The emergence of SARS-CoV-2/2019 novel coronavirus (COVID-19) has created a global pan-demic with no approved treatments or vaccines. Many treatments have already been administered to COVID-19 patients but have not been systematically evaluated. We performed a systematic literature review to identify all treatments reported to be administered to COVID-19 patients and to assess time to clinically meaningful response for treatments with sufficient data. We searched PubMed, BioRxiv, MedRxiv, and ChinaXiv for articles reporting treatments for COVID-19 patients published between 1 December 2019 and 27 March 2020. Data were analyzed descriptively. Of the 2706 articles identified, 155 studies met the inclusion criteria, comprising 9152 patients. The cohort was 45.4% female and 98.3% hospitalized, David C. Fajgenbaum and Johnson S. Khor contributed equally to this study.

Idiopathic multicentric Castleman disease (iMCD) is a rare and poorly understood hematologic disorder characterized by lymphadenopathy, systemic inflammation, cytopenias, and life-threatening multiorgan dysfunction. Interleukin-6 (IL-6) inhibition effectively treats approximately one-third of patients. Limited options exist for nonresponders, because the etiology, dysregulated cell types, and signaling pathways are unknown. We previously reported 3 anti-IL-6 nonresponders with increased mTOR activation who responded to mTOR inhibition with sirolimus. We investigated mTOR signaling in tissue and serum proteomes from iMCD patients and controls. mTOR activation was increased in the interfollicular space of iMCD lymph nodes (N = 26) compared with control lymph nodes by immunohistochemistry (IHC) for pS6, p4EBP1, and p70S6K, known effectors and readouts of mTORC1 activation. IHC for pS6 also revealed increased mTOR activation in iMCD compared with Hodgkin lymphoma, systemic lupus erythematosus, and reactive lymph nodes, suggesting that the mTOR activation in iMCD is not just a product of lymphoproliferation/inflammatory lymphadenopathy. Further, the degree of mTOR activation in iMCD was comparable to autoimmune lymphoproliferative syndrome, a disease driven by mTOR hyperactivation that responds to sirolimus treatment. Gene set enrichment analysis of serum proteomic data from iMCD patients (n = 88) and controls (n = 42) showed significantly enriched mTORC1 signaling. Finally, functional studies revealed increased baseline mTOR pathway activation in peripheral monocytes and T cells from iMCD remission samples compared with healthy controls. IL-6 stimulation augmented mTOR activation in iMCD patients, which was abrogated with JAK1/2 inhibition. These findings support mTOR activation as a novel therapeutic target for iMCD, which is being investigated through a trial of sirolimus (NCT03933904).

Summary Geographically dispersed patients, inconsistent treatment tracking, and limited infrastructure slow research for many orphan diseases. We assess the feasibility of a patient-powered study design to overcome these challenges for Castleman disease, a rare hematologic disorder. Here, we report initial results from the ACCELERATE natural history registry. ACCELERATE includes a traditional physician-reported arm and a patient-powered arm, which enables patients to directly contribute medical data and biospecimens. This study design enables successful enrollment, with the 5-year minimum enrollment goal being met in 2 years. A median of 683 clinical, laboratory, and imaging data elements are captured per patient in the patient-powered arm compared with 37 in the physician-reported arm. These data reveal subgrouping characteristics, identify off-label treatments, support treatment guidelines, and are used in 17 clinical and translational studies. This feasibility study demonstrates that the direct-to-patient design is effective for collecting natural history data and biospecimens, tracking therapies, and providing critical research infrastructure.

Castleman disease (CD) describes a group of rare hematologic conditions involving lymphadenopathy with characteristic histopathology and a spectrum of clinical abnormalities. CD is divided into localized or unicentric CD (UCD) and multicentric CD (MCD) by imaging. MCD is further divided based on etiological driver into human herpesvirus-8-associated MCD, POEMS-associated MCD, and idiopathic MCD. There is notable heterogeneity across MCD, but increased level of pro-inflammatory cytokines, particularly interleukin-6, is an established disease driver in a portion of patients. FDG-PET/CT can help determine UCD versus MCD, evaluate for neoplastic conditions that can mimic MCD clinico-pathologically, and monitor therapy responses. CD requires more robust characterization, earlier diagnosis, and an accurate tool for both monitoring and treatment response evaluation; FDG-PET/CT is particularly suited for this. Moving forward, future prospective studies should further characterize the use of FDG-PET/CT in CD and specifically explore the utility of global disease assessment and dual time point imaging.Trial registration ClinicalTrials.gov, NCT02817997, Registered 29 June 2016, https://clinicaltrials.gov/ct2/show/NCT02817997

Background Human herpes-virus 8-negative/idiopathic multicentric Castleman disease (iMCD) is a rare inflammatory disorder involving multicentric lymphadenopathy with characteristic histopathology. Clinical presentation is heterogenous and includes cytokine-driven constitutional symptoms, cytopenias, systemic inflammation, and multi-organ dysfunction. International consensus treatment guidelines are based on a large cohort of case studies and a few clinical trials, but the available evidence is limited. Siltuximab, an anti-IL-6 therapy, is the only FDA-approved treatment for iMCD; 34% of patients achieved durable symptomatic and tumor response in the phase II trial. Tocilizumab, an anti-IL-6 receptor therapy, is frequently used off label and demonstrated promising results in an open-label study in Japan. The treatment guidelines recommend siltuximab ± corticosteroids (CS) as first-line therapy for all iMCD patients and tocilizumab as a substitute when siltuximab is not available. Rituximab, a CD20 antibody, is recommended as an alternate first-line therapy in patients who are non-severe and do not exhibit marked cytokine-driven symptoms. In all other patients, rituximab is recommended second-line; however, it has never been systematically evaluated in iMCD. Chemotherapies, immunosuppressants, and immunomodulators are recommended second- or third-line, but again, effectiveness is not well described. Better understanding of treatment effectiveness is urgently needed. Herein, we describe treatment and response in a real-world cohort of iMCD patients. Methods Data were collected and abstracted for 68 patients enrolled in an on-going IRB-approved natural history study of Castleman disease. Diagnosis is graded by an expert panel of clinicians and pathologists on an on-going basis; patients unlikely to have iMCD were excluded from analysis (N=12). Of the 56 patients included, 37 (66%) are expert panel-confirmed and 19 (34%) are awaiting confirmation. Durable response is defined as achieving ≥50% improvement in the proportion of abnormal iMCD minor clinical and laboratory diagnostic criteria sustained for ≥1 year. Small sample size prevented statistical comparisons. Results Median age at diagnosis is 33 years (range: 1-65 years). The cohort is 52.9% female, 63% white, and 4 (7%) patients died. Thirty-three unique drugs, including anti-IL-6 therapies, CS, chemotherapies, immunosuppressants, and others have been administered across the 56 patients. Rituximab is the most frequently used drug, administered to 39 (70%) patients. Siltuximab (29 patients, 52%) and tocilizumab (19 patients, 34%) are the next two most frequently used targeted therapies. There was a 52% response (15/29) to regimens inclusive of siltuximab, 50% response (9/18) to those inclusive of tocilizumab, and 25% response (9/26) to those inclusive of rituximab. Siltuximab±CS induced response in 15/24 (63%) patients, tocilizumab±CS in 4/7 (57%), and rituximab±CS in 2/13 (15%). Among the 37 expert-confirmed iMCD patients, we found a 58% response (11/19) to regimens inclusive of siltuximab, 47% (8/17) to those inclusive of tocilizumab, and 27% (7/26) to those inclusive of rituximab. Further, in these patients, siltuximab±CS induced response in 11/16 (69%), tocilizumab±CS in 3/6 (50%), and rituximab±CS in 1/6 (17%) patients. Of note, 3 of 4 deceased patients received both anti-IL-6 therapy and rituximab and all 4 received chemotherapies and immunosuppressants but did not respond to any drug. Discussion These data reveal that despite there being one FDA-approved treatment, iMCD is treated with a variety of agents. Among the full cohort, siltuximab±CS demonstrated a 63% durable response, which was higher than the response reported in the clinical trial (not statistically compared). This may reflect differences in response criteria and/or disease activity of patients in clinical trials versus real world settings. Siltuximab and tocilizumab have never been systematically compared; in this cohort they demonstrated similar response. Considering the morbidity and mortality of iMCD, these data suggest that current therapies demonstrate important activity. However, additional agents are needed for refractory patients, who have few options and are at risk of death due to disease progression. Further data are needed to compare groups and identify optimal treatment protocols. Disclosures Liu: BridgeBio Pharma: Employment, Equity Ownership. Gibson:EUSA Pharma: Employment. Kanhai:EUSA Pharma: Employment. Martin:EUSA Pharma: Employment. Srkalovic:Takeda: Speakers Bureau; Janssen: Speakers Bureau; Foundation Medicine: Speakers Bureau; EUSA Pharma: Speakers Bureau. Uldrick:Patent: Patents & Royalties: co-inventor on US Patent 10,001,483 entitled ; Celgene: Other: research support from Celgene through a CRADA at the NCI; Roche: Other: commercial research support through a CTA with Fred Hutchinson Cancer Research Center; Merck: Other: drug for a clinical trial from Merck through a CRADA with the NCI. van Rhee:Takeda: Consultancy; Sanofi Genzyme: Consultancy; Karyopharm Therapeutics: Consultancy; EUSA: Consultancy; Adicet Bio: Consultancy; Kite Pharma: Consultancy; Castleman Disease Collaborative Network: Consultancy. Fajgenbaum:Janssen Pharmaceuticals: Research Funding. OffLabel Disclosure: Tocilizumab, a monoclonal antibody directed against IL-6-receptor, is approved for use in rheumatoid arthritis in the US. It is frequently used off-label in idiopathic multicentric Castleman disease (iMCD) and is recommended as a substitute first-line therapy in the International Consensus iMCD treatment guidelines. Rituximab, a monoclonal antibody directed against CD20, is used in rheumatoid arthritis and other autoimmune and cancerous disorders. It is frequently used off-label in iMCD and is recommended as an alternate first-line or a second-line therapy in the International Consensus iMCD treatment guidelines. Corticosteroids are used broadly in iMCD and are recommended as needed as useful adjunctive therapy in the International Consensus iMCD treatment guidelines.

8548 Background: Castleman disease (CD) describes a group of lymphoproliferative disorders that share characteristic histopathology. Unicentric CD (UCD) and idiopathic multicentric CD (iMCD) are differentiated by the number of enlarged lymph node (LN) regions: UCD involves 1 region and iMCD involves > 1 region. UCD typically has mild or no symptoms whereas iMCD requires abnormal labs and symptoms for diagnosis and can progress to life-threatening multi-organ failure. Review of an international natural history registry of CD revealed patients across a broad spectrum with regards to number of enlarged LN regions and disease severity. We hypothesize that there is a positive correlation between disease activity and the number of enlarged LNs and that the spectrum of CD is more complex than a binary UCD-iMCD dichotomy. Methods: Herein, enrolled UCD and iMCD patients whose diagnosis was confirmed by an expert-panel were selected for analysis (N = 81). A standardized disease activity score (scale 0-1) was computed for each patient using available diagnostic values of C-reactive protein, hemoglobin, and albumin (CHA score). Results: We looked at the association between number of enlarged LNs and CHA and found a significant positive correlation (R = 0.65, p < 0.0001). Given this, we divided the cohort into groups of mild, moderate, and extensive lymphadenopathy according to the number of regions of enlarged LNs at the time of diagnosis: group 1 (1 enlarged LN region); group 2 (2-4 enlarged LN regions); and group 3 (≥5 enlarged LN regions). We identified 20 patients in group 1, 19 in group 2, and 42 in group 3 with no statistical differences in sex, race, or age at diagnosis. Histopathological subtype differed significantly among groups. Group 1 was 89% hyaline vascular (HV)/ hypervascular (HpV) and 11% mixed (Mx); group 2 was 74% HV/HpV, 21% Mx, and 5% plasmacytic (Pl); and group 3 was 64% HV/HpV, 32% Mx, and 5% Pl. We then looked at CHA score in these groups and found that group 3 patients have a significantly greater CHA score (median [IQR]: 0.46 [0.49]) than both group 2 (0.08 [0.14]) and group 1 (0.0 [0.10]) (adjusted p < 0.001 for both) while there was no difference between groups 1 and 2. Conclusions: These results suggest that disease severity is positively associated with the number of enlarged LNs. The different proportions of histopathological subtypes between the three groups could indicate different pathologic mechanisms are involved. Further work is needed to determine if patients with a few enlarged LNs exhibit disease more closely to UCD or iMCD and to understand long-term outcomes for these patients.

The emergence of SARS-CoV-2/2019 novel coronavirus (COVID19) has created a global pandemic with no approved treatments or vaccines. Many treatments have already been administered to COVID19 patients but have not been systematically evaluated. We performed a systematic literature review to identify all treatments reported to be administered to COVID19 patients and assess time to clinically meaningful response for treatments with sufficient data. We searched PubMed, BioRxiv, MedRxiv, and ChinaXiv for articles reporting treatments for COVID19 patients published between 12/1/2019-3/27/2020. Data were analyzed descriptively. Of the 2,706 articles identified, 155 studies met inclusion criteria, comprising 9,152 patients from 14 different countries. The cohort was 45.4% female and 98.3% hospitalized and mean (SD) age was 44.4 years (SD 21.0). The most frequently administered drug classes were antivirals, antibiotics, and corticosteroids, and of the 115 reported drugs, the most frequently administered was combination lopinavir/ritonavir, which was associated with a time to clinically-meaningful response (complete symptom resolution or hospital discharge) of 11.7 (1.09) days. There was insufficient data to compare across treatments. A large number of treatments have been administered to the first 9,152 reported cases of COVID19. These data serve as the basis for an open-source registry of all reported treatments given to COVID19 patients. Further work is needed to prioritize drugs for investigation in well-controlled clinical trials and treatment protocols.