Glossary of terms

Glossary of terms
CSR report

Glossary of terms, to be read only in conjunction with this Q3 Report 2018.


100 points clinical response

Percentage of patients achieving a 100-point decrease in CDAI score during a clinical trial in CD patients


American College of Rheumatology

ACR20 (ACR 20/50/70)

American College of Rheumatology 20% response rate signifies a 20% or greater improvement in the number of swollen and tender joints as well as a 20% or greater improvement in three out of five other disease-activity measures. ACR50 and ACR70 reflect the same, for 50% and 70% response rates, respectively


ADAMTS-5 is a key enzyme involved in cartilage breakdown (Larkin 2015)


A common virus that causes cold-like symptoms and is used as a research tool for the lab in the discovery of new drugs


Autosomal dominant polycystic kidney disease, a disease where typically both kidneys become enlarged with fluid-filled cysts, leading to kidney failure. Other organs may be affected as well


American Depositary Share; Galapagos has a Level 3 ADS listed on Nasdaq with ticker symbol GLPG and CUSIP number 36315X101. One ADS is equivalent to one ordinary share in Galapagos NV


Dutch Authority for the Financial Markets


Condition in which the patient has an inadequate number of red blood cells to carry oxygen to the body’s tissues

Ankylosing spondylitis (AS)

AS is a systemic, chronic, and progressive spondyoloarthropathy primarily affecting the spine and sacroiliac joints, and progressing into severe inflammation that fuses the spine, leading to permanent painful stiffness of the back


Tumor necrosis factor. An anti-TNF drug acts by modulation of TNF


Laboratory tests to determine characteristics

Atopic dermatitis (AtD)

Also known as atopic eczema, atopic dermatitis is a common pruritis inflammatory condition affecting the skin, which most frequently starts in childhood


ATS, the American Thoracic Society improves global health by advancing research, patient care, and public health in pulmonary disease, critical illness, and sleep disorders

Attrition rate

The historical success rate for drug discovery and development, based on publicly known development paths. Statistically seen, investment in at least 12 target-based programs is required to ensure that at least one of these will reach a Phase 3 study. Most new drug R&D programs are discontinued before reaching Phase 3 because they are not successful enough to be approved

Autotaxin (ATX)

An enzyme important for generating the signaling molecule lypophosphatidic acid (LPA). Ziritaxestat targets autotaxin for IPF and SSc

BID dosing

Twice-daily dosing (bis in die)


Assessment of the amount of product candidate that reaches a body’s systemic circulation after (oral) administration


Substance used as an indicator of a biological process, particularly to determine whether a product candidate has a biological effect

Black & Scholes model

A mathematical description of financial markets and derivative investment instruments that is widely used in the pricing of European options and subscription rights

Bleomycin model

A preclinical model involving use of bleomycin (a cancer medication) to induce IPF symptoms

Bridging trial

Clinical trial performed to "bridge" or extrapolate one dataset to that for another situation, i.e. to extrapolate data from one population to another for the same drug candidate, or to move from IV to subcutaneous dosing


Phase 1 program with GLPG3970 in psoriasis

Cash position

Current financial investments and cash and cash equivalents


Crohn’s Disease Activity Index, evaluating patients on eight different factors, each of which has a pre-defined weight as a way to quantify the impact of CD

CDAI remission

In the FITZROY trial, the percentage of patients with CD who showed a reduction of CDAI score to <150


Cystic fibrosis transmembrane conductance regulator (CFTR) is a membrane protein and chloride channel in vertebrates that is encoded by the CFTR gene. It is hypothesized that inhibition of the CFTR channel might reduce cyst growth and enlargement for patients with ADPKD. GLPG2737 is a CFTR inhibitor


Chitotriosidase (CHIT1) is a protein coding gene, and AMCase is an inactive acidic mamalian chitinase. CHIT1 is predominantly involved in macrophage activation. Inhibition of chitinase activity translates into a potential therapeutic benefit in lung diseases like IPF, as shown in preclinical models. GLPG4716 is a CHIT1/AMCase inhibitor targeting a key pathway in tissue remodeling


Committee for Medicinal Products for Human Use is the European Medicines Agency's (EMA) committee responsible for human medicines and plays a vital role in the authorization of medicines in the European Union (EU)


Crédit d’Impôt Recherche, or research credit. Under the CIR, the French government refunds up to 30% of the annual investment in French R&D operations, over a period of three years. Galapagos benefits from the CIR through its operations in Romainville, just outside Paris

Clinical Proof of Concept (PoC)

Point in the drug development process where the product candidate first shows efficacy in a therapeutic setting

Complete Response Letter (CRL)

A letter send by the FDA to indicate that the review cycle for an application is complete and the application is not ready for approval in its present form


A chemical substance, often a small molecule with drug-like properties

Contract research organization (CRO)

Organization which provides drug discovery and development services to the pharmaceutical, biotechnology and medical devices industry


Any of a group of steroid hormones produced in the adrenal cortex or made synthetically. They have various metabolic functions and some are used to treat inflammation

Crohn's disease (CD)

An IBD involving inflammation of the small and large intestines, leading to pain, bleeding, and ultimately in some cases surgical removal of parts of the bowel


C-reactive protein is a protein found in the blood, the levels of which rise in response to inflammation

Cystic fibrosis (CF)

A life-threatening genetic disease that affects approximately 80,000 people worldwide. Although the disease affects the entire body, difficulty breathing is the most serious symptom as a result of clogging of the airways due to mucus build-up and frequent lung infections


A category of small proteins which play important roles in signaling in processes in the body


Phase 2 program for filgotinib in RA. DARWIN 1 explored three doses, in twice-daily and once-daily administration, for up to 24 weeks in RA patients with insufficient response to methotrexate (MTX) and who remained on their stable background treatment with MTX. DARWIN 2 explored three once-daily doses for up to 24 weeks in RA patients with insufficient response to methotrexate (MTX) and who washed out of their treatment with MTX. DARWIN 1 and 2 were double-blind, placebo-controlled trials which recruited approximately 900 patients globally and for which results were reported in 2015. DARWIN 3 is a long term extension trial in which all patients are on 200 mg filgotinib, except for U.S. males who are on 100 mg. The week 156 results from DARWIN 3 were reported in 2019

DDI study

Drug-drug interaction study. This type of study will assess if there is a change in the action or side effects of a drug caused by concomitant administration with another drug

Deep venous thrombosis (DVT)

The formation of one or more blood clots in one of the body's large veins, most commonly in the lower limbs. The blood clots can travel to the lung and cause a pulmonary embolism


The process by which proteins are lost through the use of drugs such as PROTACs or small molecules


All activities required to bring a new drug to the market. This includes preclinical and clinical development research, chemical and pharmaceutical development and regulatory filings of product candidates


Process by which new medicines are discovered and/or designed. At Galapagos, this is the department that oversees target and drug discovery research through to nomination of preclinical candidates


Addresses the disease itself, modifying the disease progression, not just the symptoms of the disease


Phase 2 programs with filgotinib in Crohn's disease. DIVERGENCE 1 was an exploratory study in small bowel CD and DIVERGENCE 2 in fistulizing CD


Phase 3 program evaluating filgotinib in CD


DLCO (diffusion capacity of the lung for carbon monoxide) is the extent to which oxygen passes from the air sacs of the lungs into the blood. This is measured in IPF patients


Disease modifying anti rheumatic drugs; these drugs address the disease itself rather than just the symptoms

Dose-range finding study

Phase 2 clinical study exploring the balance between efficacy and safety among various doses of treatment in patients. Results are used to determine doses for later studies


Term to characterize a clinical trial in which neither the physician nor the patient knows if the patient is taking placebo or the treatment being evaluated


Effectiveness for intended use


European Medicines Agency, in charge of European market authorization of new medications


A non-surgical procedure involving use of an endoscope to examine a person’s digestive tract


A Phase 2 trial with filgotinib in psoriatic arthritis patients


An approved drug (pirfenidone) for IPF, marketed by Roche

Fast Track

A designation by the FDA of an investigational drug for expedited review to facilitate development of drugs which treat a serious or life-threatening condition and fill an unmet medical need


The U.S. Food and Drug Administration is an agency responsible for protecting and promoting public health and in charge of American market approval of new medications


Payment system where the service provider is paid a specific amount for each procedure or service performed

Fibrotic score

The Ashcroft fibrotic score involves measuring pulmonary fibrosis through examination of histopathology tissue


First-in-human clinical trial, usually conducted in healthy volunteers with the aim to assess the safety, tolerability and pharmacokinetics of the product candidate


Formerly known as GLPG0634, commercial name is Jyseleca. Small molecule preferential JAK1 inhibitor, approved in RA in Europa and Japan. In the U.S. a CRL was received in RA. Application for approval for ulcerative colitis was filed in Europe. Filgotinib is partnered with Gilead. Filgotinib currently is in Phase 3 trials in CD


Phase 3 program evaluating filgotinib in RA

Fistulizing CD

Fistulae are inflammatory tracts that most often occur between the distal colon and the perianal region. Fistulae are one of the most severe sequelae of luminal CD and the lifetime risk of occurrence is close to 50% of those with active CD


A double-blind, placebo controlled Phase 2 trial with filgotinib in 177 CD patients for up to 20 weeks. Full results were published in The Lancet in 2016


A double-blind, placebo-controlled exploratory Phase 2a trial with ziritaxestat in up to 24 IPF patients; topline results were reported in August 2017


Form 20-F is an SEC filing submitted to the US Securities and Exchange Commission


Functional respiratory imaging is a technology which enhances 3D visualization and quantification of a patient’s airway and lung geometry


The Belgian market authority: Financial Services and Markets Authority, or Autoriteit voor Financiële Diensten en Markten


Full-time equivalent; a way to measure an employee’s involvement in a project. For example, an FTE of 1.0 means that the equivalent work of one full-time worker was used on the project

Futility analysis

Analysis of the likelihood of a trial to meet its primary endpoint, based on a subset of the total information to be gathered. The term 'futility' is used to refer to the low likelihood of a clinical trial to achieve its objectives. In particular, stopping a clinical trial when the interim results suggest that it is unlikely to achieve statistical significance can save resources that could be used on more promising research


Forced vital capacity is the amount of air which can be forcibly exhaled from the lungs after taking the deepest breath possible. FVC is used to help determine both the presence and severity of lung diseases such as IPF

G&A expenses

General & administrative expenses


An organism's complete set of genetic information needed to build that organism and allow it to grow and develop


Phase 2 Proof of Concept trial with SIK2/SIK3 inhibitor GLPG3970 in Sjögren's syndrome


A JAK1 inhibitor currently in Phase 1b in osteoarthritis


Molecule number currently known as filgotinib and Jyseleca


A GPR84 inhibitor discovered by us. We reported topline results in 2020 from the PINTA Phase 2 patient trial with GLPG1205 in IPF


Autotaxin inhibitor discovered by us and currently known as ziritaxestat. All development with ziritaxestat was discontinued in February 2021


GLPG1972/S201086, also referred to as GLPG1972, is part of the OA collaboration with Servier. Galapagos and Servier reported there was no signal of activity in the ROCCELLA global Phase 2b trial with GLPG1972/S201086


A compound currently in Phase 2 in PKCD. This compound is part of the CF collaboration with AbbVie but Galapagos regained rights outside of CF


A compound currently in Phase 1 targeting JAK1/TYK2 directed toward inflammation


A SIK1/SIK2/SIK3 inhibitor directed towards inflammation (IBD). Work on this molecule is discontinued


A TYK2 kinase inhibitor discovered by us, currently in Phase 1b in psoriasis


A SIK2/SIK3 inhibitor currently in multiple Phase 2 Proof of Concept studies. Currently the lead molecule in the Toledo program


A compound currently in Phase 1 with undisclosed mode of action directed toward metabolic diseases


A SIK3 inhibitor currently in the preclinical phase directed toward inflammation


A compound with undisclosed mode of action currently in the preclinical phase directed toward fibrosis. This is the first preclinical candidate to emerge from the collaboration with Fibrocor


A SIK2/SIK3 inhibitor in the preclinical phase, currently directed toward fibrosis


A chitinase inhibitor inlicensed from OncoArendi, directed toward fibrosis


A SIK2/SIK3 inhibitor in the preclinical phase, currently directed toward inflammation

GPR84 inhibitor

Drug candidate aimed at inhibiting or blocking G-protein coupled receptor 84. GLPG1205 is a GPR84 inhibitor aimed at IPF


High-density lipoprotein. HDL scavenges and reduces low-density lipoprotein (LDL) which contributes to heart disease at high levels. High levels of HDL reduce the risk for heart disease, while low levels of HDL increase the risk of heart disease


A protein inside red blood cells that carries oxygen from the lungs to tissues and organs in the body and carries carbon dioxide back to the lungs


Study of the microscopic structures of tissues


Microscopic examination of tissues for manifestations of a disease


Inflammatory Bowel Disease. This is a general term for an autoimmune disease affecting the bowel, including CD and UC. CD affects the small and large intestine, while UC affects the large intestine. Both diseases involve inflammation of the intestinal wall, leading to pain, bleeding, and ultimately, in some cases, surgical removal of part of the bowel


Receiving/granting permission from/to another company or institution to use a brand name, patent, or other proprietary right, in exchange for a fee and/or royalty

In vitro

Studies performed with cells outside their natural context, for example in a laboratory

In vivo

Studies performed with animals in a laboratory setting

Inflammatory diseases

A large, unrelated group of disorders associated with abnormalities in inflammation

Inspiratory capacity

Total lung capacity or the amount of gas contained in the lung at the end of a maximal inhalation

Intellectual property

Creations of the mind that have commercial value and are protected or protectable, including by patents, trademarks or copyrights


Occurring between the different operations of a company

Investigational New Drug (IND) Application

United States Federal law requires a pharmaceutical company to obtain an exemption to ship an experimental drug across state lines, usually to clinical investigators, before a marketing application for the drug has been approved. The IND is the means by which the sponsor obtains this exemption, allowing them to perform clinical studies


Idiopathic pulmonary fibrosis. A chronic and ultimately fatal disease characterized by a progressive decline in lung function. Pulmonary fibrosis involves scarring of lung tissue and is the cause of shortness of breath. Fibrosis is usually associated with a poor prognosis. The term “idiopathic” is used because the cause of pulmonary fibrosis is still unknown


Phase 3 clinical program investigating ziritaxestat in IPF patients. All development with ziritaxestat was discontinued in February 2021


Janus kinases (JAK) are critical components of signaling mechanisms utilized by a number of cytokines and growth factors, including those that are elevated in RA. Filgotinib is a preferential JAK1 inhibitor


Jyseleca® is the brand name for filgotinib


Phase 2 program with GLPG3970 in rheumatoid arthritis


Low-density lipoprotein. LDL contributes to heart disease at high levels


Lipoproteins are substances made of protein and fat that carry cholesterol through your bloodstream. There are two main types of cholesterol: High-density lipoprotein (HDL), or "good" cholesterol and Low-density lipoprotein (LDL), or "bad" cholesterol

Liver enzymes

Inflamed or injured liver cells secrete higher than normal amounts of certain chemicals, including liver enzymes, into the bloodstream


Lysophosphatidic acid (LPA) is a signaling molecule involved in fibrosis


Type of white blood cell that is part of the immune system


Major adverse cardiovascular events; a composite endpoint frequently used in cardiovascular research


A Phase 2 semen parameter trial with filgotinib in male patients with CD or UC


Phase 2 semen parameter trial with filgotinib in male patients with RA, PsA, or AS


Japanese Ministry of Health, Labor and Welfare (MHLW), in charge of Japanese market authorization of new medications


Major achievement in a project or program; in our alliances, this is usually associated with a payment


The process by which the function of proteins is changed through the use of drugs such as small molecules, peptides, antibodies or cell therapy

Molecule collections

Chemical libraries, usually consisting of drug-like small molecules that are designed to interact with specific target classes. These collections can be screened against a target to generate initial “hits” in a drug discovery program


Methotrexate; a first-line therapy for inflammatory diseases


New Drug Application


Type of immune system cell which is one of the first cell types to travel to the site of an infection in the body. Neutrophils are another type of white blood cell which fight infection by ingesting and killing microorganisms

NK cells

Natural killer cells, type of white blood cell with granules of enzymes which can attack tumors or viruses


A Phase 2 trial to evaluate ziritaxestat in systemic sclerosis (SSc). All development with ziritaxestat was discontinued in February 2021


An approved drug (nintedanib) for IPF, marketed by Boehringer Ingelheim


Short DNA or RNA molecule that can be used as research tools or therapeutic drug to change protein expression

Oral dosing

Administration of medicine by the mouth, either as a solution or solid (capsule, pill) form

Osteoarthritis (OA)

The most common form of arthritis, usually occurring after middle age, marked by chronic breakdown of cartilage in the joints leading to pain, stiffness, and swelling


Contracting work to a third party


Polycystic kidney disease is a genetic disorder in which the renal tubules become structurally abnormal, resulting in the development and growth of multiple cysts within the kidney

Pharmacokinetics (PK)

Study of what a body does to a drug; the fate of a substance delivered to a body. This includes absorption, distribution to the tissues, metabolism and excretion. These processes determine the blood concentration of the drug and its metabolite(s) as a function of time from dosing

Phase 1

First stage of clinical testing of an investigational drug designed to assess the safety and tolerability, pharmacokinetics of a drug, usually performed in a small number of healthy human volunteers

Phase 2

Second stage of clinical testing, usually performed in no more than several hundred patients, in order to determine efficacy, tolerability and the dose to use

Phase 3

Large clinical trials, usually conducted in several hundred to several thousand patients to gain a definitive understanding of the efficacy and tolerability of the candidate treatment; serves as the principal basis for regulatory approval

Phenotypic screening

Phenotypic screening is a strategy used in drug discovery to identify molecules with the ability to alter a cell’s disease characteristics. Animal models and cell-based assays are both strategies used to identify these molecules. In contrast to target-based drug discovery, phenotypic screening does not rely on knowing the identity of the specific drug target or its hypothetical role in the disease. A key benefit this approach has over target-based screening, is its capacity to capture complex biological mechanisms that are not otherwise achievable


Phase 2 trial with GPR84 inhibitor GLPG1205 in IPF patients

Pivotal trials

Registrational clinical trials


A substance having no pharmacological effect but administered as a control in testing a biologically active preparation


Stage of drug research development, undertaken prior to the administration of the drug to humans. Consists of in vitro and in vivo screening, pharmacokinetics, toxicology, and chemical upscaling

Preclinical candidate (PCC)

A new molecule and potential drug that meets chemical and biological criteria to begin the development process

Product candidate

Substance that has satisfied the requirements of early preclinical testing and has been selected for development, starting with formal preclinical safety evaluation followed by clinical testing for the treatment of a certain disorder in humans

Proof of Concept (POC)

A clinical trial in which first evidence for efficacy of a candidate drug is gathered. A Proof of Concept trial is usually with a small number of patients and for short duration to get a first impression of drug activity

Proof of Concept study

Phase 2 patient study in which activity as well as safety in patients is evaluated, usually for a new mechanism of action


Proteolysis targeting chimera, a special small molecule capable of removing unwanted proteins that play a role in disease processes


A chronic skin disease which results in scaly, often itchy areas in patches.

Psoriatic arthritis (PsA)

Psoriatic arthritis or PsA is an inflammatory form of arthritis, affecting up to 30% of psoriasis patients. Psoriatic arthritis can cause swelling, stiffness and pain in and around the joints, and cause nail changes and overall fatigue

Pulmonary embolism

A blockage in one of the pulmonary arteries in the lungs

QD dosing

Once-daily dosing (qd from the Latin quaque die)

R&D operations

Research and development operations; unit responsible for discovery and developing new product candidates for internal pipeline or as part of risk/reward sharing alliances with partners


The process by which DNA is copied to produce two identical DNA molecules during the process of cell division

Rheumatoid arthritis (RA)

A chronic, systemic inflammatory disease that causes joint inflammation, and usually leads to cartilage destruction, bone erosion and disability


Global Phase 2b trial, together with our collaboration partner Servier, with GLPG1972/S201086 (GLPG1972) in osteoarthritis (OA). In 2020, Galapagos and Servier reported that no signal of efficacy was found in the ROCCELLA trial, and have stopped further development of GLPG1972 in this indication


Method usually applied at the beginning of a drug discovery campaign, where a target is tested in a biochemical assay against a series of small molecules or antibodies to obtain an initial set of “hits” that show activity against the target. These hits are then further tested or optimized


Phase 2 program with GLPG3970 in ulcerative colitis


Securities and Exchange Commission in the US


Phase 3 program evaluating filgotinib in UC patients

SES-CD scores

Simple endoscopic score for CD, involving review of five pre-defined bowel segments, assigning values from 0 (unaffected) to 3 (highly affected)

Short interfering RNA

A research tool that is used to silence the activity of specific genes


Salt-inducible kinase. This is the target family for the portfolio of molecules in the Toledo program

Sjögrens syndrome

Sjögren’s Syndrome is a systemic inflammatory disease which can be felt throughout the body, often resulting in chronic dryness of the eyes and mouth

S&M expenses

Sales and marketing expenses

Small bowel CD (SBCD)

CD causes chronic inflammation and erosion of the intestines. It can affect different regions of gastrointestinal tract including the stomach and small and large intestines. While isolated SBCD is an uncommon presentation of CD, involvement of some portion of the small bowel, particularly the ileum, is common


Statins are a class of lipid-lowering medications that reduce illness and mortality in those who are at high risk of cardiovascular disease. They are the most common cholesterol-lowering drugs. Low-density lipoprotein (LDL) carriers of cholesterol play a key role in the development of atherosclerosis and coronary heart disease via the mechanisms described by the lipid hypothesis

Systemic lupus erythematosus

An autoimmune disease, with systemic manifestations including skin rash, erosion of joints or even kidney failure.

Systemic sclerosis (SSc)

Systemic sclerosis (SSc) or scleroderma is an autoimmune disease. One of the most visible manifestations is hardening of the skin. In diffuse cutaneous SSc, which has one of the highest mortality rates among rheumatic diseases, fibrosis occurs in multiple organs, such as the lung


Phase 2 Proof of Concept trial with SIK2/SIK3 inhibitor GLPG3970 in SLE


Proteïn that has been shown to play a role in a disease process and that forms the basis of a therapeutic intervention or discovery of a medicine

Target discovery

Identification and validation of proteins that have been shown to play a role in a disease process


Treatment Emergent Adverse Event, is any event not present prior to the initiation of the treatments or any event already present that worsens in either intensity or frequency following exposure to the treatments

Technology access fee

License payment made in return for access to specific technology (e.g. compound or virus collections)


Toledo is the program name for the target family of SIK inhibitors

Topical corticosteroids

Corticosteroids which are administered through the skin using an ointment


The process of making an RNA copy of a DNA gene sequence


The process by which a protein is synthetized from mRNA


Tyrosine kinase is an enzyme that can transfer a phosphate group from ATP to the tyrosine residues of specific proteins inside a cell. It functions as an "on" or "off" switch in many cellular functions. Tyrosine kinases belong to a larger class of enzymes known as protein kinases which also attach phosphates to other amino acids such as serine and threonine. GLPG3667 is a reversible and selective TYK2 kinase domain inhibitor

Ulcerative colitis (UC)

UC is an IBD causing chronic inflammation of the lining of the colon and rectum (unlike CD with inflammation throughout the gastrointestinal tract)


Uveitis is the term that refers to inflammation inside the eye. This inflammation can be caused by infection, autoimmune reaction, or by conditions confined primarily to the eye

Venous thrombotic events

When a blood clot breaks loose and travels in the blood, this is called a venous thromboembolism (VTE). The abbreviation DVT/PE refers to a VTE where a deep vein thrombosis (DVT) has moved to the lungs (PE or pulmonary embolism)


Formerly known as GLPG1690. Ziritaxestat is a novel drug candidate targeting autotaxin; all development with ziritaxestat was discontinued in February 2021