Momelotinib (JAK1/JAK2/ACVR1 inhibitor): mechanism of action, clinical trial reports, and therapeutic prospects beyond myelofibrosis

Helicobacter pylori infection induces DNA double-strand breaks through the ACVR1/IRF3/POLD1 signaling axis to drive gastric tumorigenesis

Helicobacter pylori (H. pylori) infection plays a pivotal role in gastric carcinogenesis through inflammation-related mechanisms. Activin A receptor type I (ACVR1), known for encoding the type I receptor for bone morphogenetic proteins (BMPs), has been identified as a cancer diver gene across various tumors. However, the specific role of AVCR1 in H. pylori-induced gastric tumorigenesis remains incompletely understood. We conducted a comprehensive analysis of the clinical relevance of ACVR1 by integrating data from public databases and our local collection of human gastric tissues. In vitro cell cultures, patient-derived gastric organoids, and transgenic INS-GAS mouse models were used for Western blot, qRT-PCR, immunofluorescence, immunohistochemistry, luciferase assays, ChIP, and comet assays. Furthermore, to investigate the therapeutic potential, we utilized the ACVR1 inhibitor DM3189 in our in vivo studies. H. pylori infection led to increased expression of ACVR1 in gastric epithelial cells, gastric organoid and gastric mucosa of INS-GAS mice. ACVR1 activation led to DNA double-strand break (DSB) accumulation by inhibiting POLD1, a crucial DNA repair enzyme. The activation of POLD1 was facilitated by the transcription factor IRF3, with identified binding sites. Additionally, treatment with the ACVR1 inhibitor DM3189 significantly ameliorated H. pylori-induced gastric pathology and reduced DNA damage in INS-GAS mice. Immunohistochemistry analysis showed elevated levels of ACVR1 in H. pylori-positive gastritis tissues, showing a negative correlation with POLD1 expression. This study uncovers a novel signaling axis of AVCR1/IRF3/POLD1 in the pathogenesis of H. pylori infection. The upregulation of ACVR1 and the suppression of POLD1 upon H. pylori infection establish a connection between the infection, genomic instability, and the development of gastric carcinogenesis.

Clinically approved small-molecule drugs for anemia therapy

Anemia, a common blood disorder characterized by reduced red blood cell or hemoglobin levels, affects a significant portion of the global population. Traditional treatments, including dietary supplements and blood transfusions, often fail to address the underlying causes of anemia, particularly in chronic or genetic forms. This review highlights representative small-molecule drugs approved for anemia treatment, focusing on their synthetic routes and clinical applications. The synthetic routes of these drugs, often involving advanced organic chemistry techniques are crucial for optimizing production efficiency and scalability. Clinically, these small-molecule drugs have shown broad-spectrum therapeutic potential, with applications extending to various forms of anemia. This review underscores the importance of understanding the synthetic pathways of these drugs, which not only facilitates industrial-scale production but also paves the way for the development of next-generation therapies. Future research is expected to further optimize these small-molecule drugs, potentially leading to more effective and accessible treatments for anemia.

Disease Phenotype Significantly Influences the Outcome After Discontinuation of Ruxolitinib in Chronic Phase Myelofibrosis

INTRODUCTION

In patients with myelofibrosis (MF), overall survival (OS) after ruxolitinib discontinuation is poor, with leukemic transformation, clonal evolution and thrombocytopenia as the main factors worsening prognosis.

PATIENTS AND METHODS

To assess the impact of disease phenotype on outcome after ruxolitinib discontinuation in chronic phase patients, we performed a sub-analysis of the "RUX-MF" study (NCT06516406), which now includes 1055 MF patients who received ruxolitinib in a real-life context.

RESULTS

After a median follow-up of 3.3 years, 397 patients discontinued ruxolitinib therapy while in chronic phase. At treatment end, 208 patients (52.4%) had a severely cytopenic phenotype (defined as platelets < 100 × 109/L and/or hemoglobin < 8 g/dL); among the remaining myeloproliferative 189 patients, 97 had no cytopenia (51.3%) and 92 (48.7%) had mild anemia only (hemoglobin between 8 and 10 g/dL). Overall, 175 patients (44.1%) had a large splenomegaly (palpable at ≥ 10 cm below costal margin). After ruxolitinib discontinuation, 3-year OS was 33.4% in severely cytopenic and 54.4% in myeloproliferative patients (P < .001); this was confirmed after adjustment for risk categories. Noncytopenic and mildly anemic patients had comparable OS (P = .73). Patients with large splenomegaly had significantly poorer OS compared to nonsplenomegalic patients (OS: 33.5% vs. 51.6% P = .01). Large splenomegaly confirmed its negative prognostic impact on OS of patients with myeloproliferative MF (60.7% vs. 44.5%, P = .05). In patients with severe cytopenia, the presence of a large splenomegaly did not influence OS (41.7% vs. 26.1%, P = .26).

CONCLUSIONS

Cytopenic phenotype and large splenomegaly in myeloproliferative MF are key prognostic determinants of outcome after ruxolitinib discontinuation.

When and how to transplant in myelofibrosis - recent trends

Allogeneic hematopoietic stem cell transplantation (AHSCT) is currently the only treatment modality that is capable of curing myelofibrosis (MF). Although outcomes of AHSCT have improved vastly in recent years owing to advancements in HLA typing, conditioning regimens, and supportive care, it remains a procedure with a considerable risk in MF patients due to conditioning regimen related toxicity, higher rates of graft failure, infections, and graft versus host disease (GVHD). Recent progress in the treatment and prevention of GVHD with post-transplant cyclophosphamide has also rendered transplantation from alternative donors feasible and safer, thus improving access to patients without HLA-identical donors. Accordingly, all patients with intermediate or high-risk MF today should be referred for potential transplant evaluation to consider the pros and cons of an early versus a delayed transplant strategy. Individual risk assessment in MF is best facilitated by contemporary prognostic models that incorporate both clinical and genetic risk factors. The current review highlights new information regarding risk stratification in MF, anchored by practical algorithms that facilitate patient selection for specific treatment actions, including AHSCT.

Identification of therapeutic target genes for age-related hearing loss through systematic genome-wide mendelian randomization of druggable genes

BACKGROUND

Age-related hearing loss (ARHL) is a common sensory disorder with significant public health implications. However, few effective treatment options are available. Mendelian randomization (MR) has been used to repurpose existing drugs and identify new therapeutic targets. Therefore, we performed a systematic genome-wide MR of drug-eligible individuals to explore potential therapeutic targets for ARHL.

METHODS

We obtained data on the expression quantitative trait locis (eQTLs) of druggable genes, which were then subjected to two-sample MR analyses and co-localisation analyses with data from the ARHL genome-wide association study to identify genes highly associated with ARHL. Additionally, we conducted phenome-wide research, enrichment analysis, protein network construction, drug prediction, and molecular docking to help develop more effective and targeted therapeutic treatments.

RESULTS

Overall, the MR analysis of eQTL data showed that 14 drug targets were significantly associated with ARHL. GO analysis of 14 potential targets revealed their primary involvement in biological processes such as the endoplasmic reticulum unfolded protein response, ER-nucleus signaling pathway, and fibroblast apoptotic process. Additionally, important cellular components include the Bcl-2 family of proteins and the endoplasmic reticulum lumen. After filtering using methods such as phenome-wide research, enrichment analysis, protein network construction, drug prediction, and molecular docking, six potentially druggable genes (BAK1, AMFR, LAMP3, STK17B, ACP5, and CD9) and six drugs (beclomethasone, propyl pyrazole triol, momelotinib, monoisoamyl-2,3-dimercaptosuccinate, pterostilbene, and naftidrofuryl) that may affect ARHL outcomes were finally identified.

CONCLUSIONS

Our findings identified 14 potential drug targets for ARHL. These findings offer promising leads for more effective treatments for ARHL and help determine the priority of drug development, potentially reducing costs.

Nitrogen-containing heterocyclic drug products approved by the FDA in 2023: Synthesis and biological activity

This article profiles 13 newly approved nitrogen-containing heterocyclic drugs by the U.S. Food and Drug Administration (FDA) in 2023. These drugs target a variety of therapeutic areas including proteinuria in patients with IgA nephropathy, migraine in adults, Rett syndrome, PI3Kδ syndrome, vasomotor symptoms, alopecia areata, acute myeloid leukemia, postpartum depression, myelofibrosis, and various cancer and tumor types. The molecular structures of these approved drugs feature common aromatic heterocyclic compounds such as pyrrole, imidazole, pyrazole, isoxazole, pyridine, and pyrimidine, as well as aliphatic heterocyclic compounds like caprolactam, piperazine, and piperidine. Some compounds also contain multiple heteroatoms like 1,2,4-thiadiazole and 1,2,4-triazole. The article provides a comprehensive overview of the bioactivity spectrum, medicinal chemistry discovery, and synthetic methods for each compound.

Clinical pharmacokinetic characteristics of Jaktinib in subjects with hepatic impairment in a phase I trial

Jaktinib is a novel Janus kinase (JAK) inhibitor, and a phase I clinical trial of single-dose Jaktinib was conducted in a population of subjects with hepatic impairment to assess the safety, tolerability, and pharmacokinetic characteristics of Jaktinib. The patients were administered orally with 100 mg Jaktinib on day 1 in all the mild hepatic impairment group (mild group, n = 8), moderate hepatic impairment group (moderate group, n = 8) and normal hepatic function group (normal group, n = 8), and the blood samples were collected for later analysis. The mild to moderate hepatic impairment affected the metabolism of Jaktinib, which may lead to accumulation of original Jaktinib. The pharmacokinetic characteristics of the metabolites (ZG0244 and ZG0245) of Jaktinib were also analyzed. The exposure of Jaktinib is approximately 2-fold in patients with mild and moderate hepatic impairment than normal hepatic function. No serious adverse events occurred. In summary, a dosage reduction is recommended for patients with mild or moderate hepatic impairment. Further investigations for the dose adjustment in mild/moderate hepatic impairment will be considered. Trial registration number: NCT04993404.

Comprehensive analysis of a necroptosis-associated diagnostic signature for myelodysplastic syndromes based on single-cell RNA-seq and bulk RNA-seq

BACKGROUND

Myelodysplastic syndromes (MDS) are heterogeneous and clonal hematological disorders. The role and mechanism of necroptosis in MDS remain poorly understood.

METHODS

mRNA expression profiles and single-cell RNA-sequencing (scRNA-seq) data were sourced from the GEO database. ScRNA-seq data were processed using the "Seurat" package. After cell annotation, necroptosis-related scores (NRscores) for each cell were calculated using the "UCell" package. Differentially expressed genes (DEGs) and their associated biological functions in NRscore-related cell populations were identified. Additionally, DEGs and necroptosis-related genes (DE-NRGs) between MDS patients and healthy controls were identified. Consensus clustering was employed to classify MDS patients into distinct subclusters based on DE-NRGs. The biological functions and immune characteristics of these classifications were analyzed. Prognostic gene signatures were determined using LASSO and SVM-RFE analyses, and a nomogram was constructed based on the prognostic gene signature.

RESULTS

A total of 12 cell types were identified in MDS and healthy controls. NRscore was found to be elevated in monocytes and common lymphoid precursors (CLPs). Enrichment analysis revealed that monocytes and CLPs with high NRscore were associated with mitochondria-related and immune-related pathways. Eleven DEGs in monocytes and CLPs between MDS patients and healthy controls were identified. Additionally, 13 DE-NRGs were identified from 951 DEGs between MDS and healthy controls. MDS patients were classified into two distinct subclusters based on these 13 DE-NRGs, revealing several immune-related processes and signaling pathways. Differences in immune subpopulations between the two subclusters were observed. A necroptosis-related diagnostic gene signature (IRF9, PLA2G4A, MLKL, BAX, JAK2, and STAT3) was identified as predictive of MDS prevalence.

CONCLUSION

Necroptosis plays a role in MDS progression by inducing inflammation. A novel necroptotic gene signature has been developed to distinguish and diagnose MDS at early stages of the disease.

A comprehensive review of small molecule drugs approved by the FDA in 2023: Advances and prospects

In 2023, the U.S. Food and Drug Administration has approved 55 novel medications, consisting of 17 biologics license applications and 38 new molecular entities. Although the biologics license applications including antibody and enzyme replacement therapy set a historical record, the new molecular entities comprising small molecule drugs, diagnostic agent, RNA interference therapy and biomacromolecular peptide still account for over 50 % of the newly approved medications. The novel and privileged scaffolds derived from drugs, active molecules and natural products are consistently associated with the discovery of new mechanisms, the expansion of clinical indications and the reduction of side effects. Moreover, the structural modifications based on the promising scaffolds can provide the clinical candidates with the improved biological activities, bypass the patent protection and greatly shorten the period of new drug discovery. Therefore, conducting an appraisal of drug approval experience and related information will expedite the identification of more potent drug molecules. In this review, we comprehensively summarized the pertinent information encompassing the clinical application, mechanism, elegant design and development processes of 28 small molecule drugs, and expected to provide the promising structural basis and design inspiration for pharmaceutical chemists.

Targeting anemia in myeloid neoplasms

Anemia-directed therapeutic approaches targeting the TGF-β-SMAD and HIF-PH pathways.

Synaptotagmin 13 Could Drive the Progression of Esophageal Squamous Cell Carcinoma Through Upregulating ACRV1

SYT13 is one of the atypical members of the synaptotagmin (SYT) family whose function has attracted considerable attention in recent years. Although SYT13 has been studied in several types of human cancers, such as lung cancer, its role in esophageal squamous cell carcinoma (ESCC) is still unclear. It was demonstrated that SYT13 is significantly upregulated in ESCC tissues compared with normal ones and correlated with higher degree of malignancy. Knockdown of SYT13 could inhibit ESCC cell proliferation and migration, while promoting cell apoptosis. Meanwhile, ESCC cells with relatively lower SYT13 expression grew slower in vivo and finally formed smaller xenografts. Furthermore, acrosomal vesicular protein 1 was identified as a potential downstream target of SYT13, which regulates cell phenotypes of ESCC cells in cooperation with SYT13. All the in vitro and in vivo results in this study identified that SYT13 silencing could be an effective strategy to inhibit the development of ESCC, which could be considered as a promising therapeutic target in the treatment of ESCC.

miR-146a-/- mice model reveals that NF-κB inhibition reverts inflammation-driven myelofibrosis-like phenotype

Emerging evidence shows the crucial role of inflammation (particularly NF-κB pathway) in the development and progression of myelofibrosis (MF), becoming a promising therapeutic target. Furthermore, tailoring treatment with currently available JAK inhibitors (such as ruxolitinib or fedratinib) does not modify the natural history of the disease and has important limitations, including cytopenias. Since recent studies have highlighted the role of miR-146a, a negative regulator of the NF-κB pathway, in the pathogenesis of MF; here we used miR-146a-/- (KO) mice, a MF-like model lacking driver mutations, to investigate whether pharmacological inhibition of JAK/STAT and/or NF-κB pathways may reverse the myelofibrotic phenotype of these mice. Specifically, we tested the JAK1/2 inhibitor, ruxolitinib; the NF-κB inhibitor via IKKα/β, BMS-345541; both inhibitors in combination; or a dual inhibitor of both pathways (JAK2/IRAK1), pacritinib. Although all treatments decreased spleen size and partially recovered its architecture, only NF-κB inhibition, either using BMS-345541 (alone or in combination) or pacritinib, resulted in a reduction of extramedullary hematopoiesis, bone marrow (BM) fibrosis and osteosclerosis, along with an attenuation of the exacerbated inflammatory state (via IL-1β and TNFα). However, although dual inhibitor improved anemia and reversed thrombocytopenia, the combined therapy worsened anemia by inducing BM hypoplasia. Both therapeutic options reduced NF-κB and JAK/STAT signaling in a context of JAK2V617F-driven clonal hematopoiesis. Additionally, combined treatment reduced both COL1A1 and IL-6 production in an in vitro model mimicking JAK2-driven fibrosis. In conclusion, NF-κB inhibition reduces, in vitro and in vivo, disease burden and BM fibrosis, which could provide benefits in myelofibrosis patients.

Momelotinib - a promising advancement in the management of myelofibrosis in adults with anemia

Myelofibrosis (MF) is a rare BCR-ABL negative myeloproliferative neoplasm characterized by clonal proliferation of stem cells, with mutations in JAK2, CALR, or MPL genes. MF presents in primary and secondary forms, with common symptoms including splenomegaly, anemia, and thrombocytopenia. Diagnostic criteria involve bone marrow examination and mutation studies. Current treatments are limited, with allogeneic stem cell transplant as the only curative option. Recent FDA approval of Momelotinib (MMB) offers new promise for MF patients with anemia. MMB, a JAK1/2 and ACVR1 inhibitor, effectively reduces spleen size, improves hemoglobin levels, and decreases transfusion dependency. The MOMENTUM trial compared MMB to danazol in JAK inhibitor-treated MF patients with anemia, showing MMB's superior symptom relief and transfusion independence rates. Additionally, the SIMPLIFY-1 and SIMPLIFY-2 trials evaluated MMB in JAK inhibitor-naïve and experienced patients, respectively, confirming MMB's non-inferiority to ruxolitinib in spleen volume reduction and highlighting its benefits in transfusion requirements. MMB's unique dual inhibition mechanism addresses anemia by suppressing hepcidin production, thus enhancing erythropoiesis. These trials collectively suggest MMB as an effective treatment for MF, improving quality of life and offering a survival advantage for patients with anemia. Despite challenges, such as trial design limitations and adverse events, MMB represents a significant advancement in MF management, providing a new therapeutic option for a previously underserved patient population.

New drugs in myelofibrosis: Critical assessment of additional value to monotherapy with JAK inhibitors

Ruxolitinib in combination with navitoclax or pelabresib in myelofibrosis: activity in JAKi-naïve patients.

Anemia in patients receiving anticancer treatments: focus on novel therapeutic approaches

Anemia is common in cancer patients and impacts on quality of life and prognosis. It is typically multifactorial, often involving different pathophysiological mechanisms, making treatment a difficult task. In patients undergoing active anticancer treatments like chemotherapy, decreased red blood cell (RBC) production due to myelosuppression generally predominates, but absolute or functional iron deficiency frequently coexists. Current treatments for chemotherapy-related anemia include blood transfusions, erythropoiesis-stimulating agents, and iron supplementation. Each option has limitations, and there is an urgent need for novel approaches. After decades of relative immobilism, several promising anti-anemic drugs are now entering the clinical scenario. Emerging novel classes of anti-anemic drugs recently introduced or in development for other types of anemia include activin receptor ligand traps, hypoxia-inducible factor-prolyl hydroxylase inhibitors, and hepcidin antagonists. Here, we discuss their possible role in the treatment of anemia observed in patients receiving anticancer therapies.

Efficacy, safety, and survival findings after long-term follow-up of ZGJAK002: A phase 2 study comparing jaktinib at 100 mg twice daily (BID) and 200 mg once daily (QD) in patients with myelofibrosis

Jaktinib, a novel JAK and ACVR1 inhibitor, has exhibited promising results in treating patients with myelofibrosis (MF). ZGJAK002 is a Phase 2 trial aimed to assess the efficacy and safety of jaktinib 100 mg BID (N = 66) and 200 mg QD (N = 52) in JAK inhibitor-naive patients with intermediate- or high-risk MF. We herein present the long-term data with a median follow-up of 30.7 months. At data cutoff, 30.3% of patients in 100 mg BID and 28.8% in 200 mg QD were still continuing their treatment. The 100 mg BID group displayed a numerically higher best spleen response compared with the 200 mg QD group (69.7% vs. 46.2%), with 50.4% from the BID and 51.2% from the QD group maintaining spleen responses over 120 weeks. The 36-month survival rates were 78.2% in BID and 73.6% in QD group. The tolerability of jaktinib remained well, and common grade ≥3 adverse drug reactions included anemia (15.2% vs. 21.2%), thrombocytopenia (15.2% vs. 11.5%), and infectious pneumonia (10.6% vs. 1.9%) in BID and QD groups, respectively. By comparing the two groups, the incidence of adverse events (AEs) were similar, except for drug-related serious AEs (24.2% vs. 9.6%) and AEs leading to treatment discontinuation (15.2% vs. 7.7%), which were higher in BID group. The percentages of AEs resulting in death were comparable, with 6.1% in BID and 5.8% in QD group. These analyses further support the long-term durable efficacy and acceptable safety of jaktinib at 100 mg BID and 200 mg QD doses for treating MF.

Clinical assessment of momelotinib drug-drug interactions via CYP3A metabolism and transporters

Momelotinib-approved for treatment of myelofibrosis in adults with anemia-and its major active metabolite, M21, were assessed as drug-drug interaction (DDI) victims with a strong cytochrome P450 (CYP) 3A4 inhibitor (multiple-dose ritonavir), an organic anion transporting polypeptide (OATP) 1B1/1B3 inhibitor (single-dose rifampin), and a strong CYP3A4 inducer (multiple-dose rifampin). Momelotinib DDI perpetrator potential (multiple-dose) was evaluated with CYP3A4 and breast cancer resistance protein (BCRP) substrates (midazolam and rosuvastatin, respectively). DDI was assessed from changes in maximum plasma concentration (Cmax), area under the concentration-time curve (AUC), time to reach Cmax, and half-life. The increase in momelotinib (23% Cmax, 14% AUC) or M21 (30% Cmax, 24% AUC) exposure with ritonavir coadministration was not clinically relevant. A moderate increase in momelotinib (40% Cmax, 57% AUC) and minimal change in M21 was observed with single-dose rifampin. A moderate decrease in momelotinib (29% Cmax, 46% AUC) and increase in M21 (31% Cmax, 15% AUC) were observed with multiple-dose rifampin compared with single-dose rifampin. Due to potentially counteracting effects of OATP1B1/1B3 inhibition and CYP3A4 induction, multiple-dose rifampin did not significantly change momelotinib pharmacokinetics compared with momelotinib alone (Cmax no change, 15% AUC decrease). Momelotinib did not alter the pharmacokinetics of midazolam (8% Cmax, 16% AUC decreases) or 1'-hydroxymidazolam (14% Cmax, 16% AUC decreases) but increased rosuvastatin Cmax by 220% and AUC by 170%. Safety findings were mild in this short-term study in healthy volunteers. This analysis suggests that momelotinib interactions with OATP1B1/1B3 inhibitors and BCRP substrates may warrant monitoring for adverse reactions or dose adjustments.

Analysis of network expression and immune infiltration of disulfidptosis-related genes in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a globally prevalent respiratory disease, and programmed cell death plays a pivotal role in the development of COPD. Disulfidptosis is a newly discovered type of cell death that may be associated with the progression of COPD. However, the expression and role of disulfidptosis-related genes (DRGs) in COPD remain unclear.

METHODS

The expression of DRGs was identified by analyzing RNA sequencing (RNA-seq) data in COPD. Further, COPD patients were classified into two subtypes by unsupervised cluster analysis to reveal their differences in gene expression and immune infiltration. Meanwhile, hub genes associated with disulfidptosis were screened by weighted gene co-expression network analysis. Subsequently, the hub genes were validated experimentally in cells and animals. In addition, we screened potential therapeutic drugs through the hub genes.

RESULTS

We identified two distinct molecular clusters and observed significant differences in immune cell populations between them. In addition, we screened nine hub genes, and experimental validation showed that CDC71, DOHH, PDAP1, and SLC25A39 were significantly upregulated in cigarette smoke-induced COPD mouse lung tissues and bronchial epithelial cells (BEAS-2B) treated with cigarette smoke extract. Finally, we predicted 10 potential small molecule drugs such as Atovaquone, Taurocholic acid, Latamoxef, and Methotrexate.

CONCLUSION

We highlighted the strong association between COPD and disulfidptosis, with DRGs demonstrating a discriminative capacity for COPD. Additionally, the expression of certain novel genes, including CDC71, DOHH, PDAP1, and SLC25A39, is linked to COPD and may aid in the diagnosis and assessment of this condition.

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.

Momelotinib expands the therapeutic armamentarium for myelofibrosis: Impact on hierarchy of treatment choices

The primary objective of treatment in myelofibrosis (MF) is prolongation of life, which is currently accomplished only by allogeneic hematopoietic stem cell transplantation (AHSCT). Determination of optimal timing for AHSCT is facilitated by molecular risk stratification. Non-transplant treatment options in MF are palliative in scope and include Janus kinase 2 (JAK2) inhibitors (JAKi): momelotinib (FDA approved on September 15, 2023), ruxolitinib (November 16, 2011), fedratinib (August 16, 2019), and pacritinib (February 28, 2022); all four JAKi are effective in reducing spleen size and alleviating symptoms, considered a drug class effect and attributed to their canonical JAK-STAT inhibitory mechanism of action. In addition, momelotinib exhibits erythropoietic effect, attributed to alleviation of ineffective erythropoiesis through inhibition of activin A receptor type-I (ACVR1). In transplant-ineligible or deferred patients, the order of treatment preference is based on specific symptoms and individual assessment of risk tolerance. Because of drug-induced immunosuppression and other toxicities attributed to JAKi, we prefer non-JAKi drugs as initial treatment for MF-associated anemia that is not accompanied by treatment-requiring splenomegaly or constitutional symptoms. Otherwise, it is reasonable to consider momelotinib as the first-line JAKi treatment of choice, in order to target the triad of quality-of-life offenders in MF: anemia, splenomegaly, and constitutional symptoms/cachexia. For second-line therapy, we favor ruxolitinib, over fedratinib, based on toxicity profile. Pacritinib and fedratinib provide alternative options in the presence of severe thrombocytopenia or ruxolitinib-resistance/intolerance, respectively. Splenectomy remains a viable option for drug-resistant symptomatic splenomegaly and cytopenia.

Molecular Genetic Profile of Myelofibrosis: Implications in the Diagnosis, Prognosis, and Treatment Advancements

Myelofibrosis (MF) is an essential element of primary myelofibrosis, whereas secondary MF may develop in the advanced stages of other myeloid neoplasms, especially polycythemia vera and essential thrombocythemia. Over the last two decades, advances in molecular diagnostic techniques, particularly the integration of next-generation sequencing in clinical laboratories, have revolutionized the diagnosis, classification, and clinical decision making of myelofibrosis. Driver mutations involving JAK2, CALR, and MPL induce hyperactivity in the JAK-STAT signaling pathway, which plays a central role in cell survival and proliferation. Approximately 80% of myelofibrosis cases harbor additional mutations, frequently in the genes responsible for epigenetic regulation and RNA splicing. Detecting these mutations is crucial for diagnosing myeloproliferative neoplasms (MPNs), especially in cases where no mutations are present in the three driver genes (triple-negative MPNs). While fibrosis in the bone marrow results from the disturbance of inflammatory cytokines, it is fundamentally associated with mutation-driven hematopoiesis. The mutation profile and order of acquiring diverse mutations influence the MPN phenotype. Mutation profiling reveals clonal diversity in MF, offering insights into the clonal evolution of neoplastic progression. Prognostic prediction plays a pivotal role in guiding the treatment of myelofibrosis. Mutation profiles and cytogenetic abnormalities have been integrated into advanced prognostic scoring systems and personalized risk stratification for MF. Presently, JAK inhibitors are part of the standard of care for MF, with newer generations developed for enhanced efficacy and reduced adverse effects. However, only a minority of patients have achieved a significant molecular-level response. Clinical trials exploring innovative approaches, such as combining hypomethylation agents that target epigenetic regulators, drugs proven effective in myelodysplastic syndrome, or immune and inflammatory modulators with JAK inhibitors, have demonstrated promising results. These combinations may be more effective in patients with high-risk mutations and complex mutation profiles. Expanding mutation profiling studies with more sensitive and specific molecular methods, as well as sequencing a broader spectrum of genes in clinical patients, may reveal molecular mechanisms in cases currently lacking detectable driver mutations, provide a better understanding of the association between genetic alterations and clinical phenotypes, and offer valuable information to advance personalized treatment protocols to improve long-term survival and eradicate mutant clones with the hope of curing MF.

Management of classical Philadelphia chromosome-negative myeloproliferative neoplasms in Asia: consensus of the Asian Myeloid Working Group

Myeloproliferative neoplasms (MPN) are a heterogeneous group of clonal hematopoietic stem cell disorders characterized clinically by the proliferation of one or more hematopoietic lineage(s). The classical Philadelphia-chromosome (Ph)-negative MPNs include polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF). The Asian Myeloid Working Group (AMWG) comprises representatives from fifteen Asian centers experienced in the management of MPN. This consensus from the AMWG aims to review the current evidence in the risk stratification and treatment of Ph-negative MPN, to identify management gaps for future improvement, and to offer pragmatic approaches for treatment commensurate with different levels of resources, drug availabilities and reimbursement policies in its constituent regions. The management of MPN should be patient-specific and based on accurate diagnostic and prognostic tools. In patients with PV, ET and early/prefibrotic PMF, symptoms and risk stratification will guide the need for early cytoreduction. In younger patients requiring cytoreduction and in those experiencing resistance or intolerance to hydroxyurea, recombinant interferon-α preparations (pegylated interferon-α 2A or ropeginterferon-α 2b) should be considered. In myelofibrosis, continuous risk assessment and symptom burden assessment are essential in guiding treatment selection. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) in MF should always be based on accurate risk stratification for disease-risk and post-HSCT outcome. Management of classical Ph-negative MPN entails accurate diagnosis, cytogenetic and molecular evaluation, risk stratification, and treatment strategies that are outcome-oriented (curative, disease modification, improvement of quality-of-life).

Safety and efficacy of jaktinib (a novel JAK inhibitor) in patients with myelofibrosis who are relapsed or refractory to ruxolitinib: A single-arm, open-label, phase 2, multicenter study

Ruxolitinib has demonstrated efficacy in patients with myelofibrosis (MF). However, substantial number of patients may not respond after 3-6 months of treatment or develop resistance over time. In this phase 2 trial, patients with a current diagnosis of intermediate or high-risk MF who either had an inadequate splenic response or spleen regrowth after ruxolitinib treatment were enrolled. All patients received jaktinib 100 mg Bid. The primary endpoint was the proportion of patients with ≥35% reduction in spleen volume (SVR 35) at week 24. The secondary endpoints included change of MF-related symptoms, anemic response, and safety profile. From July 6, 2021, to January 24, 2022, 34 ruxolitinib-refractory or relapsed patients were enrolled, 52.9% (18 of 34) were DIPSS intermediate 2 or high risk. SVR 35 at week 24 was 32.4% (11 of 34, 95% CI 19.1%-49.2%) in all patients and 33.3% (6 of 18, 95% CI 16.3%-56.3%) in the intermediate 2 or high-risk group. A total of 50% (8 of 16) transfusion-independent patients with hemoglobin (HGB) <100 g/L at baseline had HGB elevation ≥20 g/L within 24 weeks. Furthermore, 46.4% (13 of 28) of patients had a ≥ 50% decrease in the total symptom score (TSS 50) at week 24. The most common grade ≥3 treatment-emergent adverse events (TEAEs) were thrombocytopenia (32.4%), anemia (32.4%), and leukocytosis (20.6%). In total, 13 (38.2%) of 34 patients had serious adverse events (SAE), of which drug-related SAEs were found in 5 patients (14.7%). These results indicate that jaktinib can be a promising treatment option for patients with MF who have either become refractory to or relapsed after ruxolitinib treatment.

Safety and efficacy of jaktinib (a novel JAK inhibitor) in patients with myelofibrosis who are intolerant to ruxolitinib: A single-arm, open-label, phase 2, multicenter study

Although ruxolitinib improves splenomegaly and constitutional symptoms in patients with myelofibrosis (MF), a substantial proportion of patients discontinue ruxolitinib because of intolerance. This phase 2 trial investigated the safety and efficacy of jaktinib, a novel JAK inhibitor in patients with ruxolitinib-intolerant MF. The primary endpoint was the proportion of patients with ≥35% reduction in spleen volume (SVR35) at week 24. The secondary endpoints included change of MF-related symptoms, anemic response, and safety profiles. Between December 18, 2019, and November 24, 2021, 51 patients were enrolled, 45 treated with jaktinib 100 mg bid (100 mg bid group) and six received non-100 mg bid doses (non-100 mg bid group). The SVR35 at week 24 in the 100 mg bid group was 43.2% (19/44, 95% CI 29.7%-57.8%). There were 41.9% (13/31) of transfusion-independent patients with hemoglobin (HGB) ≤100 g/L who had HGB elevation ≥20 g/L within 24 weeks. The proportion of patients with a ≥50% decrease in the total symptom score (TSS 50) at week 24 was 61.8% (21/34). The most commonly reported grade ≥3 treatment-emergent adverse events (TEAEs) in the 100 mg bid group were anemia 31.1%, thrombocytopenia 22.2%, and infectious pneumonia 17.8%. A total of 16 (35.6%) in the 100 mg bid group had serious adverse events, and 4 (8.9%) were considered possibly drug related. These results indicate jaktinib can provide a treatment option for patients with MF who are intolerant to ruxolitinib.

Polycythemia vera: 2024 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Polycythemia vera (PV) is a JAK2-mutated myeloproliferative neoplasm characterized by clonal erythrocytosis; other features include leukocytosis, thrombocytosis, splenomegaly, pruritus, constitutional symptoms, microcirculatory disturbances, and increased risk of thrombosis and progression into myelofibrosis (post-PV MF) or acute myeloid leukemia (AML).

DIAGNOSIS

A working diagnosis is considered in the presence of a JAK2 mutation associated with hemoglobin/hematocrit levels of >16.5 g/dL/49% in men or 16 g/dL/48% in women; morphologic confirmation by bone marrow examination is advised but not mandated.

CYTOGENETICS

Abnormal karyotype is seen in 15%-20% of patients with the most frequent sole abnormalities being +9 (5%), loss of chromosome Y (4%), +8 (3%), and 20q- (3%).

MUTATIONS

Over 50% of patients harbor DNA sequence variants/mutations other than JAK2, with the most frequent being TET2 (18%) and ASXL1 (15%). Prognostically adverse mutations include SRSF2, IDH2, RUNX1, and U2AF1, with a combined incidence of 5%-10%.

SURVIVAL AND PROGNOSIS

Median survival is ⁓15 years but exceeds 35 years for patients aged ≤40 years. Risk factors for survival include older age, leukocytosis, abnormal karyotype, and the presence of adverse mutations. Twenty-year risk for thrombosis, post-PV MF, or AML are ⁓26%, 16% and 4%, respectively.

RISK FACTORS FOR THROMBOSIS

Two risk categories are considered: high (age >60 years or thrombosis history) and low (absence of both risk factors). Additional predictors for arterial thrombosis include cardiovascular risk factors and for venous thrombosis higher absolute neutrophil count and JAK2V617F allele burden.

TREATMENT

Current goal of therapy is to prevent thrombosis. Periodic phlebotomy, with a hematocrit target of <45%, combined with once- or twice-daily aspirin (81 mg) therapy, absent contraindications, is the backbone of treatment in all patients, regardless of risk category. Cytoreductive therapy is reserved for high-risk disease with first-line drugs of choice being hydroxyurea and pegylated interferon-α and second-line busulfan and ruxolitinib. In addition, systemic anticoagulation is advised in patients with venous thrombosis history.

ADDITIONAL TREATMENT CONSIDERATIONS

At the present time, we do not consider a drug-induced reduction in JAK2V617F allele burden, which is often incomplete and seen not only with peg-IFN but also with ruxolitinib and busulfan, as an indicator of disease-modifying activity, unless accompanied by cytogenetic and independently-verified morphologic remission. Accordingly, we do not use the specific parameter to influence treatment choices. The current review also includes specific treatment strategies in the context of pregnancy, splanchnic vein thrombosis, pruritus, perioperative care, and post-PV MF.