Cherry, Mohamad

Introduction CD19 CAR T cell therapies are highly effective for several aggressive B-cell malignancies. Emerging data suggest that these therapies may lead to durable, treatment-free responses in multiple autoimmune diseases, including systemic lupus erythematosus (SLE), idiopathic inflammatory myopathies (IIMs), systemic sclerosis (SSc), and multiple sclerosis (MS). BMS-986353 (CC-97540) is an investigational CAR T cell therapy expressing the CD19-targeting CAR used in FDA-approved lisocabtagene maraleucel (liso-cel). BMS-986353 is manufactured using the NEX-TTM process, which shortens manufacturing time and optimizes phenotypic attributes of the CAR T cell product. Here, we report updated data on BMS-986353 in severe, refractory autoimmune diseases. Methods Two phase 1, multicenter, open-label studies are investigating BMS-986353 in patients (pts) with severe, refractory SLE, IIM, and SSc (CA061-1001; NCT05869955), and relapsing or progressive forms of MS (CA061-1006; NCT06220201). CAR T cells were manufactured using the NEX-T process and autoimmune-directed therapies were tapered before BMS-986353 infusion. Two to 9 d after lymphodepletion (3 d of fludarabine [30 mg/m2/d], cyclophosphamide [300 mg/m2/d]), a single infusion of BMS-986353 was administered. Pts were treated with 5 × 106 (MS only), 10 × 106, or 25 × 106 CAR+ T cells according to dose level. Pharmacokinetics were evaluated using droplet digital PCR to detect transgene copy numbers, and pharmacodynamics were measured using flow cytometry. Results As of Jul 12, 2024, 7 pts were treated with BMS-986353 (SLE, n=5; SSc, n=1; relapsing-remitting MS [RRMS], n=1). Seven pts were evaluable for safety; 4 pts were evaluable for efficacy (median follow-up of 167.5 d [range, 68-240]). All 5 pts with SLE had history of renal organ system involvement (BILAG category A) and disease refractory to multiple prior therapies (range 5-8); at screening, scores were (median [range]): SLE Disease Activity Index 2000 (SLEDAI-2K), 12.0 (7.0-22.0); Physician's Global Assessment (PGA), 2.3 (1.5-2.5). The pt with SSc was aged 43 y, and had history of progression of diffuse cutaneous SSc after 2 therapies and a modified Rodnan skin score of 18; the pt with RRMS was aged 33 y, and had history of active clinical disease despite 3 prior anti-CD20 therapies and an Expanded Disability Status Scale score of 3.0. Cytokine release syndrome was reported in 1 pt with SLE (grade [gr] 1) and 1 pt with SSc (gr 2), both resolved within 1 d. ICANS was reported in 1 pt with SSc (gr 1) and resolved in 1 d. Gr 3/4 transient lymphodepletion-related cytopenia occurred in 4 pts with SLE and 1 pt with MS. There were no prolonged gr ≥3 cytopenias or dose-limiting toxicities reported. In all efficacy evaluable pts, significant improvements in SLEDAI-2K (median, 4.0) and PGA (median, 0.55) were observed. dsDNA seroconverted and complements normalized for all pts who had abnormal values at screening. All pts remain off autoimmune-directed therapies without evidence of disease flare. Pts with SLE treated with 10 x 106 CAR+ T cell dose of BMS-986353 showed complete B-cell depletion and similar robust cellular expansion compared with pts with diffuse large B-cell lymphoma treated with liso-cel (TRANSFORM; NCT03575351) at the recommended phase 2 dose (RP2D; 100 x 106 CAR+ T cells). At the time of B-cell reconstitution following BMS-986353, re-emerging B cells were predominantly naive. Conclusions BMS-986353, a NEX-T investigational CD19-targeted CAR T cell therapy, has a more rapid manufacturing time and optimized phenotypic attributes. In pts with severe, refractory autoimmune diseases, BMS-986353 demonstrates a low rate of low gr CRS and ICANS events. Preliminary data suggest promising efficacy in pts with SLE despite discontinuation of all lupus therapies. Robust CAR T cell expansion comparable to the RP2D of liso-cel and complete B-cell depletion were observed after BMS-986353 at a dose of 10 x 106 CAR+ T cells despite being 1/10 of the RP2D of liso-cel. The studies continue to enroll pts in all autoimmune indications. Updated safety, efficacy, and translational data will be presented.

INTRODUCTION: Luxeptinib (CG-806; LUX) is an orally active noncovalent kinase inhibitor of Bruton's tyrosine kinase (BTK), wild type and mutant forms of Fms-like tyrosine kinase 3 (FLT3) (including the internal tandem duplicates (ITD), tyrosine kinase domain (TKD), and F691L mutant forms), and growth receptors like KIT, CSF1R, PDGFRα, and TRKs. In prior studies, LUX has been shown to suppress aberrant proliferative signaling in B cell malignancies and acute myeloid leukemia (AML) via regulation of BTK, LYN, SYK, AKT, ERK, and MAPK. LUX is cytotoxic to primary AML cells insensitive to other FLT3 inhibitors and to malignant B-cells insensitive to ibrutinib, at pM and nM concentrations, respectively. AIMS: The primary objectives of these studies are to assess the safety, tolerability, and pharmacokinetics (PK) of LUX and determine recommended phase 2 doses for relapsed or refractory (R/R) AML and B cell malignancy patients. METHODS: In two studies (NCT04477291; NCT03893682), LUX (original formulation, G1) was administered continuously as oral capsules BID in 28-day cycles of ascending cohorts (relapsed or refractory de novo, secondary, or therapy-related AML or higher risk myelodysplastic syndrome (MDS), and relapsed and refractory for B cell lymphoma and chronic lymphocytic/small lymphocytic leukemia). A novel generation 3 (G3) formulation of LUX designed to increase bioavailability was tested at a single-dose (sub-study) for relative bioavailability (RBA), followed by continuous dosing in subsequent R/R AML patients. RESULTS: In the B-cell study (as of 15 th May 2023), LUX has been administered to 36 patients at dose levels from 150 mg to 900 mg BID in patients with a median of 3 lines of prior treatment, with 47.2% having received a BTK-inhibitor. Only one (2.8%) patient had a DLT of hypertension and 14 (38.9%) experienced at least one drug related ≥Grade3 treatment emergent adverse event (TEAE). Two patients (900 mg) are currently on study with no DLT and no ≥Grade 3 related TEAEs. A Follicular lymphoma patient is at cycle 28, and achieved a best response as partial response (PR) with a decrease in lesion size of 76.2%; an SLL patient is at cycle 13, and achieved stable disease (SD) showing a decrease in lesion size of 43.1% (Figure A). The overall best response achieved among the 17 patients who have been on treatment for more than 12 weeks are stable disease (SD) (n=11), partial response (PR) (n=3), minor response (n=2) and complete response (CR) (n=1). As of 5 th June 2023, in the AML trial, a total of 40 patients (16 (40%) FLT3-ITD, 21 (52.5%) FLT3-WT, 2 (5.0%) FLT3-TKD, and 1 (2.5%) unknown mutations) with a median of 3 prior treatments (range, 1 - 10) have been treated with LUX G1 formulation at dose levels from 450 mg - 900 mg BID (n=34) or with 50 mg BID of G3 formulation (n=6). Four (10%) experienced drug related SAE and 7 (17.5%) had a drug related grade ≥3 TEAEs. The most common related TEAEs were lymphocyte count decrease, platelet count decrease, and anemia (n=2; 5% patients each). One (2.5%) patient at 450 mg dose, reported complete remission without minimum residual disease (CRmrd) and remained on study for 56 weeks. In the RBA sub-study, G3 (50 mg) produced comparable exposures to G1 (450-900 mg range) (Figure B) and was, therefore, selected as the starting dose for use in the R/R AML study. Six patients were treated with a continuous dosing of 50 mg BID G3; with plasma levels of 274 ng/mL and 195 ng/mL LUX observed by the end of C1D15 and C1D22 respectively. No drug related Grade ≥3 TEAEs or DLTs were observed in 50 mg BID G3 LUX treated patients; with no new safety signals observed for the G3 formulation. Based on these findings and expected exposures for higher dose levels, the cohort safety review committee has approved escalation of G3 dosing to 200 mg BID at which dosing is ongoing. CONCLUSIONS: LUX has a favorable safety profile in patients at all tested dose levels, for multiple cycles, for both studies. Antitumor activity was observed in a heavily pretreated relapsed AML patient and in multiple B-NHL subtypes and CLL/SLL patients including several with prior ibrutinib exposure. Continuous dosing of patients with R/R AML and Higher-Risk MDS with the G3 formulation is ongoing; with updated clinical data (200 mg dose level) to be presented at the meeting.

Abstract INTRODUCTION: Luxeptinib (CG-806) is a potent, non-covalent oral inhibitor of BTK and FLT3. It suppresses BCR signaling pathways (LYN, SYK, BTK, AKT, ERK) and other oncogenic pathways in cell lines and primary CLL cells, kills malignant B-cells insensitive to ibrutinib or venetoclax at low nM concentrations, and shows enhanced activity in combination with venetoclax. Luxeptinib is currently being evaluated in a Phase 1a/b trial in patients with relapsed or refractory B-cell malignancies (NCT03893682). AIMS: Primary objectives are to assess the safety and tolerability of luxeptinib and determine the recommended expansion dose for future clinical trials in patients with R/R CLL/SLL or B-NHL. Key secondary objectives include elucidation of the pharmacokinetic (PK) and pharmacodynamic (PD) characteristics, and evidence of antitumor activity. METHODS: Luxeptinib is administered continuously as oral capsules BID in 28-day cycles, in ascending cohorts of 3 patients. Treatment emergent adverse events (TEAEs) and tumor responses are evaluated per disease specific guidelines. RESULTS: As of June 7, 2021, a total of 23 patients (median age 64.0 years, 11 CLL/SLL, 4 follicular lymphoma (FL), 1 Richter's transformation lymphoma, 2 Waldenstrom's macroglobulinemia (WM), 2 mantle cell lymphoma, 3 diffuse large B cell lymphoma (DLBCL)) with a median of 3 prior systemic regimens (range of 1 - 12) have been treated with luxeptinib at doses of 150 mg (n=1), 300 mg (n=1), 450 mg (n=9), 600 mg (n=4) and 750 mg (n=8). Drug related grade ≥ 3 TEAEs included neutropenia (n=5, 21.7%), leukocytosis (n=2, 8.7%), decreased white blood cell count, decreased platelet count, anemia, increased alanine aminotransferase, diarrhea, hypertension, and headache (n=1, 4.3 % each). One patient, who experienced progressive hypertension before receiving luxeptinib, developed grade 1 hypertension during screening evolving to grade 2 prior to dosing on C1D1, experienced grade 4 hypertension after luxeptinib treatment at 750 mg BID for 5 days. While this was considered a DLT per protocol, luxeptinib plasma levels in this patient were lower than those observed in patients at this and lower dose levels, and no drug-related hypertension has been observed in any other patient treated to date. The average steady-state (C min) plasma levels of luxeptinib in patients treated with 750 mg BID were > 1µM and were sustained over multiple cycles. PD analysis demonstrated that C min of luxeptinib in the plasma of patients treated with doses of 300 mg or higher significantly reduced levels of phosphorylated BTK, SYK, ERK and FLT3 in EOL-1 reporter cells in a plasma inhibitor activity assay, demonstrating multi-target engagement. Response evaluations were available for 12 patients who had at least one imaging study or IgM measurements (WM patients) after starting treatment. Eight out of these 12 patients had various reductions of lesion size or IgM measurements compared to baseline (3 SLL, 2 FL, 1 CLL, 1 WM and 1 DLBCL), demonstrating anti-tumor activity. FDG PET-CT scans in one FL patient, who had 2 prior regimens, revealed lesion growth during treatment with luxeptinib at 450 mg BID for 7 cycles. After dose-escalation to 600 mg BID in Cycle 8, lesion measurements demonstrated continuous reduction. By C15D1, target lesions decreased by 42.5% and 11.3% when compared with peak tumor size and baseline measurements, respectively. One WM patient in Cohort 5 (750 mg BID), who had 2 prior regimens including ibrutinib, has had a 24.9% reduction in IgM level by C3D1 compared with baseline as her best response so far. CONCLUSIONS: Luxeptinib has a favorable safety profile in patients treated with 150 mg to 600 mg BID over multiple cycles. A single apparent DLT (grade 4 hypertension in one patient with pre-existing hypertension) led to expansion of the 750 mg dose level to 6 patients. Pharmacodynamic studies documented inhibition of SYK, BTK and ERK in the BCR signaling pathway. Anti-tumor activity was observed in multiple B-NHL subtypes and CLL/SLL patients. Enrollment of patients with R/R CLL/SLL and B-NHL at dose level 5 (750 mg) is ongoing and updated clinical data will be presented at the meeting. Disclosures Samaniego: Arog: Research Funding; Imbrium: Membership on an entity's Board of Directors or advisory committees. Burke: AstraZeneca: Consultancy; Verastem: Consultancy; Bristol Myers Squibb: Consultancy; Epizyme: Consultancy; Kura: Consultancy; Kymera: Consultancy; SeaGen: Consultancy, Speakers Bureau; X4 Pharmaceuticals: Consultancy; Adaptive Biotechnologies: Consultancy; Beigene: Consultancy, Speakers Bureau; AbbVie: Consultancy; MorphoSys: Consultancy; Roche/Genentech: Consultancy. Mahadevan: caris: Speakers Bureau; Guardanthealt: Speakers Bureau; PFIZER: Other: Clinical trial Adverse events committee; TG Therapeuticals: Other: Clinical trial Adverse events committee. Cherry: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees. Sadiq: Dava Oncology: Honoraria. Reid: ADC Therapeutics: Other: Serves as Principle Investigator, Research Funding; Aptose Biosciences: Other: Serves as Principle Investigator, Research Funding; Millennium Pharmaceuticals: Other: Serves as Principle Investigator, Research Funding; Xencor: Other: Serves as Principle Investigator, Research Funding. Roeker: TG Therapeutics: Consultancy; Pfizer: Consultancy, Research Funding; AbbVie, AstraZeneca, Janssen, LOXO, Pharmacyclics, TG Therapeutics, Vaniam Group, Verastem: Consultancy; Loxo Oncology: Consultancy; Abbot Laboratories: Current equity holder in publicly-traded company; Pharmacyclics: Consultancy. Melear: Astrazeneca: Speakers Bureau; TG Therapeutics: Speakers Bureau; Janssen: Speakers Bureau. Zhang: Aptose Biosciences, Inc.: Current Employment. Rastgoo: Aptose Biosciences, Inc.: Current Employment. Benbatoul: Aptose Biosciences, Inc.: Current Employment. Haney: Aptose Biosciences, Inc.: Current Employment. Jin: Aptose Biosciences, Inc.: Current Employment. Marango: Aptose Biosciences, Inc.: Current Employment, Current equity holder in publicly-traded company. Howell: Aptose Biosciences, Inc.: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees, Research Funding. Rice: Oncolytics Biotech Inc.: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Aptose Biosciences, Inc.: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties. Bejar: Astex: Consultancy; Silence Therapeutics: Consultancy; Aptose Biosciences, Inc.: Current Employment, Current equity holder in publicly-traded company; Epizyme: Consultancy, Honoraria; Takeda: Research Funding; Gilead: Consultancy, Honoraria; BMS: Consultancy, Research Funding.

Abstract Introduction Cancer associated thrombosis is the second most common cause of mortality among patients with malignancy. While preventive low molecular weight heparin is effective in preventing venous thromboembolism (VTE), lack of agreement on risk stratification methods have precluded its widespread use. The most studied VTE prediction tool is the Khorana score, but it does not capitalize on the use of novel biomarkers. We aimed to evaluate the value of biomarkers in prediction of VTE among patients with active cancer receiving outpatient chemotherapy. Methods We prospectively collected pre-chemotherapy blood samples on adult patients with solid organ tumors. We excluded patients on anticoagulation and those unable or unwilling to consent. Along with demographics and cancer specific variables, potential novel predictors of VTE were selected a priori and included: coated platelets (CP), D dimer (DD), protein C (PC), fibrin monomers (FM), mean platelet volume (MPV), platelet microparticles (PMP). Type of cancer was grouped according to the Khorana score (Very high risk: Stomach, Pancreas; High risk: Lung, Gynecologic, Bladder, Testicular; Low/Moderate risk: all other sites). VTE events were adjudicated at 6 months of follow up. For all statistical analyses we used SAS 9.2 (SAS Institute Inc., Cary, NC, USA). A p value of <0.05 was considered as statistically significant. We only performed univariate analysis at this point of our study due to the stage of recruitment and period of follow-up. Results We have recruited a total of 101 patients (mean + standard deviation age 59.7+11 years, 68% female), 20% of the 75 patients with complete follow up have developed a VTE. We found no significant association between the incidence of VTE and age, gender, or baseline Khorana score. The variables associated with incident VTE were: BMI (odds ratio [OR] 8.5 for BMI<25 kg/m2, p<0.001), type of cancer (OR 14.5 for very high risk compared to high risk, p<0.01) and protein C (OR 3.3 for protein C<110ug/mL the lowest tertile, p=0.05). The rest of the tested potential biomarkers did not have a strong association with incident VTE in the current analysis (Table). Twenty percent of the patients were on aspirin and none of them developed VTE compared to 23% of those not taking aspirin who developed VTE, (p=0.2). Conclusion Pre Chemotherapy level of Protein C is a potential biomarker for the incidence of VTE. We confirm that cancer type and BMI are predictors of cancer associated VTE. In addition, lower BMI is not usually recognized as a potential predictor of VTE in other prediction scores. We were underpowered to detect differences in the VTE incidence according to Khorana score. Finally, aspirin may have a role in outpatient cancer associated VTE prevention and deserves further investigation. Disclosures: Tafur: Stago Diagnostica: Research Funding. Rathbun:Stago Diagnostica: Research Funding.

Abstract Introduction Erlotinib is an epidermal growth factor receptor small-molecule inhibitor and is FDA approved for the treatment of lung and pancreatic cancers. In preclinical study, in vitro colony culture assays revealed that erlotinib at micro-molar concentrations effectively suppressed the growth and expansion of Polycythemia Vera (PV) hematopoietic progenitor cells while having little effect on normal cells. Several JAK inhibitors are being studied for the management of PV, one of which has been approved for the treatment of myelofibrosis (ruxolitinib). Aim To study the clinical effect of erlotinib in pts diagnosed with JAK2V617F + PV. Methods We conducted a single arm, prospective phase II study at the University of Oklahoma and the Oklahoma City VA hospitals in pts with WHO defined JAK-2 V617F positive PV from June 2010 to August 2012. Appropriate IRB approval was obtained in accordance with Hilsinki declaration. Pts had to be requiring phlebotomy. Toxicity was assessed by treating physicians using NCI version 4. Dose modification for erlotinib was done using label recommendations. Results Five Caucasian pts were enrolled (3 (60%) males, with median age at enrollment of 63 years, range 26-79). Pts had pretreatment median hemoglobin14.4 g/dL (10.4 -19.2 g/dL), median platelet count 511 x109 (424-681 x109), median white blood cell (WBC) 14.4 x109(7.8- 18.3 x109). Three pts had splenomegaly prior to treatment. Median number of prior pharmacologic treatments (hydroxyurea, anagralide or interferon) was 1, range 0-2. Pts were given erlotinib 150 mg orally daily for 16 weeks: responders (phlebotomy free or decrease in spleen size) were allowed to continue a total of 1 year of treatment, while non-responders were taken off the study. Three (60%) patients received therapy for 16 weeks and did not achieve hematological response or improvement in spleen size. Two (40%) pts were taken off the study after 2 doses secondary to severe toxicities (grade 3 colitis in 1 case, and grade 3 facial rash in 1case). No therapy continued beyond 16 weeks (due to toxicity or lack of response). All pts in the study developed rash (grade 1 – 3) and diarrhea (grade 1 – 2). Three pts developed mucositis (see Table 1). No death was observed during the study and follow up period (median follow up was 23 months, range 12-37 months). Study was closed due to lack of efficacy. Conclusions Despite in vitro efficacy of erlotinib as potent inhibitor of JAK-2 activity, erlotinib is not effective in pts with JAK-2 V617F positive PV with poor toxicity profile. Poor accrual was related to potential toxicity of erlotinib compared to alternative treatments in view of lack of clinical efficacy. Disclosures: No relevant conflicts of interest to declare.