Efficacy and Safety Profile of Ivosidenib in the Management of Patients with Acute Myeloid Leukemia (AML): An Update on the Emerging Evidence

Ivosidenib significantly reduces triazole levels in patients with acute myeloid leukemia and myelodysplastic syndrome

BACKGROUND

Ivosidenib is primarily metabolized by CYP3A4; however, it induces CYP450 isozymes, including CYP3A4 and CYP2C9, whereas it inhibits drug transporters, including P-glycoprotein. Patients with acute myeloid leukemia are at risk of invasive fungal infections, and therefore posaconazole and voriconazole are commonly used in this population. Voriconazole is a substrate of CYP2C9, CYP2C19, and CYP3A4; therefore, concomitant ivosidenib may result in decreased serum concentrations. Although posaconazole is a substrate of P-glycoprotein, it is metabolized primarily via UDP glucuronidation; thus, the impact of ivosidenib on posaconazole exposure is unknown.

METHODS

Patients treated with ivosidenib and concomitant triazole with at least one serum trough level were included. Subtherapeutic levels were defined as posaconazole <700 ng/mL and voriconazole <1.0 µg/mL. The incidences of breakthrough invasive fungal infections and QTc prolongation were identified at least 5 days after initiation of ivosidenib with concomitant triazole.

RESULTS

Seventy-eight serum triazole levels from 31 patients receiving ivosidenib-containing therapy and concomitant triazole were evaluated. Of the 78 concomitant levels, 47 (60%) were subtherapeutic (posaconazole: n = 20 of 43 [47%]; voriconazole: n = 27 of 35 [77%]). Compared to levels drawn while patients were off ivosidenib, median triazole serum levels during concomitant ivosidenib were significantly reduced. There was no apparent increase in incidence of grade 3 QTc prolongation with concomitant azole antifungal and ivosidenib 500 mg daily.

CONCLUSIONS

This study demonstrated that concomitant ivosidenib significantly reduced posaconazole and voriconazole levels. Voriconazole should be avoided, empiric high-dose posaconazole (>300 mg/day) may be considered, and therapeutic drug monitoring is recommended in all patients receiving concomitant ivosidenib.

Isocitrate Dehydrogenase 1 Mutation and Ivosidenib in Patients With Acute Myeloid Leukemia: A Comprehensive Review

Acute myeloid leukemia (AML) arises from immature myeloid progenitors, resulting in a stem-cell-like proliferative state. This leads to excessive pools of immature cells that cannot function, which usually happens at the cost of the production of mature functional cells, leading to deleterious consequences. The management of AML has intensified as newer targeted therapies have come into existence owing to deeper genetic analysis of the disease and patients. Isocitrate dehydrogenase (IDH) is a cytosolic enzyme that is a part of the Krebs cycle and is extremely important in maintaining the homeostasis of the cell. It is produced by two different genes: IDH1 and IDH2. Ivosidenib has been associated with IDH1 inhibition and has been studied in numerous cancers. This review highlights the studies that have dealt with ivosidenib, an IDH1 inhibitor, in AML, the side effect profile, and the possible future course of the drug. After a scoping review of the available literature, we have identified that studies have consistently shown positive outcomes and that ivosidenib is a promising avenue for the management of AML. But it also has to be kept in mind that resistance to IDH inhibitors is on the rise, and the need to identify ways to circumvent this is to be addressed.

New Targeted Drugs for Acute Myeloid Leukemia and Antifungals: Pharmacokinetic Challenges and Opportunities

BACKGROUND

Acute myeloid leukemia (AML) is a life-threatening disease whose treatment is made difficult by a number of mutations or receptor overexpression in the proliferating cellular clones. Life expectancy of patients diagnosed with new, relapsed-refractory, or secondary AML has been improved by drugs targeted at such moieties. Regrettably, however, clinical use of new AML drugs is complicated by pharmacokinetic interactions with other drugs the patient is exposed to.

SUMMARY

The most relevant drug-drug interactions (DDI) with clinical implications build on competition for or induction/inhibition of CYP3A4, which is a versatile metabolizer of a plethora of pharmacological agents. Here, we review DDI between AML drugs and the agents used to prevent or treat invasive fungal infections (IFI). The pathophysiology of AML, characterized by functionally defective white blood cells and neutropenic/immunosuppressive effects of concomitant induction chemotherapy, can in fact increase the risk of infectious complications, with IFI causing high rates of morbidity and mortality. Triazole antifungals, such as posaconazole, are strong inhibitors of CYP3A4 and may thus cause patient's overexposure to AML drugs that are metabolized by CYP3A4. We describe potential strategies to minimize the consequences of DDI between triazole antifungals and targeted therapies for AML and the role that collaboration between clinical pharmacologists, hematologists, and clinical or laboratory microbiologists may have in these settings.

KEY MESSAGES

Therapeutic drug monitoring and clinical pharmacology stewardship could represent two strategies that best express multidisciplinary collaboration for improving patient management.

Tracing the electron flow in redox metabolism: The appropriate distribution of electrons is essential to maintain redox balance in cancer cells

Cancer cells are characterized by sustained proliferation, which requires a huge demand of fuels to support energy production and biosynthesis. Energy is produced by the oxidation of the fuels during catabolism, and biosynthesis is achieved by the reduction of smaller units or precursors. Therefore, the oxidation-reduction (redox) reactions in cancer cells are more active compared to those in the normal counterparts. The higher activity of redox metabolism also induces a more severe oxidative stress, raising the question of how cancer cells maintain the redox balance. In this review, we overview the redox metabolism of cancer cells in an electron-tracing view. The electrons are derived from the nutrients in the tumor microenvironment and released during catabolism. Most of the electrons are transferred to NAD(P) system and then directed to four destinations: energy production, ROS generation, reductive biosynthesis and antioxidant system. The appropriate distribution of these electrons achieved by the function of redox regulation network is essential to maintain redox homeostasis in cancer cells. Interfering with the electron distribution and disrupting redox balance by targeting the redox regulation network may provide therapeutic implications for cancer treatment.

Precision Medicine in Cholangiocarcinoma: Past, Present, and Future

Cholangiocarcinoma (CCA), or biliary tract cancer, has a poor prognosis. The median survival time among patients with CCA is under 2 years from diagnosis, and the global 5-year survival rate is only 10%. First-line therapy with chemotherapeutic agents, gemcitabine plus cisplatin, has traditionally been used to treat unresectable advanced CCA. In recent years, precision medicine has become a mainstream cancer treatment due to innovative next-generation sequencing technology. Several genetic alterations, including mutations, gene fusions, and copy number variations, have been found in CCA. In this review, we summarized the current understanding of genetic profiling in CCA and targeted therapy in CCA. Owing to the high heterogeneity of CCA, tumor microenvironmental factors, and the complexity of tumor biology, only pemigatinib, infigratinib, ivosidenib, larotrbctinib, and entrectinib are currently approved for the treatment of CCA patients with fibroblast growth factor receptor 2 gene (FGFR2) fusion, isocitrate dehydrogenase gene (IDH1) mutation, and neurotrophin receptor tyrosine kinase gene (NRTK) fusion, respectively. Additional targeted therapies, including other FGFR2 inhibitors, PI3K/AKT/mTOR inhibitors, and BRAF-directed targeted therapy, have been discussed for the management of CCA, and immune checkpoint inhibitors, particularly pembrolizumab, can be administered to patients with high microsatellite instability tumors. There is a further need for improvement in precision medicine therapies in the treatment of CCA and discuss the approved and potential targeted therapies for CCA.

Cancer Therapy Guided by Mutation Tests: Current Status and Perspectives

The administration of many cancer drugs is tailored to genetic tests. Some genomic events, e.g., alterations of EGFR or BRAF oncogenes, result in the conformational change of the corresponding proteins and call for the use of mutation-specific compounds. Other genetic perturbations, e.g., HER2 amplifications, ALK translocations or MET exon 14 skipping mutations, cause overproduction of the entire protein or its kinase domain. There are multilocus assays that provide integrative characteristics of the tumor genome, such as the analysis of tumor mutation burden or deficiency of DNA repair. Treatment planning for non-small cell lung cancer requires testing for EGFR, ALK, ROS1, BRAF, MET, RET and KRAS gene alterations. Colorectal cancer patients need to undergo KRAS, NRAS, BRAF, HER2 and microsatellite instability analysis. The genomic examination of breast cancer includes testing for HER2 amplification and PIK3CA activation. Melanomas are currently subjected to BRAF and, in some instances, KIT genetic analysis. Predictive DNA assays have also been developed for thyroid cancers, cholangiocarcinomas and urinary bladder tumors. There is an increasing utilization of agnostic testing which involves the analysis of all potentially actionable genes across all tumor types. The invention of genomically tailored treatment has resulted in a spectacular improvement in disease outcomes for a significant portion of cancer patients.

Targeted Therapies for the Evolving Molecular Landscape of Acute Myeloid Leukemia

Despite considerable growth in our understanding of the heterogeneous biology and pathogenesis of acute myeloid leukemia (AML) in recent decades, for nearly forty years, little progress was gained in the realm of novel therapeutics. Since 2017, however, nine agents have been FDA-approved for patients with AML in both the upfront and relapsed/refractory (R/R) settings. Most of these compounds function as inhibitors of key cell cycle enzymatic pathways or mediators of leukemic proliferation and survival. They have been approved both as single agents and in combination with conventional or reduced-intensity conventional chemotherapeutics. In this article, we review the molecular landscape of de novo vs. R/R AML and highlight the potential translational impact of defined molecular disease subsets. We also highlight several recent agents that have entered the therapeutic armamentarium and where they fit in the AML treatment landscape, with a focus on FLT3 inhibitors, IDH1 and IDH2 inhibitors, and venetoclax. Finally, we close with a survey of two promising novel agents under investigation that are poised to enter the mainstream clinical arena in the near future.