Dose-escalation Clinical Study Research Articles

Preclinical Safety Assessment of the EBS-LASV Vaccine Candidate against Lassa Fever Virus.

There are currently no prophylactic vaccines licensed to protect against Lassa fever caused by Lassa virus (LASV) infection. The Emergent BioSolutions (EBS) vaccine candidate, EBS-LASV, is being developed for the prevention of Lassa fever. EBS-LASV is a live-attenuated recombinant Vesicular Stomatitis Virus (rVSV)-vectored vaccine encoding the surface glycoprotein complex (GPC) from LASV and has two attenuating vector modifications: a gene shuffle of the VSV N gene and a deletion of the VSV G gene. Preclinical studies were performed to evaluate EBS-LASV's neurovirulence potential following intracranial (IC) injection and to determine the biodistribution and vector replication following intramuscular (IM) inoculation in mice. In addition, the potential EBS-LASV toxicity was assessed using repeated-dose IM EBS-LASV administration to rabbits. All mice receiving the IC injection of EBS-LASV survived, while mice administered the unattenuated control vector did not. The vaccine was only detected in the muscle at the injection site, draining lymph nodes, and the spleen over the first week following IM EBS-LASV injection in mice, with no detectable plasma viremia. No toxicity was observed in rabbits receiving a three-dose regimen of EBS-LASV. These studies demonstrate that EBS-LASV is safe when administered to animals and supported a first-in-human dose-escalation, safety, and immunogenicity clinical study.

Abstract CT249: A study to evaluate the safety and tolerability of the covalent phosphoinositide-3-kinase (PI3K)-alpha Inhibitor, TOS-358, in adult subjects with select solid tumors

Abstract Background: TOS-358 is an orally available, highly selective covalent inhibitor of PI3Kα capable of achieving a deep and durable inhibition of PI3K-AKT signaling with virtually no off-target effects. In patient-derived xenograft models, TOS-358 has shown anti-cancer activity in several different tumor types including breast, colorectal, gastric, head and neck, bladder, and esophageal cancer, and its’ activity was superior to non-covalent compounds targeting PI3Kα. Administered at the equivalent dose, TOS-358 has shown a good safety profile in 28-day repeat dose toxicity studies in rats and dogs. Methods: The TOS-358-001 study is a multicenter dose escalation (phase 1) and dose expansion (phase 1b) clinical study evaluating the safety, tolerability, and preliminary efficacy of TOS-358. Eligible subjects are adults with one of protocol-defined tumor types, known PIK3CA mutation or amplification, adequate organ function, ECOG performance status 0 or 1, available archived or fresh tumor tissue for PIK3CA mutation detection and no prior treatment with PI3K, AKT or mTOR inhibitors (except subjects with breast cancer). The phase 1 portion of the study follows a 3+3 dose escalation design and is intended to determine the minimum effective dose (MED) and the maximum tolerated dose (MTD) of TOS-358 when administered orally on a once daily (QD) or a twice daily (BID) schedule, and the recommended phase 2 dose (RP2D). Cohort expansions at the MTD and MED to support the RP2D selection are planned. The phase 1b portion of the study will enroll subjects with tumor PIK3CA mutations or amplifications in several tumor-specific cohorts (colorectal, gastric, non-small cell lung, breast, squamous cell carcinoma of the head and neck, urothelial and select gynecological cancers) to further assess the safety and tolerability of TOS-358 and to evaluate the initial efficacy of the investigational agent. Enrolment to the study commences in US with European sites planned to open later in 2023. Clinical trial information: NCT05683418. Citation Format: Marwan Fakih, Davendra P. Sohal, Navid Hafez, Jordan D. Berlin, Kimberly Hari, Ovid C. Trifan. A study to evaluate the safety and tolerability of the covalent phosphoinositide-3-kinase (PI3K)-alpha Inhibitor, TOS-358, in adult subjects with select solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT249.

Preclinical characterization and clinical translation of pharmacodynamic markers for MK-5890: a human CD27 activating antibody for cancer immunotherapy

BackgroundImmune checkpoint inhibitors (ICI) have radically changed cancer therapy, but most patients with cancer are unresponsive or relapse after treatment. MK-5890 is a CD27 agonist antibody intended to complement ICI...

Abstract CT240: A first-in-human study of the dual A2A/A2B adenosine receptor antagonist M1069 in patients with advanced solid tumors

Abstract A2A and A2B adenosine receptors have been shown to mediate immunosuppressive and tumor-promoting signals in the tumor microenvironment and their inhibition may be a promising treatment strategy for patients with advanced solid tumors. Dual A2A/A2B inhibition has shown an acceptable safety profile as monotherapy and early signs of clinical activity in combination with chemotherapy in patients with advanced solid tumors. M1069 is a novel, orally administered, highly selective dual antagonist of the A2A and A2B adenosine receptors that has recently demonstrated significant anti-tumor activity in vivo as monotherapy and in combination with chemotherapeutic agents in adenosine-rich tumor models. The aim of this Phase Ia First in Human noncontrolled, open-label, multicentre, dose escalation clinical study (NCT05198349) is to investigate the safety, tolerability, pharmacokinetics, pharmacodynamics and preliminary activity of M1069 in patients with metastatic or locally advanced unresectable solid tumors. Study Design: Patients aged ≥18 years, with an Eastern Cooperative Oncology Group performance status ≤1, adequate baseline hematological, renal and hepatic function, and with locally advanced or metastatic disease refractory to, or who have progressed with, standard therapy are eligible. Patients who have had prior treatment with another agent targeting the adenosine signalling pathway or prior anticancer treatment within 4 weeks or 5 half-lives are excluded. The study includes a 28-day screening period, a study intervention period of 21-day cycles, a 21-day dose-limiting toxicity observation period, an end of study intervention visit and a safety follow-up period of 30±7 days. Patients (approximately 21-30) will receive M1069 monotherapy twice daily in 21-day cycles until disease progression, unacceptable toxicity, withdrawal of consent or any criterion for withdrawal from study intervention. The starting dose is M1069 150 mg twice daily, with dose escalation decisions (300, 450, 600 and 700 mg twice daily) made by the safety monitoring committee and supported by results of a Bayesian Logistic Regression Model (BLRM). The primary objectives of the study are to determine the dose toxicity relationship and maximum tolerated dose (MTD), if reached, of M1069 and to determine the recommended dose for expansion of M1069 for further exploratory clinical development. These will be measured by the occurrence of dose-limiting toxicities, adverse events and treatment-related adverse events, and, through analysis of the safety, tolerability, pharmacokinetics, pharmacodynamics and post-treatment changes in the tumor microenvironment in available paired tumor biopsies, respectively. The target dose-limiting toxicity probability for the MTD is 30% which will be estimated by the BLRM. Pharmacokinetic parameters will be calculated using noncompartmental analysis. The study is open and patients are being treated at the first dose level. Citation Format: Lillian L. Siu, Martin E. Gutierrez, Guelseren Guezel, Katia Ruth, Ping Hu, Thomas Kitzing, Christina Habermehl, Meredith McKean. A first-in-human study of the dual A2A/A2B adenosine receptor antagonist M1069 in patients with advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT240.

Abstract 1756: Antitumor effect of XMT1660, a B7H4 targeting antibody drug conjugate, in an unselected panel of patient derived xenograft models of breast cancer

Abstract Introduction: XMT-1660 is a first-in-class Dolasynthen Antibody-Drug Conjugate (ADC) targeting B7-H4 and carrying a DolaLock payload with controlled bystander effect. B7-H4 is an immunoregulatory protein that is expressed in breast, ovarian and endometrial tumors. Expression of B7-H4 has been described in both tumor cells and in tumor associated macrophages, and B7-H4 shows infrequent co-expression with PD-L1, suggesting distinct immunoregulatory functions. XMT-1660 is built on the Dolasynthen platform which incorporates several attributes, including site-specific bioconjugation and precise control over drug-antibody ratio (DAR). The XMT-1660 ADC contains 6 DolaLock Auristatin F-hydroxypropyl amide (AF-HPA) anti-tubulin payloads per antibody (DAR-6). Previously, we demonstrated the cytotoxic effect of XMT-1660 in cell line xenograft and patient derived xenograft models of breast cancer known to have B7-H4 target expression. The purpose of this study was to evaluate the anti-tumor activity of XMT-1660 across an unselected panel of breast cancer patient derived xenograft (PDX) models, evaluate the level of B7-H4 expression across this panel of breast PDX models, and assess the correlation between B7-H4 expression and anti-tumor activity following a single dose of XMT-1660. Methods: A panel of 30 breast cancer patient-derived xenograft models, annotated by prior treatment history, and divided between TNBC and ER-positive subtypes, was implanted into athymic Nude-Foxn1n mice. When tumors reached an average volume of 150-300 mm3, animals (n=3) were treated with a single administration of either XMT-1660 0.15mg/kg (calculated by payload dose)/4.71 mg/kg (calculated by antibody dose) IV/QD X1 or saline vehicle. Tumor volumes were evaluated until the planned endpoint of mean tumor volume of control group of 1500 mm3 or day 28. At the endpoint, xenografts, or tumor beds (in the case of no palpable mass) were collected as formalin fixed paraffin embedded material. The xenograft material was evaluated for B7-H4 expression by protein and RNA methods and expression was compared to the anti-tumor activity. Results: In this panel of breast patient derived xenograft models, a range of anti-tumor activities has been observed following administration of a single dose of XMT-1660. The relationship between XMT-1660 anti-tumor activity and B7-H4 expression was demonstrated. Conclusion: XMT-1660 elicits a range of anti-tumor activity across a series of primary breast cancer xenograft models. XMT-1660 is currently in IND-enabling studies and is expected to enter a Phase I dose escalation clinical study in 2022. The efficacy/expression relationship of B7-H4 will be further evaluated in an upcoming clinical study with a goal to identify patients most likely to respond to XMT-1660. Citation Format: Scott D. Collins, Pamela S. Shaw, Shawn P. Fessler, Jason Wang, Rebecca Mosher. Antitumor effect of XMT1660, a B7H4 targeting antibody drug conjugate, in an unselected panel of patient derived xenograft models of breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1756.

First-in-Human Clinical Study of a Novel CD7-Targeted Chimeric Antigen Receptor (CAR)-T Cell Therapy for Refractory/Relapsed Mixed Phenotype Acute Leukemia (MPAL)

IntroductionMixed phenotype acute leukemia (MPAL) is a rare subtype of acute leukemia with features of both acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). The blast cells of MPAL express multilineage immunophenotypic markers and may have a shared B/T/myeloid phenotype. CD7 is expressed by the leukemic blasts and malignant progenitor cells of approximately 30% of AML patients. MPAL is usually associated with a relatively poor prognosis which is even worse compared to either AML or ALL, and even among patients that undergo allogeneic hematopoietic stem cell transplantation (allo-HSCT), underscoring the need for new therapies for these patients. CAR-T cell therapy has shown to be efficacious with a tolerable safety profile in a subset of hematological malignancies. Here, we explored the safety and efficacy of CAR-T therapy in treating refractory/relapsed (r/r) MPAL patients with CD7-positive in a phase I dose-escalation clinical study (https://clinicaltrials.gov NCT04938115).MethodsPeripheral blood (PB) mononuclear cells were obtained from patient themselves or patient transplant donors for those who relapsed post-transplant by leukapheresis. T-cells were purified using CD3+ magnetic beads or CD4+ and CD8+ magnetic beads. The second-generation CD7 CAR with a 4-1BB costimulatory domain was manufactured per the manufacturer's protocol. This phase I dose escalation study was initiated to explore the safety and efficacy of CD7 CAR-T in treating patients with MPAL. Prior to the CAR-T cells infusion, patients received systemic bridging chemotherapy due to rapid disease progression and then all patients received intravenous fludarabine (30mg/m 2/d) and cyclophosphamide (300mg/m 2/d) (FC) lymphodepleting chemotherapy for 3 consecutive days (Day -5 to Day -3). The median time from leukapheresis to CAR-T cell infusion was 14 days.ResultsFrom Nov. 2020 to June 2021, 5 adult acute leukemia patients with CD7-positive (4 MPAL, 1 FLT3-mutated AML) were enrolled and infused with CD7 CAR T-cells, one with a low-dose (1.5×10 5/kg), 2 with a medium dose (5.0×10 5/kg), and 3 with a high dose infusion (1.0×10 6/kg). The median transduction efficiency of products was 70.4% (range: 32.0%-96.9%). As of July 30, 2021 cut-off date, the median observation time was 37 days (range: 35-232 days). Characteristics of enrolled patients are shown in Table 1. The median age was 33 years (range: 21-37 years), and the median bone marrow (BM) blasts percentage by morphology was 28.0% (range: 2.5-51.5%) at enrollment. Four patients had prior allo-HSCT history including one who had extramedullary disease (EMD) who relapsed following a 2 nd transplant and had also received CD19 CAR-T cell therapy prior to enrollment in the current trial. The median interval period from prior transplant to CD7 CAR-T cell infusion was 16 months (range: 8-23 months). Following infusion, the median peak of circulating CD7 CAR-T cell was 1.17×10 5copies/μg (0.651~7.04×10 5copies/μg) genomic DNA which occurred around Day 21 (Day14 - Day21) and 59.2% (4.28%~74.58%) occurring on Day18 (Day11-Day21) by q-PCR and flow cytometry respectively (Fig.1).Four weeks post CD7 CAR-T cell infusion, 4/5 patients achieved complete remission (CR) or CR with incomplete blood recovery (CRi) in BM and all achieved minimal residual disease (MRD)-negative CR. One patient who relapsed post 2 nd transplant, also with EMD, achieved CR in BM, however, remission was not achieved in EMD through PET-CT evaluation on Day 35.One MRD-negative CR patient subsequently underwent consolidative allo-HSCT 120 days post CD7 CAR T-cell infusion and has remained in MRD-negative CR. Other 3 patients without consolidative allo-HSCT remained in MRD-negative CR till the last follow-up. All 5 patients developed cytokine release syndrome (CRS)-three of 5 patients had grade I CRS, one patient had grade II and one patient had grade III CRS. None of the patients had neurotoxicity. Among the 4 patients who had prior allo-HSCT, 1 developed grade I graft-versus-host disease post CAR-T therapy.ConclusionThis study demonstrated that CD7-targeted CAR-T therapy offers an opportunity to achieve CR for CD7-positive MPAL patients even for those who relapsed post-transplant. Safety was manageable, however, more data on additional patients and longer observation times are needed to further evaluate the efficacy of CD7 CAR-T products. [Display omitted] DisclosuresBa: SenlangBio: Current Employment.

Abstract 6710: AVID200, a first-in-class selective TGF-beta 1 and -beta 3 inhibitor, sensitizes tumors to immune checkpoint blockade therapies

Abstract AVID200 is a first-in-class rationally designed receptor ectodomain trap that selectively neutralizes TGF-beta 1 and -beta 3 with pM potency while sparing TGF-beta 2, thereby reducing the potential for toxicities associated with neutralization of this isoform. A Phase 1 dose-escalation clinical study of AVID200 monotherapy has recently been completed and established that the agent was well tolerated and exhibited target engagement at all dose levels tested without reaching a maximally tolerated dose. To explore the potential of AVID200 as a combination agent with immunotherapy, expression analysis of TGF-beta isoforms across various solid tumors has been carried out and the ability of AVID200 to increase anti-tumor immunity as a single agent and in combination has been explored in vivo. Analysis of >10,000 tumor samples from TCGA revealed that TGF-beta1 and -beta3 are the predominant isoforms expressed in solid tumors, with TGF-beta2 showing only minimal expression. This corroborates the attractiveness of TGF-beta1 and -beta3 as promising anti-cancer targets and emphasizes the need to target both isoforms simultaneously. Furthermore, AVID200 increased T-cell-mediated cytotoxicity as a single agent as well as potentiating the efficacy of immune checkpoint inhibitors (ICI) in syngeneic mouse tumor models. In line with these observations, we have found that AVID200 increases the infiltration of T-cells in the tumor microenvironment. In conclusion, AVID200, a first-in-class, potent and selective TGF-beta trap, enhances the activity of ICI agents in vivo and holds promise as a potential novel immunotherapy combination regimen which warrants exploration in patients with solid tumor malignancies. Phase 1 clinical trials are underway in various indications. Citation Format: Gilles Tremblay, Tina Gruosso, Jean-François Denis, Rene Figueredo, Jim Koropatnick, Maureen O'Connor-McCourt. AVID200, a first-in-class selective TGF-beta 1 and -beta 3 inhibitor, sensitizes tumors to immune checkpoint blockade therapies [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6710.

Safety and tolerability of intratumorally administered OH2, an oncolytic herpes simplex virus 2, in patients with advanced solid tumors: A phase I dose escalation clinical study.

3139 Background: There have been limited reports concerning treatment outcomes of oncolytic viruses in solid tumors other than melanoma. OH2 is a genetically engineered oncolytic herpes simplex virus type 2 designed to selectively amplify in tumor cells and express GM-CSF to enhance tumor-specific immune responses. Methods: We conducted an open-label, single-center, phase 1 study. Eligible pts were 18-75 years of age; had histologically confirmed advanced solid tumor; had progressed after standard systemic treatments. Pts were required to have tumor(s) deemed safe to inject, with a longest diameter of at least 0.5cm. Other eligibility criteria included measurable lesion as per RECIST v1.1; ECOGPS score of 0-1 and adequate organ functions. A 3+3 dose-escalation strategy was used in the study and 3 dose levels (106, 107 and 108 CCID50/mL) of OH2 were assessed. OH2 was administered intratumorally every 3 weeks for the first cycle and every 2 weeks.Treatment may continue afterwards in ptswith potential clinical benefit at the discretion of the investigators. The primary objective was the safety and tolerability of OH2 injection as defined by the dose limiting toxicities (DLTs) within the first 3 weeks of therapy, and the maximum tolerated dose (MTD). Secondary objectives included efficacy and immunogenicity of OH2. Results: 11 pts were enrolled between April 17, 2019 and November 4, 2019. The median follow-up duration was 8.36 months (95%CI: 5.64-11.08). OH2 was well-tolerated as no DLTs were reported and no MTD reached. Before the end of the DLT assessment period,1 pt withdrew consent, and 1 pt died of arrhythmia unrelated to OH2, with negative OH2 DNA copies in serum, urine and saliva samples. Most treatment-related adverse events (TRAEs) observed were of grade 1-2, except that 1 pt in the 108 CCID50/mL group developed grade 3 fever. The most common TRAEs were fever (n =5) and blood bilirubin level increase (n = 4). There were no grade 4 or 5 TRAEs. One pt(rectal cancer) had PR and 2 (appendix cancer and ovarian cancer) had SD as per RECIST v1.1. One patient (esophageal cancer) achieved iPR as per iRECIST criteria. The duration of follow-up for the 2 responders were 9.70 months and 8.36 months, respectively, and both had ongoing responses. Notably, regression of a non-injected lesion was observed in 1 patient. Conclusions: OH2 had a favorable safety profile with no DLTs and MTD. The dose expansion study in selected tumor types is currently underway. Clinical trial information: NCT03866525 .

KTN0158, a Humanized Anti-KIT Monoclonal Antibody, Demonstrates Biologic Activity against both Normal and Malignant Canine Mast Cells.

Purpose: KTN0158 is a novel anti-KIT antibody that potently inhibits wild-type and mutant KIT. This study evaluated the safety, biologic activity, and pharmacokinetic/pharmacodynamics profile of KTN0158 in dogs with spontaneous mast cell tumors (MCT) as a prelude to human clinical applications.Experimental Design: Cell proliferation, KIT phosphorylation, and mast cell degranulation were evaluated in vitro KTN0158 was administered to 4 research dogs to assess clinical effects and cutaneous mast cell numbers. Thirteen dogs with spontaneous MCT were enrolled into a prospective phase I dose-escalating open-label clinical study of KTN0158 evaluating 3 dose levels and 2 schedules and with weekly assessments for response and clinical toxicities.Results: KTN0158 was a potent inhibitor of human and dog KIT activation and blocked mast cell degranulation in vitro In dogs, KTN0158 was well tolerated and reduced cutaneous mast cell numbers in a dose-dependent manner. Clinical benefit of KTN0158 administration in dogs with MCT (n = 5 partial response; n = 7 stable disease) was observed regardless of KIT mutation status, and decreased KIT phosphorylation was demonstrated in tumor samples. Histopathology after study completion demonstrated an absence of neoplastic cells in the primary tumors and/or metastatic lymph nodes from 4 dogs. Reversible hematologic and biochemical adverse events were observed at doses of 10 and 30 mg/kg. The MTD was established as 10 mg/kg.Conclusions: KTN0158 inhibits KIT phosphorylation, demonstrates an acceptable safety profile in dogs, and provides objective responses in canine MCT patients with and without activating KIT mutations, supporting future clinical evaluation of KTN0158 in people. Clin Cancer Res; 23(10); 2565-74. ©2016 AACR.

SCD-101: A New Anti-Sickling Drug Reduces Pain and Fatigue and Improves Red Blood Cell Shape in Peripheral Blood of Patients with Sickle Cell Disease

Background: Sickle cell disease (SCD) is the most common inherited blood disorder in the United States, caused by polymerization of a mutated form of hemoglobin (HbS). HbS can form long polymers inside red blood cells (RBCs) that affect RBC shape and adhesion, resulting in RBC destruction, acute and chronic pain, inflammation and cumulative organ damage. SCD-101 is a botanical drug with in vitro and in vivo anti-sickling activity. The mechanism by which SCD-101 inhibits sickling is unknown; however, it does not bind directly to Hb or change the affinity of Hb for oxygen. We recently completed a dose-escalation clinical study of SCD-101 in adults with sickle cell disease in steady state, and other clinical studies are on-going.Methods: The initial prospective, open-label, Phase 1B dose-escalation study enrolled homozygous (SS) sickle cell patients and S/beta0 thalassemia patients ages 18-55 with baseline Hb levels 6.0-9.0 g/dL and hemoglobin F ≤10%. Admission within 30 days, transfusion within 90 days, and hydroxyurea within 6 months were exclusions. SCD-101 was dosed orally for 28-days with a 14-day follow-up visit. Doses administered during the dose escalation study were 550 mg, 1100 mg, 2200 mg and 4400 mg BID. The primary endpoint was safety, and the secondary endpoints were mean change in Hb, Hct, percent reticulocytes, LDH, indirect bilirubin, CRP, PROMIS fatigue questionnaire score, and percent circulating partially oxygenated sickle cells (POSCs) in venous whole blood fixed in 2% glutaraldehyde without exposure to air. A repeat cohort study is ongoing with dose adjusted to 2750 mg TID, a 6-minute walk test added as a functional endpoint and measurement of inflammatory cytokines by ELISA to explore the effect of SCD-101 on inflammation.Results: As of August 4, 2016, 26 patients with sickle cell disease have been enrolled, 20 patients have completed the 28-day dose-escalation study and 3 were discontinued before receiving their first dose of SCD-101. Three patients are enrolled in the 28-day repeat cohort study. There have been no dose reductions or interruptions due to drug-related effects. SCD-101 was generally well-tolerated with mild-moderate bloating and flatulence at the highest dose on a BID schedule in the dose-escalation study, which were not observed with a TID schedule in the repeat cohort study. There were no significant changes in safety laboratory tests and no significant changes in hemoglobin, hematocrit, LDH, unconjugated bilirubin, or reticulocytes. No significant changes were observed in renal, hepatic or other safety chemistries or electrocardiograms. SCD-101 participants treated at higher doses reported a decrease in chronic pain and fatigue after 7-14 days, which returned post-treatment when measured on the 14-day follow-up visit. Participants at the two highest doses reported an increase in exercise capacity and an improvement in sleep. Two participants with ankle ulcers, enrolled at the two highest doses, showed improved healing. Analysis of peripheral blood smears revealed an improvement in the shape of circulating RBCs. There was no change in inflammatory cytokines in the first 7 days in the repeat cohort study, though the Day 28 data may show a different result.Conclusions: SCD-101 is a promising new drug for the treatment of sickle cell disease, based on the results from the studies reported here. SCD-101 was well tolerated over an 8-fold dose range, and dose-dependent anti-sickling effects on RBC were observed, though without significant changes in hemolysis. Clinical benefits included reduced chronic pain and fatigue, improved sleep and improved ulcer healing. While the identity of the active substance(s) in SCD-101 and the mechanism(s) of action are unknown, SCD-101 has a direct anti-sickling effect on RBCs, compatible with an intracellular or membrane effect on RBCs. We hypothesize that the observed effects could be explained by increased vascular flow or increased oxygen delivery or a reduction in inflammation. A placebo-controlled crossover study will be completed in 2016 including a 6-minute walk test as a primary clinical endpoint, and a multi-site Phase 2 study is planned for 2017. As a botanical drug, SCD-101 may be a useful treatment for sickle cell disease worldwide. [Display omitted] [Display omitted] [Display omitted] DisclosuresSwift:Global Blood Therapeutics: Equity Ownership; Mast Therapeutics: Equity Ownership; SCD Development: Employment, Equity Ownership.

Highlights of This Issue

Disrupting BRD4 activity through the use of small molecule probes has proven to be a widely effective preclinical anticancer strategy. To date, all reported BRD4 probes and clinical drug candidates operate through a monovalent binding mode. In this report, Rhyasen, Hattersley, and colleagues describe the pharmacology of AZD5153, a bivalent BRD4 inhibitor. The unique bivalent binding mode affords AZD5153 enhanced binding affinity, cell potency, and in vivo efficacy against hematologic cancer models. Targeting BRD4 through a bivalent binding mode therefore represents an attractive anticancer strategy.While most anticancer drugs have a single target, SF1126 inhibits two key signaling proteins within the liver cancer cell, PI3K and BRD4. Inhibition of PI3K enhances MYC degradation and BRD4 inhibition and prevents MYC transcription, providing a “first-in-class” approach to maximally block MYC-driven cancers. Singh, Joshi, Burgoyne and colleagues report this novel strategy of targeting two central signaling nodes with one agent that is antitumorigenic in vitro and in vivo and synergistic with the multikinase inhibitor Sorafenib. SF1126 is expected to enter HCC Phase I trials later this year.Chondrosarcoma is a real challenge in orthopedic oncology and is notoriously chemoresistant. In this study, Peyrode, Weber, and colleagues develop an attractive proteoglycans-targeting chemotherapy approach using a quaternary ammonium conjugate of melphalan (Mel-QA). This work demonstrated the crucial role of the QA carrier for in vitro binding to aggrecan. In vivo, in chondrosarcoma-bearing rats, radiolabeled [3H]-Mel-QA was shown to accumulate in tumor tissue respectively to melphalan, which was associated with tumor growth inhibition and improvement of the therapeutic index. These results open new perspectives in the therapeutic management of chondrosarcoma.AC0010 is a novel, irreversible, epidermal growth factor receptor (EGFR) inhibitor designed to overcome T790M-induced resistance in non–small cell lung cancer (NSCLC) patients. Preclinical studies demonstrate that AC0010 is a selective and potent inhibitor of EGFR activation and T790M mutations. A Phase 1 dose-escalation clinical study indicates that AC0010 is safe and effective in late-stage NSCLC patients. In this study, no pneumonitis, hyperglycemia, or grade 3 prolongation of the corrected QT interval event were observed. The preclinical and clinical evidence warranted further development of AC0010 as an alternative therapeutic agent for NSCLC patients who acquire resistance to first-generation EGFR TKIs.

Mapping T-Cell Peptide Epitopes on Activated Recombinant Factor VII (rFVIIa) Contributing to Inhibitor Antibody Response

Bypassing agents such as activated recombinant factor VII (rFVIIa) are used to treat acute bleeding episodes in patients with hemophilia and inhibitors to coagulation factors VIII (FVIII) or IX. BAY 86-6150 is a modified rFVIIa protein with 6 amino acid substitutions in the rFVII molecule that prolong half-life and improve potency compared with the currently available rFVIIa.In a dose-escalation clinical study, 1 patient out of a cohort of 10 treated with 6.5 μg/kg BAY 86-6150 developed low-titer neutralizing antibodies that were detected after the third exposure. The patient's anti-BAY 86-6150 antibodies also cross-reacted with and neutralized wild-type FVIIa (WT-FVIIa) in vitro. T-cell epitope mapping was performed to identify BAY 86-6150 sequence(s) that may have contributed to the immunogenic response in the patient by measuring CD4+ T-cell response to individual 15-mer peptides spanning BAY 86-6150.The epitope mapping study did not identify any of the 14 peptides unique to BAY 86-6150 as epitopes recognized by the patient's T cells. However, strong responses were detected against 2 WT-FVIIa peptides, WT p6-20 (EELRPGSLERECKEE) and WT p156-170 (GKVCPKGECPWQVLL), indicating that CD4+ T helper cells recognizing these WT peptides may have contributed to the immune response that resulted in the production of anti-BAY 86-6150 antibodies during treatment. It should be noted that although the patient had no detectable anti-FVIIa antibodies before the start of the study, he had been treated with factor eight inhibitor bypassing activity (FEIBA), which contains active FVII, on 3 consecutive days 3 months before entry into the study. Hence it is possible that the patient had been primed for a response against FVIIa that was triggered by the subsequent exposure to BAY 86-6150.The fact that the patient's T cells only responded to WT-FVIIa peptides might be explained if the WT-FVIIa peptides were seen as foreign/non-self peptides by his T-cell repertoire. Unfortunately, the patient's FVII gene sequence was not obtainable, and this possibility remains unanswered.The Universal Protein Resource (UniProt) database reports 2 natural FVII gene variants that encompass the WT p6-20 sequence (Millar, et al. Hum Genet. 2000;107:327-42; Herrmann, et al. Haemophilia. 2009;15:267-280) and one for the WT p156-170 sequence (Wulff and Herrmann. Hum Mutat. 2000;15:489-496) that resulted from single amino acid substitutions. Hence the possibility exists that the patient's T-cell repertoire sees WT-FVIIa sequences as foreign and immunogenic. T cells from 40 healthy donors were also tested for reactivity against the peptide panel to assess relative immunogenicity of BAY 86-6150 vs WT-FVIIa. Seven BAY 86-6150 neoepitopes were stimulatory for 8 unrelated healthy donor T cells, but their mean stimulation indices were not statistically higher than those observed against WT FVIIa peptides. Mean % stimulation values of the positive responses against the 7 BAY 86-6150 neoepitopes versus 39 WT FVIIa peptides were 1.09 (N=13 responses) vs 1.01 (N=70 responses; P =0.5059). Statistical analysis of the in vitro T-cell response indicates that specific mutations to BAY 86-6150 do not result in BAY 86-6150 being more immunogenic than WT FVIIa. This would suggest that BAY 86-6150 will not elicit stronger or higher frequency of anti-FVIIa antibody response than WT FVIIa in patients with hemophilia. DisclosuresPaz:Bayer HealthCare: Employment. Schroeder:Bayer Pharma AG: Employment. Mathew:Bayer HealthCare Pharmaceuticals: Employment. Hardtke:Bayer Pharma AG: Employment. Aswad:Bayer HealthCare: Employment.

First Preclinical Report of the Efficacy and PD Results of KHK2823, a Non-Fucosylated Fully Human Monoclonal Antibody Against IL-3Rα

Human interleukin-3 receptor alpha (IL-3Ra, CD123), which promotes the proliferation and differentiation of hematopoietic cells, is highly expressed in myeloid malignancies, including acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS).We newly generated KHK2823, a non-fucosylated fully human IgG1 monoclonal antibody against human IL-3Ra, by utilizing the POTELLIGENT® technology. Here, we describe the in vitro and in vivo preclinical efficacy and safety of KHK2823, as well as its pharmacodynamic (PD) profile.At first, we explored that KHK2823 bound to various hematological malignant cells and leukemic stem cells. The cells from AML and MDS bone marrows were found to be bound by KHK2823. A significant part of bone marrow cells derived from B-cell acute lymphoblastic leukemia (B-ALL) patients was also bound by KHK2823.KHK2823 bound to soluble human IL-3Ra protein with a sub-nanomolar dissociation constant (KD), and recognized CD34+ CD38+ (leukemic blast) and/or CD34+ CD38- (leukemic stem cell) cells in patients with AML/MDS, as well as AML cell lines, thereby obtaining a high antibody-dependent cellular cytotoxic activity without complement-dependent cytotoxicity. Interestingly, KHK2823 did not interfere with the binding of IL-3 to IL-3R. The lack of a receptor-ligand interaction may conserve the IL-3 signal, which plays an important role in normal hematopoiesis. In a tumor model xenografting the human AML cell line MOLM-13 on nude rats, KHK2823 significantly suppressed the tumor growth at doses of 0.1 and 1 mg/kg (Figure 1).The PD and toxicity profiles of KHK2823 were assessed in cynomolgus monkeys administered at doses ranging from 0.1 to 100 mg/kg by i.v. infusion, once weekly for 4 weeks. KHK2823 was generally well tolerated in monkeys, even at 100 mg/kg. The number of IL-3Ra-positive cells in the peripheral blood of cynomolgus monkeys decreased in all groups receiving KHK2823, which suggest KHK2823 could exert its depletion activity of IL-3Ra-positive cells in human (Figure 2). Currently, the safety and tolerability of KHK2823 is being investigated in patients with AML or MDS in a Phase 1 study (NCT02181699, https://clinicaltrials.gov/ct2/show/NCT02181699). This is the first non-randomized, open-label, dose escalation clinical study to investigate the safety, PK, immunogenicity and PD of repeated doses of KHK2823.In summary, KHK2823 was confirmed to bind to AML, MDS and B-ALL cells as the IL-3Ra in accordance with other publications. KHK2823 was also found to eliminate AML cells in vitro and also suppressed the AML tumor growth in the in vivo model. In addition, the number of IL-3Ra-positive cells in cynomolgus monkeys decreased following i.v. infusion of 0.1mg/kg KHK2823 with a tolerable safety profile, even at a dose of 100 mg/kg. Taken together, KHK2823 may therefore be a promising anti-IL-3Ra therapeutic drug for the treatment of AML. [Display omitted] [Display omitted] DisclosuresAkiyama:Kyowa Hakko Kirin Co., Ltd.: Employment. Takayanagi:Kyowa Hakko Kirin Co., Ltd.: Employment. Maekawa:Kyowa Hakko Kirin Co., Ltd.: Employment. Shimabe:Kyowa Hakko Kirin Co., Ltd.: Employment. Nishikawa:Kyowa Hakko Kirin Co., Ltd.: Employment. Yamawaki:Kyowa Hakko Kirin Co., Ltd: Employment. Iijima:Kyowa Hakko Kirin Co., Ltd: Employment. Hiura:Kyowa Hakko Kirin Co., Ltd.: Employment. Takahashi:Kyowa Hakko Kirin Co., Ltd.: Employment. Akashi:Asahi Kasei: Research Funding, Speakers Bureau; Chugai: Research Funding, Speakers Bureau; Bristol-Myers Squibb: Research Funding, Speakers Bureau; Novartis Pharma K.K.: Consultancy, Research Funding, Speakers Bureau; Kyowa Hakko Kirin Co., Ltd.: Consultancy, Research Funding, Speakers Bureau; Celgene: Research Funding, Speakers Bureau; Shionogi: Research Funding, Speakers Bureau; Astellas: Research Funding, Speakers Bureau. Tawara:Kyowa Hakko Kirin Co., Ltd: Employment.

Phase I/II study of weekly LOC-paclitaxel (LOC-pac) injection in patients (pts) with metastatic melanoma (MM).

9053 Background: LOC-paclitaxel (LOC-pac) is a covalent conjugate of paclitaxel linked to an omega-6 fatty acid designed to enhance uptake of paclitaxel into tumors leading to higher intra-cellular drug concentrations and potentially enhance anti-tumor activity of paclitaxel. This is a first in human, phase I, open label, dose-escalating clinical study of LOC-pac administered weekly in patients (pts) with metastatic melanoma (MM). Methods: Adult MM pts who were refractory to prior systemic therapy or were ineligible for other therapy of higher priority with normal organ function and ECOG PS 0-2 were eligible for this trial. Patients with baseline peripheral neuropathy over grade 1, prior exposure to taxane chemotherapy, hypersensitivity to cremaphor or with serious concurrent medical conditions were excluded. LOC-pac was given intravenously over 1 hour on days 1, 8, 15, 22 and 29 every 42 days. LOC-pac dosing was escalated from 100mg/m2 to 1000mg/m2 after safety of the prior dose level was confirmed in co...

Safety and Exploratory Efficacy Of Ex Vivo Expanded Umbilical Cord Blood (UCB) Hematopoietic Stem and Progenitor Cells (HSPC) Using Cytokines and Stem-Regenin 1 (SR1): Interim Results Of a Phase 1/2 Dose Escalation Clinical Study

BackgroundDespite enhanced tolerability of HLA mismatch, the reduced number of HSPC in an UCB graft limits the use of this stem cell source because of delayed hematopoietic recovery and increased risk of graft failure, particularly in adults. For this reason, we explored the effectiveness of SR1, an aryl hydrocarbon receptor antagonist, in the presence of cytokines to expand HSPC ex vivo prior to transplantation. Patients and MethodsNine patients with high-risk lympho-hematopoietic malignancy and two partially HLA (4-6/6)-matched UCB units were treated with cyclophosphamide 120 mg/kg, fludarabine 75 mg/m2 and total body irradiation 1320 cGy followed by double UCB transplantation. Unit1 (the unmanipulated larger of the two units) was infused followed by SR1-expanded UCB HSPC (derived from CD34 selected Unit2 cells cultured for 15 days) as well as rethawed CD34 negative Unit2 cells. GVHD prophylaxis was cyclosporine A and mycophenolate mofetil. ResultsCulture in the presence of SR1 resulted in a median of 248-fold (range, 66-446) expansion of CD34+ cells. The median number of CD34+ cells and CD3+ cells infused for Unit1 and Unit2 were 0.3 x 106/kg (range, 0.2-0.9) and 11.0 x 106/kg (range, 1.4-48.9), and 7.3 x 106/kg (range, 4.6-10.6) 2.8 x 106/kg (range, 0.4-4.9), respectively. There were no infusional toxicities noted. Based on a presumed graft-graft interaction, the HSC835 product predominated in 5 of 9 patients and resulted in sustained hematopoiesis for a median follow up of 303 days (range 140-401). The median time to neutrophil recovery (days to absolute neutrophil count of ≥500/uL) was shorter in recipients of HSC835 (i.e., 16 days [range, 6-23] versus 24 days [range, 22-30]) with the speed of neutrophil recovery correlating with the number of CD34+ cells infused (r2 = -0.87, p<0.05, Figure 1). With a median follow-up of 161 days (range, 40-401), six patients are alive. Primary causes of death were CMV pneumonitis, alveolar hemorrhage and interstitial pneumonitis in three patients. [Display omitted] ConclusionThe AHR antagonist SR1 is a potent inhibitor of HSC differentiation, resulting in marked expansion of HSPC. Hematopoietic reconstitution as early as day 6 is dependent on CD34+ cell dose in the expanded product, HSC835. Based on the long-term engraftment potential of HSC835 in half of the patients using the double UCB platform and the accelerated neutrophil recovery seen in patients recovering with HSC835, future patients will receive HSC835 alone eliminating the confounding graft-graft effects and potentially further reducing the time to neutrophil recovery. Disclosures:Wagner:Novartis: Research Funding. Brunstein:Novartis: Research Funding. McKenna:Novartis: Research Funding. Sumstad:Novartis: Research Funding. Maahs:Novartis: Employment. Boitano:Novartis: Employment. Cooke:Novartis: Employment. Bleul:Novartis: Employment.

Abstract 474: Complete regression and long-term specific protective immune responses obtained in rodent tumor models after intratumoral treatment with LTX-315 .

Abstract LTX-315 is a de novo designed peptide derived from a naturally occurring host defence peptide. LTX-315 has the potential to induce long-term specific protective immune responses by stimulating immune cells, inducing tumor cell lysis with subsequent release of danger signals (e.g. HMGB1) and tumor associated antigens (TAA`s). A complete tumor regression has been obtained in several syngenic rodent tumor models by intratumoral (i.t.) injection with LTX-315. The effect was T- cell- dependent since the intervention was inefficient in immune-deficient animals. Studies on treated tumor tissue confirmed infiltration of immune cells and a switch in the cytokine profile towards a Th1 response. Successfully treated animals were protected against re-challenge with the tumor cell type treated, but not against other types of tumor cells. Moreover, tumor resistance could be adoptively transferred by spleen cells from LTX-315-treated animals. The resistance was abrogated by depletion of T- lymphocytes. Additional studies also indicate that LTX-315`s potential to locally activate the innate immune system by the immunogenic stressing of cells, in addition to the subsequent release of endogenous adjuvants and natural danger signals, provides a strong rationale for using LTX-315 as an adjuvant for vaccines based on tumor-associated antigens (TAA) and for combination with other types of immune–modulatory therapies. LTX-315 is currently being tested in a Phase I dose escalation clinical study and may represents a novel strategy for personalized in situ vaccination against cancer. Citation Format: Øystein Rekdal, Gunnar Kvalheim, Pål-Dag Line, Bent Rolstad, Ketil Camilio, Gerd Berge, Janne Nestvold, Mengyu Wang, Jihua Shi, Ali Areffard, Baldur Sveinbjørnsson. Complete regression and long-term specific protective immune responses obtained in rodent tumor models after intratumoral treatment with LTX-315 . [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 474. doi:10.1158/1538-7445.AM2013-474

DVC1-0101 to Treat Peripheral Arterial Disease: A Phase I/IIa Open-label Dose-escalation Clinical Trial

We here report the results of a Phase I/IIa open-label four dose-escalation clinical study assessing the safety, tolerability, and possible therapeutic efficacy of a single intramuscular administration of DVC1-0101, a new gene transfer vector based on a nontransmissible recombinant Sendai virus (rSeV) expressing the human fibroblast growth factor-2 (FGF-2) gene (rSeV/dF-hFGF2), in patients with peripheral arterial disease (PAD). Gene transfer was done in 12 limbs of 12 patients with rest pain, and three of them had ischemic ulcer(s). No cardiovascular or other serious adverse events (SAEs) caused by gene transfer were detected in the patients over a 6-month follow-up. No infectious viral particles, as assessed by hemagglutination activity, were detected in any patient during the study. No representative elevation of proinflammatory cytokines or plasma FGF-2 was seen. Significant and continuous improvements in Rutherford category, absolute claudication distance (ACD), and rest pain were observed (P < 0.05 to 0.01). To the best of our knowledge, this is the first clinical trial of the use of a gene transfer vector based on rSeV. The single intramuscular administration of DVC1-0101 to PAD patients was safe and well tolerated, and resulted in significant improvements of limb function. Larger pivotal studies are warranted as a next step.

A Randomized, Placebo Controlled, Double Blind, Parallel Group, Multiple Dosing, Dose Escalation Clinical Study to Evaluate Pharmacokinetics/Pharmacodynamics and Tolerability of Zofenopril in Healthy Korean Subjects

Background: Zofenopril is a new Angiotensin Converting Enzyme (ACE) inhibitor for the treatment of the patients with hypertension and congestive heart failure. This study aimed to evaluate the pharmacokinetics (PKs)/pharmacodynamics (PDs) and tolerability of zofenopril in healthy Korean subjects. Methods: A randomized, double blind, placebo-controlled, multiple dosing parallel group study with two dosage groups (zofenopril 30 mg or 60 mg) was conducted in healthy Korean male subjects. Each dosage group consisted of 10 subjects and they were randomly assigned to receive zofenopril or placebo with a ratio of 4:1. PK characteristics of zofenopril and its active metabolite, zofenoprilat, were evaluated after single or multiple dosing. Serum ACE activities and blood pressures were measured for PD evaluation. Adverse events, clinical laboratory tests, electrocardiograms, vital signs and physical examinations were performed for tolerability evaluation. Results: The PK characteristics of zofenopril and zofenoprilat after single dose and multiple doses were similar to one another. The metabolic ratio of zofenoprilat to zofenopril after single dose and multiple doses were 12.4 and 14.9, respectively, in the 30 mg dosage group, and were 6.8 and 6.6, respectively, in the 60 mg dosage group. Complete serum ACE activity inhibition was observed within 1 hour in both doses but it was maintained longer in the 60 mg dosage group compared to the 30 mg dosage group. There were no clinically significant abnormalities in tolerability evaluations.

Adoptive Transfer of EBV-specific T Cells Results in Sustained Clinical Responses in Patients With Locoregional Nasopharyngeal Carcinoma

Patients with recurrent or refractory Epstein Barr Virus (EBV)-positive nasopharyngeal carcinoma (NPC) continue to have poor outcomes. Our earlier Phase I dose escalation clinical study of 10 NPC patients showed that infusion of EBV-specific cytotoxic T cells (EBV-CTLs) was safe and had antitumor activity. To better define the overall response rate and discover whether disease status, EBV-antigen specificity, and/or in vivo expansion of infused EBV-CTLs predicted outcome, we treated 13 additional NPC patients with EBV-CTLs in a fixed-dose, Phase II component of the study. We assessed toxicity, efficacy, specificity, and expansion of infused CTLs for all 23 recurrent/refractory NPC patients treated on this Phase I/II clinical study. At the time of CTL infusion, 8 relapsed NPC patients were in remission and 15 had active disease. No significant toxicity was observed. Of the relapsed patients treated in their second or subsequent remission, 62% (5/8) remain disease free (at 17 to 75 mo), whereas 48.7% (7/15) of those with active disease had a CR/CRu (33.3%) or PR (15.4%). In contrast to locoregional disease, metastatic disease was associated with an increased risk of disease progression (HR: 3.91, P=0.015) and decreased overall survival (HR: 5.55, P=0.022). Neither the specificity of the infused CTLs for particular EBV antigens nor their measurable in vivo expansion discernibly influenced outcome. In conclusion, treatment of patients with relapsed/refractory EBV-positive NPC with EBV-CTLs is safe and can be associated with significant, long-term clinical benefit, particularly for patients with locoregional disease.

Priming of CD4+ and CD8+ T cell responses using a HCV core ISCOMATRIX™ vaccine: A phase I study in healthy volunteers

The disease burden and public health impact of chronic HCV infection continues to be a major problem globally. Current treatment for chronic HCV infection is not effective in all patients and is frequently associated with unacceptable side effects. Clearly a need exists for improved treatments and one such strategy is the use of therapeutic vaccines. Although still not completely understood, emerging data indicate that the generation of CD4+ and CD8+ T cells are important for the clearance of HCV. We have developed a prototype vaccine with the HCV Core protein and ISCOMATRIX™ adjuvant (HCV Core ISCOMATRIX™ vaccine). ISCOMATRIX™ vaccines have been shown to induce CD4+ and CD8+ T cell responses to a range of antigens in both animal models and in human studies. Additionally, ISCOMATRIX™ vaccines have been shown to be safe and generally well tolerated in several clinical trials. Preliminary studies demonstrated that the prototype HCV Core ISCOMATRIX™ vaccine induced strong CD4+ and CD8+ T cell responses in monkeys following immunisation. Here we show the results of a Phase I placebo controlled, dose escalation clinical study designed to evaluate the safety, tolerability and immunogenicity of the HCV Core ISCOMATRIX™ vaccine in healthy individuals. The 30 subjects received 3 immunisations of HCV Core ISCOMATRIX™ vaccines or placebo vaccine on days 0, 28 and 56. The HCV Core ISCOMATRIX™ vaccines contained 5, 20 or 50 μg HCV Core protein with 120 μg ISCOMATRIX™ adjuvant. The adverse events reported were generally mild to moderate in severity, of short duration and self-limiting. The most common adverse events were injection site reactions such as pain and redness as well as myalgia. Antibody responses were detected in all but one of the participants receiving the HCV Core ISCOMATRIX™ vaccine and there was no indication of a dose response. CD8+ T cell responses were only detected in 2 of the 8 participants receiving the highest dose. T cell cytokines were detected in 7 of the 8 participants in the highest dose group. The results of this study support the further evaluation of this prototype HCV Core ISCOMATRIX™ vaccine in HCV infected subjects.