates were found regarding the testing methods or kit manufacturers. Moreover, the individual performance of the laboratories improved when they participated in more PT scheme rounds. The data demonstrated that the performance of individual Chinese laboratories for EML4-ALK testing continuously improved over time by participating PT schemes, regardless of their method. However, care must be taken in standardized operations and validations.

Clinical consequences of resistance to ALK inhibitors in non-small cell lung cancer

Introduction: ALK rearrangements are present in 2-7% of non-small cell lung cancer (NSCLC) cases, where the EML4-ALK fusion is the most frequent. Rearrangement of ALK with other fusion partners occurs only in ≈5% of NSCLC ALK-positive. These patients have benefited from ALK inhibitors, and currently, there are three generations of drugs as the standard of care. The first-generation ALK inhibitor crizotinib is approved in the front-line setting for the treatment of advanced NSCLC; unfortunately, these tumors may eventually develop resistance to this molecule. The Second-generation ALK inhibitors, ceritinib, alectinib, and brigatinib, are approved for patients recently diagnosed or in relapse. The third-generation inhibitor lorlatininb is approved for patients who have developed resistance to any ALK inhibitor.Areas covered: In this review, an unstructured search in Pubmed and SCOPUS was conducted. We summarized the mechanisms of resistance to ALK inhibitors and its consequences in the treatment-decision making in advanced or metastatic NSCLC after failure to a first-line ALK inhibitor.Expert opinion: Currently, there are a growing number of options of therapeutic agents against ALK+ NSCLC (approved and in development); however, adequate selection and sequencing of agents are crucial to deal with the tumor evolution.

Alternative and New Radiopharmaceutical Agents for Lung Cancer

BACKGROUND

FDG PET/CT imaging has an established role in lung cancer (LC) management. Whilst it is a sensitive technique, FDG PET/CT has a limited specificity in the differentiation between LC and benign conditions and is not capable of defining LC heterogeneity since FDG uptake varies between histotypes.

OBJECTIVE

To get an overview of new radiopharmaceuticals for the study of cancer biology features beyond glucose metabolism in LC.

METHODS

A comprehensive literature review of PubMed/Medline was performed using a combination of the following keywords: "positron emission tomography", "lung neoplasms", "non-FDG", "radiopharmaceuticals", "tracers".

RESULTS

Evidences suggest that proliferation markers, such as 18F-Fluorothymidine and 11CMethionine, improve LC staging and are useful in evaluating treatment response and progression free survival. 68Ga-DOTA-peptides are already routinely used in pulmonary neuroendocrine neoplasms (NENs) management and should be firstly performed in suspected NENs. 18F-Fluoromisonidazole and other radiopharmaceuticals show a promising impact on staging, prognosis assessment and therapy response in LC patients, by visualizing hypoxia and perfusion. Radiolabeled RGD-peptides, targeting angiogenesis, may have a role in LC staging, treatment outcome and therapy. PET radiopharmaceuticals tracing a specific oncogene/signal pathway, such as EGFR or ALK, are gaining interest especially for therapeutic implications. Other PET tracers, like 68Ga-PSMA-peptides or radiolabeled FAPIs, need more development in LC, though, they are promising for therapy purposes.

CONCLUSION

To date, the employment of most of the described tracers is limited to the experimental field, however, research development may offer innovative opportunities to improve LC staging, characterization, stratification and response assessment in an era of increased personalized therapy.

Properties of FDA-approved small molecule protein kinase inhibitors: A 2020 update

Because genetic alterations including mutations, overexpression, translocations, and dysregulation of protein kinases are involved in the pathogenesis of many illnesses, this enzyme family is currently the subject of many drug discovery programs in the pharmaceutical industry. The US FDA approved four small molecule protein kinase antagonists in 2019; these include entrectinib, erdafitinib, pexidartinib, and fedratinib. Entrectinib binds to TRKA/B/C and ROS1 and is prescribed for the treatment of solid tumors with NTRK fusion proteins and for ROS1-postive non-small cell lung cancers. Erdafitinib inhibits fibroblast growth factor receptors 1-4 and is used in the treatment of urothelial bladder cancers. Pexidartinib is a CSF1R antagonist that is prescribed for the treatment of tenosynovial giant cell tumors. Fedratinib blocks JAK2 and is used in the treatment of myelofibrosis. Overall, the US FDA has approved 52 small molecule protein kinase inhibitors, nearly all of which are orally effective with the exceptions of temsirolimus (which is given intravenously) and netarsudil (an eye drop). Of the 52 approved drugs, eleven inhibit protein-serine/threonine protein kinases, two are directed against dual specificity protein kinases, eleven target non-receptor protein-tyrosine kinases, and 28 block receptor protein-tyrosine kinases. The data indicate that 46 of these drugs are used in the treatment of neoplastic diseases (eight against non-solid tumors such as leukemias and 41 against solid tumors including breast and lung cancers; some drugs are used against both tumor types). Eight drugs are employed in the treatment of non-malignancies: fedratinib, myelofibrosis; ruxolitinib, myelofibrosis and polycythemia vera; fostamatinib, chronic immune thrombocytopenia; baricitinib, rheumatoid arthritis; sirolimus, renal graft vs. host disease; nintedanib, idiopathic pulmonary fibrosis; netarsudil, glaucoma; and tofacitinib, rheumatoid arthritis, Crohn disease, and ulcerative colitis. Moreover, sirolimus and ibrutinib are used for the treatment of both neoplastic and non-neoplastic diseases. Entrectinib and larotrectinib are tissue-agnostic anti-cancer small molecule protein kinase inhibitors. These drugs are prescribed for the treatment of any solid cancer harboring NTRK1/2/3 fusion proteins regardless of the organ, tissue, anatomical location, or histology type. Of the 52 approved drugs, seventeen are used in the treatment of more than one disease. Imatinib, for example, is approved for the treatment of eight disparate disorders. The most common drug targets of the approved pharmaceuticals include BCR-Abl, B-Raf, vascular endothelial growth factor receptors (VEGFR), epidermal growth factor receptors (EGFR), and ALK. Most of the approved small molecule protein kinase antagonists (49) bind to the protein kinase domain and six of them bind covalently. In contrast, everolimus, temsirolimus, and sirolimus are larger molecules (MW ≈ 1000) that bind to FK506 binding protein-12 (FKBP-12) to generate a complex that inhibits the mammalian target of rapamycin (mTOR) protein kinase complex. This review presents the physicochemical properties of all of the FDA-approved small molecule protein kinase inhibitors. Twenty-two of the 52 drugs have molecular weights greater than 500, exceeding a Lipinski rule of five criterion. Excluding the macrolides (everolimus, sirolimus, temsirolimus), the average molecular weight of the approved drugs is 480 with a range of 306 (ruxolitinib) to 615 (trametinib). More than half of the antagonists (29) have lipophilic efficiency values of less than five while the recommended optima range from 5 to 10. One of the troublesome problems with both targeted and cytotoxic drugs in the treatment of malignant diseases is the near universal development of resistance to every therapeutic modality.

Simultaneous Quantification of Brigatinib and Brigatinib-Analog in Rat Plasma and Brain Homogenate by LC-MS/MS: Application to Comparative Pharmacokinetic and Brain Distribution Studies

Brigatinib and brigatinib-analog are potent and selective ALK inhibitors with the similar structure. A simple and sensitive high-performance liquid chromatography with tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of brigatinib and brigatinib-analog in rat plasma and brain homogenate was developed and validated. Chromatographic separation was carried out on an ODS column with acetonitrile and 0.1% formic acid in water as the mobile phase with gradient elution at a flow rate of 0.5 mL/min. Detections were performed using a TSQ Quantum Ultra mass spectrometric detector with electrospray ionization (ESI) interface, which was operated in the positive ion mode. A simple protein precipitation preparation process was used. The lower limits of quantification (LLOQs) were 1.0 ng/mL and 0.5 ng/mL for analytes in rat plasma and brain homogenate, respectively. The intrabatch and interbatch precision and accuracy of brigatinib and brigatinib-analog were well within the acceptable limits of variation. The simple and sensitive LC-MS/MS method was successfully applied to the pharmacokinetic and brain distribution studies following a single oral administration of brigatinib and brigatinib-analog to rats. The above studies would lay a good foundation for the further applications of brigatinib and brigatinib-analog.

[Therapeutic strategies in advanced ALK positive non-small cell lung cancer]

Anaplastic lymphoma kinase (ALK) rearrangement is a therapeutically targetable oncogenic driver found in 5% of patients with non-small-cell lung cancer (NSCLC). The objective of this paper is to synthesise current knowledge on ALK rearrangement and its impact on the management of advanced NSCLC. Several inhibitors of the tyrosine kinase of ALK (crizotinib, ceritinib, alectinib) have been approved as first line therapies in patients with advanced ALK positive NSCLC, which are associated with a better median progression-free survival than conventional chemotherapy. Unfortunately, the emergence of drug resistance leads to tumor progression. In patients with oligoprogressive disease if local ablative therapy can be effected, continuing with the same ALK tyrosine kinase inhibitor is one option. In patients with progression, clinicians may consider switching to another therapy. Rebiopsy of the tumor or liquid biopsy could be attempted to identify the mechanisms of resistance and to customize ALK-target therapy. The emergence of crizotinib drug resistance has prompted the development of next generation drugs including ceritinb, alectinib, brigatinib and lorlatinib. The ability to quickly develop targeted therapies against specific oncogenic drivers will require close co-operation between pathologists, pulmonologists and oncologists in the future to keep pace with drug discoveries and to define optimal therapeutic strategies.

Synthesis and anti-tumor efficacy of novel 2, 4-diarylaminopyrimidine derivatives bearing N-(3-pyridinylmethyl) urea moiety as anaplastic lymphoma kinase inhibitors

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase responsible for development of various tumor types. In this study, we synthesized a series of novel 2,4-diarylaminopyrimidine derivatives possessing a unique N-(3-pyridinylmethyl)urea moiety as ALK inhibitors. The most promising analog 5m bearing a 3-methoxy-4-morpholinophenyl substituent significantly inhibited proliferation of ALK positive H3122 and Karpas-299 cells with IC₅₀ values about 10 nM, which were comparable with positive control LDK378. Compound 5m suppressed phosphorylation of ALK and its downstream proteins, and showed low cytotoxicity on normal human primary fibroblast cells (BJ cells). The binding mode of 5m was proposed by docking simulation, which explains the important role of N-(3-pyridinylmethyl)urea moiety. Furthermore, compound 5m exhibited favorable liver microsomal stability and significant efficacy in H3122 xenograft mice model. Interestingly, compound 5m also showed broader anti-proliferative activity on other human tumor cell lines, which was different from other ALK inhibitors.

Drug Discovery Targeting Anaplastic Lymphoma Kinase (ALK)

As a receptor tyrosine kinase of insulin receptor (IR) subfamily, anaplastic lymphoma kinase (ALK) has been validated to play important roles in various cancers, especially anaplastic large cell lymphoma (ALCL), nonsmall cell lung cancer (NSCLC), and neuroblastomas. Currently, five small-molecule inhibitors of ALK, including Crizotinib, Ceritinib, Alectinib, Brigatinib, and Lorlatinib, have been approved by the U.S. Food and Drug Administration (FDA) against ALK-positive NSCLCs. Novel type-I¹/₂ and type-II ALK inhibitors with improved kinase selectivity and enhanced capability to combat drug resistance have also been reported. Moreover, the "proteolysis targeting chimera" (PROTAC) technique has been successfully applied in developing ALK degraders, which opened a new avenue for targeted ALK therapies. This review provides an overview of the physiological and biological functions of ALK, the discovery and development of drugs targeting ALK by focusing on their chemotypes, activity, selectivity, and resistance as well as potential therapeutic strategies to overcome drug resistance.

Novel derivatives of anaplastic lymphoma kinase inhibitors: Synthesis, radiolabeling, and preliminary biological studies of fluoroethyl analogues of crizotinib, alectinib, and ceritinib

Anaplastic lymphoma kinase (ALK), an oncogenic receptor tyrosine kinase, is a therapeutic target in various cancers, including non-small cell lung cancer. Although several ALK inhibitors, including crizotinib, ceritinib, and alectinib, are approved for cancer treatment, their long-term benefit is often limited by the cancer's acquisition of resistance owing to secondary point mutations in ALK. Importantly, some ALK inhibitors cannot cross the blood-brain barrier (BBB) and thus have little or no efficacy against brain metastases. The introduction of a lipophilic moiety, such as a fluoroethyl group may improve the drug's BBB penetration. Herein, we report the synthesis of fluoroethyl analogues of crizotinib 1, alectinib 4, and ceritinib 9, and their radiolabeling with ¹⁸F for pharmacokinetic studies. The fluoroethyl derivatives and their radioactive analogues were obtained in good yields with high purity and good molar activity. A cytotoxicity screen in ALK-expressing H2228 lung cancer cells showed that the analogues had up to nanomolar potency and the addition of the fluorinated moiety had minimal impact overall on the potency of the original drugs. Positron emission tomography in healthy mice showed that the analogues had enhanced BBB penetration, suggesting that they have therapeutic potential against central nervous system metastases.

Molecular Modeling of ALK L1198F and/or G1202R Mutations to Determine Differential Crizotinib Sensitivity

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase that has been recognized as a therapeutic target for EML4-ALK fusion-positive nonsmall cell lung cancer (NSCLC) treatment using type I kinase inhibitors such as crizotinib to take over the ATP binding site. According to Shaw’s measurements, ALK carrying G1202R mutation shows reduced response to crizotinib (IC₅₀ = 382 nM vs. IC₅₀ = 20 nM for wild-type), whereas L1198F mutant is more responsive (IC₅₀ = 0.4 nM). Interestingly, the double mutant L1198F/G1202R maintains a similar response (IC₅₀ = 31 nM) to the wild-type. Herein we conducted molecular modeling simulations to elucidate the varied crizotinib sensitivities in three mutants carrying L1198F and/or G1202R. Both L1198 and G1202 are near the ATP pocket. Mutation G1202R causes steric hindrance that blocks crizotinib accessibility, which greatly reduces efficacy, whereas mutation L1198F enlarges the binding pocket entrance and hydrophobically interacts with crizotinib to enhance sensitivity. With respect to the double mutant L1198F/G1202R, F1198 indirectly pulls R1202 away from the binding entrance and consequently alleviates the steric obstacle introduced by R1202. These results demonstrated how the mutated residues tune the crizotinib response and may assist kinase inhibitor development especially for ALK G1202R, analogous to the ROS1 G2302R and MET G1163R mutations that are also resistant to crizotinib treatment in NSCLC.