The Vedotin Antibody-Drug Conjugate Payload Drives Platform-Based Nonclinical Safety and Pharmacokinetic Profiles.

Nonclinical safety and pharmacokinetic data for monomethyl auristatin E (MMAE) and 14 vedotin antibody-drug conjugates (ADC) were evaluated to determine patterns of toxicity, consistency of pharmacokinetic results, and species differences between rats and monkeys. Most nonclinical toxicities were antigen-independent, common across ADCs, and included hematologic, lymphoid, and reproductive toxicity related to MMAE pharmacology. Hematologic toxicity was the dose-limiting toxicity (DLT) or predominant toxicity for the majority of vedotin ADCs in both species. Tissue expression of the targeted antigen of an ADC rarely correlated with DLT; only two ADCs had antigen-dependent skin DLTs. For two additional ADCs, antigen-dependent delivery of MMAE in the bone marrow may have exacerbated the antigen-independent hematologic DLT. The highest tolerated doses and pharmacokinetics were similar within a given species, with rats tolerating higher doses than monkeys. Studies longer than 1 month in duration detected the same or fewer toxicities than 1-month studies and had no additional findings that affected the human risk assessment. These data support opportunities to streamline ADC toxicity assessments without compromising human starting dose selection or target organ identification.

SGN-B6A: A New Vedotin Antibody-Drug Conjugate Directed to Integrin Beta-6 for Multiple Carcinoma Indications.

Integrin beta-6, a component of the heterodimeric adhesion receptor alpha-v/beta-6, is overexpressed in numerous solid tumors. Its expression has been shown by multiple investigators to be a negative prognostic indicator in diverse cancers including colorectal, non-small cell lung, gastric, and cervical. We developed SGN-B6A as an antibody-drug conjugate (ADC) directed to integrin beta-6 to deliver the clinically validated payload monomethyl auristatin E (MMAE) to cancer cells. The antibody component of SGN-B6A is specific for integrin beta-6 and does not bind other alpha-v family members. In preclinical studies, this ADC has demonstrated activity in vivo in models derived from non-small cell lung, pancreatic, pharyngeal, and bladder carcinomas spanning a range of antigen expression levels. In nonclinical toxicology studies in cynomolgus monkeys, doses of up to 5 mg/kg weekly for four doses or 6 mg/kg every 3 weeks for two doses were tolerated. Hematologic toxicities typical of MMAE ADCs were dose limiting, and no significant target-mediated toxicity was observed. A phase I first-in-human study is in progress to evaluate the safety and antitumor activity of SGN-B6A in a variety of solid tumors known to express integrin beta-6 (NCT04389632).

Perspectives on the evaluation and adoption of complex in vitro models in drug development: Workshop with the FDA and the pharmaceutical industry (IQ MPS Affiliate).

Complex in vitro models (CIVM) offer the potential to improve pharmaceutical clinical drug attrition due to safety and/ or efficacy concerns. For this technology to have an impact, the establishment of robust characterization and qualifi­cation plans constructed around specific contexts of use (COU) is required. This article covers the output from a workshop between the Food and Drug Administration (FDA) and Innovation and Quality Microphysiological Systems (IQ MPS) Affiliate. The intent of the workshop was to understand how CIVM technologies are currently being applied by pharma­ceutical companies during drug development and are being tested at the FDA through various case studies in order to identify hurdles (real or perceived) to the adoption of microphysiological systems (MPS) technologies, and to address evaluation/qualification pathways for these technologies. Output from the workshop includes the alignment on a working definition of MPS, a detailed description of the eleven CIVM case studies presented at the workshop, in-depth analysis, and key take aways from breakout sessions on ADME (absorption, distribution, metabolism, and excretion), pharmacology, and safety that covered topics such as qualification and performance criteria, species differences and concordance, and how industry can overcome barriers to regulatory submission of CIVM data. In conclusion, IQ MPS Affiliate and FDA scientists were able to build a general consensus on the need for animal CIVMs for preclinical species to better determine species concordance. Furthermore, there was acceptance that CIVM technologies for use in ADME, pharmacology and safety assessment will require qualification, which will vary depending on the specific COU.

Novel neutralizing hedgehog antibody MEDI-5304 exhibits antitumor activity by inhibiting paracrine hedgehog signaling.

The hedgehog pathway has been implicated in the tumorigenesis, tumor progression, and metastasis of numerous human cancers. We generated the first fully human hedgehog antibody MEDI-5304 and characterized its antitumor activity and preclinical toxicology. MEDI-5304 bound sonic hedgehog (SHH) and Indian hedgehog (IHH) with low picomolar affinity and neutralized SHH and IHH activity in cellular mGLI1 reporter assays. The antibody inhibited transcription of hedgehog target genes and osteoblast differentiation of C3H10T1/2 cells. We evaluated the activity of MEDI-5304 in vivo in model systems that allowed us to evaluate two primary hypotheses of hedgehog function in human cancer, paracrine signaling between tumor and stromal cells and cancer stem cell (CSC) self-renewal. MEDI-5304 displayed robust pharmacodynamic effects in stromal cells that translated to antitumor efficacy as a single agent in an HT-29/MEF coimplantation model of paracrine hedgehog signaling. MEDI-5304 also improved responses to carboplatin in the HT-29/MEF model. The antibody, however, had no effect as a single agent or in combination with gemcitabine on the CSC frequency or growth of several primary pancreatic cancer explant models. These findings support the conclusion that hedgehog contributes to tumor biology via paracrine tumor-stromal signaling but not via CSC maintenance or propagation. Finally, the only safety study finding associated with MEDI-5304 was ondontodysplasia in rats. Thus, MEDI-5304 represents a potent dual hedgehog inhibitor suitable for continued development to evaluate efficacy and safety in human patients with tumors harboring elevated levels of SHH or IHH.

Liver failure due to hepatic angiosarcoma in an adolescent with dyskeratosis congenita.

Dyskeratosis congenita (DC) is a multisystem disease caused by genetic mutations that result in defective telomere maintenance. Herein, we describe a 17-year-old patient with severe DC, manifested by bone marrow failure, severe immunodeficiency, and enterocolitis requiring prolonged infliximab therapy, who developed fatal hepatic failure caused by an aggressive, infiltrating hepatic angiosarcoma. Although DC patients have known increased risk of developing liver failure and multiple types of malignancy, this report is the first to describe angiosarcoma in a DC patient. Malignancy should thus be considered in the differential diagnosis of progressive liver dysfunction in DC patients.

Acquired factor XI deficiency in a child with membranoproliferative glomerulonephritis.

We describe a 7-year-old male with membranoproliferative glomerulonephritis who presented with nephrotic syndrome and subsequently developed factor XI (fXI) deficiency. An association between these conditions has not been described previously. In this case, fXI deficiency was caused by an antibody to fXI that enhanced clearance of the protein from plasma. Loss of fXI in the urine did not appear to be involved. Antibody-mediated clearance of prothrombin or factor X can cause acquired deficiencies of these proteins. This is the first report, to our knowledge, of an antibody that causes fXI deficiency by this mechanism.

Nasal turbinate enlargement due to cartilage and bone proliferation: a normal developmental finding in young ferrets.

Toxicity studies of intranasally administered, live attenuated influenza virus vaccine candidates conducted in male and female ferrets led to the microscopic observation of individual differences in the size of nasal turbinates, especially in the dorsal aspect of the nasal cavity. The association of these enlarged turbinates with acute to subacute inflammation, which is sometimes common in ferrets given live attenuated influenza virus vaccine candidates, led to this detailed microscopic evaluation of turbinate enlargement (cartilaginous and osseous thickening, or COT) in control animals dosed intranasally with saline. Results of this evaluation led to the conclusion that COT is a normal developmental feature of growing ferrets, irrespective of inflammation in nasal tissues or inflammatory exudate in the nasal cavity.

Phase II randomized comparison of topotecan plus cyclophosphamide versus topotecan alone in children with recurrent or refractory neuroblastoma: a Children's Oncology Group study.

PURPOSE: Single-agent topotecan (TOPO) and combination topotecan and cyclophosphamide (TOPO/CTX) were compared in a phase II randomized trial in relapsed/refractory neuroblastoma. Because responders often underwent further therapies, novel statistical methods were required to compare the long-term outcome of the two treatments. PATIENTS AND METHODS: Children with refractory/recurrent neuroblastoma (only one prior aggressive chemotherapy regimen) were randomly assigned to daily 5-day topotecan (2 mg/m(2)) or combination topotecan (0.75 mg/m(2)) and cyclophosphamide (250 mg/m(2)). A randomized two-stage group sequential design enrolled 119 eligible patients. Toxicity and response were estimated. Long-term outcome of protocol therapy was assessed using novel methods-causal inference-which allowed adjustment for the confounding effect of off-study therapies. RESULTS: Seven more responses were observed for TOPO/CTX (complete response [CR] plus partial response [PR], 18 [32%] of 57) than TOPO (CR+PR, 11 [19%] of 59;P = .081); toxicity was similar. At 3 years, progression-free survival (PFS) and overall survival (OS) were 4% +/- 2% and 15% +/- 4%, respectively. PFS was significantly better for TOPO/CTX (P = .029); there was no difference in OS. Older age at diagnosis and lack of MYCN amplification predicted increased OS (P < .05). Adjusting for randomized treatment effect and subsequent autologous stem-cell transplantation, there was no difference between TOPO and TOPO/CTX in terms of the proportion alive at 2 years. CONCLUSION: TOPO/CTX was superior to TOPO in terms of PFS, but there was no OS difference. After adjustment for subsequent therapies, no difference was detected in the proportion alive at 2 years. Causal inference methods for assessing long-term outcomes of phase II therapies after subsequent treatment can elucidate effects of initial therapies.

Induction of cell death in neuroblastoma by inhibition of cathepsins B and L.

A specific irreversible inhibitor of both cathepsins B and L, Fmoc-Tyr-Ala-CHN(2) (FYAD) induced apoptosis of neuroblastoma cells but not other tumor cells. Cysteine protease inhibitors that were not efficient inhibitors of both proteases did not cause death of any cell line tested. Apoptosis was preceded by accumulation of large electron dense vesicles and multivesicular bodies in the cytoplasm. Exposure of cells to the cathepsin D inhibitor, pepstatin, failed to rescue cells from FYAD-induced death. These results indicate that inhibition of cathepsins B and L may provide a unique mechanism for selectively inducing death of neuroblastoma with limited toxicity to normal cells and tissues.

Outcomes of children with intermediate-risk neuroblastoma after treatment stratified by MYCN status and tumor cell ploidy.

PURPOSE: The goal of Pediatric Oncology Group 9243 was to improve outcomes for children with intermediate-risk neuroblastoma (NB). PATIENTS AND METHODS: Patients were assigned to treatments on the basis of age, tumor MYCN status, and tumor cell ploidy. Children in the less intensive arm A received cyclophosphamide/doxorubicin and surgery. Patients not in complete remission postoperatively were treated with cisplatin/etoposide, cyclophosphamide/doxorubicin, and additional surgery. Patients with less favorable features were assigned to arm B, which consisted of carboplatin, etoposide, ifosfamide, and surgery. Survival rates were determined using an intent-to-treat approach. RESULTS: For arm-A patients, the 6-year event-free survival (EFS) was 86% with an SE of 3%. For arm-B patients, the 6-year EFS was 46% with an SE of 7%. MYCN status was the only statistically significant prognostic variable. Among patients whose tumors were MYCN nonamplified, a trend toward improved EFS was seen in children with hyperdiploid versus diploid tumors. However, many of these children responded well to salvage therapy, and overall survival rates did not differ on the basis of ploidy. Six-year EFS rates for arm B were patients with MYCN nonamplified, hyperdiploid tumors, 86% with an SE of 3%; patients with MYCN nonamplified, diploid tumors, 74% with an SE of 10%; patients with MYCN-amplified, hyperdiploid tumors, 46% with an SE of 15%; and patients with MYCN-amplified, diploid tumors, 22% with an SE of 10%. CONCLUSION: Outcomes for patients with MYCN-nonamplified, hyperdiploid tumors were excellent. Therapy reductions for these patients merit study. A trend toward less favorable outcomes for patients with MYCN-nonamplified, diploid tumors was observed; more children may need to be evaluated before therapy is reduced for this subgroup. For patients with MYCN-amplified tumors, new strategies are needed.

Gene expression profiling of mouse host response to Listeria monocytogenes infection.

The purpose of this study was to evaluate gene expression profiles in the liver and blood for prediction of infection severity from Listeria monocytogenes (LM). Mice were injected with medium broth (control) or a nonlethal or lethal dose of LM and sacrificed 6 h later. Gene expression changes were determined using Affymetrix MGU74Av2 GeneChips and confirmed by real-time polymerase chain reaction analysis. We identified discernable genes whose gene expression profiles can be used in pattern recognition to predict and classify samples in differently treated groups, with >or=90% accuracy in liver samples and 80% accuracy in blood at prediction; however, different genes were predictive in each tissue. Our results suggest that gene expression profiling in response to LM in mice may be able to distinguish samples in groups with varying severity of infection and provide information in finding molecular mechanisms and early biomarkers for subsequent conventional clinical endpoints.

Translocation (11;15;19): a highly specific chromosome rearrangement associated with poorly differentiated thymic carcinoma in young patients.

Thymic carcinoma is a rare epithelial neoplasm of the thymus. The presence of a specific chromosomal abnormality may augment diagnosis and therapeutic stratification. We report a 15-year-old boy diagnosed with thymic carcinoma who presented with a large anterior mediastinal mass, pleural effusion, and bone metastasis. The pleural fluid, cytology, bony lesions, and bone marrow were examined and chromosomal studies were performed. Histologic and immunohistochemical studies confirmed a poorly differentiated squamous cell type of thymic carcinoma. The karyotype of the pleural fluid at the time of diagnosis revealed a complex three-way translocation t(11;15;19)(p15;q12;p13.3). The constitutional karyotype was 46,XY. Five months after diagnosis, a bone marrow aspirate demonstrated tetraploidy with all translocation chromosomes in duplicate, as well as an unbalanced rearrangement involving chromosome 1: 92,XXYY,t(11;15;19)(p15;q12;p13.3)x2[15]/92,XXYY,idem,add(1)(qter)[5]. Despite aggressive multiagent chemotherapy, the patient's condition progressed with bone marrow disease and he died 6 months after diagnosis. Several case reports of a similar chromosomal abnormality have been reported for thymic carcinoma in young patients with poor outcome. This karyotypic abnormality appears to mark a cohort of patients with thymic carcinoma who have a poor prognosis despite aggressive chemotherapy.

90-day oral toxicity study of a grape seed extract (IH636) in rats.

To assess the safety of grape seed extract with less than 5.5% catechin monomers (IH636), 4 groups of male and female Sprague-Dawley rats were provided grape seed extract in the diet at levels of 0 (control), 0.5, 1.0, or 2.0% for a period of 90 days. All animals survived the duration of the study, and no significant changes in clinical signs, hematological parameters, organ weights, ophthalmology evaluations, or histopathological findings were observed. A significant increase in food consumption was observed in male and female rats provided the grape seed extract diets compared to that of the control rats, especially in male rats consuming 2.0% grape seed extract. This effect was not accompanied by increases in body weight gains. Grape seed extract appeared to increase the insoluble fraction of the diet. Male rats in the high-dose group exhibited decreased serum iron levels and decreased serum iron/total iron binding capacity ratio compared to those of the controls, although all values were within historical ranges for Sprague-Dawley rats. In conclusion, administration of the grape seed extract IH636 to male and female Sprague-Dawley rats in the feed at levels of 0.5, 1.0, or 2.0% for 90 days did not induce any significant toxicological effects.