Rigel (United States)

BackgroundOlutasidenib is an oral, selective inhibitor of mutant isocitrate dehydrogenase 1 (mIDH1), FDA-approved for relapsed/refractory (R/R) acute myeloid leukemia (AML) based on a registrational, phase 2, open-label, multicenter trial.MethodsResults from the pre-planned interim analysis were previously published (data cut-off [DCO]: June 2021). In this final-follow up analysis, we report an additional 2 years of efficacy and safety data (DCO: June 2023).ResultsAt study completion, the overall population included 153 patients (median age, 71 years); 66% had received ≥ 2 prior treatment regimens, and 39% with a hypomethylating agent. Among the 147 efficacy-evaluable patients, 51 achieved complete remission (CR) or CR with partial hematologic recovery (CRh), resulting in a CR/CRh rate of 35% (P < 0.001; 95% CI, 27–43), with 32% of responders achieving CR. The median time to CR/CRh was 1.9 months (range, 0.9–5.6 months). Among responders, 33% achieved CR/CRh within 2–4 months and 12% required ≥ 4 months. The overall response rate (ORR) was 48% (n = 71; 95% CI, 40–56.7). Median duration of CR/CRh was 25.3 months (95% CI, 13.5–not reached), and median overall survival (OS) was 11.5 months (95% CI, 8.3–15.5). Patients with 1–2 prior regimens had a higher CR/CRh rate (41%) and longer median OS (13 months) than those with ≥ 3 prior regimens (CR/CRh: 24%; median OS: 8.9 months). CR/CRh rates were higher among patients with R132C (42%) and R132L/G/S mutations (33%) compared with those harboring R132H mutations (17%). Response rates decreased with increasing numbers of co-mutations. Few new adverse events (AEs) and no treatment discontinuations due to AEs occurred beyond Year 3.ConclusionThese 5-year data support the durable efficacy and manageable safety profile of olutasidenib in R/R mIDH1 AML, including heavily pretreated patients. Findings highlight the potential role of olutasidenib in earlier lines of treatment, and support sustaining therapy for at least 6 months to allow for a clinical response. Further research is warranted to optimize treatment sequencing and patient selection.Trial registrationNCT02719574.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13045-025-01751-w.

BackgroundOlutasidenib is a potent, selective, oral, small molecule inhibitor of mutant IDH1 (mIDH1) which induced durable remissions in high-risk, relapsed/refractory (R/R) mIDH1 AML patients in a phase 1/2 trial. We present a pooled analysis from multiple cohorts of the phase 1/2 trial of patients with R/R AML who received combination olutasidenib and azacitidine therapy.MethodsAdult patients with mIDH1R132 AML received 150 mg olutasidenib twice daily plus standard-of-care azacitidine (OLU + AZA) and were evaluated for response and safety.ResultsSixty-seven patients with R/R mIDH1R132 AML received combination OLU + AZA. Median age was 66 years (range 28–82) and 54% were male. Most patients (83%) had 2 + prior regimens, including a hypomethylating agent in 40%, IDH1 inhibitor therapy in 31% (olutasidenib in 24%), and hematopoietic stem cell transplant in 10%. Cytogenetic risk was intermediate in 72%, poor in 18% and unknown in 10%. CR/CRh was achieved in 21/67 (31%; 95% CI 21–44) patients, with a median duration of 14.7 months (95% CI 4.6-not reached). CR was achieved in 18/67 (27%; 95% CI 17–39) patients, with median duration of 20.3 months (95% CI 3.7-not reached). Overall response (partial remission or better) was achieved in 34/67 (51%; 95% CI 38–63) patients. Median overall survival was 12.9 months (95% CI 18.7–19.3). In a subset analysis excluding patients who had prior OLU exposure (N = 51), CR/CRh was achieved in 19/51 (37%; 95% CI 24–52) patients, CR was achieved in 16/51 (31%; 95% CI 19–46), and overall response was achieved in 30/51 (59%; 95% CI 44–72). In patients who achieved CR/CRh and were transfusion-dependent at baseline, transfusion independence (RBC and platelets) was achieved in 64% (7/11) and 57% (4/7) of patients, respectively. The most common Grade 3 or 4 adverse events (> 20% patients) were decreased platelet count (37%), red blood cell count (25%), and neutrophil count (24%). Six patients (9%) experienced differentiation syndrome. Four (6%) discontinued treatment due to an adverse event.ConclusionsOlutasidenib plus azacitidine induced high response rates and durable remissions with a tolerable side effect profile in patients with R/R AML with diverse treatment histories. The results represent another therapeutic option for patients with mIDH1 AML who may benefit from a targeted therapy.Trial registrationNCT02719574.

Introduction: Chronic immune thrombocytopenia purpura (ITP) in adults is a serious autoimmune disease in which platelets are prematurely destroyed, leaving the patient vulnerable to bruising and bleeding. Initial treatment starts with corticosteroids. In patients who become resistant or intolerant to corticosteroids, the thrombopoietic agents (TPOs), consisting of romiplostim (ROM), eltrombopag (ELT), and avatrombopag (AVA), or the spleen tyrosine kinase inhibitor fostamatinib (FOS), are appropriate next lines of therapy. In this study, the comparative safety, effectiveness, and cost of care between fostamatinib and the TPOs were evaluated in a real-world setting. Methods: A retrospective analysis of 17 community hematology practices across the USA was conducted to identify adult ITP patients who received one of the four agents. Data collection consisted of patient demographics, disease characteristics, as well as number and type of prior treatments. From the first day until the end of treatment, data were also collected on platelet (PLT) counts, adverse events, the use of rescue IVIG, platelet transfusions, and corticosteroids. Multivariable logistic regression analysis was used to compare PLT-related endpoints between agents. Results: A sample of 179 ITP patients who had received at least one of the four agents was identified. This resulted in a final sample of 51, 87, 127, and 44 patients who received FOS, ELT, ROM, or AVA, respectively. At month six, there were no significant differences between FOS and the TPOs in terms of the proportion of patients with the PLT count being ≥30 × 103/μL, ≥50 × 103/μL as well as the proportion of patients whose PLT levels doubled relative to baseline. The frequency of thromboembolic events (TEs) was 3.9% in FOS patients compared to 9.2%, 4.7%, and 11.4% in the ELT, ROM, and AVA groups. The mean cost per patient with FOS was $99,209 (95% CI: $59,595–$115,074), compared to $92,426 (95% CI: $68,331–$115,519), $108,482 (95% CI: $84,782–$132,182), and $131,050 (95% CI: $83,327–$179,897) for ELT, ROM, or AVA, respectively. Conclusions: In this real-world analysis, FOS was comparable to the TPOs in maintaining PLTs at clinically beneficial levels. Given these findings, the choice of therapy should be based on overall patient safety, preexisting risk factors for TEs, and cost effectiveness.

Syk is a cytoplasmic protein tyrosine kinase that plays a role in signaling via B cell and Fc receptors (FcR). FcR engagement and signaling via Syk is thought to be important in antineutrophil cytoplasm antibody (ANCA) IgG-mediated neutrophil activation. This study was undertaken to investigate the role of Syk in ANCA-induced myeloid cell activation and vasculitis pathogenesis. Phosphorylation of Syk in myeloid cells from healthy controls and ANCA-associated vasculitis (AAV) patients was analyzed using flow cytometry. The effect of Syk inhibition on myeloperoxidase (MPO)-ANCA IgG activation of cells was investigated using functional assays (interleukin-8 and reactive oxygen species production) and targeted gene analysis with NanoString. Total and phosphorylated Syk at sites of tissue inflammation in patients with AAV was assessed using immunohistochemistry and RNAscope in situ hybridization. We identified increased phosphorylated Syk at critical activatory tyrosine residues in blood neutrophils and monocytes from patients with active AAV compared to patients with disease in remission or healthy controls. Syk was phosphorylated in vitro following MPO-ANCA IgG stimulation, and Syk inhibition was able to prevent ANCA-mediated cellular responses. Using targeted gene expression analysis, we identified up-regulation of FcR- and Syk-dependent signaling pathways following MPO-ANCA IgG stimulation. Finally, we showed that Syk is expressed and phosphorylated in tissue leukocytes at sites of organ inflammation in AAV. These findings indicate that Syk plays a critical role in MPO-ANCA IgG-induced myeloid cell responses and that Syk is activated in circulating immune cells and tissue immune cells in AAV; therefore, Syk inhibition may be a potential therapeutic option.

Leukemia stem cells (LSCs) in chronic myeloid leukemia (CML) are quiescent, insensitive to BCR-ABL1 tyrosine kinase inhibitors (TKIs) and responsible for CML relapse. Therefore, eradicating quiescent CML LSCs is a major goal in CML therapy. Here, using a G0 marker (G0M), we narrow down CML LSCs as G0M- and CD27- double positive cells among the conventional CML LSCs. Whole transcriptome analysis reveals NF-κB activation via inflammatory signals in imatinib-insensitive quiescent CML LSCs. Blocking NF-κB signals by inhibitors of interleukin-1 receptor-associated kinase 1/4 (IRAK1/4 inhibitors) together with imatinib eliminates mouse and human CML LSCs. Intriguingly, IRAK1/4 inhibitors attenuate PD-L1 expression on CML LSCs, and blocking PD-L1 together with imatinib also effectively eliminates CML LSCs in the presence of T cell immunity. Thus, IRAK1/4 inhibitors can eliminate CML LSCs through inhibiting NF-κB activity and reducing PD-L1 expression. Collectively, the combination of TKIs and IRAK1/4 inhibitors is an attractive strategy to achieve a radical cure of CML.

AimWe evaluated the efficacy of a novel brain permeable “metformin-like” AMP-activated protein kinase activator, R481, in regulating glucose homeostasis.Materials and MethodsWe used glucose sensing hypothalamic GT1-7 neuronal cells and pancreatic αTC1.9 α-cells to examine the effect of R481 on AMPK pathway activation and cellular metabolism. Glucose tolerance tests and hyperinsulinemic-euglycemic and hypoglycemic clamps were used in Sprague-Dawley rats to assess insulin sensitivity and hypoglycemia counterregulation, respectively.Results In vitro, we demonstrate that R481 increased AMPK phosphorylation in GT1-7 and αTC1.9 cells. In Sprague-Dawley rats, R481 increased peak glucose levels during a glucose tolerance test, without altering insulin levels or glucose clearance. The effect of R481 to raise peak glucose levels was attenuated by allosteric brain permeable AMPK inhibitor SBI-0206965. This effect was also completely abolished by blockade of the autonomic nervous system using hexamethonium. During hypoglycemic clamp studies, R481 treated animals had a significantly lower glucose infusion rate compared to vehicle treated controls. Peak plasma glucagon levels were significantly higher in R481 treated rats with no change to plasma adrenaline levels. In vitro, R481 did not alter glucagon release from αTC1.9 cells, but increased glycolysis. Non brain permeable AMPK activator R419 enhanced AMPK activity in vitro in neuronal cells but did not alter glucose excursion in vivo.ConclusionsThese data demonstrate that peripheral administration of the brain permeable “metformin-like” AMPK activator R481 increases blood glucose by activation of the autonomic nervous system and amplifies the glucagon response to hypoglycemia in rats. Taken together, our data suggest that R481 amplifies the counterregulatory response to hypoglycemia by a central rather than a direct effect on the pancreatic α-cell. These data provide proof-of-concept that central AMPK could be a target for future drug development for prevention of hypoglycemia in diabetes.