BMS-986158, a Small Molecule Inhibitor of the Bromodomain and Extraterminal Domain Proteins, in Patients with Selected Advanced Solid Tumors: Results from a Phase 1/2a Trial

This phase 1/2a, open-label study (NCT02419417) evaluated the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics of BMS-986158, a selective bromodomain and extraterminal domain (BET) inhibitor. Dose escalation was performed with 3 BMS-986158 dosing schedules: A (5 days on, 2 days off; range, 0.75–4.5 mg), B (14 days on, 7 days off; 2.0–3.0 mg), and C (7 days on, 14 days off; 2.0–4.5 mg). Eighty-three patients were enrolled and received ≥1 BMS-986158 dose. Diarrhea (43%) and thrombocytopenia (39%) were the most common treatment-related adverse events (TRAEs). A lower incidence of TRAEs was found with schedules A (72%) and C (72%) vs. B (100%). Stable disease was achieved in 12 (26.1%), 3 (37.5%), and 9 (31.0%) patients on schedules A, B, and C, respectively. Two patients on schedule A with a 4.5-mg starting dose (ovarian cancer, n = 1; nuclear protein in testis [NUT] carcinoma, n = 1) experienced a partial response. BMS-986158 demonstrated rapid-to-moderate absorption (median time to maximum observed plasma concentration, 1–4 h). As expected with an epigenetic modifier, expression changes in select BET-regulated genes occurred with BMS-986158 treatment. Schedule A dosing (5 days on, 2 days off) yielded tolerable safety, preliminary antitumor activity, and a dose-proportional PK profile.

Application of Pharmacokinetic/Pharmacodynamic Modeling to Bridge Mouse Antitumor Efficacy and Monkey Toxicology Data for Determining the Therapeutic Index of an Interleukin-10 Fc Fusion Protein

Pharmacokinetic/pharmacodynamic (PK/PD) modeling was performed to quantitatively integrate preclinical pharmacology and toxicology data for determining the therapeutic index (TI) of an interleukin-10 (IL-10) fragment crystallizable (Fc) fusion protein. Mouse Fc fused with mouse IL-10 (mFc-mIL-10) was studied in mice for antitumor efficacy, and the elevation of interleukin-18 (IL-18) was examined as a PD biomarker. The in vivo mFc-mIL-10 EC₅₀ for the IL-18 induction was estimated to be 2.4 nM, similar to the in vitro receptor binding affinity (K_d) of 3.2 nM. The IL-18 induction was further evaluated in cynomolgus monkeys, where the in vivo induction EC₅₀ by a human IL-10 human Fc-fusion protein (hFc-hIL-10) was 0.08 nM vs. 0.3 nM measured as the in vitro K_d. The extent of the IL-18 induction correlated with mouse antitumor efficacy and was used to connect mouse efficacy to that in monkeys. The PD-based efficacious dose projected in monkeys was comparable to the results obtained using a PK-based method in which mouse efficacious exposure was targeted and corrected for affinity differences between the species. Furthermore, PK/PD relationships were developed for anemia and thrombocytopenia in monkeys treated with hFc-hIL-10, with thrombocytopenia predicted to be dose-limiting toxicity. Using quantitative pharmacology and toxicology information obtained through modeling work in the same species, the TI of hFc-hIL-10 in monkeys was determined to be 2.4 (vs. PD-based efficacy) and 1.2–3 (vs. PK-based efficacy), indicating a narrow safety margin. The model-based approaches were proven valuable to the developability assessment of the IL-10 Fc-fusion protein.

Report of the First International Symposium on NUT Carcinoma

NUT carcinoma is a rare, aggressive cancer defined by rearrangements of the NUTM1 gene. No routinely effective treatments of NUT carcinoma exist, despite harboring a targetable oncoprotein, most commonly BRD4-NUT. The vast majority of cases are fatal. Poor awareness of the disease is a major obstacle to progress in the treatment of NUT carcinoma. While the incidence likely exceeds that of Ewing sarcoma, and BRD4-NUT heralded the bromodomain and extra-terminal domain (BET) inhibitor class of selective epigenetic modulators, NUT carcinoma is incorrectly perceived as "impossibly rare," and therefore receives comparatively little private or governmental funding or prioritization by pharma. To raise awareness, propagate scientific knowledge, and initiate a consensus on standard and targeted treatment of NUT carcinoma, we held the First International Symposium on NUT Carcinoma on March 3, 2021. This virtual event had more than eighty attendees from the Americas, Europe, Asia, and Australia. Patients with NUT carcinoma and family members were represented and shared perspectives. Broadly, the four areas discussed by experts in the field included (1) the biology of NUT carcinoma; (2) standard approaches to the treatment of NUT carcinoma; (3) results of clinical trials using BET inhibitors; and (4) future directions, including novel BET bromodomain inhibitors, combinatorial approaches, and immunotherapy. It was concluded that standard chemotherapeutic approaches and first-generation BET bromodomain inhibitors, the latter complicated by a narrow therapeutic window, are only modestly effective in a minority of cases. Nonetheless, emerging second-generation targeted inhibitors, novel rational synergistic combinations, and the incorporation of immuno-oncology approaches hold promise to improve the prognosis of this disease.

Kynurenine-Induced Aryl Hydrocarbon Receptor Signaling in Mice Causes Body Mass Gain, Liver Steatosis, and Hyperglycemia

OBJECTIVE

The aryl hydrocarbon receptor (AHR) plays a key role in obesity. In vitro studies revealed that the tryptophan metabolite kynurenine (Kyn) activates AHR signaling in cultured hepatocytes. The objective of this study was to determine whether Kyn activated the AHR in mice to induce obesity.

METHODS

Mice were fed a low-fat diet and the same diet supplemented with Kyn. Body mass, liver status, and the expression of identified relevant genes were determined.

RESULTS

Kyn caused mice to gain significant body mass, develop fatty liver and hyperglycemia, and increase expression levels of cytochrome P450 1B1 and stearoyl-CoA desaturase 1. The hyperglycemia was accompanied with decreased insulin levels, which may have been due to the repression of genes involved in insulin secretion. Kyn plasma concentrations and BMI were measured in female patients, and a significant association was observed between Kyn and age in patients with obesity but not in patients who were lean.

CONCLUSIONS

Results show that (1) Kyn or a metabolite thereof is a ligand responsible for inducing AHR-based obesity, fatty liver, and hyperglycemia in mice; (2) plasma Kyn levels increase with age in women with obesity but not in lean women; and (3) an activated AHR is necessary but not sufficient to attain obesity, a status that also requires fat in the diet.

Abstract 1742: Inhibition of BET signaling leads to reversible GATA1-associated repression of hematopoietic progenitors: translation from preclinical assessment to clinical development

Bromodomain and extraterminal (BET) proteins recognize acetylated lysine residues for the purpose of transcriptional regulation of genes, including those involved in stem cell renewal and oncogenes such as MYC. Inhibition of BET proteins BRD2, BRD3, BRD4, and BRDT represents a promising treatment option for patients with cancer. However, little is known about the consequence of BET inhibition on normal stem cell renewal processes, such as hematopoiesis. This study explored the mechanistic effects of BET inhibition on bone marrow (BM) hematopoiesis. Rats treated with BET inhibitors JQ1, BMS-X, or BMS-986158 for 4 days in vivo showed dose-dependent pan-cellular BM atrophy and reduction of hematopoietic progenitors of myeloid and erythroid lineage (combination of anti-rat CD45, CD11b, anti-granulocyte, CD71, anti-erythroid, and CD90 via flow cytometry) and consequential reductions in circulating platelet and reticulocyte counts, with complete reversibility within 10 days of stopping treatment with BET inhibitors. Primary rat BM stem and progenitor cells treated with BET inhibitors in vitro were evaluated with the colony-forming unit assay and resulted in dose-dependent reduction of multiple lineage progenitor colonies, especially the erythroid and megakaryocyte lineages. To further elucidate pathways involved in BET-related BM atrophy, erythropoiesis and thrombopoiesis genes regulated by GATA1, a BRD-associated transcription factor, from rat BM, as well as rat and human whole-blood samples exposed to BET inhibitor(s) were evaluated via RNAseq and RT-PCR. Dose-dependent responses in genes involved in erythropoiesis (Alas2, ABCme, PBG-D, HMBS) and thrombopoiesis (NFE2, PF4, GP1Bb, MPL) were observed after 4 days of treatment with BMS-986158. In a clinical trial (NCT02419417), patients with solid tumors treated with BMS-986158 demonstrated reversible thrombocytopenia and downregulation of NFE2, PF4, and HMBS expression, similar to that observed in rats. GATA1 was also downregulated in rat BM, with target engagement in rat and human demonstrated by the induction of HEXIM1 transcription, a pharmacodynamic (PD) biomarker of growth inhibition and apoptosis induced by BRD4 inhibition. Overall, our results suggest inhibition of BET signaling causes target-related, dose-dependent repression of hematopoietic progenitors through alterations of GATA1-associated erythropoiesis and thrombopoiesis regulation in rat BM and human blood samples, and these effects are reversible on cessation of BET inhibitor treatment. This is the first in vivo study demonstrating the mechanism of BET inhibition resulting in GATA1-associated repression of hematopoietic progenitors that is correlated to clinical pharmacokinetics and PD (Chen X, et al. AACR 2020) and is translatable from preclinical evaluation to clinical experience.

Citation Format: Cindy Zhang, Ke Xu, Julie Panzica-Kelly, Jennifer Price, Denise Bounous, Shodeinde Coker, Kezi Unsal-Kacmaz, Danielle Greenawalt, Ashvinikumar Gavai, Ronald Fleming, Karen Augustine-Rauch, Richard Westhouse. Inhibition of BET signaling leads to reversible GATA1-associated repression of hematopoietic progenitors: translation from preclinical assessment to clinical development [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 1742.

Abstract 3021: Integrated pharmacokinetic (PK)/pharmacodynamic (PD) modeling leveraging PK, biomarker, and safety data to support dose and schedule selection for the BET inhibitor BMS-986158

Background: BMS-986158 is a potent, selective, and orally bioavailable small-molecule inhibitor of the bromodomain and extraterminal (BET) family of transcription modulators being evaluated in patients with various tumors in a phase 1 clinical study (NCT02419417). An integrated PK/PD analysis leveraging PK, biomarker, and safety data from the phase 1 study was performed to support dose and schedule (Sch) selection further clinical studies with BMS-986158.

Methods: Five doses (0.75-4.5 mg) and 3 dosing regimens (Sch A: 5 days on, 2 days off over 21 days; Sch B: 14 days on, 7 days off; Sch C: 7 days on, 14 days off) were evaluated. Reversible thrombocytopenia (TTP) was the primary safety signal observed, and peripheral gene expression modulation was a PD biomarker indicative of drug target engagement. BMS-986158 serum PK was characterized with a 2-compartment population PK (PPK) model. A semimechanistic PK/PD model describing the platelet-reducing effect with BMS-986158 was developed to characterize platelet profiles for individual patients and to simulate and project the incidence of TTP at different doses and dosing regimens. The association of BMS-986158 exposure with expression modulation of select peripheral BET target genes, including HEXM1 and CCR2, was also examined.

Results: BMS-986158 exhibited linear PK with rapid oral absorption (Tmax ≈ 2-4 h) and a terminal half-life of ≈ 60 h over the dose range of 0.75-4.5 mg. PPK modeling and simulation suggested that at the same dose level, Sch A led to comparable Cmax, with a higher Ctrough and Cavg at steady state compared with Sch B and C across the dosing interval. The semimechanistic PK/PD model predicted a higher incidence rate of TTP with Sch A than Sch C at the same dose level, and the predictions agreed with observed primary safety data from the phase 1 study. The model predicted grade 4 TTP incidence rates of 24% (95% CI, 21%-26%) and 43% (95% CI, 38%-45%) at 4.5 and 6 mg, respectively, with Sch A. This suggests that 4.5 mg would be the maximum tolerated dose, given that a 6 mg dose was predicted to exceed the target dose-limiting toxicity (DLT) rate of grade 4 TTP at 27%. The exploratory analysis of BMS-986158 exposure and expression of selected peripheral genes associated with the BET pathway suggested a direct association between BMS-986158 exposure and the magnitude of peripheral gene expression modulation.

Conclusions: An integrated PK/PD analysis of BMS-986158 incorporating incidence of reversible TTP and modulation of peripheral BET target genes identified a maximum dose of 4.5 mg at Sch A for further clinical development. With the assumption that sustained gene expression modulation is desirable for BMS-986158 efficacy, Sch A, which provides sustained drug exposure, is recommended to enable continuous BET target gene expression modulation.

Citation Format: Xi (Cindy) Chen, Lora Hamuro, Shodeinde Coker, John Hilton, Jennifer R. Diamond, Capucine Baldini, Mark Voskoboynik, Mihaela Cristea, William Edenfield, Kezi Unsal-Kacmaz, Donald Jackson, Abraham Apfel, Ke Xu, Li Zhu, Amit Roy, Akintunde Bello, Ronald Fleming, Paul Statkevich. Integrated pharmacokinetic (PK)/pharmacodynamic (PD) modeling leveraging PK, biomarker, and safety data to support dose and schedule selection for the BET inhibitor BMS-986158 [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 3021.

Treatment Considerations for Patients with Unresectable Metastatic Melanoma Who Develop Pembrolizumab-Induced Guillain-Barré Toxicity: A Case Report

Immunotherapy has improved outcomes in many malignancies, most notably in melanoma, lung cancer, and bladder cancer. Understanding the side effects associated with these medications is an important part of managing our patients. Although fatigue, rash, and diarrhea are commonly reported side effects, it is important to be cognizant of rarer ones, such as neuropathy. Amongst the different neurological toxicities that have been reported in the literature, Guillain-Barré-like neuropathies are quite rare. However, the occurrence of such neuropathies in a patient can be life threatening. The problem this poses in treating cancers such as melanoma is that it eliminates an effective class of medication available to the patient, which can ultimately affect their prognosis. We present a case of a 65-year-old female with unresectable metastatic melanoma who developed Guillain-Barré-like neuropathy after two doses of pembrolizumab. Her clinical course was complicated by three separate hospitalizations over 3 months due to recurring bouts of neuropathy, which resulted in a significant decline in performance status and delay in subsequent treatment of her melanoma. Her prolonged recovery eventually resulted in progression of her melanoma nearly 1 year later, while off therapy. Instead of discontinuing immunotherapy completely, she agreed to a re-challenge with ipilimumab. After one dose, her melanoma regressed and continues to show a sustained response nearly 1 year after treatment without any signs of relapse in her neuropathy. Guillain-Barré toxicity resulting from immune checkpoint inhibition poses a difficult challenge to an oncologist who is determining the next line of treatment for patients with unresectable metastatic melanoma that have progressed while off therapy and who have no targetable mutations. Our case raises the question of whether a re-challenge with a different class of immunotherapy agent is a reasonable option.

Levamisole-induced occlusive necrotising vasculitis in cocaine abusers: an unusual cause of skin necrosis and neutropenia

We present three cases describing the various skin manifestations of presumed levamisole-contaminated cocaine use. Antibody-mediated vasculitis and neutropenia were consistent findings in these cases and repeat exposure resulted in distinct dermatologic complications. This phenomenon of levamisole-induced vasculitis and neutropenia is being increasingly described and has characteristic wound manifestations that must be recognised and treated early.

An analysis of subdomain orientation, conformational change and disorder in relation to crystal packing of aspartic proteinases

The analysis reported here describes detailed structural studies of endothiapepsin (the aspartic proteinase from Endothia parasitica), with and without bound inhibitors, and human pepsin 3b. Comparison of multiple crystal structures of members of the aspartic proteinase family has revealed small but significant differences in domain orientation in different crystal forms. In this paper, it is shown that these differences in domain orientation do not necessarily correlate with the presence or absence of bound inhibitors, but appear to stem at least partly from crystal contacts mediated by sulfate ions. However, since the same inherent flexibility of the structure is observed for other enzymes in this family such as human pepsin, the native structure of which is also reported here, the observed domain movements may well have implications for the mechanism of catalysis.

Crystallization and preliminary X-ray diffraction analysis of the protease from Southampton norovirus complexed with a Michael acceptor inhibitor

Noroviruses are the predominant cause of human epidemic nonbacterial gastroenteritis. Viral replication requires a cysteine protease that cleaves a 200 kDa viral polyprotein into its constituent functional parts. Here, the crystallization of the recombinant protease from the Southampton norovirus is described. Whilst the native crystals were found to diffract only to medium resolution (2.9 Å), cocrystals of an inhibitor complex diffracted X-rays to 1.7 Å resolution. The polypeptide inhibitor (Ac-EFQLQ-propenyl ethyl ester) possesses an amino-acid sequence designed to match the substrate specificity of the enzyme, but was synthesized with a reactive Michael acceptor group at the C-terminal end.

Permutation distribution estimation applied to the comparison of the profile of the activity of two antianginal drugs

The comparison of the anti-ischemic activity of trimetazidine and propranolol was evaluated by multiple end points (clinical, exercise test, and ambulatory electrocardiogram [ECG] monitoring criteria) in 149 male patients with effort angina who received either trimetazidine 20 mg tid or propranolol 40 mg tid during a period of 3 months. The distribution of the standardized differences between the two treatments for each variable was obtained by a permutation method. The medians (estimation of the actual difference between the two treatments) and the 5, 25, 75 and 95% quantiles were represented on the same diagram for all end points. The pattern of the standardized distribution of the differences showed a similar activity of both drugs on symptoms and nitrates consumption, on exercise tolerance and increase in ischemic threshold at exercise, and on ischemia recorded at ambulatory ECG monitoring. Conversely, only propranolol decreased heart rate and rate pressure product at rest as well as at exercise, underlining the difference in the mode of action of the two drugs. This descriptive technique is an attractive method to evaluate the differences between drugs considering multiple criteria favouring the estimation of these differences together with their variability.

An evaluation of the efficacy of supervised cognitive behavioral self-help bulimia nervosa

Eighty two patients with bulimia nervosa were managed by providing them with supervision in the use of a highly structured cognitive behavioral self-help manual. Their progress was assessed in an open clinical trial. The 67 patients who completed the course of self-help experienced considerable benefit; the frequency of bulimic episodes and self-induced vomiting decreasing by 80% and 79%, respectively. Compared to those who benefited, those who had a poor outcome or dropped out of treatment were more than twice as likely to have had anorexia nervosa in the past and were somewhat more likely to have a personality disorder. Three-quarters of those who persisted with the programme of supervised self-help were followed up a year after commencing treatment. Clinical gains were well maintained: almost two thirds were abstinent with respect to both bulimic episodes and self-induced vomiting. It would seem appropriate that, as part of a stepped care approach to the management of bulimia nervosa, supervised cognitive behavioral self-help should routinely be the first line treatment.

Self-help for bulimia nervosa: a preliminary report

Eighteen patients with DSM-III-R bulimia nervosa were treated by providing them with supervision in the use of a self-help manual based on the cognitive behavioral treatment for the disorder. The patients were assessed before beginning the self-help program, and again 4 to 6 months later, using standardized measures of psychopathology. The findings were encouraging. At follow-up one half of the patients had ceased bulimic episodes and self-induced vomiting, and most of the remainder had made significant improvements. These preliminary findings, together with related published work, suggest that supervised self-help might be an appropriate first line treatment for patients with bulimia nervosa and that for many patients it could be sufficient.

Onset of bulimia nervosa in a 64-year-old woman

A woman aged 64 years presented with recent onset bulimia nervosa following the death of her husband. Her eating disorder was successfully treated with a course of cognitive-behavioral therapy.

Early diagnosis of spinal cord arteriovenous malformation in a 7-year-old child

Spinal cord arteriovenous malformations (AVMs) are relatively uncommon in the pediatric age group. Early diagnosis is rarely made and the resulting complications arising from the AVM may have devastating long-lasting neurologic sequelae. Early diagnosis requires a high degree of clinical suspicion. We report the case of spinal cord AVM in a child who presented with two episodes of "neck stiffness" without headache in whom the prompt diagnosis and treatment prevented neurologic sequelae.

Hypercholesterolemia in bulimia nervosa

Patients with bulimia nervosa may present with serum cholesterol levels higher than the recommended range. Giving advice on dietary modification to reduce cholesterol levels runs contrary to the cognitive behavioral strategies used to treat bulimia nervosa. This would not be a problem if it were found that cholesterol levels fell with clinical improvement in the eating disorder.

Pediatric Miller Fisher syndrome requiring intubation: a case report

In 1956, C. Miller Fisher described a clinical syndrome of ophthalmoplegia, ataxia, and areflexia. This syndrome, which now bears his name, shares certain features with the Guillain-Barré syndrome (GBS) and generally follows a benign, restricted clinical course, especially in the pediatric population. The authors report a pediatric case of Miller Fisher syndrome (MFS) who subsequently required intubation and mechanical ventilation.

Patients with bulimia nervosa who fail to engage in cognitive behavior therapy

Although cognitive behavioral treatment is the treatment of choice in bulimia nervosa, patients' response is variable. A minority of patients do not respond at all and some never engage in treatment. This paper concerns the latter group. A case series of six such patients with whom treatment could not be initiated is compared with a group who received a full course of treatment. The group with whom treatment could not begin were found to have a longer history of disorder, to report excessive laxative abuse, to have more severe depressed mood and a greater dissatisfaction with their body weight. In addition, they were more likely to have abused psychoactive substances, engaged in episodes of self-harm, and have a lower self-esteem. They were also more likely to be diagnosed as having borderline personality disorder. Patients presenting with the wide range of difficulties characteristic of this group require a more intensive form of treatment than standard outpatient cognitive behavior therapy.

The construction and preliminary validation of a scale for measuring eating disorders

The present paper reports on the construction and validation of a new scale for measuring eating disorders, the Eating Habits Questionnaire (EHQ), which is designed to assess not only existing disorders but also the likelihood of developing such disorders. The EHQ was initially validated on a large sample of university students, followed by further tests of reliability and validity amongst a number of both eating-disordered and normal comparison groups. Factor analysis of the initial item pool produced a 57-item, three-factor structure concerned with weight and dieting, restrained eating patterns, and overeating. Concurrent validation confirmed anticipated relationships with existing self-report scales, and the EHQ was found to be both internally consistent and stable over time. The new scale distinguished reliably between diagnosed eating-disordered patients and normal subjects, and results indicated that around 5% of undiagnosed female undergraduates scored in the same range as the patient population.

Neonatal posterior fossa subdural hematoma

Hemorrhage into the posterior fossa is a rare neurosurgical emergency in neonates. CT scanning is diagnostic. Blood layering under the apex of the tentorium cerebelli, however, may resemble a dilated vascular structure, and the rigidity of the pressured tentorium may prevent upward transmission of increased intracranial pressure, resulting in a soft fontanelle.