The United States COVID-19 Forecast Hub dataset

Academic researchers, government agencies, industry groups, and individuals have produced forecasts at an unprecedented scale during the COVID-19 pandemic. To leverage these forecasts, the United States Centers for Disease Control and Prevention (CDC) partnered with an academic research lab at the University of Massachusetts Amherst to create the US COVID-19 Forecast Hub. Launched in April 2020, the Forecast Hub is a dataset with point and probabilistic forecasts of incident cases, incident hospitalizations, incident deaths, and cumulative deaths due to COVID-19 at county, state, and national, levels in the United States. Included forecasts represent a variety of modeling approaches, data sources, and assumptions regarding the spread of COVID-19. The goal of this dataset is to establish a standardized and comparable set of short-term forecasts from modeling teams. These data can be used to develop ensemble models, communicate forecasts to the public, create visualizations, compare models, and inform policies regarding COVID-19 mitigation. These open-source data are available via download from GitHub, through an online API, and through R packages.

The United States COVID-19 Forecast Hub dataset

Academic researchers, government agencies, industry groups, and individuals have produced forecasts at an unprecedented scale during the COVID-19 pandemic. To leverage these forecasts, the United States Centers for Disease Control and Prevention (CDC) partnered with an academic research lab at the University of Massachusetts Amherst to create the US COVID-19 Forecast Hub. Launched in April 2020, the Forecast Hub is a dataset with point and probabilistic forecasts of incident cases, incident hospitalizations, incident deaths, and cumulative deaths due to COVID-19 at county, state, and national, levels in the United States. Included forecasts represent a variety of modeling approaches, data sources, and assumptions regarding the spread of COVID-19. The goal of this dataset is to establish a standardized and comparable set of short-term forecasts from modeling teams. These data can be used to develop ensemble models, communicate forecasts to the public, create visualizations, compare models, and inform policies regarding COVID-19 mitigation. These open-source data are available via download from GitHub, through an online API, and through R packages.

GDC-9545 (Giredestrant): A Potent and Orally Bioavailable Selective Estrogen Receptor Antagonist and Degrader with an Exceptional Preclinical Profile for ER+ Breast Cancer

Breast cancer remains a leading cause of cancer death in women, representing a significant unmet medical need. Here, we disclose our discovery efforts culminating in a clinical candidate, 35 (GDC-9545 or giredestrant). 35 is an efficient and potent selective estrogen receptor degrader (SERD) and a full antagonist, which translates into better antiproliferation activity than known SERDs (1, 6, 7, and 9) across multiple cell lines. Fine-tuning the physiochemical properties enabled once daily oral dosing of 35 in preclinical species and humans. 35 exhibits low drug-drug interaction liability and demonstrates excellent in vitro and in vivo safety profiles. At low doses, 35 induces tumor regressions either as a single agent or in combination with a CDK4/6 inhibitor in an ESR1^Y537S mutant PDX or a wild-type ERα tumor model. Currently, 35 is being evaluated in Phase III clinical trials.

Venetoclax combines synergistically with FLT3 inhibition to effectively target leukemic cells in FLT3-ITD+ acute myeloid leukemia models

FLT3 internal tandem duplication (FLT3-ITD) mutations account for ~25% of adult acute myeloid leukemia cases and are associated with poor prognosis. Venetoclax, a selective BCL-2 inhibitor, has limited monotherapy activity in relapsed/refractory acute myeloid leukemia with no responses observed in a small subset of FLT3-ITD+ patients. Further, FLT3-ITD mutations emerged at relapse following venetoclax monotherapy and combination therapy suggesting a potential mechanism of resistance. Therefore, we investigated the convergence of FLT3-ITD signaling on the BCL-2 family proteins and determined combination activity of venetoclax and FLT3-ITD inhibition in preclinical models. In vivo, venetoclax combined with quizartinib, a potent FLT3 inhibitor, showed greater anti-tumor efficacy and prolonged survival compared to monotherapies. In a patient-derived FLT3-ITD+ xenograft model, cotreatment with venetoclax and quizartinib at clinically relevant doses had greater anti-tumor activity in the tumor microenvironment compared to quizartinib or venetoclax alone. Use of selective BCL-2 family inhibitors further identified a role for BCL-2, BCL-XL and MCL-1 in mediating survival in FLT3-ITD+ cells in vivo and highlighted the need to target all three proteins for greatest anti-tumor activity. Assessment of these combinations in vitro revealed synergistic combination activity for quizartinib and venetoclax but not for quizartinib combined with BCL-XL or MCL-1 inhibition. FLT3-ITD inhibition was shown to indirectly target both BCL-XL and MCL-1 through modulation of protein expression, thereby priming cells toward BCL-2 dependence for survival. These data demonstrate that FLT3-ITD inhibition combined with venetoclax has impressive anti-tumor activity in FLT3-ITD+ acute myeloid leukemia preclinical models and provides strong mechanistic rational for clinical studies.

Abstract 3406: GDC-9545: A pure antiestrogen clinical candidate that immobilizes the estrogen receptor and profoundly alters chromatin accessibility in vivo

Estrogen Receptor-positive (ER+) breast cancer is a significant unmet medical need. Tumors expressing ER exhibit evidence of mitogenic ER signaling throughout disease progression, including after acquired resistance to existing endocrine agents. Such continued dependence on ER signaling highlights the need for next generation therapies that more effectively block ER function in tumors. Fulvestrant was first discovered as a “pure antiestrogen”, in contrast to earlier generation ER therapeutic ligands that exhibit weak agonistic activity, such as tamoxifen. After its discovery as a full ER antagonist, fulvestrant was demonstrated to decrease ER protein levels through proteasome-mediated degradation. These observations led to the compelling hypothesis that elimination of ER by fulvestrant drives suppression of ER signaling. Importantly however, we recently demonstrated that fulvestrant and other full ER antagonists (e.g. GDC-0927) dramatically slow the intranuclear mobility of ER [Cell 178:4 (2019)]. We argue that such immobilization prevents ER function, and that increased ER turnover is a downstream consequence of immobilization, rather than a cause of ER inhibition. Here, we describe GDC-9545, our latest generation ER antagonist, currently being evaluated in clinic, that robustly immobilizes ER, and drives profound ER suppression in vivo. In the HCI-011 PDX model, we find that GDC-9545 can achieve greater ER pathway inhibition than can be achieved by tamoxifen. Intriguingly, although tamoxifen exhibits partial ER inhibition, likely through preventing recruitment of co-activators to the ER ligand binding domain, it drives increased accessibility at ~2500 chromatin sites, as determined by ATAC-seq. Chromatin regions exhibiting increased accessibility upon tamoxifen treatment are significantly enriched for the ERE motif, while a smaller number of sites exhibiting decreased accessibility upon treatment are enriched for AP-1 motifs. In contrast, GDC-9545 profoundly decreases chromatin accessibility at both ERE and AP-1 motifs, despite not fully eliminating ER protein. Notably, sites exhibiting decreased accessibility upon GDC-9545 treatment in the PDX in vivo, significantly overlap with sites displaying increased accessibility in estrogen-stimulated MCF7 cells in vitro. GDC-9545-treatment additionally alters accessibility at sites enriched for the FOXA1 motif, though unexpectedly, a sub-set of these sites exhibit increased accessibility while a distinct sub-set of sites exhibit decreased accessibility. We speculate that this particular pattern of accessibility changes may reflect redistribution of FOXA1 upon GDC-9545 treatment, and we will further explore this hypothesis. These data provide further insights into the impact of ER immobilization by the latest generation of pure antiestrogens.

Citation Format: Ciara Metcalfe, Wei Zhou, Jane Guan, Robert A. Blake, Tom De Bruyn, Jennifer M. Giltnane, Ellen Ingalla, Tracy Kleinheinz, Jun Liang, Vidhi Mody, Jason Oeh, Savita Ubhayakar, Ingrid Wertz, Amy Young, Jason Zbieg, Xiaojing Wang, Marc Hafner. GDC-9545: A pure antiestrogen clinical candidate that immobilizes the estrogen receptor and profoundly alters chromatin accessibility in vivo [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 3406.

Discovery of GNE-149 as a Full Antagonist and Efficient Degrader of Estrogen Receptor alpha for ER+ Breast Cancer

Estrogen receptor alpha (ERα) is a well-validated drug target for ER-positive (ER+) breast cancer. Fulvestrant is FDA-approved to treat ER+ breast cancer and works through two mechanisms-as a full antagonist and selective estrogen receptor degrader (SERD)-but lacks oral bioavailability. Thus, we envisioned a "best-in-class" molecule with the same dual mechanisms as fulvestrant, but with significant oral exposure. Through lead optimization, we discovered a tool molecule 12 (GNE-149) with improved degradation and antiproliferative activity in both MCF7 and T47D cells. To illustrate the binding mode and key interactions of this scaffold with ERα, we obtained a cocrystal structure of 6 that showed ionic interaction of azetidine with Asp351 residue. Importantly, 12 showed favorable metabolic stability and good oral exposure. 12 exhibited antagonist effect in the uterus and demonstrated robust dose-dependent efficacy in xenograft models.

Discovery of a C-8 hydroxychromene as a potent degrader of estrogen receptor alpha with improved rat oral exposure over GDC-0927

Phenolic groups are responsible for the high clearance and low oral bioavailability of the estrogen receptor alpha (ERα) clinical candidate GDC-0927. An exhaustive search for a backup molecule with improved pharmacokinetic (PK) properties identified several metabolically stable analogs, although in general at the expense of the desired potency and degradation efficiency. C-8 hydroxychromene 30 is the first example of a phenol-containing chromene that not only maintained excellent potency but also exhibited 10-fold higher oral exposure in rats. The improved in vivo clearance in rat was hypothesized to be the result of C-8 hydroxy group being sterically protected from glucuronide conjugation. The excellent potency underscores the possibility of replacing the presumed indispensable phenolic group at C-6 or C-7 of the chromene core. Co-crystal structures were obtained to highlight the change in key interactions and rationalize the retained potency.

Abstract 1648: Discovery and evolution of orally bioavailable selective estrogen receptor degraders for ER+ breast cancer: From GDC-0810 to GDC-0927

Breast cancer is the most frequently diagnosed cancer among women and remains the second leading cause of cancer death in women. An estimated 70% of all breast cancers express estrogen receptor alpha (ERα); and endocrine therapies have validated ERα as a target for the treatment of breast cancer. Despite effective endocrine therapies, many patients eventually relapse and become resistant to standard of care treatments. Endocrine resistant tumors often remain dependent on ERα for growth and survival, as evidenced by their sensitivity to the selective estrogen receptor degrader (SERD), fulvestrant. However, fulvestrant may be limited in achieving maximal target occupancy due to pharmaceutical and pharmacokinetics properties which necessitates intramuscular route of administration. Consequently, SERDs with superior drug-like properties were sought to allow consistent and rapid achievement of maximal therapeutic exposure. GDC-0810 and GDC-0927 as first and second generation orally bioavailable SERDs were discovered through a prospective lead optimization on ERα degradation. The evolution from GDC-0810 to GDC-0927 will be described and provides new insights into ERα biology and biochemistry. By shifting away from the acrylic acid moiety in GDC-0810, GDC-0927 achieved increased potency and more consistent, complete suppression of ER signaling. Co-crystal structures of both GDC-0810 and GDC-0927 with ERα will be shared. Subsequent optimization of GDC-0927 resulting in improved pharmacokinetic properties will also be highlighted.

Citation Format: Mehmet Kahraman, Steven P. Govek, Johnny Y. Nagasawa, Andiliy Lai, Celine Bonnefous, Karensa Douglas, John Sensintaffar, Nhin Lu, KyoungJin Lee, Anna Aparicio, Josh Kaufman, Jing Qian, Gang Shao, Rene Prudente, James D. Joseph, Beatrice Darimont, Daniel Brigham, Richard Heyman, Peter J. Rix, Jeffrey H. Hager, Nicholas D. Smith, Robert A. Blake, Jae Chang, Edna Choo, Anneleen Daemen, Lori S. Friedman, Jane Guan, Steven Hartman, Ellen Ingalla, James R. Kiefer, Tracy Kleinheinz, Sharada Labadie, Ciara Metcalfe, Vidhi Mody, Michelle Nannini, Deepak Sampath, Amy Young, Maia Vinogradova, Wei Zhou, Jun Liang, Xiaojing Wang. Discovery and evolution of orally bioavailable selective estrogen receptor degraders for ER+ breast cancer: From GDC-0810 to GDC-0927 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1648.

Toxicity of ultraviolet radiation exposure to the lens expressed by maximum tolerable dose

The maximum tolerable dose (MTD2.3:16) for avoidance of cataract on exposure to ultraviolet radiation (UVR)-300 nm in the rat was here estimated at 3.65 kJ/m2. Sprague-Dawley rats were unilaterally exposed to UVR in the 300 nm wavelength region. One week after the exposure, the intensity of forward light scattering was measured. Toxicity for continuous response events can be estimated with MTD. Current safety standards for avoidance of cataract after exposure to UVR are based on a binary response event. It has, however, recently been shown that UVR-induced cataract is a continuous dose-dependent event. MTD provides a statistically well-defined criterion of toxicity for continuous response events.

Regulation of arginase isoforms I and II by IL-4 in cultured murine peritoneal macrophages

Macrophages can express two arginase isoforms with distinct subcellular localization (cytosolic AI and mitochondrial AII). These isoforms are products of different genes and are capable of differential induction. Experiments were performed to identify the specific arginase isoforms induced by interleukin (IL)-4, a Th2 cytokine shown by others to increase arginase activity in macrophages, and serum. Results indicate IL-4, in concert with serum, increases AI, but not AII, mRNA in cultured murine macrophages. Moreover, they show serum to induce both arginase isoforms and to be required for maximal AI induction by IL-4. Together with the enhanced expression of AI, IL-4 induced the expression of the cationic amino acid transporter MCAT-2 and increased L-arginine transport into the cells. Present results confirm, then, specificity in the ability of macrophage arginase isoforms to be induced by different stimuli. Moreover, they suggest that a decrease in intracellular L-arginine concentration resulting from its consumption by arginase may be repaired by concurrent increases in L-arginine influx into the cell.

Eikenella corrodens endocarditis in an intravenous drug user: case report and literature review

A rare case of Eikenella corrodens endocarditis in an intravenous drug user is reported. Repeated blood cultures from the patient established the diagnosis of this infection. However, evaluation of the cardiac function using two-dimensional echocardiography with Doppler flow demonstrated a large pedunculated tricuspid vegetation. Also evident on this study was a dilated right ventricle with diminished contractility and regurgitation. Complete sterilization of the blood was achieved after a 2-week course of intravenous penicillin and gentamicin followed by an additional 4-week course of intravenous penicillin alone. Clinicians treating suspected IV drug users should be aware of the potential pathogenicity of this rare, facultative, anaerobic gram-negative bacillus (E corrodens). A combination of intravenous penicillin and aminoglycoside should be considered as the initial treatment followed by an additional course of intravenous penicillin for such patients with valvular vegetation.

Malaria infection in transplant recipient

A case of P. malariae infection occurring in a kidney transplant recipient is reported. The diagnosis was delayed because of atypical clinical presentation secondary to altered immune response. Serologic tests for antimalarial antibody are not reliable and diagnosis is established by visualization of the parasites in the peripheral blood smear. We can only guess what role this infection played in rejection of the transplant and whether earlier diagnosis and treatment would have saved it.