A Phase 1 interventional study of GIGA-2339 and Placebo in Hepatitis B Virus Infection, sponsored by GigaGen, Inc.. Recruiting at 20 sites in 5 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-25.
Sponsored by GigaGen, Inc. (part of Grifols) · Phase 1, Interventional, and Treatment
The primary purpose of this study is to assess the safety and tolerability of single and multiple intravenous (IV) doses of GIGA-2339 in participants with chronic Hepatitis B Virus (HBV) infection.
1,045 studies on the registry are indexed under Hepatitis B; 139 are open to participants now.
This study's planned enrollment of 48 is below the median of 147 across 756 interventional studies indexed under Hepatitis B.
Browse Hepatitis B studies →GigaGen, Inc. is the lead sponsor of 3 studies on the registry; 2 are open to participants now.
First submitted after GigaGen, Inc. became part of Grifols.
Counted across the registry records on this site, refreshed daily.
Key Inclusion Criteria:
Key Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
QT and QTc
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECG (electrocardiogram)
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Excipients
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Live vaccines
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants will receive a single IV infusion of either GIGA-2339 or placebo in ascending doses on Day 1.
Drug: GIGA-2339 · Drug: Placebo
Participants will receive multiple IV infusions of either GIGA-2339 or placebo, once every 4 weeks, at a dose determined in Part 1.
Drug: GIGA-2339 · Drug: Placebo
Administered by intravenous infusion
Administered by intravenous infusion
SAD and MAD: Number of Participants With Treatment-emergent Adverse Events (TEAEs) and Serious Adverse Events (SAEs)
Time frame: SAD: Up to Day 105; MAD: Up to Day 245
SAD and MAD: Maximum Serum Concentration (Cmax) of GIGA-2339
Time frame: SAD: Pre-dose and at multiple timepoints post-dose up to Day 105; MAD: Pre-dose and at multiple timepoints post-dose up to Day 245
SAD and MAD: Area Under the Concentration Time Curve (AUC) from 0 to the Last Quantifiable Concentration (AUC0-t) of GIGA-2339
Time frame: SAD: Pre-dose and at multiple timepoints post-dose up to Day 105; MAD: Pre-dose and at multiple timepoints post-dose up to Day 245
SAD: AUC From 0 to Infinity (AUC0-∞) of GIGA-2339
Time frame: Pre-dose and at multiple timepoints post-dose up to Day 105
SAD: Dose Normalized Maximum Serum Concentration (DN_Cmax). of GIGA-2339
Time frame: Pre-dose and at multiple timepoints post-dose up to Day 105
SAD: Dose Normalized AUC From 0 to the Last Quantifiable Concentration (DN_AUC0-t) of GIGA-2339
Time frame: Pre-dose and at multiple timepoints post-dose up to Day 105
SAD: Dose Normalized AUC From 0 to Infinity (DN_AUC0-∞) of GIGA-2339
Time frame: Pre-dose and at multiple timepoints post-dose up to Day 105
SAD and MAD: Time to Obtain Maximum Concentration (Tmax) of GIGA-2339
Time frame: SAD: Pre-dose and at multiple timepoints post-dose up to Day 105; MAD: Pre-dose and at multiple timepoints post-dose up to Day 245
SAD and MAD: Terminal Half-Life (t1/2) of GIGA-2339
Time frame: SAD: Pre-dose and at multiple timepoints post-dose up to Day 105; MAD: Pre-dose and at multiple timepoints post-dose up to Day 245
SAD and MAD: Volume of Distribution (Vz) of GIGA-2339
Time frame: SAD: Pre-dose and at multiple timepoints post-dose up to Day 105; MAD: Pre-dose and at multiple timepoints post-dose up to Day 245
SAD and MAD: Systemic Clearance (CL) of GIGA-2339
Time frame: SAD: Pre-dose and at multiple timepoints post-dose up to Day 105; MAD: Pre-dose and at multiple timepoints post-dose up to Day 245
MAD: Serum Concentration at the End of the Dosing Interval (Ctrough) of GIGA-2339
Time frame: Pre-dose and at multiple timepoints post-dose up to Day 245
MAD: AUC Versus Time Curve During the Dosing Interval (AUC0-tau) of GIGA-2339
Time frame: Pre-dose and at multiple timepoints post-dose up to Day 245
MAD: Accumulation Ratio Cmax (ARCmax) of GIGA-2339
Time frame: Pre-dose and at multiple timepoints post-dose up to Day 245
MAD: Accumulation Ratio AUC (ARAUCs) of GIGA-2339
Time frame: Pre-dose and at multiple timepoints post-dose up to Day 245
Not enrolling at this site.
Plan to share: Undecided
No publications or documents are linked to this record.
Started Nov 2024 (actual). Primary completion is estimated for Nov 2028, 48 months after the start.
Of 49 industry-sponsored phase 1 interventional studies under Hepatitis B, half reached primary completion within 13 months of starting (the median), counting those still running; a quarter within 7 and three quarters within 24. This study's planned 48 months is above that.
Counting every sponsor, half of 58 studies reached it within 14 months; a quarter within 7 and three quarters within 27.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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