Inhibitor Of Mutant Isocitrate Dehydrogenase Research Articles

CTNI-66. IDH-MUTANT GLIOMA PATIENTS TREATED WITH VORASIDENIB: ONGOING DATA FROM THE VORASIDENIB EXPANDED ACCESS PROGRAM

Abstract BACKGROUND Vorasidenib (VOR) is an oral, brain-penetrant dual inhibitor of mutant isocitrate dehydrogenase 1/2 (mIDH1/2) demonstrating clinical efficacy and safety in patients with mIDH1/2 glioma in the phase 3 INDIGO study (NCT04164901). Servier launched an expanded access program (EAP, NCT05592743) in November 2022 designed to provide access to VOR for patients with mIDH1/2 glioma. Early clinical outcomes of patients treated in this EAP are presented. METHODS Eligible participants were aged ≥12 years with mIDH1/2 glioma and, in the opinion of the treating oncologist, would potentially benefit from treatment with VOR. Safety assessments occur every two weeks for the first two 28-day cycles, then monthly for the duration of treatment. RESULTS As of the March 31, 2024 data cutoff, 71 participants have initiated treatment with VOR. Mean (SD) age was 42.7 (14.8) years; 39 (55%) were male; and 34 (48%) with astrocytoma. mIDH mutation status was 46 (65%) mIDH1. One participant had separate tumors with either mIDH1 or mIDH2 identified. The majority of participants had grade 2 gliomas (n=51 [72%]) and non-contrast–enhancing disease (n=49 [69%]). As of the data cutoff, 62 (87%) participants remain on treatment, with the majority initiating treatment within the past 6 months (n=49 [69%]). Nine (13%) participants have discontinued treatment due to: radiographic progressive disease (n=3); clinical progressive disease (n=4); adverse event (AE) unrelated to treatment (n=1); or other reason (n=1). Three participants have died (disease progression [n=2], unrelated infection [n=1]). At least one AE of any grade was seen in 35 (49%) participants, with 4 (6%) experiencing unrelated serious AEs. Eight (11%) patients had AEs of special interest (defined as grade 2 or higher ALT/AST elevations). Ten (14%) patients had AEs that led to dose interruption and one (1%) patient had dose reduction. Additional treatment duration and various subgroup analyses will be presented.

Vorasidenib: First Approval.

Vorasidenib (VORANIGO®; Servier) is an orally administered, first-in-class, highly brain-penetrant dual inhibitor of mutant isocitrate dehydrogenase 1 and 2 (IDH1/2) enzymes being developed for use in IDH-mutant diffuse glioma. Vorasidenib received its first approval on 6 August 2024, in the USA, for the treatment of adult and pediatric patients aged 12 years and older with grade 2 astrocytoma or oligodendroglioma with a susceptible IDH1 or IDH2 mutation following surgery, including biopsy, sub-total resection, or gross total resection. Approval was based on results from the multinational phase III INDIGO trial, in which vorasidenib significantly improved progression-free survival and time to the next anticancer intervention relative to placebo. In the EU and other countries worldwide, regulatory review of vorasidenib in IDH-mutant glioma is currently underway. This article summarizes the milestones in the development of vorasidenib leading to this first approval for glioma.

Clinical and radiological response of Maffucci related enchondromas to mutant IDH1 inhibitor Ivosidenib

Ollier Disease (OD) and Maffucci syndrome (MS) is a rare bone disorder that affects the growth and development of the bones, with an estimated prevalence of 1 in 100,000 people. It is associated with somatic mosaicism of isocitrate dehydrogenase-1 (IDH1) or 2 (IDH2) pathogenic variants. Ivosidenib is indicated for the treatment of acute myeloid leukemia and locally advanced or metastatic cholangiocarcinoma and is currently investigated in low-grade glioma with a susceptible isocitrate dehydrogenase-1 (IDH1) pathogenic variant, but its effects in patients with OD or MS are unknown. We here report the first case of a patient with MS who was treated with Ivosidenib for recurrent IDH-1 mutated glioma. Besides the stabilization of the tumor size, the patient observed significant improvement in his enchondromas that became stiffer, with reduced pain, and significant modification of the mineralization of the enchondromas observed on X-rays. This first case report provides hope for the medical management of patients suffering because of OD or MS. Future clinical research is urgently needed to evaluate long-term benefit risk profile of IDH inhibitors in these rare diseases.

Altered Oxidative Phosphorylation Confers Vulnerability on IDH1-Mutant Leukemia Cells: Is This Therapeutically Tractable?

Isocitrate dehydrogenase (IDH)-mutant acute myeloid leukemia (AML) is treatable with inhibitors of mutant IDH and also responds well to combination therapies including venetoclax, but most patients with IDH-mutant AML either never achieve complete remission or relapse because mutant hematopoietic stem cells persist despite treatment. An interesting new study in Blood Cancer Discovery characterizes a specific vulnerability in the mitochondrial oxidative phosphorylation system in preleukemic hematopoietic stem cells from patients with IDH1 mutations that is not present in those with IDH2 mutations; will this susceptibility prove amenable to therapy? See related article by Landberg et al., p. 114 (10).

Inhibitors of mutant isocitrate dehydrogenase for isocitrate dehydrogenase-mutant gliomas: A new standard of care?

Inhibitors of mutant isocitrate dehydrogenase for isocitrate dehydrogenase-mutant gliomas: A new standard of care?

Olutasidenib Alone or in Combination with Azacitidine Induces Durable Complete Remissions in Patients with mIDH1 Myelodysplastic Syndromes/Neoplasms (MDS)

Introduction Olutasidenib is a potent, selective, oral, small-molecule inhibitor of mutant isocitrate dehydrogenase 1 (mIDH1). Olutasidenib is approved in the US for the treatment of relapsed/refractory (R/R) acute myeloid leukemia (AML) based on the pivotal cohort (n=153) of a registrational Phase 1/2 trial (NCT02719574), which demonstrated a rate of complete remission (CR) or CR with partial hematologic recovery (CRh) of 35%, with a duration of response of 25.9 months. The Phase 1/2 study also enrolled patients with mIDH1 myelodysplastic syndromes/neoplasms (MDS), and here we report results from this subset of 22 patients. Methods The Phase 1/2 open-label study enrolled 332 adult patients with mIDH1 AML or intermediate-, high-, or very high-risk MDSfrom 57 centers in 9 countries. Inclusion criteria included an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 and adequate liver and renal function. Patients were R/R to prior therapy or, if treatment-naïve (TN), had to be eligible for azacitidine therapy (to be enrolled in a combination therapy cohort). Olutasidenib was administered at 150 mg BID (n=3) or 100-150 QD (n=3) as monotherapy or in combination with azacitidine (n=16), given at 75 mg/mm 2 daily for 7 consecutive days, in 28-day cycles. The primary efficacy endpoint for MDS was the CR rate, based on response criteria of the International Working Group in MDS. Secondary efficacy endpoints included overall response (CR/PR/marrow CR), time to response, duration of response and safety. Results Twenty-two patients with MDS were enrolled, including 6 who received monotherapy (4 R/R and 2 TN) and 16 who received combination therapy (11 R/R and 5 TN). Baseline demographics and disease characteristics are shown in Table 1. The age ranged from 59-87 years, and 59% of the study population were male. Seven patients were treatment-naïve and 15 were R/R with 1-4 prior treatment regimens. For the pooled Phase 1 and 2 data (n=22), 6 (27%) patients achieved CR and 7 (32%) patients achieved marrow CR with no PRs, generating a 59% overall response rate. The median time to response was 2.0 months. The median duration of response was not reached (NR) at 30.1+ months ( Table 2). The overall response rate was 2/6 (33%) for monotherapy and 11/16 (69%) for combination therapy. Three of 6 patients received monotherapy at a lower dose (100-150 QD) than the approved dose level, and none responded. Of the 3 patients who received monotherapy at the approved dose level (150mg BID), 2 (66%) responded. In the 7 TN patients, the overall response rate was 86%. In the 15 R/R patients, the overall response rate was 47%. All patients with MDS experienced at least 1 treatment-emergent adverse event (TEAE). The most frequent TEAEs in the study were nausea, constipation, vomiting, thrombocytopenia, neutropenia, diarrhea, and fatigue. Grade 3 TEAEs occurred in 19/22 (86%) patients, and Grade 4 TEAEs in 9/22 (41%). The most frequent Grade 3/4 TEAEs reported were cytopenias. Grade 3 transaminitis occurred in 4 patients. Grade 3 differentiation syndrome was reported in 1 patient, who discontinued treatment after 23 days due to pneumonia, which lead to respiratory failure and death. TEAEs resulting in death occurred in 5 patients and included disease progression (3), pneumonia (1, mentioned above) and chest fungal infection (1). The overall safety profile in patients with MDS was consistent with what has been reported in patients with AML in this study (Watts, et al., Lancet Hematol, 2022; de Botton et al., Blood Adv, 2023). Conclusions Olutasidenib, both as monotherapy and in combination with azacitidine, induced durable remissions in patients with intermediate-, high-, or very high-risk MDS. Patients had varying treatment backgrounds, including treatment-naïve and up to four prior regimens. This treatment had a tolerable and manageable safety profile. These encouraging results, which warrant further investigation with a larger number of patients, show that olutasidenib has clinically meaningful activity in patients with mIDH1 MDS.

LTBK-06. IMPACT OF VORASIDENIB TREATMENT ON MUTANT IDH1 OR IDH2 DIFFUSE GLIOMA TUMOR GROWTH RATE: RESULTS FROM THE RANDOMIZED, DOUBLE-BLIND, PHASE 3 INDIGO STUDY

Abstract INTRODUCTION The INDIGO study (NCT04164901) showed that vorasidenib, an oral, brain-penetrant, dual inhibitor of mutant isocitrate dehydrogenase (mIDH) 1/2, significantly improved imaging-based progression-free survival and time-to-next-intervention compared with placebo in patients with grade 2 mIDH1/2 glioma previously treated with surgery only. Given the limitations of traditional bi-dimensional measurements, evaluating volumetry and tumor growth rate (TGR) is an additional method of measuring treatment effect in these diffuse growing tumors. METHODS Magnetic resonance imaging (MRI) scans were performed at baseline and every 12 weeks on-treatment; up to three pre-treatment MRI scans were requested when available. Tumor volumes were derived per blinded independent review committee using a semi-automated approach. TGR was defined as percentage change in tumor volume every 6 months. Patients with evaluable baseline and ≥ 1 MRI during the corresponding period were included in the analysis. The difference in TGR in each arm was assessed by slope of tumor growth over time using a linear mixed model. RESULTS 331 patients were randomized to vorasidenib (n=168) or placebo (n=163). Median follow-up was 14.2 months. On-treatment TGR was −2.5% (95% CI, −4.7, −0.2) with vorasidenib (n=167) and 13.9% (95% CI, 11.1, 16.8) with placebo (n=161). In patients with available imaging data, TGR pre- and post-treatment with vorasidenib (n=56) was 13.2% (95% CI, 10.3, 16.3) and −3.3% (95% CI, −5.2, −1.2), respectively, while placebo (n=67) was 18.3% (95% CI, 15.0, 21.7) and 12.2% (95% CI, 9.5, 14.9), respectively. In patients who crossed over from placebo with available imaging data (n=38), TGR pre- and post-crossover was 22.4% (95% CI, 15.7, 29.4) and 5.2% (95% CI, −3.8, 15.0), respectively. CONCLUSIONS Tumor growth was observed in patients with mIDH1/2 gliomas before receiving vorasidenib or placebo. Treatment with vorasidenib reduced the TGR and shrunk tumor volume, whereas continued growth in tumor volume was observed in patients receiving placebo.

CTNI-51. A RANDOMIZED DOUBLE-BLIND PHASE 3 STUDY OF VORASIDENIB VS PLACEBO IN PATIENTS WITH MUTANT IDH1/2 DIFFUSE GLIOMA (INDIGO): EXPLORATORY ANALYSIS OF VARIANT ALLELE FREQUENCY AND PROGRESSION-FREE SURVIVAL

Abstract INTRODUCTION Vorasidenib is an oral, brain-penetrant, inhibitor of mutant isocitrate dehydrogenase (mIDH) 1/2 enzymes. The INDIGO study (NCT04164901) showed significantly improved radiographic progression-free survival (PFS) by blinded independent review committee (BIRC) with vorasidenib, compared with placebo, in patients with mIDH1/2 adulttype diffuse glioma (hazard ratio [HR] 0.39, 95% CI 0.27–0.56; one-sided P = 0.000000067 [Mellinghoff N Engl J Med 2023]). The key secondary endpoint of time-to-next-intervention was also met. METHODS In this double-blind Phase 3 study, patients aged ≥ 12 years with residual/recurrent grade 2 mIDH1/2 oligodendroglioma or astrocytoma, measurable non-enhancing disease, and no prior treatment for glioma were randomized 1:1 to receive vorasidenib 40 mg or placebo daily in 28-day cycles. An investigational clinical trial assay centrally confirmed IDH1 R132H/C/G/S/L or IDH2 R172K/M/W/S/G mutation variants. Pretreatment (archival) tumor tissue was analyzed by next-generation sequencing for CDKN2A/B homozygous deletion and other co-mutations (ACE Extended Cancer Panel). RESULTS As of Sep 6, 2022 (preplanned second interim analysis), 168 patients were randomized to vorasidenib and 163 to placebo (median age, 40.0 years; Karnofsky performance scale = 100, 53.5%; oligodendroglioma, 172; astrocytoma, 159; mIDH1, 315; mIDH2, 16). Two patient subgroups were defined by baseline IDH1/2 variant allele frequency (VAF): lower/higher than the median value (0.377). The median PFS results favored vorasidenib over placebo in both subgroups (low VAF, one-sided P = 0.0116; high VAF, one-sided P < 0.0001). Vorasidenib and placebo groups had similar and a low number of co-mutations in known/likely oncogenic genes at baseline (median number of co-mutations across both groups was 4). CDKN2A homozygous deletion was detected in only two participants (both in the placebo group). Additional data will be presented. CONCLUSION In the first randomized Phase 3 study of a targeted therapy in grade 2 mIDH1/2 glioma, vorasidenib prolonged median PFS by BIRC, relative to placebo, irrespective of IDH1/2 VAF.

QOL-26. A RANDOMIZED, DOUBLE-BLIND PHASE 3 STUDY OF VORASIDENIB VS PLACEBO IN PATIENTS WITH MUTANT IDH1/2DIFFUSE GLIOMA (INDIGO): ANALYSIS OF HEALTH-RELATED QUALITY OF LIFE, NEUROCOGNITION AND SEIZURES

Abstract INTRODUCTION The Phase 3 INDIGO study (NCT04164901) is a randomized, double-blind evaluation of vorasidenib, an oral, brain-penetrant inhibitor of mutant isocitrate dehydrogenase (mIDH) 1/2 enzymes, compared with placebo, in patients with grade 2 mIDH1/2 diffuse gliomas, whose only prior treatment was surgery. The primary endpoint, radiographic progression-free survival by blinded independent review committee, and the key secondary endpoint, time-to-next-intervention, were significantly improved with vorasidenib versus placebo. As these patients are young, with several years’ life expectancy, impact of treatments on health-related quality of life (HRQoL), cognition and symptomatic burden is of interest. METHODS HRQoL, assessed by Functional Assessment of Cancer Therapy-Brain (FACTBr) questionnaire, was a secondary endpoint. FACT-Br was collected at baseline, Cycles 2 and 3, then every 3 months. Scores were interpreted using an estimate of clinically meaningful deterioration change from baseline for each arm. Exploratory endpoints included neurocognitive function, assessed by a validated battery of cognitive performance instruments, and seizure frequency and severity, assessed using a subject diary. RESULTS 331 patients were randomized to vorasidenib (n = 168) or placebo (n = 163) (median age, 40.0 years; Karnofsky performance scale = 100, 53.5%; ongoing medical history of seizures, 54.1%). Median follow-up was 14.2 months. No clinically meaningful deterioration from baseline FACT-Br total score and subscales were observed at any timepoint through the median treatment duration (Cycle 13) in either arm. At baseline, active seizures (≥ 1 seizure in the previous 30 days) were reported in 20/168 (11.9%) vorasidenib patients and 20/163 (12.3%) placebo patients. On-treatment seizure frequencies and cognition outcomes will be presented by arm. CONCLUSION INDIGO is the first randomized Phase 3 study of targeted therapy in grade 2 mIDH1/2 diffuse glioma. HRQoL, as measured by FACT-Br, was maintained during treatment with vorasidenib. These data support the clinical benefit of vorasidenib in this patient population for whom chemotherapy and radiotherapy are being delayed.

Ivosidenib: A Review in Advanced Cholangiocarcinoma.

Ivosidenib (Tibsovo®), a first-in-class, oral small molecule, potent and selective inhibitor of mutant isocitrate dehydrogenase 1 (mIDH1), is approved in the EU and USA for the treatment of adults with pretreated, advanced, mIDH1 cholangiocarcinoma (CCA). It is presumed to exert its cytostatic effects in this setting by suppressing 2-hydroxyglutarate, an oncometabolite produced by mIDH1 that impairs cellular differentiation and promotes tumorigenesis. In the multinational phase 3 ClarIDHy study in patients with pretreated, advanced mIDH1 CCA, monotherapy with ivosidenib once daily significantly prolonged progression-free survival (PFS) and almost doubled the disease control rate compared with placebo. Moreover, it had a favourable effect on overall survival (OS), which was also significantly prolonged after correcting for a high rate of crossover from the placebo group (permitted by the trial protocol). Ivosidenib treatment preserved health-related quality of life (HRQOL) relating to physical function, pain and appetite loss/eating and was generally well tolerated, with the most common treatment-emergent adverse events being low-grade diarrhoea, nausea and fatigue. Thus, ivosidenib represents a novel and valuable targeted therapy for the subset of patients with pretreated, advanced CCA tumors harbouring mIDH1.

P19.04.B EXAMINATION OF THE ROLES OF KDM6A AND KDM6B HISTONE DEMETHYLASES IN ISOCITRATE DEHYDROGENASE (IDH) MUTANT GLIOMA

Abstract Glioma, comprising 80% percent of all malignant brain tumors, is one of the most aggressive and difficult to treat tumors. Isocitrate dehydrogenase (IDH) is an enzyme that catalyzes the oxidative decarboxylation of isocitrate, producing α-ketoglutarate. Most IDH-mutant gliomas have a heterozygous point mutation in IDH1 that causes an arginine-to-histidine substitution at amino acid 132. Mutant IDH enzyme leads to 2-hydroxyglutarate accumulation in cells, inhibiting DNA and histone demethylases and ultimately generating a hypermethylated epigenetic phenotype. Considering that the mutant IDH enzyme generates a discrete epigenetic profile, we aimed to develop an epigenetic-based therapy approach for IDH mutant glioma. To this end, we performed chemical library screens consisting of inhibitors of important epigenetic enzymes and identified GSK-J4 as a chemical selectively targeting IDH1 mutant cells.GSK-J4 is a well-known inhibitor for histone demethylases KDM6A and KDM6B; therefore, we aimed to phenocopy the effects of the chemical approach with the genetic approach by depleting KDM6A and/or KDM6B using CRISPR/Cas9. We successfully established IDH-mutant primary glioma cell lines deficient in KDM6A and/or KDM6B expression, as revealed by qRT-PCR and Western Blots. Cells with double knockout were markedly slower in growth compared to controls which had received nontargeting gRNA or single gRNAs targeting each enzyme. In the future, we will examine changes in cell cycle and apoptosis pathways upon KDM6A and KDM6B knockouts and test the response of these cells to mutant IDH inhibitors, TMZ, or irradiation. In parallel, genome-wide changes in gene expression and cellular pathways, histone modifications, and chromatin accessibility will be analyzed, via RNA-seq, ChIP-seq, and ATAC-seq techniques, respectively.Even though KDM6A and KDM6B have been shown to have important but sometimes conflicting roles in various tumor types, no study showed their roles in IDH mutant glioma. Therefore, revealing the functional mechanisms of KDM6A and KDM6B in IDH-mutant gliomas will serve as an important step that leads to the development of novel epigenetic-based therapeutic approaches for IDH-mutant gliomas.This project is supported by TUBITAK with the given grant number: 219S882.

Olutasidenib (FT-2102) induces durable complete remissions in patients with relapsed or refractory IDH1-mutated AML.

Olutasidenib (FT-2102) is a potent, selective, oral, small-molecule inhibitor of mutant isocitrate dehydrogenase 1 (mIDH1). Overall, 153 IDH1 inhibitor-naive patients with mIDH1R132 relapsed/refractory (R/R) acute myeloid leukemia (AML) received olutasidenib monotherapy 150mg twice daily in the pivotal cohort of this study. The median age of participants was 71 years (range, 32-87 years) and the median number of prior regimens received by patients was 2 (1-7). The rate of complete remission (CR) plus CR with partial hematologic recovery (CRh) was 35%, and the overall response rate was 48%. Response rates were similar in patients who had, and who had not, received prior venetoclax. With 55% of patients censored at the time of data cut-off, the median duration of CR/CRh was 25.9months. The median duration of overall response was 11.7months, and the median overall survival was 11.6months. Of 86 patients who were transfusion dependent at baseline, a 56-day transfusion independence was achieved in 29 (34%), which included patients in all response groups. Grade 3 or 4 treatment-emergent adverse events (≥10%) were febrile neutropenia and anemia (n= 31; 20% each), thrombocytopenia (n= 25; 16%), and neutropenia (n= 20; 13%). Differentiation syndrome adverse events of special interest occurred in 22 (14%) patients, with 14 (9%) grade ≥3 and 1 fatal case reported. Overall, olutasidenib induced durable remissions and transfusion independence with a well-characterized and manageable side effect profile. The observed efficacy represents a therapeutic advance in this molecularly defined, poor-prognostic population of patients with mIDH1 R/R AML. This trial was registered at www.clinicaltrials.gov as #NCT02719574.

Olutasidenib in post-venetoclax patients with mIDH1 AML.

e19041 Background: Olutasidenib is a potent, selective, oral inhibitor of mutant isocitrate dehydrogenase 1 (mIDH1). Olutasidenib is FDA approved for the treatment of relapsed/refractory (R/R) acute myeloid leukemia (AML) based on the registrational cohort (n = 153) of the Phase 2 trial, which demonstrated a rate of complete remission (CR) or CR with partial hematologic recovery (CRh) of 35%, with a duration of response of 25.9 months. Venetoclax (VEN) in combination with a hypomethylating agent (HMA) is standard treatment for AML patients unfit for chemotherapy and has adequate efficacy in IDH1-mutated AML. The sequence of therapy following failure of a VEN-based regimen in IDH1-mutated AML has not been established. We evaluated the efficacy and safety of olutasidenib in a subset of 17 patients from the Phase 2 trial (NCT02719574) previously treated with VEN combination regimens. Methods: Adults with mIDH1 R/R AML received olutasidenib 150 mg twice daily alone (n = 15) or in combination with azacitadine (AZA) (n = 2). The primary endpoint was achievement of a CR/CRh. Secondary endpoints included time to and duration of CR+CRh and rate of transfusion independence (TI). Data cut-off for the analysis was 18 June 2021. Results: Of 17 patients with prior VEN treatment, 5 are ongoing and 12 discontinued due to progressive disease (6), adverse events (4), or withdrawal by subject (2). Median age was 73 (range 65-83). Median time since diagnosis was 19.5 months (1.2-41). Cytogenetic risk class was intermediate in 9, poor in 6, favorable in 1 and unknown in 1. Most patients had relapsed; 6 were refractory to prior treatment. The median number of prior regimens was 2 (range 1-6); 13 had prior HMA, 2 had prior olutasidenib. VEN was generally used for induction. Some patients received VEN in multiple regimens. VEN was used with azacytidine (AZA) in 8 patients, after AZA (1), and with decitabine (5), cytarabine +/- idarubicin (5), and dinaciclib (2). The best response to olutasidenib was CR/CRh in 5/17 (29.4%), of which 4 (23.5%) were CR. In the 8 patients who previously received the combination of VEN-AZA, 3 (37.5%) patients achieved a CR/CRh. Time to CR/CRh was median 2.1 months (actual: 1, 1.9, 2.1, 2.8 and 2.8). Duration of CR/CRh was median 18.5+ months (4.8, 9.0+, 18.5+, 22.6+, and 28.5+ months as of cut-off date). Other responses included CR with incomplete blood count recovery (CRi) in 2 patients, stable disease (SD) in 2, progressive disease (PD) in 3, not done (ND) in 2, not evaluable (NE) in 1 and not listed in 2. At baseline 14/17 were red blood cell (RBC) dependent, and 4 of the 14 (28%) had a 56-day period of RBC transfusion independence (TI). Ten were platelet dependent at baseline and 5 of the 10 (50%) had a 56-day period of platelet TI while receiving olutasidenib. Conclusions: Olutasidenib induced durable remissions in patients with mIDH1 R/R AML, including those failing prior treatment with a venetoclax-based regimen. Clinical trial information: NCT02719574 .

Olutasidenib: A ray of hope in the treatment of acute myeloid leukaemia

Acute myeloid leukaemia (AML) or Myelodysplastic syndrome (MDS) is one of the most common and life-threatening forms of blood cancer spreading worldwide. AML is characterized by some common sign and symptoms including fever, fatigue, easy bruising/bleeding, and sometimes with major differentiation syndrome. The pathogenesis of AML is attributed to the extreme differentiation of abnormally proliferated myeloid cell i.e., myeloblasts. Due to the cytotoxic potential of available chemical agents towards healthy cell, there is emerging need to develop target based selective medication with least adverse effects. Olutasidenib, is a quinoline-2-one analogue that selectively binds to mutated isocitrate dehydrogenase-1 to resist the formation of oncometabolite 2-hydroxyglutarate (2-HG) and hence, leads to cancerous cell apoptosis. Olutasidenib was approved on December 1, 2022, by FDA with the brand name Rezlidhea as one of the effective treatments against acute myeloid leukaemia via targeting IDH1m gene. In this review, a comprehensive report has been derived on olutasidenib with keen emphasis on pathophysiology of AML, mechanism of action, adverse effects along with pharmacokinetics and pharmacodynamics aspects of olutasidenib. Also, this review is focused on different clinical trials associated with the drug. Olutasidenib is a mutant IDH1 (Isocitrate dehydrogenase-1) inhibitor with significant potential in the management of acute myeloid leukaemia.

Phase I study of the mutant IDH1 inhibitor ivosidenib: Long-term safety and clinical activity in patients with conventional chondrosarcoma.

11532 Background: Chondrosarcomas (CS) are rare primary bone malignancies for which there are no approved systemic therapies. 85% of CS are the conventional subtype. Mutations in the isocitrate dehydrogenase 1 ( IDH1) gene occur in ~50% of conventional CS. In a phase 1 study in patients (pts) with IDH1-mutated advanced solid tumors, ivosidenib (IVO), an oral potent inhibitor of mutant IDH1, demonstrated manageable toxicity (without dose-limiting toxicities), suppression of the oncometabolite 2-hydroxyglutarate at dose levels ≥300 mg/day, and disease control in pts with conventional CS. We report long-term safety, tolerability and efficacy of IVO in pts with conventional CS. Methods: In this phase I multicenter open-label dose-escalation and expansion study, IVO was administered orally (100 mg twice/day [BID] to 1200 mg once/day [QD]) in continuous 28-day cycles. Primary outcome was safety and tolerability; secondary outcomes included clinical activity (objective response rates [ORR, defined as complete response (CR) + partial response (PR)], stable disease [SD] and progression-free survival [PFS]). Adverse events (AEs) were assessed every visit and reported per the Common Terminology Criteria for Adverse Events (CTCAE version 4.03). Responses were assessed every other cycle using Response Evaluation Criteria in Solid Tumors (RECIST version 1.1). Results: 13 pts with advanced conventional CS were included in this analysis (data cut off 15 September 2022; women, n = 4; median age 54.0; AJCC tumor grade I [n = 2], II [n = 8], III [n = 1], unknown [n = 2]; 6 had received prior systemic therapy; received 100 mg IVO BID [n = 1], 400 mg QD [n = 1], 500 mg QD [n = 7], 800 mg QD [n = 2], and 1200 mg QD [n = 2]). Median treatment duration was 11.3 months (range: 0.5-92.6 months). Four pts (30.8%) have continued therapy for > 6 years (two of which were treated for > 7 years). Median relative dose intensity was 100%. The most frequent treatment emergent AEs (in > 4 pts; mostly grade 1/2) were diarrhea (n = 5) and nausea (n = 5). Six pts experienced grade ≥3 AEs. Three pts experienced serious AEs (none considered related to treatment). There were no discontinuations, dose reductions or deaths due to AEs. The ORR was 23.1%. Median duration of response was 42.5 months (range: 25.8-51.8 months). One pt with a base of the skull lesion achieved a CR (1200 mg IVO QD); two achieved PR (one 500 mg and one 1200 mg IVO QD); seven had SD (five received ≥500 mg IVO QD) and two had PD (both received ≥500 mg IVO QD). All responses occurred after > 2 years on treatment. Median PFS was 7.4 months (95% CI: 2.0-61.3). Conclusions: In pts with IDH1 mutated advanced conventional CS, IVO demonstrates manageable toxicity and durable disease control including long-term responses, extending several years for a proportion of pts. Future studies are warranted to better understand the efficacy of IVO in pts with advanced conventional CS. Clinical trial information: NCT02073994 .

Pharmacophore-based Identification of Potential Mutant Isocitrate Dehydrogenases I/2 Inhibitors: An Explorative Avenue in Cancer Drug Design.

Heterozygous mutations in the cytoplasmic and mitochondrial isoforms of isocitrate dehydrogenase enzymes 1 and 2 subtypes have been extensively exploited as viable druggable targets, as they decrease the affinity of isocitrate and higher affinity of D-2-hydroxyglutarate, an oncometabolite. Vorasidenib (AG-881) has recently been reported as a promising dual inhibitor of mutant isocitrate dehydrogenase 1 and 2 with the ability to penetrate the blood-brain barrier towards the treatment of low-grade glioma. In order to combat drug resistance and toxicity levels, this compelled us to further investigate this substance as a basis for the creation of potential selective inhibitors of mutant isocitrate dehydrogenases 1 and 2. By employing a wide range of computational techniques, binding moieties of AG-881 that contributed towards its selective binding to isocitrate dehydrogenase enzymes 1 and 2 were identified and subsequently used to generate pharmacophore models for the screening of potential inhibitor drugs that were further assessed by their pharmacokinetics and physicochemical properties. AG-881 was identified as the most favorable candidate for isocitrate dehydrogenase enzyme 1, exhibiting a binding free energy of -28.69 kcal/mol. ZINC93978407 was the most favorable candidatefor isocitrate dehydrogenase enzyme 2, displaying a strong binding free energy of -27.10 kcal/mol. ZINC9449923 and ZINC93978407 towards isocitrate dehydrogenase enzyme 1 and 2 showed good protein structural stability with a low radius of gyration values relative to AG-881. We investigated that ZINC9449923 of isocitrate dehydrogenase enzyme 1 and ZINC 93978407 of isocitrate dehydrogenase enzyme 2 could serve as promising candidates for the treatment of lower-grade glioma as they cross the blood-brain barrier, and present with lower toxicity levels relative to AG-881.

Abstract 3701: Targeting wild-type IDH1 enhances chemosensitivity in pancreatic cancer

Abstract Introduction: Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer mortality in the United States. The poor prognosis is in part due to development of chemotherapy resistance, despite improvements in multiagent regimens. Our previous work demonstrated that oxidative stress plays an important role in drug resistance. Wild-type isocitrate dehydrogenase 1 (IDH1) is an important enzyme that generates cytosolic NADPH to maintain redox homeostasis and protect cancer cells from oxidative damage. Additionally, we demonstrated that ivosidenib (AG-120), an FDA-approved mutant IDH1 inhibitor, is actually a potent inhibitor of wild-type IDH1, under low magnesium and nutrient levels that are present in the tumor microenvironment. Methods: We evaluated IDH1 expression in PDAC using The Cancer Genome Atlas (TCGA). Cell viability was assessed by Trypan blue and PicoGreen in drug combination assays. Cellular reactive oxygen species (ROS) levels were determined by the DCFDA method. To further assess the therapeutic potential of AG-120 in combination with chemotherapy, tumor volume analyses were performed using patient-derived xenografts (PDX) in athymic nude mice, and survival studies were performed in C57BL/6J mice transplanted with orthotopic murine pancreatic cancer. Results: Analysis of TCGA data indicated that IDH1 is overexpressed in pancreatic cancer tumors. Treatment of MiaPaca2 and Panc1 cancer cells with 5- fluorouracil (5-FU) induced expression of wild-type IDH1 in vitro. Short-term cell viability data demonstrated that targeting IDH1 with AG-120 when combined with DNA-damaging agents (5-FU, oxaliplatin) had a synergistic effect with a positive synergy score and Bliss score greater than 1. Additionally, we assessed long-term cell survival using colony formation assays, which yielded a dramatic reduction in cell survival for both Panc1 and MiaPaCa-2 cells when 5-FU was combined with AG-120, as compared to single-agent controls. Inhibiting IDH1 impairs the ability of pancreatic cancer cells to scavenge ROS levels, enhances chemotherapy-induced apoptosis in pancreatic cancer cells via ROS-mediated damage in vitro. Both PDX tumor volume studies and overall survival analyses revealed that the combination of these AG-120 and chemotherapy synergistically enhanced anti-tumor activity and doubled the survival benefits as compared to single-agent alone. Conclusion: IDH1 plays a critical role in tumorigenesis and chemoresistance in pancreatic cancer. Our data demonstrate that IDH1 inhibition with AG-120 may enhance chemotherapy efficacy and represents an important area for future investigation in the form of clinical trials. Citation Format: Mehrdad Zarei, Omid Hajihassani, Jonathan J. Hue, Hallie J. Graor, Arian Hajihassani, Alexander W. Loftus, Luke D. Rothermel, Jordan M. Winter. Targeting wild-type IDH1 enhances chemosensitivity in pancreatic cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3701.

Olutasidenib alone or with azacitidine in IDH1-mutated acute myeloid leukaemia and myelodysplastic syndrome: phase 1 results of a phase 1/2 trial

Olutasidenib (FT-2102) is a potent, selective, oral, small-molecule inhibitor of mutant isocitrate dehydrogenase 1 (IDH1). The aims for phase 1 of this phase 1/2 study were to assess the safety, pharmacokinetics, pharmacodynamics, and clinical activity of olutasidenib, as monotherapy or in combination with azacitidine, in patients with acute myeloid leukaemia or myelodysplastic syndrome, harbouring mutant IDH1. In this phase 1/2, multicentre, open-label clinical trial, we enrolled patients aged 18 years or older with acute myeloid leukaemia or intermediate, high, or very high risk myelodysplastic syndrome harbouring mutant IDH1 at 18 study sites in the USA, Australia, France, and Spain. Other key eligibility criteria included Eastern Cooperative Oncology Group performance status 0-2 with adequate liver and renal function. The primary outcomes were dose-limiting toxicities and the maximum tolerated dose, maximum evaluated dose, and the recommended phase 2 dose of olutasidenib. Olutasidenib was administered orally in doses of 150 mg once daily, 150 mg twice per day, and 300 mg once daily. Azacitidine (75 mg/m2) was administered subcutaneously or intravenously daily for 7 days on, 21 days off. The study was ongoing at the data cutoff (Oct 2, 2019) and is registered with ClinicalTrials.gov, NCT02719574. Patients were enrolled between Aug 8, 2016, and Nov 14, 2018. 78 patients received olutasidenib as monotherapy (n=32) or in combination with azacitidine (n=46). The median follow-up was 8·3 months (IQR 3·1-13·3) for monotherapy and 10·1 months (4·2-15·3) for combination therapy. 16 (50%) of 32 patients in the monotherapy group and 24 (52%) of 46 patients in the combination therapy group were women. Most patients were White (26 [81%] for monotherapy and 31 [67%] for combination therapy). No dose-limiting toxicities were reported in the dose-escalation cohorts and 150 mg twice per day was declared the recommended phase 2 dose on the basis of safety, pharmacokinetics and pharmacodynamics, and clinical activity. The most common (≥20%) grade 3-4 treatment-emergent adverse events with monotherapy were thrombocytopenia (nine [28%] of 32 patients), febrile neutropenia (seven [22%] of 32), and anaemia (seven [22%] of 32); and with combination therapy were thrombocytopenia (19 [41%] of 46), febrile neutropenia (13 [28%] of 46), neutropenia (13 [28%] of 46), and anaemia (nine [20%] of 46). 11 (34%) of 32 patients in the monotherapy group and nine (20%) of 46 patients in the combination therapy group died (most commonly from disease progression [three (9%) of 32 and four (9%) of 46]). No deaths were considered study-drug related. For patients with relapsed or refractory acute myeloid leukaemia, 41% (95% CI 21-64; nine of 22) receiving monotherapy and 46% (27-67; 12 of 26) receiving combination therapy had an overall response. For treatment-naive patients with acute myeloid leukaemia, 25% (1-81; one of four) receiving monotherapy and 77% (46-95; ten of 13) receiving combination therapy had an overall response. Olutasidenib, with or without azacitidine, was well tolerated and showed meaningful clinical activity in patients with IDH1-mutated acute myeloid leukaemia. The results of this phase 1 study provide rationale for the continued evaluation of olutasidenib in multiple patient populations with myeloid malignancies. Forma Therapeutics.

De novo pyrimidine synthesis is a targetable vulnerability in IDH mutant glioma.

SUMMARYMutations affecting isocitrate dehydrogenase (IDH) enzymes are prevalent in glioma, leukemia, and other cancers. Although mutant IDH inhibitors are effective against leukemia, they seem to be less active in aggressive glioma, underscoring the need for alternative treatment strategies. Through a chemical synthetic lethality screen, we discovered that IDH1-mutant glioma cells are hypersensitive to drugs targeting enzymes in the de novo pyrimidine nucleotide synthesis pathway, including dihydroorotate dehydrogenase (DHODH). We developed a genetically engineered mouse model of mutant IDH1-driven astrocytoma and used it and multiple patient-derived models to show that the brain-penetrant DHODH inhibitor BAY 2402234 displays monotherapy efficacy against IDH-mutant gliomas. Mechanistically, this reflects an obligate dependence of glioma cells on the de novo pyrimidine synthesis pathway and mutant IDH’s ability to sensitize to DNA damage upon nucleotide pool imbalance. Our work outlines a tumor-selective, biomarker-guided therapeutic strategy that is poised for clinical translation.

P556: CHANGES IN HEALTH-RELATED QUALITY OF LIFE IN PATIENTS WITH NEWLY-DIAGNOSED ACUTE MYELOID LEUKEMIA RECEIVING IVOSIDENIB + AZACITIDINE OR PLACEBO + AZACITIDINE

Background: Ivosidenib (IVO) is a potent, targeted inhibitor of mutant isocitrate dehydrogenase 1 (mIDH1) that is approved for acute myeloid leukemia (AML). IVO plus azacitidine (AZA) demonstrated clinical benefit compared with placebo and AZA in the AGILE study (NCT03173248). Aims: To assess the impact of IVO+AZA versus placebo+AZA on health-related quality of life (HRQoL) using data from the AGILE study. Methods: In the double-blind, placebo-controlled phase 3 AGILE study, patients (pts) were randomized 1:1 to IVO 500 mg QD + AZA 75 mg/m2 SC or IV for 7 days in 28-day cycles, or placebo+AZA. HRQoL was a secondary endpoint assessed using two validated questionnaires: the European Organisation of Research and Treatment of Cancer Core Quality of Life Questionnaire (EORTC QLQ-C30) and the EuroQol 5-dimension 5-level questionnaire (EQ-5D-5L). Questionnaires were administered pre-dose on cycle (C) 1 Day (D) 1, on C1D15, C2D1, C2D15, and on D1 of every odd cycle thereafter until the end of treatment. Score change from baseline across visits for all subscales of EORTC QLQ-C30 was analyzed with mixed models. A 10-point threshold in EORTC QLQ-C30 subscale score was used to evaluate clinically meaningful changes from baseline or differences between arms. Two-sided nominal p-values are reported. All patients gave written informed consent. Results: At baseline, 69 and 68 pts out of 72 receiving IVO+AZA completed the EORTC QLQ-C30 and EQ-5D-5L, respectively, and 66 pts out of 74 receiving placebo+AZA completed both. Mean baseline HRQoL scores were similar between treatment arms (EORTC QLQ-C30 global health status [GHS/QoL] score was 56.3 and 53.2 in the IVO+AZA and placebo+AZA arms, respectively). There was an initial decline in HRQoL (EORTC QLQ-C30 GHS/QoL) in both arms for ~4 months, consistent with time to response, and which was generally not clinically meaningful (Table). IVO+AZA was associated with preserved or improved HRQoL compared to baseline for most subscales of the EORTC QLQ-C30 from C5 to C19 (after which no placebo+AZA HRQoL data were available), and at most timepoints for EQ-5D-5L VAS scores and index values. EORTC QLQ-C30 subscales with clinically meaningful improvements from baseline at most timepoints from C5 to C19 in the IVO+AZA arm included GHS/QoL (Table), fatigue, pain and appetite loss. In contrast, there were few clinically meaningful improvements from baseline in placebo+AZA pts. GHS/QoL scores were significantly improved (p≤0.05) for IVO+AZA versus placebo+AZA at C2D1, C2D15, C7 and C9 (Table), and differences between treatment arms were clinically meaningful at C2D1, C2D15, C7, C9, C13, C15 and C19 (Table). Likewise, improvements in EORTC QLQ-C30 fatigue, appetite loss, nausea and vomiting, diarrhea, cognitive functioning and social functioning favored IVO+AZA over placebo+AZA at multiple timepoints. Image:Summary/Conclusion: Data from the AGILE study show that patients with mIDH1 AML receiving treatment with IVO+AZA tended to report maintenance or improved HRQoL from cycle 5 through to cycle 19 compared with placebo+AZA.