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Coronavirus in the crosshairs, Part 4: Antibody therapeutics

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The Antibody Society’s series “Coronavirus in the crosshairs” examines the ongoing discovery and development of COVID-19 interventions for broad use, including small molecule and biologic drugs, and vaccines. Parts 1 and 2 examined re-purposed small molecule and biologic drugs and new vaccines, respectively, while Part 3 focused on COVID-19 convalescent plasma treatments in development. The specific content of the posts is prioritized based on when the interventions might be available to either patients or healthy people, including health care workers. Re-purposed small molecule and biologic drugs are likely to be available first, followed by new vaccines and drugs.

In Part 4 of the series, we provide additional details about re-purposed biologics, such as monoclonal antibodies (mAbs) that are marketed or in clinical studies for other indications, that might ameliorate COVID-19 symptoms and that are already in clinicals studies of COVID-19 patients. We also discuss anti-SARS-CoV-2 antibodies that are in preclinical development and may enter clinical study by the end of 2020.

As mentioned in Part 3, there is no current evidence from randomized controlled trials to recommend any specific anti-SARS-CoV-2 treatment for patients with suspected or confirmed SARS-CoV-2 infection. Therefore, clinical studies must be done to determine the safety and efficacy of the agents when administered to COVID-19 patients.

Re-purposed mAbs in clinical studies

To date, nearly 100 mAb therapeutics are approved and currently marketed in at least one country. A number of these products have mechanisms of action that are relevant to COVID-19, although they are not anti- SARS-CoV-2 agents. Zhou et al. have shown that SARS-CoV-2 infection leads to activation of CD4+ T lymphocytes, which become pathogenic T helper (Th) 1 cells and generate cytokines such as Granulocyte-macrophage colony-stimulating factor, GM-CSF. This environment induces CD14+CD16+ monocytes with high expression of IL-6, which accelerates inflammation. Moreover, Chen et al. reported that IL-6 levels were significantly elevated in critically ill COVID-19 patients, and the extremely high IL-6 level was closely correlated with the incidence of RNAemia. Taken together, these results suggest that mAbs targeting interleukin 6 receptor (IL-6R), IL-6 or GM-CSF, may potentially limit SARS-CoV-2-related immunopathology, and thereby provide more time for anti-viral agents to work.

Anti-IL-6R mAbs tocilizumab (Actemra®) and sarilumab (Kevara®).

Tocilizumab was first approved in Japan in 2005, and it is currently marketed for rheumatoid arthritis in adults, juvenile rheumatoid arthritis, as well as treatment of chimeric antigen receptor T cell-induced severe or life-threatening cytokine release syndrome (CRS) in patients two years of age and older. Since severe or life-threatening cytokine release is part of the pathology of COVID-19, tocilizumab may help ameliorate symptoms of the disease. As listed on clinicaltrials.gov on March 27, 2020, 3 clinical studies of tocilizumab are recruiting COVID-19 patients and 2 additional studies are not yet recruiting patients:

  • Started on February 20, 2020, NCT04306705 is a retrospective study evaluating safety and efficacy of tocilizumab compared to continuous renal replacement therapy in controlling CRS triggered by COVID-19. The study site is Tongji Hospital, Wuhan, Hubei, China. The estimated enrollment is 120 patients and the estimated primary completion date is May 30, 2020.
  • Started on March 8, 2020, NCT04310228 is multicenter, randomized and controlled clinical trial evaluating favipiravir combined with tocilizumab in the treatment of COVID-19. The study sites are in China. The estimated enrollment is 150 patients and the estimated primary completion date is in May 2020.
  • Started on March 19, 2020, NCT04317092 is a Phase 2 study of tocilizumab in COVID-19 pneumonia. The study sites are in Italy. The estimated enrollment is 330 patients and the estimated primary completion date is in December 2020.
  • Due to start in March, NCT04315480 is a Phase 2 study of tocilizumab (RoActemra) as early treatment of patients affected by SARS-CoV2 infection with severe multifocal interstitial pneumonia. Patients will receive a single intravenous administration of 8 mg/kg tocilizumab. The study site is in Italy. The estimated enrollment is 30 patients and the estimated primary completion date is April 2020.
  • Due to start on April 3, 2020, NCT04320615 is a Phase 3 study randomized, double-blind, placebo-controlled, multicenter study to evaluate the safety and efficacy of tocilizumab in patients with severe COVID-19 pneumonia. The study sites are not yet listed. The estimated enrollment is 330 patients and the estimated primary completion date is August 31, 2021.

Sarilumab was first approved in the US in 2017, and it is currently marketed for rheumatoid arthritis in adults. As of March 27, 2020, one clinical trial of sarilumab in COVID-19 that is recruiting patients is listed on clinicaltrials.gov and 2 studies are listed as not yet recruiting:

  • Started on March 16, 2020, the Phase 2/3 NCT04315298 study is evaluating the efficacy and safety of sarilumab in hospitalized patients with COVID-19. The study site is in New York City. The estimated enrollment is 400 patients and the estimated primary completion date is March 2021.
  • Due to start in March 2020, the NCT04321993 Phase 2 study will evaluate sarilumab or small molecules as treatment of moderate to severe COVID-19 in hospitalized patients. The study includes 4 arms: 1) Lopinavir/ritonavir; 2) Hydroxychloroquine sulfate; 3) Baricitinib; and 4) Sarilumab (200 mg subcutaneous injection once). The study sites are not yet listed; the study sponsors are based in Canada. The estimated enrollment is 1000 patients and the estimated primary completion date is February 2021.
  • Due to start March 26, 2020, the Phase 2/3 NCT04324073 study will assess an intravenous dose of 400 mg of sarilumab in a 1 hour-infusion vs the best standard of care. The study site is in Paris, France. The estimated enrollment is 180 patients and the estimated primary completion date is March 2021.

In addition, tocilizumab and sarilumab will be tested head-to-head in a Phase 2 study in COVID-19 patients that is not yet recruiting.

  • Due to start on March 25, 2020, NCT04322773 is a an open-label, multicenter sequential and cluster randomized Phase 2 study of the effectiveness of interleukin-6 receptor inhibitors in the management of patients with severe SARS-CoV-2 pneumonia. The study has 3 arms: 1) single dose treatment with tocilizumab 400 mg intravenously; 2) single dose treatment with tocilizumab 2 x 162 mg subcutaneously; and 3) single dose treatment with sarilumab 1 x 200 mg subcutaneously. The study site is in Copenhagen, Denmark. The estimated enrollment is 200 patients and the estimated primary completion date is June 1, 2021.

Anti-IL-6 siltuximab (SYLVANT®)

Siltuximab was first approved in the US in 2014, and it is currently marketed for treatment of patients with multicentric Castleman’s disease. As of March 27, 2020, one clinical trial of siltuximab in COVID-19 is listed on clinicaltrials.gov:

Started on March 19, 2020, NCT04322188 is an observational case-control study of the use of siltuximab in patients diagnosed with COVID-19 infection who have developed serious respiratory complications. Patients in Cohort A and Cohort B are treated with siltuximab in a non-ICU and ICU setting, respectively. Each patient will have a matched control receiving standard treatment without siltuximab. The study site is in Italy. The estimated enrollment is 50 patients and the estimated primary completion date is May 19, 2020.

Anti-GM-CSF mAbs

No anti-GM-CSF mAbs have been approved, but 7 investigational mAbs with potentially relevant mechanisms of action are in clinical studies. Five target GM-CSF (TJ003234, Gimsilumab, Lenzilumab, Otilimab and Namilumab), 1 targets the GM-CSF receptor (Mavrilimumab) and 1 targets beta common receptor for GM-CSF, IL-3, IL-5 (CSL311). To date, companies developing TJ003234, Gimsilumab, and Lenzilumab have indicated that they plan on starting clinical studies of COVID-19 patients.

  • On March 13, 2020, I-Mab Biopharma announced that it is initiating the development of TJM2 (TJ003234) to treat cytokine storm associated with severe and critical illness caused by COVID-19. Discovered by I-Mab, TJM2’s development will start following the FDA’s acceptance of I-Mab’s Investigational New Drug application. Study sites will initially be in the US, with possible expansion into other hardest-hit countries. TJM2 was previously evaluated in a Phase 1 study of healthy adults.
  • On March 18, 2020, Roivant Sciences announced that it has engaged with regulators in the United States, Europe, and Asia to rapidly advance the clinical development of gimsilumab for the treatment of acute respiratory distress syndrome associated with SARS-CoV-2 infection. Gimsilumab has been tested two clinical studies, including a 4-week Phase 1 study of a subcutaneous formulation in healthy volunteers.
  • On March 27, 2020, Humanigen, Inc., announced that the company has submitted an initial protocol synopsis to the FDA in support of the company’s plans to initiate a multi-center, US, Phase 3 study in COVID-19 patients. Humanigen has already conducted two Phase 1 and two Phase 2 studies, including in patients with severe respiratory conditions.

Novel anti-SARS-CoV-2 antibodies in preclinical development

Numerous organizations and groups have announced plans or progress in developing anti-SARS-CoV-2 antibody therapeutics. The race will go to the swift, in this case organizations that are:

  • Already experienced in anti-infective antibody discovery;
  • Adept at antibody design, engineering and selection;
  • Able to manufacture antibodies; and
  • Experienced in regulatory affairs.

If any of these elements are missing, then the organization must be able to quickly contract the work or engage a collaborator or partner with the missing expertise.

It must be noted, however, that a single product is unlikely to meet the currently very substantial medical need, and not all product candidates will be successful in clinical studies. Therefore, many initiatives aimed at developing investigational antibodies are needed.

The development of anti-SARS-CoV-2 antibody therapeutics involves the following major steps:

  • Initiation of the discovery process using, e.g., transgenic mouse, display technology or human B cell from COVID-19 patient;
  • Identification and characterization of suitable antibodies via in vitro methods;
  • Non-clinical assessment via in vivo methods;
  • Manufacturing of material suitable for administration to humans;
  • Demonstration of safety and efficacy in humans.

Due to the severity of the pandemic, the pace of the process, which typically is quite slow, has been substantially accelerated.

As of March 27, 2020, early progress on multiple anti-SARS-CoV-2 antibody discovery programs had already been announced. For example:

  • Shanghai Junshi Biosciences Ltd. and the Institute of Microbiology of the Chinese Academy of Sciences are developing neutralizing antibodies derived from patients who recovered from COVID-19 as a potential treatment for COVID-19. The program will progress to clinical trials soon. According to a March 24, 2020 announcement, they have obtained neutralizing antibodies that can effectively block viral invasion in laboratory assays, conducted animal experiments, and are now verifying the preclinical toxicology and in vivo activity of the antibodies. An investigational new drug application, needed to initiate clinical studies, is in preparation.
  • Mabpharm Limited has generated a mAb-based fusion protein (CMAB020, STI-4920, ACE-MAB) that binds to the spike protein of the SARS-CoV-2 virus. Designed as a bispecific molecule, ACE-MAB has two functional arms: 1) a human antibody that targets the spike protein of SARS-CoV-2 with high affinity and 2) a truncated ACE2 protein that binds to a different epitope of the spike protein. ACE-MAB is in the cGMP cell line development stage by Mabpharm Limited, and could be ready for large-scale production for human clinical trials and commercialization upon receipt of requisite regulatory approvals. Mabpharma and Sorrento Therapeutics, Inc. have partnered in the development of ACE-MAB.
  • Vir Biotechnology, Inc., working with partners Xencor, Biogen and WuXi, has identified multiple human monoclonal antibody (mAb) development candidates that neutralize SARS-CoV-2. Two candidates will progress into human testing as soon as possible, with Phase 1/2 clinical testing planned for summer 2020.
  • Regeneron Pharmaceuticals has isolated virus-neutralizing, human antibodies from transgenic VelocImmune® mice, and antibodies from COVID-19 patients. From this large pool of candidates, Regeneron will select the top two antibodies for a ‘cocktail’ treatment based on potency and binding ability to the SARS-CoV-2 spike protein, as well as other desirable qualities. Regeneron aims to have an anti-SARS-CoV-2 antibody treatment ready for human testing by early summer.
  • James Crowe, MD, director of the Vanderbilt Vaccine Center announced that Vanderbilt University Medical Center, in collaboration with academic, governmental and corporate partners already have discovered SARS-CoV-2 antibodies. The collaborators aim to have antibodies for human clinical trials by summer 2020.
  • Distributed Bio has identified thousands of anti-SARS-CoV-19 antibodies, and their scientists are currently working on  engineering, selection, screening and production of candidates.
  • AbCellera has identified over 500 unique human antibody sequences derived from the immune cells of COVID-19 patients. AbCellera and Eli Lilly and Company have partnered to co-develop antibody products for the treatment and prevention of COVID-19.
  • Celltrion has identified a library of antibodies sourced from the blood of recovered COVID-19 patients in Korea. These antibodies are undergoing further screening to identify those that are most effective in neutralizing SARS-CoV-2. Selected candidates will form the basis of anti-viral treatment to be tested in preclinical and clinical trials in the third quarter of 2020. Celltrion also plans to develop a ‘super antibody’ that can attach and neutralize all kinds of coronavirus-related strains, enabling further protection against unforeseen or unexpected mutations.
  • Utrecht University, Erasmus Medical Center and Harbor BioMed have developed a human antibody, 47D11, that targets the a conserved epitope on the viral spike receptor binding domain and can inhibit SARS-CoV-2. Data show that 47D11 neutralizes SARS-CoV and SARS-CoV-2 through a yet unknown mechanism that is different from receptor binding interference.
  • The lab of Xavier Saelens (VIB-UGent Center for Medical Biotechnology), in cooperation with the labs of Jason McLellan (University of Texas at Austin, US) and Markus Hoffmann and Stefan Pöhlmann (German Primate Center – Leibniz Institute for Primate Research, Göttingen, Germany) have discovered a unique antibody that is capable of binding SARS-CoV-2 and neutralizing a lab variant of the virus.

Other groups are also working on discovery initiatives. For example, the international research association Antibody Therapy Against Corona Virus, which includes the Technical University Braunschweig and colleagues from Sweden, Belgium, Italy and Switzerland, is developing antibody-based therapies that target SARS-CoV-2. Details about additional biopharmaceutical product candidates in development for COVID-19 may be found here.

The Antibody Society will continue to monitor anti-SARS-CoV-2 antibody development, and report on progress with these and other COVID-19 interventions in the next installment of “Conronavirus in the crosshairs”.

Photo by Fusion Medical Animation on Unsplash

Coronavirus in the crosshairs, Part 3: Antibodies from human plasma

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Antibodies have extraordinary potential as agents for the treatment of COVID-19 or possible prevention of infection by SARS-CoV-2, the coronavirus that causes the disease. Anti-SARS-CoV-2 antibodies can neutralize the virus, and antibodies that target inflammatory factors such as cytokines can ameliorate symptoms of COVID-19.

The Antibody Society’s series “Coronavirus in the crosshairs” examines the discovery and development of all types of interventions for COVID-19.  In Part 3 of the series, we focus on the use of natural antibodies, i.e., anti-SARS-CoV-2 polyclonal antibodies found in convalescent plasma, in treating COVID-19. In the current emergency when time is of the essence, medical professionals are applying the century-old knowledge that antibody-rich plasma derived from blood donated by people who have recovered from a disease may aid other patients. The efficacy of convalescent plasma was studied in outbreaks of other respiratory infections, including the 2009-2010 H1N1 influenza virus pandemic, 2003 SARS-CoV-1 epidemic, and the 2012 MERS-CoV epidemic. [1, and references therein]

There is, however, no current evidence from randomized controlled trials to recommend any specific anti-SARS-CoV-2 treatment for patients with suspected or confirmed SARS-CoV-2 infection.[2] Anti-SARS-CoV-2 blood products are thus considered investigational drugs that require clinical study and approval by regulatory agencies before they can be administered broadly to treat COVID-19 patients or potentially prevent disease in healthy people, such as health care workers.

FDA response to the need for COVID-19 convalescent plasma

To address the short-term need for treatments, the US Food and Drug Administration (FDA) is facilitating access to COVID-19 convalescent plasma for use in patients with serious or immediately life-threatening COVID-19 infections through emergency Investigational New Drug Applications that will enable administration to a single patient. Highly time sensitive requests will receive a response from FDA within 4 to 8 hours.[3]

In the longer-term, FDA is working with other agencies, such as the National Institutes of Health and the Centers for Disease Control and Prevention, to develop master protocols for use by multiple investigators in order to coordinate the collection and use of COVID-19 convalescent plasma.[3]

Ongoing clinical studies of convalescent plasma

Medical professionals in countries greatly affected by COVID-19, such as China and Italy, are evaluating plasma-based treatments for COVID-19. Clinicaltrials.gov lists several clinical studies evaluating the use of convalescent plasma:

  • NCT04292340. In this observational study recruiting patients at the Shanghai Public Health Clinical Center, the investigators collected the clinical information and clinical outcomes of the COVID-19 patients using anti-2019-nCoV inactivated convalescent plasma. The study objective is to evaluate the efficacy and safety of anti-2019-nCoV inactivated convalescent plasma in the treatment of COVID-19 pneumonia. Primary outcome measures are the virological clearance rate of throat swabs, sputum, or lower respiratory tract secretions at day 1, 3 and 7, and the patient outcome at 4 weeks. The actual study start date is February 1, 2020 and the estimated primary completion date is July 31, 2020.
  • NCT04321421. In this study being conducted in Italy, 49 participants are administered plasma from donors recovered from COVID-19 as therapy at day 1 and, based on clinical response, on day 3 and 5., The dose, 250-300 mL of convalescent plasma, was selected based on published literature for this type of therapy. The primary outcome measure is death from any cause within 7 days. The actual study start date is March 17, 2020 and the estimated primary completion date is May 31, 2020.

Similar trials are listed on the Chinese clinical trials registry, e.g.,

  • ChiCTR2000030841, Exploratory study for immunoglobulin from cured COVID-19 patients in the treatment of acute severe novel coronavirus (COVID-19); study registered March 15, 2020.
  • ChiCTR2000030929, A randomized, double-blind, parallel-controlled trial to evaluate the efficacy and safety of anti-SARS-CoV-2 virus inactivated plasma in the treatment of severe novel coronavirus pneumonia (COVID-19); study registered March 17, 2020.

New plasma-derived COVID-10 product candidates in development

On March 4, 2020, Takeda Pharmaceutical Company Limited announced that they are initiating development of an anti-SARS-CoV-2 polyclonal hyperimmune globulin (H-IG) to treat high-risk individuals with COVID-19. Referred to as TAK-888, Takeda plans initially to produce the plasma-derived anti-SARS-CoV-2 polyclonal H-IG in a segregated area within its manufacturing facility in Georgia.

On March 11, 2020, Emergent BioSolutions Inc. announced that it has initiated development of two product candidates for the treatment and prevention of coronavirus disease (COVID-19). COVID-HIG, manufactured from human plasma with antibodies to SARS-CoV-2, will be developed as a potential treatment for severe hospitalized patients as well as protection for at-risk individuals. In parallel, COVID-EIG, manufactured from plasma of immunized horses with antibodies to SARS-CoV-2, will be developed as a potential treatment for severe hospitalized patients. Emergent has initiated plasma collection efforts for both human and equine platforms with a goal of manufacturing clinical material within the next four to five months in anticipation of beginning a clinical study as early as the third quarter of 2020.

Upcoming “Coronavirus in the crosshairs” posts

In Part 4 of “Coronavirus in the crosshairs”, we will discuss recombinant antibodies that may ameliorate symptoms of COVID-19, and examine ongoing efforts to discover and develop recombinant anti-SARS-CoV-2 antibodies.

1. Chen et al. Convalescent plasma as a potential therapy for COVID-19. The Lancet. February 27, 2020. DOI:https://doi.org/10.1016/S1473-3099(20)30141-9
2. World Health Organization. Clinical management of severe acute respiratory infection when novel coronavirus (2019-nCoV) infection is suspected. Interim guidance. 28 January 2020.
3. US Food and Drug Administration. Investigational COVID-19 Convalescent Plasma – Emergency INDs. March 24, 2020.

Photo by Fusion Medical Animation on Unsplash

Coronavirus in the crosshairs, Part 2: Vaccines in development

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Biopharmaceutical companies, government agencies, academic institutions and non-profits located world-wide have mobilized in an unprecedented effort to develop interventions that are effective against SARS-CoV-2, the virus that causes COVID-19. This global pandemic, however, affects people of all ages and every health status. As a consequence, we need a wide array of medicines, as well as vaccines, to ensure the right intervention is given to the right person. And we need these interventions as quickly as possible.

In Part 1 of ‘Coronavirus in the crosshairs’, we focused on early clinical studies for small molecule drugs that were re-purposed, i.e., drugs that were already approved or in clinical studies for another disease, but were tested for efficacy in COVID-19 patients. In Part 2 of this series, we focus on vaccines currently in clinical study. Part 3 will focus on the use of anti-SARS-CoV-2 polyclonal antibodies found in convalescent plasma as a treatment for COVID-19, and Part 4 will examine efforts to quickly discover anti-SARS-CoV-2 antibody therapeutics.

Vaccines in preclinical and clinical development

The World Health Organization has compiled a list of SARS-CoV-2 vaccine initiatives that, as of March 20, 2020, included 42 vaccines in preclinical development and 2 vaccines in human Phase 1 studies, National Institutes of Health (NIH)/Moderna’s mRNA-1273 vaccine and CanSino Biological Inc./Beijing Institute of Biotechnology’s adenovirus Type 5 vector (Ad5-nCoV) vaccine.

In addition, the Regulatory Affairs Professionals Society is maintaining the Regulatory Focus COVID-19 Tracker, which is a resource for information on COVID-19 vaccine development that is updated weekly.

mRNA-1273 vaccine candidate

mRNA-1273 is a novel lipid nanoparticle-encapsulated mRNA-based vaccine that encodes for a full-length, prefusion stabilized spike protein of SARS-CoV-2. The  vaccine candidate has shown promise in animal models. Manufacturing of mRNA-1273 for the Phase 1 study (NCT04283461) was supported by the Coalition for Epidemic Preparedness Innovations. On March 16, 2020, NIH announced the study, which will assess the safety and immunogenicity of mRNA-1273,  had started. A total of 45 adults between the ages of 18 to 55 years will be enrolled, and the estimated primary completion date of the study is June 1, 2021. According to the protocol, however, the immunogenicity data will start being collected by mid-May 2020. Moderna announced on March 23, 2020 that, under emergency use, a vaccine could be available to some people, possibly including healthcare professionals, in the fall of 2020, although a commercially-available vaccine is not likely to be available for at least 12-18 months.

Enrollment will occur at the Kaiser Permanente Washington Health Research Institute. Forty-five healthy adults will be administered one of three doses (25 microgram [mcg], 100 mcg, 250 mcg). They will receive an intramuscular injection of mRNA-1273 on Days 1 and 29 in the deltoid muscle, and will be followed through 12 months post second vaccination (Day 394). The first four participants will receive one injection with the low dose, and the next four participants will receive the 100 mcg dose. Investigators will review safety data before vaccinating the remaining participants in the 25 and 100 mcg dose groups and before participants receive their second vaccinations. Another safety review will be done before participants are enrolled in the 250 mcg cohort. Follow-up visits will occur 1, 2 and 4 weeks post each vaccination, as well as 3, 6 and 12 months post second vaccination.

The primary objective is to evaluate the safety and reactogenicity and the secondary objective is to evaluate the immunogenicity as measured by IgG ELISA to the 2019-nCoV S protein following a 2-dose vaccination schedule of mRNA-1273 at Day 57.

Ad5-nCoV vaccine candidate

On March 17, 2020, CanSino Biologics Inc. announced that its recombinant novel coronavirus vaccine Ad5-nCoV, co-developed with Beijing Institute of Biotechnology, has been approved to enter into a Phase 1 clinical trial. The Phase 1 ChiCTR2000030906 study was listed as recruiting patients when its record was accessed March 23, 2020; NCT04313127 is assumed to be the same study.

The single-center, open and dose-escalation Phase 1 clinical trial will evaluate Ad5-nCoV in healthy adults aged between 18 and 60 years. Three doses will be evaluated, with a total of 108 patients (36 per study arm) receiving a low (5E10 vp Ad5-nCoV), medium (1E11 vp Ad5-nCoV) or high (1.5E11vp Ad5-nCoV) dose of vaccine. Various types of antibody responses will be measured at Day 14, 28, and months 3 and 6 post injection.

Other vaccine candidates

Clinical studies of two additional vaccine candidates, Covid-19 aAPC Vaccine and Covid-19 Synthetic Minigene Vaccine, are listed on clinicaltrials.gov as recruiting patients (NCT04299724 and NCT04276896, respectively), although the status of these initiatives could not be confirmed as of March 23, 2020. Both vaccine candidates are sponsored by Shenzhen Geno-Immune Medical Institute, Shenzhen Third People’s Hospital, and Shenzhen Second People’s Hospital.

Coronavirus image from: CDC/ Alissa Eckert, MS; Dan Higgins, MAMS

Coronavirus in the crosshairs, Part 1

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Coronaviruses (CoVs) are enveloped positive-sense single-stranded RNA viruses that can cause highly lethal respiratory disease in humans, such as Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS). The current coronavirus disease (COVID-19) pandemic is caused by the SARS-CoV-2 coronavirus. Infection in humans is initiated through exposure of the respiratory tract to the virus, which enters cells by binding angiotensin-converting enzyme 2 (ACE2) found on the cell surface.[1] Wrapp et al.[2] have shown that the SARS-CoV-2 spike protein binds to ACE2 with ~10- to 20-fold higher affinity than the spike protein of SARS–CoV, which is a coronavirus that caused an epidemic in 2002-2003.

An urgent and immediate need for knowledge about COVID-19 and for drugs to inhibit the virus and treat symptoms has existed since the disease started to spread in December 2019. To address this need, medical professionals have initiated numerous trials to identify key characteristics of the infections and the effects of investigational and approved drugs, including those used during the MERS and SARS outbreaks. As of March 19, 2020, clinicaltrials.gov already included ~115 studies related to COVID-19, with ~40 designed as observational studies or studies of diagnostics or devices, and ~75 designed to evaluate interventions such as antiviral drugs. Of the interventional studies, ~40 are currently recruiting patients, and the rest have not yet started recruiting. The earliest of these studies were started in China in late January 2020; additional studies may be listed on the Chinese clinical trials registry. Many studies are designed to produce results rapidly, which may greatly assist treatment of patients in the near future.

Effective in vitro inhibition of SARS-CoV-2 by remdesivir and chloroquine has been reported,[3] and numerous clinical studies are underway to determine the efficacy of these drugs as COVID-19 treatments.[4] Remdesivir (GS-5734, Gilead Sciences Inc) is an investigational monophosphoramidate prodrug of an adenosine analog with potent activity against an array of RNA virus families, including Filoviridae, Paramyxoviridae, Pneumoviridae, and Orthocoronavirinae, through the targeting of the viral RNA-dependent RNA polymerase. It was previously tested in humans with Ebola virus disease, and has demonstrated positive results in animal models of MERS.[5] Numerous clinical studies of the effects are remdesivir are ongoing, including:

  • NCT04257656, started February 6, 2020 in China, with estimated enrollment of 453 patients and a primary completion date of April 3, 2020.
  • NCT04252664, started February 12, 2020 in China, with estimated enrollment of 308 patients and a primary completion date of April 20, 2020.
  • NCT04280705, started February 21, 2020 in the US, South Kora and Singapore, with estimated enrollment of 394 patients and a primary completion date of April 1, 2020.[6]
  • NCT04292899, started March 6, 2020 in the US, South Kora and Singapore, with estimated enrollment of 400 patients and a primary completion date of May 2020.
  • NCT04292730, started on March 15, 2020 in the US, South Kora and Singapore, with estimated enrollment of 600 patients and a primary completion date of May 2020.

The U.S. Army Medical Research and Development Command is sponsoring a study of remdesivir (NCT04302766) with enrollment limited to DoD-affiliated personnel (including active and reserve component service members, US civilian employees, contractors, other US personnel, and dependents of any age, as well as allied military forces and local nationals) who have a COVID-19 diagnosis and have been granted access to the medical facility.

Hydroxychloroquine, which is FDA-approved as a treatment for malaria, lupus and rheumatoid arthritis, appears to interfere with terminal glycosylation of ACE2 and is known to elevate endosomal pH, which may inhibit virus binding and subsequent infection.[7] Preliminary evidence from a small study in humans suggests that the combination of azithromycin and hydroxychloroquine is significantly more efficient for virus elimination.[8] 

At least 3 clinical studies of the effects are hydroxychloroquine are ongoing:

  • NCT04261517, started February 6, 2020 in Shanghai, with estimated enrollment of 30 patients and a primary completion date of August 2020.
  • NCT04307693, started March 11, 2020 in Seoul, South Korea, with estimated enrollment of 150 patients and a primary completion date of May 2020.
  • NCT04308668, started March 2020 in Minneapolis, Minnesota, United States, with estimated enrollment of 1500 patients and a primary completion date of May 2021.

On March 18, 2020, the World Health Organization announced that they are planning a multi-arm clinical trial that will evaluate the following drugs as treatments for COVID-19:

  • Remdesivir;
  • Hydroxychloroquine or chloroquine;
  • Lopinavir-ritonavir (a combination of two HIV drugs marketed as Kaletra or Aluvia); and
  • Lopinavir-ritonavir plus interferon beta.

Argentina, Bahrain, Canada, France, Iran, Norway, South Africa, Spain, Switzerland, and Thailand have offered study sites, and sites in other countries may be added in the future. The study, called SOLIDARITY, will use an adaptive design, which allows study arms to be modified, added or eliminated based on the results of ongoing data collection.[9] The lopinavir-ritonavir arms are included in the SOLIDARITY study despite the negative results of a clinical study of 199 hospitalized adult patients with severe COVID-19 in China, which showed no benefit from adding lopinavir–ritonavir treatment to standard care.[10] Further study is needed to understand whether factors such as the drug dose or patient characteristics (age, severity of disease, underlying medical conditions) affected the possibility of a treatment benefit.

In addition, positive results have been reported for the antiviral agent favipiravir (Avigan), which was evaluated in COVID-19 patients in clinical trials conducted in Wuhan and Shenzhen, China. Favipiravir was approved in 2014 in Japan for treatment of influenza, although use is limited because the drug may cause fetal deaths or deformities. Additional studies in COVID-19 are needed, however, results reported by Japanese health officials suggest the drug is less effective in patients with more severe symptoms.[11]

Other antiviral treatments are currently being evaluated, including anti-SARS-CoV-2 inactivated convalescent plasma (NCT04292340), as are therapies that can ameliorate symptoms of the disease, including anti-IL-6 sarilumab (NCT04315298) and anti-IL-6 receptor tocilizumab (NCT04306705, NCT04310228), which may reduce lung inflammation and improve lung function in COVID-19 patients.

Scientists are searching for new treatments and vaccines, which will be discussed in our upcoming posts.

1. Walls et al. Structure, Function, and Antigenicity of the SARS-CoV-2 Spike Glycoprotein. Cell. March 09, 2020. DOI:https://doi.org/10.1016/j.cell.2020.02.058
2. Wrapp et al. Cryo-EM structure of the 2019-nCoV spike in the prefusion conformation. Science 2020, 367, 1260-1263.
3. Wang et al. Remdesivir and chloroquine effectively inhibit the recently emerged novel coronavirus (2019-nCoV) in vitro. Cell Research 2020, 30, 269–271.
4. Food and Drug Administration, March 19, 2020. Coronavirus (COVID-19) Update: FDA Continues to Facilitate Development of Treatments.
5. National Institutes of Health, February 13, 2020. Remdesivir Prevents MERS Coronavirus Disease in Monkeys.
6. National Institutes of Health, February 25, 2020. NIH clinical trial of remdesivir to treat COVID-19 begins.
7. Vincent et al. Chloroquine is a potent inhibitor of SARS coronavirus infection and spread. Virology Journal 2005, 2, 69.
8. Gautret et al. (2020) Hydroxychloroquine and azithromycin as a treatment of COVID‐19: results of an open‐label non‐randomized clinical trial. International Journal of  Antimicrobial Agents – In Press 17 March 2020 – DOI : 10.1016/j.ijantimicag.2020.105949
9. WHO Director-General’s opening remarks at the media briefing on COVID-19 – 18 March 2020.
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Coronavirus image from: CDC/ Alissa Eckert, MS; Dan Higgins, MAMS

FDA issues guidance on conducting clinical trials during the COVID-19 pandemic

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In these challenging times, the biopharmaceutical industry, government agencies, as well as academic and non-profit organizations, are working toward the development of antibody therapeutics and vaccines for the treatment and prevention of infection by SARS-CoV-2, the virus that causes COVID-19. The Antibody Society is currently compiling information on these efforts, which will soon be posted on our website and distributed via email to our members. Many existing antiviral treatments are also being re-purposed in the fight against the virus.

The Society is an authoritative source of information on antibody therapeutics in the clinical pipeline. The COVID-19 pandemic, however, may delay ongoing clinical studies that are evaluating the safety and efficacy of therapeutics for other diseases. In a March 18, 2020 press release, the U.S. Food and Drug Administration (FDA) notes that challenges may arise from quarantines, site closures, travel limitations, interruptions to the supply chain for the investigational product, or other considerations if site personnel or trial subjects become infected with SARS-CoV-2. These challenges may lead to difficulties in conducting the clinical trials. Protocol modifications may be required, and there may be unavoidable protocol deviations due to COVID-19.

Information about FDA’s guidance for industry, investigators and institutional review boards conducting clinical trials during the coronavirus (COVID-19) pandemic can be found here.

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