Theralizumab: Difference between revisions

{{Short description|Monoclonal antibody}}

{{Use dmy dates|date=January 2020}}

| Watchedfields = changed

| verifiedrevid = 448717516

| tradename =

| pregnancy_category =

| legal_status = not approved by any regulatory agency, highly toxic

| ChemSpiderID = none

| UNII = POO0DOD3AS

| CAS_number=906068-56-2

'''Theralizumab''' (also known as '''TGN1412''', '''CD28-SuperMAB''', and '''TAB08''') is an [[immunomodulator]]y drug developed by [[Immunology|immunologist]] [[:de:Thomas_Hünig|Thomas Hünig]] of the [[University of Würzburg]]. It was withdrawn from development after inducing severe inflammatory reactions as well as chronic organ failure in the [[Phases of clinical research#Phase I|first-in-human study]] by [[Parexel]] in London in March 2006.<ref name=":0">{{Cite book | vauthors = Goldacre B |title=Bad Pharma |publisher=Fourth Estate |year=2012 |isbn=9780007350742 |location=London |pages=8–10, 104–105 |author-link=Ben Goldacre}}</ref> The developing company, TeGenero Immuno Therapeutics ([[:de:TeGenero|TeGenero]]), a [[Corporate spin-off|spin-off]] of the University of Würzburg around immunologist Thomas Hünig, co-founder and [[chief scientific officer]] (CSO) Thomas Hanke and [[chief executive officer]] (CEO) Benedikte Hatz went bankrupt later that year.<ref name=":0" /><ref>{{Cite journal |last=Hünig |first=Thomas |date=2016-05-18 |title=The rise and fall of the CD 28 superagonist TGN 1412 and its return as TAB 08: a personal account |url=https://febs.onlinelibrary.wiley.com/doi/10.1111/febs.13754 |journal=The FEBS Journal |language=en |volume=283 |issue=18 |pages=3325-3334 |doi=10.1111/febs.13754 |issn=1742-464X |pmid=27191544}}</ref><ref>{{Cite web |title=Thomas Hanke |url=https://theorg.com/org/tubulis/org-chart/thomas-hanke |archive-url=https://web.archive.org/web/20240825110739/https://theorg.com/org/tubulis/org-chart/thomas-hanke |archive-date=2024-08-25 |access-date=2024-08-25 |website=The Org (theorg.com) |language=en}}</ref> The commercial rights were then acquired by a Russian startup, [[TheraMAB]].<ref>{{Cite news | vauthors = Hirschler B |date=24 March 2015 |title=Exclusive: Drug that caused 'elephant man' side effect makes comeback after 2006 disaster |work=Reuters |url=https://www.reuters.com/article/us-drug-comeback-exclusive/exclusive-drug-that-caused-elephant-man-side-effect-makes-comeback-after-2006-disaster-idUSKBN0MK1SQ20150324 |access-date=26 November 2020}}</ref> The drug was renamed TAB08. Phase I and II clinical trials have been completed for arthritis<ref>{{cite journal |title=Safety, Tolerability, Pharmacodynamics and Efficacy Study of TAB08 in Patients With Rheumatoid Arthritis in Which Methotrexate (MTX) Treatment is Not Effective |url=https://clinicaltrials.gov/ct2/show/study/NCT01990157 |website=ClinicalTrials.gov |publisher=US National Library of Medicine |access-date=1 July 2021 |date=27 February 2017}}</ref> and clinical trials have been initiated for cancer.

| date = 20 February 2006

| access-date = 16 March 2006

|archive-url = https://web.archive.org/web/20060412052458/http://www.tegenero.com/research__development/drug_development/index.php <!-- Bot retrieved archive --> |archive-date = 12 April 2006}}</ref> TGN1412 is a [[humanized antibody|humanised monoclonal antibody]] that not only binds to, but is a strong [[agonist]] for, the [[CD28]] receptor of the [[immune system]]'s [[T cell]]s.<ref name="Lin2004">{{cite journal | vauthors = Lin CH, Kerkau T, Guntermann C, Trischler M, Beyersdorf N, Scheuring Y, Tony HP, Kneitz C, Wilhelm M, Mueller P, Huenig T | title = Superagonistic Anti-CD28 Antibody TGN1412 as a Potential Immunotherapeutic for the Treatment of B Cell Chronic Lymphocytic Leukemia. | date = 16 November 2004 | journal = Blood (ASH Annual Meeting Abstracts) | volume = 104 | issue = 11 | pages = Abstract 2519 | url = http://meeting.bloodjournal.org/cgi/content/abstract/104/11/2519 | archive-url = https://archive.today/20130414093610/http://meeting.bloodjournal.org/cgi/content/abstract/104/11/2519 | url-status = dead | archive-date = 14 April 2013 }}</ref> CD28 is the co-receptor for the T cell receptor; It binds to receptors on the interacting partner in the reaction through one of its ligands ([[B7 family]]).

The drug, which was designated as an [[orphan drug|orphan medical product]] by the [[European Medicines Agency]] in March 2005, was developed by TeGenero, tested by [[Parexel]] and manufactured by [[Boehringer Ingelheim]].<ref name="TeGenero2005-03-13">{{cite press release

|publisher = TeGenero

|date = 13 March 2005

|title = TeGenero AG receives EU-orphan drug designation for Humanized Agonistic Anti-CD28 Monoclonal Antibody TGN1412 for the treatment of B-cell Chronic Lymphocytic Leukaemia, B-CLL

|url = http://www.tegenero.com/documents/pr_tegenero_march_11_2005.pdf

|url-status = dead

|archive-url = https://web.archive.org/web/20060319033931/http://www.tegenero.com/documents/pr_tegenero_march_11_2005.pdf

|archive-date = 19 March 2006

|df = dmy-all

}}</ref><ref name="TeGenero2003-11-17">

{{cite press release

|publisher = TeGenero

|date = 17 November 2003

|title = Boehringer Ingelheim and TeGenero sign agreement to develop and manufacture CD28-SuperMAB

|url = http://www.tegenero.com/documents/2003_11_tg005_pressrelease_e.pdf

|url-status = dead

|archive-url = https://web.archive.org/web/20060318205642/http://tegenero.com/documents/2003_11_tg005_pressrelease_e.pdf

|archive-date = 18 March 2006

|df = dmy-all

}}</ref> TeGenero announced the first elucidation of the molecular structure of CD28 almost exactly one year prior to commencement of the TGN1412 phase I clinical trial.

==Production==

{{More citations needed section|date=July 2021}}

Mice of the inbred strain BALB/c were immunized with recombinant human CD28-Fc fusion proteins and boosted with a B lymphoma cell line transfected to express human CD28. Hybridomas were obtained by fusing B cells with the hybridoma partner X63Ag8.653 and screened for reactivity with human CD28 and TCR-independent mitogenic activity. Two monoclonals called 5.11A1 and 9D7 were identified. The more active of the two, 5.11A1, is a mouse IgG1 immunoglobulin.

The [[complementarity-determining region]]s of 5.11A1 were cloned into the framework of human IgG and combined with IgG1 (TGN1112) or IgG4 (TGN1412) constant regions. According to the company's Investigator Brochure, "TGN1412 is a humanised monoclonal antibody directed against the human CD28 antigen. The molecule was genetically engineered by transfer of the complementarity determining regions (CDRs) from heavy and light chain variable region sequences of a monoclonal mouse anti-humanC28 {{sic}} antibody (5.11A1, Luhder et al., 2003) into human heavy and light chain variable frameworks. Humanised variable regions were subsequently recombined with a human gene coding for the IgG4 gamma chain and with a human gene coding for a human kappa chain, respectively."<ref>{{Cite web |last=TeGenero AG |date=2005-12-19 |title=Investigator's Brochure. TGN1412 Humanized Agonistic Anti-CD28 Monoclonal Antibody |url=https://www.circare.org/foia5/tgn1412investigatorbrochure.pdf |archive-url=https://web.archive.org/web/20060629023059/https://www.circare.org/foia5/tgn1412investigatorbrochure.pdf |archive-date=2006-06-29 |website=circare.org |publisher=Citizens For Responsible Care and Research (CIRCARE)}}</ref>

The recombinant genes were transfected into [[Chinese hamster ovary cell]]s and the recombinant antibody harvested from culture supernatant.

==Pharmacology==

===Mechanism of action===

[[File:T cell activation.svg|thumb|right|250px|T lymphocyte activation pathway is triggered when a T cell encounters its cognate antigen, coupled to an MHC molecule, on the surface of an infected cell or a phagocyte.]]

[[T cell#Activation|Activation of T cells]] normally requires both engagement of the [[T cell receptor|antigen receptor]] (signal 1) and [[co-stimulation]] (signal 2). Studies of monoclonal antibodies specific for mouse, rat, or human CD28 identified so-called "superagonistic" antibodies that could stimulate T cells without concurrent antigen-receptor stimulation (signal 1). Whether this activity represents a stronger activity or a different activity is uncertain.

Two antibodies specific for human CD28 were identified. The more active of the two, TGN1112 (originally called 5.11A1), belonged to the IgG1 class of immunoglobulins. The other, TGN1412 (clone 9D7), belonged to the IgG4 class. The TCR-independent agonism of these antibodies involved binding to a specific part of the CD28 molecule called the C"D loop.<ref name="Luhder2003">{{cite journal | vauthors = Lühder F, Huang Y, Dennehy KM, Guntermann C, Müller I, Winkler E, Kerkau T, Ikemizu S, Davis SJ, Hanke T, Hünig T | display-authors = 6 | title = Topological requirements and signaling properties of T cell-activating, anti-CD28 antibody superagonists | journal = The Journal of Experimental Medicine | volume = 197 | issue = 8 | pages = 955–66 | date = April 2003 | pmid = 12707299 | pmc = 2193880 | doi = 10.1084/jem.20021024 }}</ref>

It was initially hypothesized that an antibody with this property could be therapeutically useful in stimulating the immune system in [[Immunosuppression|immunosuppressed]] patients. However, ''[[in vitro]]'' and ''[[in vivo]]'' data from animal studies later suggested that administration would lead to preferential activation of [[regulatory T cell]]s, leading to a net effect of T-cell downregulation. On its website, the company wrote: "A pronounced T-cell activation and expansion mediated by CD28-SuperMAB in animal models is accompanied by the expression of anti-inflammatory [[cytokine]]s, like IL-10, rather than by the severe [[cytokine release syndrome]] of pro-inflammatory mediators induced by other agents that address the TCR complex.".<ref name="TeGenero2006-02-20"/> As it turned out, the results of the first trial in humans indicate that this may not always be the case.

A new explanation for the trial mishap was suggested by the findings of a paper in ''Clinical Immunology''. Pillai ''et al.'' found that all T cells that get activated using conventional TCR-mediated stimulation become regulatory for a brief time and express FOXP3. However, eventually most of these cells downregulate their regulatory capabilities and become [[Plasma cell|effector cells]]. Thus, attempts to induce FOXP3+ T cells might also induce effector cells capable of causing tissue damage.<ref>{{cite journal | vauthors = Pillai V, Ortega SB, Wang CK, Karandikar NJ | title = Transient regulatory T-cells: a state attained by all activated human T-cells | journal = Clinical Immunology | volume = 123 | issue = 1 | pages = 18–29 | date = April 2007 | pmid = 17185041 | pmc = 1868523 | doi = 10.1016/j.clim.2006.10.014 }}</ref>

Other cells activated by CD28 ligation in humans are [[eosinophil granulocyte]]s. They can release IFN-γ, IL-2, IL-4, and IL-13.<ref name="pmid10449520">{{cite journal | vauthors = Woerly G, Roger N, Loiseau S, Dombrowicz D, Capron A, Capron M | title = Expression of CD28 and CD86 by human eosinophils and role in the secretion of type 1 cytokines (interleukin 2 and interferon gamma): inhibition by immunoglobulin a complexes | journal = The Journal of Experimental Medicine | volume = 190 | issue = 4 | pages = 487–95 | date = August 1999 | pmid = 10449520 | pmc = 2195599 | doi = 10.1084/jem.190.4.487 }}</ref><ref name="pmid12377947">{{cite journal|vauthors=Woerly G, Lacy P, Younes AB, Roger N, Loiseau S, Moqbel R, Capron M|date=October 2002|title=Human eosinophils express and release IL-13 following CD28-dependent activation|journal=Journal of Leukocyte Biology|volume=72|issue=4|pages=769–79|doi=10.1189/jlb.72.4.769|pmid=12377947|s2cid=10820672 |doi-access=free}}</ref> However, most ''in vitro'' experiments are limited to the use of purified peripheral blood mononuclear cells (PBMN's) that do not contain those cells.

To function as an agonist, it has been suggested that TGN1412 needs to be a whole [[antibody]], including the constant (Fc) region. According to a report by TeGenero, the F(ab)2 is not able to generate the required stimulation.<ref>{{cite web |url=http://www.mhra.gov.uk/home/idcplg?IdcService=GET_FILE&dDocName=CON2023519&RevisionSelectionMethod=LatestReleased |archive-url=https://web.archive.org/web/20070821215621/http://www.mhra.gov.uk/home/idcplg?IdcService=GET_FILE&dDocName=CON2023519&RevisionSelectionMethod=LatestReleased |url-status=dead |archive-date=21 August 2007 |title=Investigations into adverse incidents during clinical trials of TGN1412 |publisher=MHRA }}</ref> Unlike the related clone TGN1112, an IgG1, TGN1412 is of the subclass IgG4. This choice was made as TGN1112 showed antibody-dependent cellular cytotoxicity on CD28+ Jurkat cells. Thus the function of antibody binding via an Fcγ receptor seems to be a requirement for the immune regulation. However, cell [[opsonisation]] by antibody leads normally to [[phagocytosis]] of the labeled cells, as seen in the case of [[HIV]].<ref>{{cite journal | vauthors = Daniel V, Melk A, Süsal C, Weimer R, Zimmermann R, Huth-Kühne A, Opelz G | title = CD4 depletion in HIV-infected haemophilia patients is associated with rapid clearance of immune complex-coated CD4+ lymphocytes | journal = Clinical and Experimental Immunology | volume = 115 | issue = 3 | pages = 477–84 | date = March 1999 | pmid = 10193421 | pmc = 1905242 | doi = 10.1046/j.1365-2249.1999.00848.x }}</ref>

==History==

In its first human [[clinical trial]]s, it caused catastrophic systemic organ failures in the subjects, despite being administered at a supposed sub-clinical dose of 0.1&nbsp;mg per kg, some 500 times lower than the dose found safe in animals.<ref name="njem" /> Six volunteers were hospitalized on 13 March 2006. At least four of them had [[multiple organ dysfunction syndrome|multiple organ dysfunction]].

The [[Phases of clinical research#Phase I|Phase I]] [[clinical trial]]s were conducted by Parexel at an independent clinical trials unit in leased space on the premises of [[Northwick Park and St. Mark's Hospital]], [[London]], on 13 March 2006.<ref name="Parexel2005-03-15">{{cite press release

| date = 13 March 2006

| access-date = 15 March 2006

| archive-date = 13 May 2006

| archive-url = https://web.archive.org/web/20060513034002/http://www.parexel.com/news_and_events/press_releasesSingle.asp?id=233

| url-status = dead

}}</ref><ref name="njem">{{cite journal | vauthors = Suntharalingam G, Perry MR, Ward S, Brett SJ, Castello-Cortes A, Brunner MD, Panoskaltsis N | title = Cytokine storm in a phase 1 trial of the anti-CD28 monoclonal antibody TGN1412 | journal = The New England Journal of Medicine | volume = 355 | issue = 10 | pages = 1018–1028 | date = September 2006 | pmid = 16908486 | doi = 10.1056/NEJMoa063842 | doi-access = free }}</ref> Parexel is a company that carries out drug trials on behalf of pharmaceutical and biotechnology companies. Healthy volunteers were recruited to the study with a £2,000 fee. The trial resulted in hospitalization of all six volunteers administered the drug, at least four of whom had [[Multiple organ dysfunction syndrome|multiple organ dysfunction]].<ref name="BBC2006-03-18">{{Cite news

| date=18 March 2006

| access-date=18 March 2006

}}</ref> The trial was a double-blind, randomized, [[placebo-controlled studies|placebo-controlled study]], with two of the eight subjects receiving a [[placebo]], and six receiving 1/500th of the highest dose used in previous experiments with [[Crab-eating Macaque|cynomolgus macaques]]. All six of the trial subjects who received the drug were male, aged 19 to 34 (median 29.5); none had a notable medical history, and all were well in the 2 weeks before the trial.<ref name="njem" /> The drug was given by [[intravenous infusion]], starting at 8{{nbsp}}am, with an interval of around 10 minutes between patients, and each infusion lasting from 3 to 6 minutes.<ref name="njem" /> Roughly fifty minutes after the first participant received his dose, he complained of a headache, and soon afterwards fever and pain. He took his shirt off, complaining that he felt like he was burning. Shortly after, the remaining participants who received the actual drug also became ill, vomiting and complaining of severe pain. The first patient was transferred to the Northwick Park Hospital's [[intensive care unit]] 12 hours after infusion, with the others following within the next 4 hours.<ref name="njem" /> A severely affected volunteer, Mohammed Abdalla, a 28-year-old, was described as having developed a ballooned head. This led to his description as being similar to the "[[Joseph Merrick|Elephant Man]]". A volunteer also lost his fingers and toes as a result of being injected with the drug.<ref>{{Cite news | url=https://www.telegraph.co.uk/finance/personalfinance/11089564/Would-you-accept-3750-to-trial-one-drug.html | title=Would you accept £3,750 to trial one drug?| date=15 October 2014| vauthors = Palmer K }}</ref>

All of the men were reported to have experienced severe [[cytokine release syndrome]] resulting in [[angioedema]], swelling of [[skin]] and [[mucous membrane]]s, akin to the effects of the [[complement cascade]] in [[severe allergic reaction]]. The patients were treated with [[corticosteroid]]s to reduce inflammation, and [[Plasmapheresis|plasma-exchange]] to attempt to remove TGN1412 from their circulation. Paradoxically, some kinds of the men's [[white blood cells]] ([[lymphocyte]]s and [[monocyte]]s, involved in immune responses) had vanished almost completely several hours after administration of TGN1412.<ref name="njem" />

According to a press release on 5 July 2006 from [[North West London Hospitals NHS Trust]], where the men were treated, the patients continued to improve and "five of them went home within a month of the incident, while one patient remained in hospital until 26 June, when he also went home".<ref>{{Cite press release |title=Latest condition of patients following drug trial at independent PAREXEL research unit |date=5 July 2006 |publisher=The North West London Hospitals NHS Trust |url=http://www.nwlh.nhs.uk/news-media/news_item.cfm?id=97&year=older |archive-url=https://web.archive.org/web/20120907074956/http://www.nwlh.nhs.uk/news-media/news_item.cfm?id=97&year=older |archive-date=7 September 2012}}</ref>

TGN1412 had not previously been given to humans, however the trial was preceded by animal testing, including in [[Primate|non-human primates]]. The company claims that these did not indicate any safety issues, and this was supported in subsequent MHRA reports.<ref name="ft2006-03-16" /> The US patent application states "it could be shown in a pilot study that an [[in vitro]] administration of anti-human CD28-SuperMAB induces in a rhesus monkey [[in vivo]] a profound activation of T cells, without clinically visible side effects" and goes on to say "This antibody—in spite of its strong T cell-stimulatory properties—is very well tolerated in vivo, in contrast to all other known [[T cell]] activating substances."<ref name="USpatent">{{cite patent |country=US |number=2006009382A1|status=|title=Use of a CD28 binding pharmaceutical substance for making a pharmaceutical composition with dose-dependent effect |pubdate=2006-01-12 |gdate= |fdate= |pridate= |inventor= |invent1=Thomas Hanke |invent2=Chia-Huey Lin |assign1= |assign2= |class= |url=}}</ref>

[[File:CD28 structure.gif|thumb|right|250px|Structure of human CD28]]

TeGenero apologised to the families involved soon after the events, insisting that the effects were completely unexpected, and that all protocols were followed.<ref>{{cite news | vauthors = Weaver M |title=Drug trial leaves men critically ill |url=https://www.theguardian.com/society/2006/mar/15/health.medicineandhealth1 |work=The Guardian |date=15 March 2006 |language=en}}</ref> In an initial review of pre-clinical data and the protocol, the MHRA stated there was nothing to cause concern, and that the trial was correctly authorised.<ref name="ft2006-03-16">{{Cite news | title=Data for botched drugs trial show 'nothing' amiss | vauthors = Urquhart L, Jack A | work=Financial Times | date=16 March 2006 | access-date=17 March 2006 | url = http://news.ft.com/cms/s/0a2ebf2a-b529-11da-aa90-0000779e2340.html }}</ref> Participants who were harmed in the drug trial received some additional financial compensation later, which one participant used to hire a [[personal trainer]] so he could regain physical fitness.<ref>{{Cite news |last=Caffrey |first=Jason |date=2016-03-19 |title='I nearly died in a medical drug trial' |language=en-GB |work=BBC News |url=https://www.bbc.com/news/magazine-35766627 |access-date=2022-10-28}}</ref>

===Investigations===

The Medicines and Healthcare products Regulatory Agency (MHRA) issued an interim report on the TGN1412 trial on 5 April 2006, followed by a final report on 25 May 2006.<ref name="MHRA20060405">{{Cite press release | url=http://www.mhra.gov.uk/NewsCentre/Pressreleases/CON2023515 | archive-url=http://webarchive.nationalarchives.gov.uk/20141205150130/http://www.mhra.gov.uk/NewsCentre/Pressreleases/CON2023515 | url-status=dead | archive-date=5 December 2014 | title=Press release: Latest findings on clinical trial suspension | author=MHRA | work=Press Release | date=5 April 2006 | access-date=4 June 2010 }}</ref><ref>{{Cite web|last=Medicines and Healthcare Products Regulatory Agency (MHRA)|date=25 May 2006|title=Clinical trial final report|url=http://www.mhra.gov.uk/NewsCentre/Pressreleases/CON2023822|url-status=dead|archive-url=http://webarchive.nationalarchives.gov.uk/20141206051830/http://www.mhra.gov.uk/NewsCentre/Pressreleases/CON2023822|archive-date=6 December 2014|access-date=29 November 2017|publisher=MHRA|language=en}}</ref>

It found no deficiencies in TeGenero's pre-clinical work and no evidence of undisclosed studies. Parexel's records and processes appeared in order, including dose measurement and administration, and no deficiencies were found that may have led to contamination or overdose. The MHRA felt that their actions did not contribute to the serious adverse events.

German regulatory authorities inspected the production of the material by [[Boehringer Ingelheim]], looking at the manufacture, testing, storage and distribution of the TGN1412, but no deficiencies were identified which could have contributed to the serious adverse effects.<ref>{{cite journal | vauthors = Tuffs A | title = Germany may change drug testing rules after debacle in England | journal = BMJ | volume = 332 | issue = 7544 | pages = 746 | date = April 2006 | pmid = 16575061 | pmc = 1420771 | doi = 10.1136/bmj.332.7544.746-c }}</ref>

The MHRA concluded that the most likely cause of the reaction in trial subjects was an unpredicted biological action of the drug in humans. The UK [[Secretary of State for Health]] agreed to establish a group of leading international experts to consider those issues and to provide a report on the future authorization of such trials with an interim report at three months, with [[Gordon Duff]], Professor of Molecular Medicine at [[Sheffield University]], as Chair of the group. Until the expert group reported, all further clinical trial applications involving first-in-humans trials of any monoclonal antibody or other novel molecules targeting the immune system were not to be authorised in the UK.<ref>{{Cite web |last=MHRA |date=5 April 2006 |title=Investigations Into Adverse Incidents During Clinical Trials of TGN1412 |url=http://www.mhra.gov.uk/home/idcplg?IdcService=GET_FILE&dDocName=CON2023519&RevisionSelectionMethod=LatestReleased |url-status=dead |archive-url=http://webarchive.nationalarchives.gov.uk/20110505014645/http://www.mhra.gov.uk/home/idcplg?IdcService=GET_FILE&dDocName=CON2023519&RevisionSelectionMethod=LatestReleased |archive-date=5 May 2011}}</ref>

In December 2006, the final report of the Expert Group on Phase One Clinical Trials was published.<ref>{{Cite report |title=Expert Group on Phase One Clinical Trials: Final report | collaboration = Expert Group on Phase One Clinical Trials | vauthors = Duff GW |date=7 December 2006 |publisher=The Stationery Office |url=http://dh.gov.uk/en/publicationsandstatistics/publications/publicationspolicyandguidance/dh_063117 |archive-url=http://webarchive.nationalarchives.gov.uk/20130107105354/http://dh.gov.uk/en/publicationsandstatistics/publications/publicationspolicyandguidance/dh_063117 |archive-date=7 January 2013}}</ref> It found that the trial had not considered what constituted a safe dose in humans, and that then-current law had not required it. It made 22 recommendations, including the need for independent expert advice before a high-risk study was allowed, testing only one volunteer at a time (sequential inclusion of participants) in case there were rapid ill effects, and administering drugs slowly by infusion rather than as an injection.<ref>{{cite journal | vauthors = Aboulghar MA, Mansour RT, Serour GI | title = Transvaginal injection of potassium chloride and methotrexate for the treatment of tubal pregnancy with a live fetus | journal = Human Reproduction | volume = 5 | issue = 7 | pages = 887–8 | date = October 1990 | pmc = 1702450 | doi = 10.1136/bmj.39062.336157.DB | pmid = 1702450 }}</ref>

===Follow up publications===

The trial has become subject of several academic publications.

In 2007, immunologists from the [[Paul Ehrlich Institute]], the German Federal Agency for Sera and Vaccines, reviewed Germany's regulatory requirements in the aftermath of the TGN1412 trial. They suggested that the predictive value of pre-clinical animal models required reevaluation, dose fixing needed refinement or redesign, and criteria for high-risk antibodies needed to be established. Additionally, they suggested that pre-Phase I studies were needed to calculate a dose with a pre-clinical "No effect" level, rather than a [[No-observed-adverse-effect level]].<ref name="pmid17256444">{{cite journal | vauthors = Liedert B, Bassus S, Schneider CK, Kalinke U, Löwer J | title = Safety of phase I clinical trials with monoclonal antibodies in Germany--the regulatory requirements viewed in the aftermath of the TGN1412 disaster | journal = International Journal of Clinical Pharmacology and Therapeutics | volume = 45 | issue = 1 | pages = 1–9 | date = January 2007 | pmid = 17256444 | doi = 10.5414/CPP45001 }}</ref>

Scientists in early 2007 put forth the theory that the drug acted in a different fashion in humans as compared with the laboratory animals in which the drug was first tried. The severe reactions in humans could have only occurred, they believe, in those with [[Memory T cell|memory T lymphocytes]]. Animals raised in a sterile lab would presumably have no 'memory' of previous illnesses, thus would not exhibit the severe reactions that occurred in the human subjects.<ref>{{Cite news| vauthors = Fleming N |date=12 April 2008|title=Study claims to solve drug trial mystery|work=The Daily Telegraph|location=London|url=https://www.telegraph.co.uk/news/uknews/1540591/Study-claims-to-solve-drug-trial-mystery.html|access-date=25 May 2010}}</ref> However this is a misunderstanding of the research: the research says that lab animals studied have fewer memory T cells than humans, and that stimulation through the CD28 receptor alone in memory T cells causes them to infiltrate organs and also activates them.<ref name="mirenda">{{cite journal|display-authors=6|vauthors=Mirenda V, Jarmin SJ, David R, Dyson J, Scott D, Gu Y, Lechler RI, Okkenhaug K, Marelli-Berg FM|date=April 2007|title=Physiologic and aberrant regulation of memory T-cell trafficking by the costimulatory molecule CD28|url=http://bloodjournal.hematologylibrary.org/cgi/content/full/109/7/2968%7C|journal=Blood|volume=109|issue=7|pages=2968–77|doi=10.1182/blood-2006-10-050724|pmid=17119120|s2cid=7709430 |doi-access=free}}</ref>

Experimental [[in-vitro]] research and modelling, published in 2008, suggested that the 0.1&nbsp;mg starting dose would bind to 86 to 91% of all CD28 receptors in the body, resulting in a possible higher than expected effect even at very low starting doses.<ref>{{cite journal | vauthors = Waibler Z, Sender LY, Kamp C, Müller-Berghaus J, Liedert B, Schneider CK, Löwer J, Kalinke U | display-authors = 6 | title = Toward experimental assessment of receptor occupancy: TGN1412 revisited | journal = The Journal of Allergy and Clinical Immunology | volume = 122 | issue = 5 | pages = 890–2 | date = November 2008 | pmid = 18805577 | doi = 10.1016/j.jaci.2008.07.049 | doi-access = free }}</ref>

In 2009, the UK [[National Institute for Biological Standards and Control]] wrote that a near-maximum immuno-stimulatory dose had been given, because a safe starting dose in man had been calculated "based upon results from pre-clinical safety testing in a non-responsive species" (''[[Macaca fascicularis]]''). It reported that the European guidelines for first-in-man phase-I clinical trials of biologics had been revised.<ref name="pmid19892543">{{cite journal | vauthors = Stebbings R, Poole S, Thorpe R | title = Safety of biologics, lessons learnt from TGN1412 | journal = Current Opinion in Biotechnology | volume = 20 | issue = 6 | pages = 673–7 | date = December 2009 | pmid = 19892543 | doi = 10.1016/j.copbio.2009.10.002 }}</ref>

In 2010, the failure to predict a severe [[cytokine release syndrome]] in humans was explained. In vitro data revealed that the CD4+ [[effector memory T-cell]]s of ''[[Macaca fascicularis]]'', the species of primate used for pre-clinical safety testing of TGN1412, lack CD28 expression. Since CD28 is the target of the TGN1412 antibody, ''M. fascicularis'' effector T-cells could not be stimulated by the drug.<ref name="pmid20880392">{{cite journal | vauthors = Eastwood D, Findlay L, Poole S, Bird C, Wadhwa M, Moore M, Burns C, Thorpe R, Stebbings R | display-authors = 6 | title = Monoclonal antibody TGN1412 trial failure explained by species differences in CD28 expression on CD4+ effector memory T-cells | journal = British Journal of Pharmacology | volume = 161 | issue = 3 | pages = 512–26 | date = October 2010 | pmid = 20880392 | pmc = 2990151 | doi = 10.1111/j.1476-5381.2010.00922.x }}</ref>

In 2013, it was described that standard pro-inflammatory markers [[TNFα]] and [[Interleukin 8|IL-8]] are not predictive of the unusual pro-inflammatory response to TGN1412, and gave a false negative result. IL-2 release and lymphoproliferation are more helpful predictors of the response.<ref name="pmid22967038">{{cite journal | vauthors = Stebbings R, Eastwood D, Poole S, Thorpe R | title = After TGN1412: recent developments in cytokine release assays | journal = Journal of Immunotoxicology | volume = 10 | issue = 1 | pages = 75–82 | date = 2013 | pmid = 22967038 | pmc = 3541671 | doi = 10.3109/1547691X.2012.711783 }}</ref>

In 2016, a study carried out on [[humanized mouse|humanized mice]] evaluated TGN1412's effects on the immune system, and confirmed that it could cause [[cytokine release syndrome]], destruction of white blood cells, and other negative effects observed during the initial human trial.<ref name="pmid26959227">{{cite journal | vauthors = Weißmüller S, Kronhart S, Kreuz D, Schnierle B, Kalinke U, Kirberg J, Hanschmann KM, Waibler Z | title = TGN1412 Induces Lymphopenia and Human Cytokine Release in a Humanized Mouse Model | journal = PLOS ONE | volume = 11 | issue = 3 | date = March 2016 | pages = e0149093 | pmid = 26959227 | pmc = 4784892 | doi = 10.1371/journal.pone.0149093 | bibcode = 2016PLoSO..1149093W | doi-access = free }}</ref>

==Controversies==

Critics argued that the company should have anticipated that the drug would provoke a severe reaction in humans. An immunologist contacted by ''[[New Scientist]]'' and who wished to remain anonymous said "You don't need to be a rocket scientist to work out what will happen if you non-specifically activate every T cell in the body."<ref name="newscientist20060317">{{Cite news | url=https://www.newscientist.com/article/dn8863-catastrophic-immune-response-may-have-caused-drug-trial-horror.html | title=Catastrophic immune response may have caused drug trial horror | vauthors = Bhattacharya S, Coghlan A | work=New Scientist | date=17 March 2006 | access-date=19 March 2006 }}</ref> While the drug had appeared to be safe in animal models, researchers noted that there were reasons why these may not be indicative of the response in humans, particularly with respect to this type of drug.<ref name="telegraph20060317">{{Cite news | url=https://www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/03/17/ntrial117.xml&sSheet=/news/2006/03/17/ixhome.html | archive-url=https://web.archive.org/web/20070518114016/http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/03/17/ntrial117.xml&sSheet=/news/2006/03/17/ixhome.html | url-status=dead | archive-date=18 May 2007 | title= Antibody 'puts immune system in overdrive' | vauthors = Hall C | work=The Daily Telegraph | date=17 March 2006 | access-date=19 March 2006 | location=London}}</ref>

The BBC reported that "two of 20 monkeys used in earlier tests suffered an increase in the size of [[lymph node]]s," but that "this information was given to the men and submitted to the test regulators."<ref name="bbc20060320">{{Cite news | url=http://news.bbc.co.uk/1/hi/england/london/4823992.stm | title=Trial drug affected animal glands | work=BBC News | date=20 March 2006 | access-date=20 March 2006 }}</ref>

TeGenero said this was transient and was evidence of the extra T cells that the drug produces.<ref name="tegenero20060319">{{Cite web

| work=TeGenero | date=19 March 2006 | access-date=20 March 2006

|archive-url = https://web.archive.org/web/20060521150601/http://www.tegenero.com/news/faqs_re_tgn1412/index.php <!-- Bot retrieved archive --> |archive-date = 21 May 2006}}</ref>

Experiments with another drug affecting the CD28 receptor (but to a lesser extent than TGN1412) had also shown side effects in human trials.<ref name="nature20060317">{{Cite news | url=http://www.nature.com/news/2006/060313/full/060313-17.html | title=Tragic drug trial spotlights potent molecule | vauthors = Pearson H | work=Nature | date=17 March 2006 | access-date=19 March 2006 }}</ref>

There have been criticisms that the risks taken and the design of the protocol were insufficiently justified by proper [[statistics|statistical evidence]].<ref name="rss2007">{{Cite journal | journal = Journal of the Royal Statistical Society | volume = 170A | pages = 517&ndash;579 | author = Working Party on Statistical Issues in First-in-Man Studies | year = 2007 | title = Statistical issues in first-in-man studies | url = http://www.rss.org.uk/site/cms/contentviewarticle.asp?article=523 | url-status = dead | archive-url = https://web.archive.org/web/20120105003015/http://www.rss.org.uk/site/cms/contentviewarticle.asp?article=523 | archive-date = 5 January 2012 | df = dmy-all }}</ref>

Critics of animal testing have cited the case to argue that experiments on nonhuman animals, even in species closely related to humans, are not necessarily predictive of human responses, and cannot justify the harm inflicted on animals or the resultant risks to humans.<ref name="Akhtar 2014">{{cite journal | vauthors = Akhtar A | title = The flaws and human harms of animal experimentation | journal = Cambridge Quarterly of Healthcare Ethics | volume = 24 | issue = 4 | pages = 407–19 | date = October 2015 | pmid = 26364776 | pmc = 4594046 | doi = 10.1017/S0963180115000079 }}</ref>

TGN1412 was created to perfectly fit inside the CD28 receptor of humans. Animal trials on mice were not necessarily predictive of human responses, as it would require a much greater dosage to get the same level of immunoactivity as in a human.

The human clinical trial of TGN1412 was the subject of the 2017 BBC [[docudrama]] ''The Drug Trial: Emergency at the Hospital''.<ref>{{Cite web|url=https://www.bbc.co.uk/programmes/b08g8np3|title=BBC Two - The Drug Trial: Emergency at the Hospital|website=BBC|language=en-GB|access-date=24 December 2019}}</ref><ref>{{Cite web|url=https://youtube.com/watch?v=a9_sX93RHOk |archive-url=https://ghostarchive.org/varchive/youtube/20211222/a9_sX93RHOk |archive-date=2021-12-22 |url-status=live|title=When a Drug Trial Goes Wrong: Emergency at the Hospital (Medical Documentary) - Real Stories|website=YouTube|language=en-US|access-date=24 March 2020}}{{cbignore}}</ref>

{{div col|colwidth=22em}}

* [[BIA 10-2474]]

{{div col end}}

{{Reflist}}

* [https://dx.doi.org/10.1038/440855a Report in Nature on TGN1412]

* [http://news.bbc.co.uk/1/hi/health/4914546.stm BBC News: Drug trial man 'may lose fingers']

* [http://news.bbc.co.uk/1/hi/health/5015224.stm BBC News: Regulators slam drug trial firm]

* [http://rosettapr.com/perspectives.php crisis communications case study of Tegenero clinical trial] {{Webarchive|url=https://web.archive.org/web/20090309033417/http://rosettapr.com/perspectives.php |date=9 March 2009 }}

{{Monoclonals for immune system|state=collapsed}}

[[Category:Clinical trial disasters]]

[[Category:Experimental monoclonal antibodies]]

[[Category:Abandoned drugs]]