Turalio (pexidartinib)

Although there remains interest in agents targeting CSF-1, hepatic toxicity appears to be a limiting factor for their use in early breast cancer.

We report three patients with histiocytic disorders harboring novel alterations who had sustained responses to off-label kinase inhibitors specific to their histiocytic disorder. Pathogenic variants outside of the MAPK pathway, including variants of unknown significant, may be targeted with readily available small molecules.

P=N/A, N=6, Completed, Daiichi Sankyo Co., Ltd. | Active, not recruiting --> Completed | Trial completion date: Mar 2025 --> Oct 2024

Furthermore, depletion of microglia by PLX3397, a colony-stimulating factor 1 receptor inhibitor, ameliorated cognitive dysfunction. These results suggest that microglia mediate periodontal infection-induced cognitive dysfunction in obesity.

Collectively, our study showed PLX-3397-related efficacy in ameliorating pain linked to the reduction of microglia and neuroinflammation in mice. Furthermore, our research provided new proof-of-concept data supporting the promise of testing PLX-3397 as an analgesic.

P2, N=21, Active, not recruiting, Daiichi Sankyo Co., Ltd. | Recruiting --> Active, not recruiting | Trial completion date: Nov 2026 --> May 2026

Inhibition of microglia by pretreatment with minocycline or depletion of microglia by PLX3397 abolished the preventive effect of low-dose LPS pre-injection on mSPS-induced anxiety- and fear-like behavior and neuroinflammatory responses. These results suggest that pre-stimulation of microglia may prevent the development of PTSD-like behaviors by attenuating the development of neuroinflammatory responses. This could help to develop new strategies to prevent the damaging effects of harmful stress on the brain.

In conclusion, targeting FLT3 as a receptor tyrosine kinase with PLX3397 represents a promising therapeutic strategy for improving outcomes in patients with FLT3-mutated AML. Further clinical investigations are warranted to validate the efficacy and safety of PLX3397 and to optimize treatment strategies for AML patients based on the FLT3 mutational status.

Myelomodulatory therapy with pexidartinib, a small molecule inhibitor of CSF1R tyrosine kinase, and the oncolytic herpes simplex virus T-VEC exhibited the most significant increase in median survival time in the highly immunogenic model. Additionally, targeting myeloid cells with the myelomodulatory therapy trabectedin, a small molecule activator of caspase-8 dependent apoptosis, augmented the survival benefit of T-VEC in a less immunogenic MPNST model...Furthermore, flow cytometry analysis following combination viroimmunotherapy revealed decreased M2 macrophages and myeloid-derived suppressor cells and increased tumor-specific gp70+ CD8 T cells within the tumor microenvironment. In summary, our findings provide compelling evidence for the potential to leverage viroimmunotherapy with myeloid cell targeting against MPNST and warrant further investigation.

The results of our study showed that blocking microglial activation via CSF1R may help prevent cancer-induced orofacial pain.

RNA-seq following combination therapy showed activation of tumor immunity. In summary, CAFs are involved in the induction and mobilization of M2 macrophage differentiation in the CRC tumor immune microenvironment, and the combination of cancer immunotherapy and PLX3397 may represent a novel therapeutic option for CRC.

These results imply that the replacement of microglia in the aged brain may alleviate brain damage and neuroinflammation, and therefore, ischemic brain damage. Thus, targeting microglia could be a promising therapeutic strategy for ischemic stroke.

Analyses of PDB holdings, the scientific literature, and related documents for each drug-target combination revealed that the impact of structural biologists and public-domain 3D biostructure data was broad and substantial, ranging from understanding target biology (100% of all drug targets), to identifying a given target as likely druggable (100% of all targets), to structure-guided drug discovery (>80% of all new small-molecule drugs, made up of 50% confirmed and >30% probable cases). In addition to aggregate impact assessments, illustrative case studies are presented for six first-in-class small-molecule anti-cancer drugs, including a selective inhibitor of nuclear export targeting Exportin 1 (selinexor, Xpovio), an ATP-competitive CSF-1R receptor tyrosine kinase inhibitor (pexidartinib,Turalia), a non-ATP-competitive inhibitor of the BCR-Abl fusion protein targeting the myristoyl binding pocket within the kinase catalytic domain of Abl (asciminib, Scemblix), a covalently-acting G12C KRAS inhibitor (sotorasib, Lumakras or Lumykras), an EZH2 methyltransferase inhibitor (tazemostat, Tazverik), and an agent targeting the basic-Helix-Loop-Helix transcription factor HIF-2α (belzutifan, Welireg).

We searched and reviewed clinical trial reports on the monotherapy of 13 FLT3 inhibitors, including sorafenib, lestaurtinib, midostaurin, gilteritinib, quizartinib, sunitinib, crenolanib, tandutinib, cabozantinib, pexidartinib, pacritinib, famitinib, and TAK-659 in patients with hematological and solid malignancies before May 31, 2023...The ORRs of FLT3 inhibitors in hematologic malignancies and solid tumors were 40.8% and 18.8%, respectively, indicating FLT3 inhibitors were more effective for hematologic malignancies than for solid tumors. In addition, time to maximum plasma concentration (Tmax) in these FLT3 inhibitors ranged from 0.7-12.0 hours, but the elimination half-life (T1/2) range was highly variable, from 6.8 to 151.8 h. FLT3 inhibitors monotherapy has shown significant anti-tumor effect in clinic, and the effectiveness may be further improved through combination medication.

P3, N=40, Active, not recruiting, Daiichi Sankyo Co., Ltd. | Trial completion date: Mar 2024 --> Feb 2026

P=N/A, N=6, Active, not recruiting, Daiichi Sankyo Co., Ltd. | Phase classification: P1/2 --> P=N/A | Trial completion date: Mar 2024 --> Mar 2025

Oxygen-glucose deprivation causes an increase in NR4A1 mRNA in astrocytes as well as its nuclear to cytoplasmic transfer. Furthermore, reoxygenation enhances NR4A1 transcription and promotes its nuclear translocation.

P1/2, N=43, Active, not recruiting, Gulam Manji | Recruiting --> Active, not recruiting | Phase classification: P2 --> P1/2 | Trial completion date: Mar 2024 --> Jun 2024

RNA-seq further confirms the enhanced immune cell function. Consequently, P@ZIF/M1-KTP has great potential as a novel adoptive cellular therapeutic strategy for tumors.

In vivo, PXB17 significantly halted CRC growth, with a stronger effect than PLX3397. In particular, PXB17 potently enhanced therapeutic activity of PD-1 mAb in CT-26 (MSS) model and prevented tumor recurrence in MC-38 (MSI-H) model by promoting formation of long-term memory immunity. Our study opens a new avenue for CSF1R in tumor innate and adaptive anti-tumor immunomodulatory activity and suggests that PXB17 is a promising immunotherapy molecule for enhancing the efficacy of PD-1 mAb or reducing tumor recurrence of CRC.

Treatment by PLX3397 in combination with paclitaxel significantly inhibited the growth of ovarian cancer both in vitro and in vivo. Blockade of CSF-1R altered the macrophage phenotype and reprogrammed the immunosuppressive cell population in the tumor microenvironment.

Our results demonstrate that pexidartinib, through the inhibition of FLT3 signaling, has a deleterious effect on DC differentiation, which may explain the limited antitumor clinical activity observed in this study. This work suggests that inhibition of FLT3 should be considered when combining TKIs with immune checkpoint inhibitors.

The results of immunoblotting assays suggested that silybinin as well as compound glycyrrhizin inhibited the protein expression of CYP3A4 and CYP2C9 in rats. Therefore, the combination of pexidartinib with silybinin and compound glycyrrhizin should be monitored to avoid clinical adverse effects.

This comparative analysis of CSF1R-targeting drugs on patient-derived GAMs and human glioblastoma avatars identified GW2580 as the most powerful inhibitor with the ability to polarize immunosuppressive GAMs to a proinflammatory phenotype, supporting antitumor T cell responses while also exerting a direct antitumor effect. These data indicate that GW2580 could be an important pillar in future therapies for glioblastoma.

Combination treatment also induced favorable systemic antitumor immunity in the spleen and lymph node. In conclusion, our findings provide insights into the synergy between mDex-based immunotherapy and PLX-3397 as the combination overcame the disadvantages associated with monotherapy and offer a therapeutic strategy for the treatment of solid tumors including melanoma.

Their temporal alteration suggests an association with tumor recurrence after BNCT, making M-MDSCs a potential intervention target. Our preliminary results showed that PLX-3397 had strong M-MDSCs, TAMs, and TIL (tumor-infiltrating lymphocyte) modulating effects that could synergize tumor control when combined with BNCT.

P1, N=54, Recruiting, National Cancer Institute (NCI) | Trial completion date: Dec 2024 --> Dec 2025 | Trial primary completion date: Dec 2024 --> Dec 2025

POx-Man nanovaccine combines with pexidartinib, a modulator of the TAM function, restricts the MC38 tumor growth, and synergizes with PD-1 blockade, controlling MC38 and CT26 tumor growth and survival. This data is further validated in the highly aggressive and poorly immunogenic B16F10 melanoma mouse model. Therefore, the synergistic anti-tumor effect induced by the combination of nanovaccines with the inhibition of both TAM- and PD-1-inducing immunosuppression, holds great potential for improving immunotherapy outcomes in solid cancer patients.

The cell membrane-derived nanoparticles (CMNPs) deriving from the MiaPaCa-2 cells (MPC2-CMNPs) were loaded with the chemotherapeutic drug paclitaxel (PTX), and the CMNPs deriving from M2-polarized macrophages (M2-CMNPs) were loaded with the colony-stimulating factor 1 receptor inhibitor, pexidartinib (PXDB). Finally, we evaluated the PTX and PXDB-loaded CMNPs' effect on the viability of all the used TME cell lines alone or in combination. Overall, this pilot study showed the potential of the CMNPs to cross an in vitro stroma model and act synergistically to treat PDAC.

In the current study, the metabolic activation of PEX was investigated in human/mouse liver microsomes (HLM/MLM) and primary human hepatocytes (PHH) using glutathione (GSH) and methoxyamine (NHOMe) as trapping reagents. CYP3A4 and CYP3A5 were identified as the primary enzymes responsible for the formation of these adducts using recombinant human P450s and CYP3A chemical inhibitor ketoconazole. Overall, our studies suggested that PEX metabolism can produce reactive metabolites mediated by CYP3A, and the association of the reactive metabolites with PEX hepatotoxicity needs to be further studied.

In two preclinical mouse models of MPNST, we combined the oncolytic virus T-VEC with myeloid-cell targeting therapeutics, Pexidartinib or Trabectedin, to assess the combination therapy's antitumor efficacy and survival benefits. Our findings provide compelling evidence that myelomodulatory therapies can augment the antitumor T-cell response and improve the therapeutic benefits of oncolytic virotherapy in murine models of MPNST. These results provide valuable insights for designing and implementing future immunotherapeutic strategies in the management of MPNST.

In Asian patients with symptomatic TGCT not amenable to improvement with surgery, pexidartinib demonstrated clinical benefit in tumor response and improvement in joint function. The overall safety profile of pexidartinib was comparable with previous data. Hepatotoxicity was manageable with frequent liver test monitoring and dose modifications as defined in the protocol, and no new safety signals were observed in this Asian population.

Pts with TGCT not amenable to surgery who received prior anti-CSF1/CSF1R therapy (including pexidartinib, cabiralizumab, or vimseltinib) were enrolled and treated with vimseltinib 30 mg twice weekly (recommended phase 2 dose). Longer follow-up demonstrated that vimseltinib continued to be well tolerated with a manageable safety profile in pts with TGCT not amenable to surgery who received prior anti-CSF1/CSF1R therapy. Antitumor activity continued to improve in this pretreated population, with an increased ORR. At week 25, all responders experienced ≥30% reductions in worst and average pain.

To assess the mechanism of CSF-1-mediated suppression of immunotherapy, Isolated PBMC, activated with phytohemagglutinin (PHA) with or without pembrolizumab (20 nM), were cultured alone, or in the presence of macrophages or on an established NSCLC monolayer...The use of Pexidartinib (PLX-3397), a CSF-1R inhibitor, reversed the effects of CSF-1 by restoring lymphocyte activation. However, these effects were dependent on the presence of monocytes/macrophages, suggesting that the immune suppression mediated by CSF-1 was an indirect effect resulting from the stimulation of monocytes that promote their differentiation into macrophages. Conclusions Our study suggests that plasma levels of CSF-1 could serve as a useful predictive biomarker for resistance to ICIs, while targeting the CSF-1/CSF-1R signaling pathway could potentially overcome resistance to ICIs in patients with NSCLC.

The presence of immunosuppressive immune cells in tumors is a significant barrier to the generation of therapeutic immune responses. In addition, we demonstrate that the PTX and PLX3397 combination provides consistent therapeutic improvement across several TNBC models, resulting from the repolarization of the immunosuppressive TME and enhanced T cell immune response that suppress both the primary tumor growth and metastasis. Overall, the work emphasizes the benefit of drug reformulation and outlines potential translational path for both PTX and PTX with PLX3397 combination therapy using POx polymeric micelles for the treatment of TNBC.

Moreover, some of them have been on the market or in clinical trials for the treatment of some kinase-related diseases (e.g., vemurafenib, pexidartinib, decernotinib). In addition, the binding modes of some azaindoles complexed with kinases were also investigated during the SARs elucidation. This review may offer an insight for medicinal chemists to rationally design more potent kinase inhibitors bearing the azaindole scaffold.

P2, N=21, Recruiting, Daiichi Sankyo Co., Ltd. | Trial completion date: Jun 2024 --> Nov 2026 | Trial primary completion date: Mar 2023 --> Feb 2025

Pexidartinib is the first CSF-1 receptor inhibitor approved for the treatment of TGCT. Here, we discuss various available treatment strategies and ongoing investigations and trials targeting diffuse TGCT, which include nilotinib, lacnotuzumab, cabiralizumab, vimseltinib, and emactuzumab.

Results show that IWR-1 could not only rescue developmental defects and immune cell number, but also downregulate the high expression of Wnt signaling pathway and inflammation-related caused by pexidartinib. Collectively, our results suggest that pexidartinib induces the developmental toxicity and immunotoxicity in zebrafish embryos through hyperactivation of Wnt signaling, providing a certain reference for the new mechanisms of pexidartinib function.