A phase 1b open-label dose-finding study of ustekinumab in young adults with type 1 diabetes

Aim We assessed the safety of ustekinumab (a monoclonal antibody used in psoriasis to target the IL-12 and IL-23 pathways) in a small cohort of recent-onset (<100 days of diagnosis) adults with type 1 diabetes (T1D) by conducting a pilot open-label dose-finding and mechanistic study (NCT02117765) at the University of British Columbia. Methods We sequentially enrolled 20 participants into four subcutaneous dosing cohorts: i) 45mg loading-weeks 0/4/16, ii) 45mg maintenance-weeks 0/4/16/28/40, iii) 90mg loading-weeks 0/4/16 and iv) 90mg maintenance-weeks 0/4/16/28/40. The primary endpoint was safety as assessed by an independent data and safety monitoring board (DSMB) but we also measured mixed meal tolerance test C-peptide, insulin use/kg, and HbA1c. Immunophenotyping was performed to assess immune cell subsets and islet antigen-specific T cell responses. Results Although several adverse events were reported, only two (bacterial vaginosis and hallucinations) were thought to be possibly related to drug administration by the study investigators. At 1 year, the 90mg maintenance dosing cohort had the smallest mean decline in C-peptide AUC (0.1pmol/mL). Immunophenotyping showed that ustekinumab reduced the percentage of circulating Th17, Th1 and Th17.1 cells and proinsulin-specific T cells that secreted IFN-γ and IL-17A. Conclusion Ustekinumab was deemed safe to progress to efficacy studies by the DSMB at doses used to treat psoriasis in adults with T1D. A 90mg maintenance dosing schedule reduced proinsulin-specific IFN-γ and IL-17A-producing T cells. Further studies are warranted to determine if ustekinumab can prevent C-peptide AUC decline and induce a clinical response.

A Phase 1, Open-Label, Dose-Escalation Study of the Safety and Efficacy of Anti-CD38 Antibody Drug Conjugate (STI-6129) in Patients with Relapsed or Refractory Multiple Myeloma

Background: With the advent of several new agents in the treatment of multiple myeloma, including proteasome inhibitors (PIs), immunomodulatory drugs (IMiDs), and anti-CD38 monoclonal antibodies (mAb), the overall survival (OS) has significantly improved in the past two decades. However, most patients become refractory to currently available therapies along the disease trajectory. The median OS in triple-class-refractory patients (i.e., anti-CD 38 mAb, PIs, and IMiDs) is 6 months (Gandhi et al. Leukemia. 2019). Although BCMA-targeted therapies are a major advance in such patients, none of them are curative thus far, with the median progression-free survival (PFS) ranging from 3 months in BCMA-antibody drug conjugates (ADCs) to approximately 1 year in BCMA chimeric antigen receptor T-cell (CAR T-cell) therapies. Furthermore, unique toxicities of BCMA-targeted agents such as ocular toxicity (ADCs), cytokine release syndrome, or neurotoxicity (CAR Ts and BiTEs) may preclude their use in many patients. Hence, there is a critical unmet need in patients with triple-class-refractory myeloma. The STI-6129 ADC is produced by conjugating STI-5171, a fully human anti-CD38 mAb, with a covalently bound tubulin inhibitor, duostatin 5.2 (DUO-5.2), using a proprietary linker technology with a 3:1 drug-antibody ratio. STI-6129 binds to different CD38 epitopes than daratumumab. Upon binding to CD38, STI-6129 ADC is internalized by the cancer cell and undergoes lysosomal degradation, releasing DUO-5.2. This in turn leads to G2-phase cell cycle arrest, followed by caspase 3/7-dependent apoptosis and cell death. In studies on cynomolgus monkeys, the serum level of DUO-5.2 remained undetectable at all doses except at the highest dose of 4.5 mg/kg, indicating low likelihood of off-target toxicity. In vitro studies of primary human plasma cells, human tumor models, and animal xenograft models have demonstrated target elimination of CD38-positive human plasma cells by STI-6129. Importantly, STI-6129 has demonstrated cytotoxic activity in human multiple myeloma cells isolated from daratumumab-refractory patients (Figure 1). Hence, further investigation on clinical activity of STI-6129 is warranted. Study Design: The 38-ADC-RRMM-101 study is a two-stage, multicenter, open-label, dose-finding phase 1/2 trial. The phase 1 trial is designed to identify the recommended phase 2 dose (RP2D) of STI-6129 by assessing safety, preliminary efficacy, and pharmacokinetics in patients with relapsed/refractory (RR) myeloma. The phase 2a stage of the trial will be a single-arm study to investigate the efficacy of STI-6129 in an expansion cohort of RR myeloma patients. Up to 25 patients will be enrolled in the phase 1 stage and 30 in the phase 2 stage of the study. The key inclusion criteria are the following: (a) RR myeloma with at least 3 prior lines of therapy in addition to being refractory to at least 1 PI, 1 IMiD, and 1 anti-CD 38 mAb; (b) measurable disease. The key exclusion criteria are: (a) receipt of the last dose of any anti-CD mAb within 90 days; (b) grade ≥3 neuropathy or grade 2 neuropathy with pain; (c) current history of CTCAE grade 3 muscle paresis, eyelid conditions, glaucoma, or any other ocular disorder that is CTCAE grade 2; (d) estimated creatinine clearance <60 ml/min; (e) left ventricular ejection fraction<40%. The primary endpoint of phase 1 stage of the study is safety, particularly any dose limiting toxicities. The primary endpoint of the phase 2 part of the study is overall response rate as per IMWG criteria. The dosing cohorts in the dose escalation phase will range from 0.25 mg/kg to 3.68 mg/kg. Given the potential for on-target off-tumor toxicity due to expression of CD38 on non-clonal plasma cells and other hematopoietic cells, blood counts and immunoglobulin levels will be closely monitored. While neurotoxicity or ocular toxicity were not observed with STI-6129 in animal models, including non-human primates, such event will be considered as adverse events of special interest (AESI) and comprehensive neurology and ocular (including slit lamp) examinations will be performed at baseline and study completion, and at any AESI. STI-6129 will be administered intravenously once in a 4-week cycle, with the intention being to treat patients until disease progression or unacceptable toxicity. Figure 1 Figure 1. Disclosures Yan: Sorrento Therapeutics: Current Employment. Royal: Sorrento Therapeutics: Current Employment.

A Phase I Open Label Dose Escalation Study of MB-CART19.1 in Relapsed and Refractory CD19+ B Cell Malignancies, Interim Preliminary Results in Pediatric ALL, Adult ALL Including CLL Cohorts

Introduction This phase I first-in-human clinical study assesses the safety and preliminary efficacy of a CD19-directed, CAR (4-1BBz) gene-modified, autologous T-cell immunotherapy (MB-CART19.1) intended for use in pediatric and adult patients with relapsed or refractory B-cell acute lymphoblastic leukemia (ALL) and Non-Hodgkin lymphoma (NHL). The study also evaluates the feasibility of a hybrid manufacturing model, combining central and academic manufacturing capabilities with central QP oversight. Methods MB-CART19.1 is evaluated in a Phase I (EudraCT 2017-002848-32) multi-center, open label, dose escalation trial enrolling 33 to 48 patients in three disease cohorts, defined by disease biology and age. Pediatric (1-17 years) and adult patients are eligible if diagnosed with relapsed/refractory (r/r) CD19-expressing B-cell ALL or B-cell high-grade and low-grade (adults) NHL, including chronic lymphocytic leukemia (CLL). Enrollment is still ongoing. The starting material, a fresh patient leukapheresis product, is enriched for CD4/CD8 T-cells, transduced with a lentiviral vector (LV) and expanded using the CliniMACS Prodigy System allowing a high degree of control and consistency of the manufacturing process in both a central and decentralized facilities. MB-CART19.1 is presented as fresh cellular dispersion for single infusion and undergoes central release. Subjects undergo lymphodepletion with fludarabine (25 mg/m 2 daily for 3 days) and cyclophosphamide (1000 mg/m 2 on day -3). Dose escalation includes 3 dose levels (DL) 5x10 5 (DL I), 1x10 6 (DL II), 3x10 6 (DL III) CAR T cells/kg BW, respectively, and a safety dose level 0. The primary objective is to determine the recommended dose of MB-CART19.1. Secondary objectives are preliminary efficacy parameters evaluation of as well as CART persistence. Results Disease cohort I: pediatric ALL and aggressive NHL, 1-17 years. Up to the data lock point for interim analysis (DLP, 02 June 2021), 9 pediatric ALL patients were treated, 6 at DL I and 3 at DL II. All 9 patients completed the 28 days safety follow-up. At DL I, 5 of 6 patients experienced CRS (4 grade I-II, 1 grade III,) starting 5 to 7 days after IMP infusion. Two CRS cases were managed with tocilizumab and resolved within 1-2 weeks. 1 patient developed signs of neurotoxicity (grade IV seizure) concurrently with grade II CRS, which was effectively managed and fully resolved within 48 hours. The event was evaluated as DLT and led to the extension of the dose group from 3 to 6 patients. No further neurotoxicities occurred. Four of 6 patients treated at DL I finished the active part of the trial (12 months after administration of IMP) in CR-MRD and entered the long term follow-up. Two patients had CD19-negative relapses 4 and 10 months post MB-CART19.1 infusion. At DL II, 1 patient completed the 6 months follow up in ongoing CR, and 2 patients relapsed. Disease cohort II adult ALL: Up to the DLP, 4 adult ALL patients were treated at DL I. 1 patient died due to progression of disease on day 20 after the IMP infusion. All 4 adult patients experienced a grade I or II CRS all cases were reversible within 1-2 weeks , 1 patient received tocilizumab One patient developed neurologic symptoms (grade III visual impairment and grade III muscle weakness right-sided) with onset 41 and 72 days after administration of MB-CART19.1, respectively. 2 of the 3 patients who completed the safety follow-up finished the active part of the trial and entered the long-term follow-up, both in molecular CR up to Month 6. Disease cohort III adult NHL/CLL: 4 patients were enrolled with the starting dose of 1x10 6 CAR+ cells/kg (DL II). 1 patient experienced grade III CRS and was treated with tocilizumab. 3 patients completed the 28 days safety follow up. One patient with CLL achieved a CR, which is maintained at 6 months. Another CLL patient was in PR at the assessment visit Day 28. Data from the 2 other patients, 1 with MCL and 1 with DLBCL were in PR at month 3. Later data is not yet available. Conclusions 18 of 19 patients completed the follow-up safety period of 28 days defined as observation period for dose limiting toxicity (DLT). One DLT was observed as well as 3 grade III CRS events and 1 grade III neurological event. Early efficacy results are very encouraging. Longer follow-up will establish whether treatment results in durable responses. The hybrid manufacturing model provides flexibility and a timely delivery of the fresh drug product to the patients Disclosures Hanssens: Miltenyi Biomedicine GmbH: Current Employment. Stelljes: MSD: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Celgene/BMS: Consultancy, Speakers Bureau; Kite/Gilead: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Medac: Speakers Bureau; Pfizer: Consultancy, Research Funding, Speakers Bureau. Bethge: Novartis: Consultancy, Honoraria, Speakers Bureau; Kite-Gilead: Consultancy, Honoraria, Speakers Bureau; Miltenyi Biotec: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Celgene: Consultancy, Honoraria, Speakers Bureau. Yakushina: Miltenyi Biomedicine GmbH: Current Employment. Holtkamp: Miltenyi Biomedicine GmbH: Current Employment. Assenmacher: Miltenyi Biotec: Current Employment. Jurk: Miltenyi Biotec: Current Employment. Rauser: Miltenyi Biomedicine GmbH: Current Employment. Schneider: Employee of Lentigen Technology, a Miltenyi Biotec Company: Current Employment. Rossig: AdBoards by Amgen: Honoraria; Novartis: Honoraria; Pfizer: Honoraria; BMS and Celgene: Honoraria.