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Anti-SARS-CoV-2 REGN-COV2 enters clinical study

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On June 11, 2020, Regeneron Pharmaceuticals, Inc. announced the start of the first clinical trial of REGN-COV2 for the prevention and treatment of COVID-19. REGN-COV2 is a cocktail of the human antibodies REGN10933 and REGN10987, which were derived from Regeneron’s parallel efforts using both humanized VelocImmune® mice and blood samples from recovered COVID-19 patients to generate a large and diverse collection of antibodies targeting multiple different regions of the receptor-binding domain of the SARS-CoV-2 spike protein. Two papers describing the creation of REGN-COV2 and its anti-viral activity have been accepted for publication in Science.

The REGN-COV2 clinical program will consist of four separate study populations: hospitalized COVID-19 patients, non-hospitalized symptomatic COVID-19 patients, uninfected people in groups that are at high-risk of exposure and uninfected people with close exposure to a COVID-19 patient. The placebo-controlled trials will be conducted at multiple sites. The first two adaptive Phase 1/2/3 studies are evaluating REGN-COV2 as a treatment for hospitalized and non-hospitalized patients with COVID-19. The Phase 1 portion will focus on virologic and safety endpoints, and the Phase 2 portion will focus on virologic and clinical endpoints. Data from the Phase 1 and Phase 2 studies will be used to refine the endpoints and determine size for the Phase 3 studies.

REGN-COV2 is the 3rd anti-SARS-CoV-2 antibody-based drug to enter clinical study in the past 2 weeks. On June 1, 2020, Eli Lilly and Company announced LY-CoV555 had entered clinical study, and on June 7. 2020, Junshi Biosciences announced JS016 had entered clinical study.

Anti-SARS-CoV-2 antibody JS016 enters first clinical study

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On June 7, 2020, Junshi Biosciences announced that a Phase 1 clinical study of JS016 in healthy volunteers had started in China. JS016 is a human monoclonal antibody that targets the SARS-CoV-2 spike protein and blocks binding of the virus to host cells. The antibody was identified by screening B cells from convalescent COVID-19 patients, and engineered to introduce LALA mutations to silence the Fc portion. JS016 was shown to provide protection from SARS-CoV-2 infection when administered to rhesus monkeys (Shi et al. Nature 2020).

The clinical study will evaluate the tolerability, safety, pharmacokinetics and immunogenicity of JS016 in healthy volunteers. If the Phase 1 study shows the antibody can be administered safely, Junshi Biosciences intends to start another clinical study in that will assess JS016’s ability to prevent and treat COVID-19.

Junshi and Eli Lilly and Company are collaborating to co-develop JS016, with Junshi leading clinical development in China and Lilly leading clinical development in the rest of the world. The antibody was jointly developed by Junshi Biosciences and the Institute of Microbiology, Chinese Academy of Sciences.

Coronavirus in the crosshairs, Part 8: FDA’s Emergency Use Authorization of Therapeutics

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During public health emergencies, the U.S. Food and Drug Administration (FDA) can allow use of unapproved medical products or unapproved uses of approved medical products to diagnose, treat, or prevent serious or life-threatening diseases or conditions caused by threat agents, such as SARS-CoV-2, when there are no adequate, approved, and available alternatives. On March 27, 2020, the Secretary of the Department of Health and Human Services declared that circumstances exist justifying the authorization of emergency use of drugs and biologics during the COVID-19 outbreak, which gave FDA the authority to issue Emergency Use Authorizations (EUA).

It is important to note that FDA’s allowance of an emergency investigational new drug application or compassionate use of a COVID-19 intervention is not equivalent to FDA issuing an EUA, and EUA issuance is not equivalent to FDA approval.

Letters of authorization issued for therapeutics

To date (May 12, 2020), although over 90 EUAs have been issued for diagnostic tests of various types, only 3 EUAs have been issued for therapeutics:

  • Fresenius Propoven 2% emulsion to maintain sedation via continuous infusion in patients greater than 16 years old who require mechanical ventilation in an Intensive Care Unit setting during the COVID-19 pandemic. The EUA was issued to Fresenius Kabi USA, LLC on May 8, 2020.
  • Remdesivir to treat adults and children with suspected or laboratory confirmed COVID-19 and severe disease defined as SpO2 ≤ 94% on room air, requiring supplemental oxygen, mechanical ventilation, or extracorporeal membrane oxygenation. The EUA was issued to Gilead Sciences, Inc. on May 1, 2020.
  • Chloroquine phosphate and hydroxychloroquine sulfate supplied from the Strategic National Stockpile for treatment of COVID-19. The EUA was issued to the Biomedical Advanced Research and Development Authority on March 28, 2020.

Limitations to the scope and duration of the authorizations, as well as specific conditions that apply, are detailed in FDA’s letters of authorization.

Possible biologic candidates for EUAs in 2020

Infection with SARS-CoV-2 leads to multiple pathologies, including inflammation, respiratory distress and abnormal coagulation.  Existing biological therapies that might ameliorate symptoms, such as monoclonal antibodies (mAbs) that target inflammatory cytokines and proteins involved in clotting, have thus been re-purposed as possible COVID-19 interventions.

Although FDA has not yet issued an EUA for a biologic COVID-19 therapeutic, numerous candidates are in late-stage clinical studies that might yield results that warrant such an authorization in 2020. Of these, 5 (Sarilumab, Emapalumab, Tocilizumab, Siltuximab and Ravulizumab) are already approved as treatments for other diseases, and thus may be available for broad distribution if the sponsoring company chooses to pursue an EUA for COVID-19 and FDA issues the authorization. The logistics of large-scale manufacturing and broad distribution of other candidates may be challenging for the sponsoring companies.

Details of 10 possible biologic candidates for EUAs in 2020 are listed here in chronological order according to the estimated primary completion dates of the relevant studies:

July – August 2020

  • Sarilumab (Kevara®; Sanofi, Regeneron), a human IgG1 mAb targeting the interleukin-6 receptor (IL-6R), is approved for rheumatoid arthritis in adults. Sanofi and Regeneron are sponsoring an adaptive Phase 3, randomized, double-blind, placebo-controlled study assessing the efficacy and safety of sarilumab for hospitalized patients with COVID-19 (NCT04327388). The primary outcome measure of the study is time to improvement of 2 points in clinical status assessment from baseline to Day 29 using the 7-point ordinal scale, and the estimated primary completion date is July 2020.
  • Emapalumab (Gamifant®; Swedish Orphan Biovitrum) is a human IgG1 mAb targeting interferon gamma  approved for treatment of pediatric (newborn and older) and adult patients with primary hemophagocytic lymphohistiocytosis (HLH) with refractory, recurrent or progressive disease or intolerance to conventional HLH therapy. Sponsored by Swedish Orphan Biovitrum, NCT04324021 is a Phase 2/3, randomized, open-label, parallel group, 3-arm, multicenter study investigating the efficacy and safety of intravenous administrations of emapalumab and anakinra (IL-1R antagonist) versus standard of care in reducing hyper-inflammation and respiratory distress in patients with SARS-CoV-2 infection. The primary outcome measure is treatment success, defined as the proportion of patients not requiring invasive mechanical ventilation or extracorporeal membrane oxygenation, up to Day 15. The estimated primary completion date of this study is July 2020.
  • Tocilizumab (Actemra®; Hoffmann-LaRoche), a humanized IG1 mAb targeting IL-6R, is approved 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 in patients two years of age and older. Clinicaltrials.gov currently lists 42 studies of tocilizumab in COVID-19 patients, with 12 of these Phase 3 studies. Only one Phase 3 study sponsored by the drug’s co-developer, Hoffmann-LaRoche, is now recruiting patients. The NCT04320615 Phase 3 study is evaluating the safety and efficacy of tocilizumab in patients with severe COVID-19 pneumonia. The primary outcome measure is clinical status assessed using a 7-category ordinal scale, and the estimated primary completion date of this study is August 31, 2020.

September – October 2020

  • Lenzilumab (Humanigen, Inc.) is a Humaneered® mAb targeting granulocyte-macrophage colony-stimulating factor. Humanigen, Inc. is sponsoring the NCT04351152 Phase 3 randomized, placebo-controlled study of lenzilumab in hospitalized patients with COVID-19 pneumonia. The primary outcome measure is the incidence of invasive mechanical ventilation and/or mortality up to 28 days. the estimated primary completion date of this study is September 2020.
  • Siltuximab (SYLVANT®; EUSA Pharma, BeiGene, Ltd.) is an anti-Il-6 chimeric IgG1 mAb marketed for treatment of patients with multicentric Castleman’s disease. University Hospital, Ghent is sponsoring the NCT04330638 Phase 3 study  evaluating siltuximab, anakinra and tocilizumab in improving oxygenation and the short- and long-term outcome of COVID-19 patients with acute hypoxic respiratory failure and systemic cytokine release syndrome. The primary outcome measure is time to clinical improvement evaluated up to Day 15. The estimated primary completion date of this study is September 2020. Preliminary results of a compassionate-use program (SISCO study; NCT04322188) sponsored by the Papa Giovanni XXIII Hospital have been reported. EUSA Pharma has exclusive rights to SYLVANT® globally. EUSA Pharma has granted BeiGene, Ltd., exclusive development and commercialization rights to SYLVANT® in Greater China.
  • Olokizumab and RPH-104 (R-Pharm International, LLC, Cromos Pharma) are being evaluated in a Phase 2/3 study of COVID-19 patients. Olokizumab is a humanized anti-Il-6 mAb and RPH-104 is a fusion protein that selectively binds and inactivates IL-1ß. R-Pharm International is sponsoring the NCT04380519 international, multicenter, randomized, double-blind, adaptive placebo-controlled study of the efficacy and safety of a single administration of olokizumab and RPH-104 with standard therapy in patients with severe SARS-CoV-2 infection. The primary outcome measure is the proportion of patients that responded to the study therapy in each of the treatment groups at Day 15. The estimated primary completion date of this study is October 15, 2020.
  • IFX-1 (InflaRx GmbH) is an IgG4 mAb targeting complement 5a, which is a component of the complement system that can trigger inflammation. InflaRx GmbH is sponsoring a pragmatic adaptive open label, randomized Phase 2/3 multicenter study of IFX-1 in patients with severe COVID-19 pneumonia (NCT04333420). The primary outcome measure is the relative change (%) from baseline in Oxygenation Index (PaO2 / FiO2) to Day 5. The estimated primary completion date of this study is October 31, 2020.

November – December 2020

  • Ravulizumab (ULTOMIRIS®, Alexion Pharmaceuticals) is a humanized IgG2/4 mAb targeting C5 that is approved for treatment of adult patients with paroxysmal nocturnal hemoglobinuria. Due to start in May 2020, NCT04369469 is a Phase 3 open-label, randomized, controlled study to evaluate the efficacy and safety of intravenously administered ravulizumab compared with best supportive care in patients with COVID-19 severe pneumonia, acute lung injury, or acute respiratory distress syndrome. The primary outcome measure is survival based on all-cause mortality at Day 29, and the estimated primary completion date of this study is November 2020.
  • Leronlimab (CytoDyn, Inc.) is an anti-CCR5 IgG4 mAb undergoing evaluation in two Phase 2 studies of COVID-19 patients. The NCT04343651 study to evaluate the efficacy and safety of leronlimab for mild to moderate COVID-19 and the NCT04347239 study to evaluate the efficacy and safety of leronlimab for patients with severe or critical COVID-19 have estimated primary completion dates of December 4 and December 31, 2020, respectively. Based on results from 10 critical COVID-19 patients who received leronlimab, disrupting the CCL5-CCR5 axis leads to rapid reduction of plasma IL-6, restoration of the CD4/CD8 ratio, and a significant decrease in SARS-CoV-2 plasma viremia.

Biologic candidates targeting SARS-CoV-2

In addition to re-purposing existing biologics for use as treatments for the symptoms of COVID-19, the global biopharmaceutical industry, as well as government, academic and non-profit organizations, are developing therapies that target SARS-CoV-2. Of the biologic candidates that target the virus, the ones most likely to be considered for EUAs in 2020 are those composed of plasma from convalescent patients. SARS-CoV-2- neutralizing antibodies in the plasma are expected to protect patients, and potentially uninfected people such as medical personnel, from the effects of the virus.

The plasma-based products could serve as a critical component of medical care until recombinant anti-viral biologics are available. The first recombinant anti-SARS-CoV-2 antibodies are expected to enter clinical study as early as June 2020. The Antibody Society, in partnership with the Chinese Antibody Society, is maintaining a list of ~60 recombinant biologics that target SARS-CoV-2, including antibodies, a DARPin®, and fusion proteins. We will report on the progress of these candidates in upcoming installments of “Coronavirus in the crosshairs”.

Coronavirus in the crosshairs, Part 5: Harnessing the human immune system

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Anti- SARS-CoV-2 antibodies produced by the human immune system are key to:

  • Serological tests, which identify past exposure;
  •  Convalescent plasma, which can be used to treat COVID-19 patients;
  •  Protection of healthy individuals, after vaccination.

In this installment of the “Coronavirus in the crosshairs” series, The Antibody Society provides updates on the status of anti-SARS-CoV-2 antibody tests, plasma-based therapeutics, and vaccines.

Serological tests

Detection of anti-SARS-CoV-2 antibodies in the blood of healthy people is critical to determining:

  • Who has previously been exposed to the virus, and may be able to resume work;
  • Who can donate plasma that may be a treatment for COVID-19 patients.

To be useful, however, serological tests must be accurate and reliable, which is typically evaluated by regulatory agencies based on data submitted to them by test developers. In response to the public health emergency caused by SARS-CoV-2 in the US, the Food and Drug Administration (FDA) issued guidance on COVID-19 diagnostic tests and initiated a virtual Town Hall Series on the immediately in effect guidance. Guidance issued February 29, 2020 describes FDA’s policy regarding laboratories immediately using tests they developed and validated while pursuing an emergency use authorization (EUA). Guidance updated March 16, 2020 describes additional policies regarding manufacturers immediately distributing tests they validated while pursuing an EUA and regarding certain serology tests.

To date, one serological test intended for use by clinical laboratories has been granted a EUA by FDA. On April 1, 2020 Cellex Inc. received an EUA for the qSARS-CoV-2 IgG/IgM Rapid Test, which is a qualitative test for the detection of IgM and IgG antibodies against SARSCoV-2 in serum and plasma blood specimens and venipuncture whole blood specimens collected from individuals suspected of COVID-19 by their healthcare provider. According to FDA’s April 7, 2020 update, over 70 test developers have notified the agency that they have serological tests available for use.

Further information about FDA’s Guidance on Coronavirus (COVID-19) Diagnostic Tests, including slides and transcripts from the virtual Town Hall Series can be found here.

Convalescent plasma

Plasma from patients who recover from infectious diseases, including SARS and Ebola, contains antibodies that can used to treat patients with the infections. Preliminary reports (Shen et al. study of 5 patients; Duan et al. study of 10 patients) suggest that plasma from COVID-19 patients who recovered, i.e., convalescent plasma, may benefit patients who are critically ill with the disease.

Early in the pandemic, numerous companies announced initiatives to develop convalescent plasma-based products, also known as hyperimmune therapies, for COVID-19. More recently, however, 6 companies (Biotest AG, Bio Products Laboratory, CSL Behring, LFB, Octapharma and Takeda Pharmaceutical Company Limited) have announced that they are collaborating to accelerate development of potential COVID-19 hyperimmune therapy. The alliance will develop one, unbranded anti-SARS-CoV-2 polyclonal hyperimmune immunoglobulin medicine with the potential to treat patients with serious complications from COVID-19.

Academic organizations and hospitals are also working together to develop convalescent plasma therapy. The National COVID-19 Convalescent Plasma Project comprises a group of physicians and scientists from 57 institutions in 46 states who self-organized to investigate the use of convalescent plasma in the current COVID-19 pandemic. The Mayo Clinic will be the lead institution providing coordinated access to investigational convalescent plasma for hospitalized patients with severe or life-threatening COVID-19, or those at high risk of progression to severe or life-threatening disease.

Regardless of the source of the material, well-controlled clinical trials must be conducted to rigorously evaluate the safety and efficacy of COVID-19 convalescent plasma. Such studies, sponsored by numerous organizations, are now on-going.
FDA’s recommendations for investigational COVID-19 convalescent plasma, including discussion of pathways for its use, can be found here.

Vaccines

Many organizations are conducting research on SARS-CoV-2 vaccines, and their efforts are yielding vaccine candidates that are now entering clinical study. For example, INOVIO Pharmaceuticals, Inc. announced that a clinical study for DNA vaccine candidate INO-4800 will begin this week. The Phase 1 open-label study (NCT04336410) will evaluate the safety, tolerability and immunogenicity of INO-4800 in healthy volunteers. Other vaccines in clinical studies include:

Additional vaccine candidates are expected to enter clinical studies in the next 3-4 months.

Substantial funding for vaccine development is being provided by non-profit organizations such as the Coalition for Epidemic Preparedness Innovations and the Bill & Melinda Gates Foundation. Extraordinary measures have been proposed to accelerate the process so that vaccines are available as quickly as possible. For example, in an interview conducted by Trevor Noah, Bill Gates stated that his Foundation could fund factories for simultaneous production of 7 vaccine candidates (at ~18min 30sec of the 22min interview).

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.
  • Specifica has used its Generation 3 platform to select hundreds of antibodies against the SARS-CoV-2 spike protein, which are undergoing testing for neutralization.
  • YUMAB has identified antibodies that were proven to inhibit infection and lyse of live cells, and plans to initiate clinical studies after regulatory permission has been granted.
  • 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 Corona Antibody Team, which includes the Technical University Braunschweig and European colleagues, 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