Taspoglutide
Taspoglutide (R1583, BIM-51077), once-weekly GLP-1 receptor agonist, development halted in phase 3
Written by Aaron CuhaReviewed Sep 2026
Also known as: R1583, BIM-51077
A once-weekly GLP-1 analogue that beat exenatide and sitagliptin on HbA1c in phase 3 and was halted in 2010 anyway. Its sponsor recorded the reason on the trial registry: high discontinuation rates mainly due to gastrointestinal tolerability and a risk mitigation plan for hypersensitivity reactions. Anti-drug antibodies were found in 46 to 49 percent of participants.
Overview
Taspoglutide is a synthetic analogue of human GLP-1 developed by Ipsen (BIM-51077) and licensed to Roche (R1583) for once-weekly subcutaneous injection in type 2 diabetes. It went into a phase 3 programme, T-emerge, of eight trials that randomised more than 6,000 people, and it is the most fully documented failure in the GLP-1 class: a drug that met its efficacy endpoints and was stopped for how people tolerated it.
The published human record is three randomised phase 3 trials. T-emerge 2 (Diabetes Care, 2013) randomised 1,189 overweight adults with type 2 diabetes on metformin to taspoglutide 10 mg weekly, 20 mg weekly or exenatide 10 mcg twice daily, open-label, for 24 weeks. From a mean baseline HbA1c of 8.1 percent, taspoglutide lowered HbA1c by 1.24 and 1.31 percentage points against 0.98 for exenatide (differences 0.26 and 0.33 points, P below 0.0001 for both). Weight fell 1.6 kg and 2.3 kg against 2.3 kg on exenatide. Nausea occurred in 53, 59 and 35 percent and vomiting in 33, 37 and 16 percent respectively; allergic and injection site reactions were more common with taspoglutide; and anti-taspoglutide antibodies were detected in 49 percent of participants. The authors' own conclusion described the glycaemic control as greater than exenatide but accompanied by what they called unacceptable levels of nausea and vomiting, injection site reactions and systemic allergic reactions. T-emerge 4 (Diabetes Therapy, 2012) randomised 666 people to taspoglutide 10 or 20 mg, sitagliptin 100 mg or placebo for 24 weeks: HbA1c fell 1.23 and 1.30 points against 0.89 for sitagliptin and 0.10 for placebo, weight fell 1.8 and 2.6 kg against 0.9 and 0.5 kg, antibodies were confirmed in 46 percent, and the authors recorded that the adverse event profile led to the discontinuation of dosing. T-emerge 3 (Journal of Clinical Endocrinology and Metabolism, 2012) randomised 326 people on metformin plus pioglitazone: HbA1c fell 1.35 and 1.40 points against 0.45 on placebo, with nausea in 35 and 44 percent against 10 and injection site reactions in 24 percent against 5.
The programme was halted in 2010. The primary record of why is the sponsor's entry on ClinicalTrials.gov for NCT01051011, a 370 person phase 3 against insulin glargine, marked TERMINATED with the reason given as high discontinuation rates mainly due to GI tolerability and implementation of risk mitigation plan to address hypersensitivity reactions. That is Roche's own statement and this profile reports it as such; it does not add reasons that appear only in secondary sources. Three further large phase 3 trials are listed as completed on the registry with no results posted and no located publication: 2,118 people with cardiovascular disease (NCT01018173), 1,072 against insulin glargine (NCT00755287) and 756 against pioglitazone (NCT00909597). Taspoglutide was never submitted for approval anywhere as far as any public record shows.
Mechanism of action
Taspoglutide is a GLP-1 receptor agonist and in people it did what the class does: it lowered HbA1c and fasting glucose, improved a homeostasis model estimate of beta cell function in T-emerge 3, and produced modest weight loss of 1 to 2.6 kg over 24 weeks. Its distinguishing property was pharmaceutical rather than pharmacological: it was formulated as a sustained-release weekly injection, one of the first in the class. The failure mechanism is the part that matters for anyone reading about peptide drugs. Between 46 and 49 percent of participants developed antibodies to the drug, and systemic allergic reactions and injection site reactions were frequent enough that the sponsor introduced a hypersensitivity risk mitigation plan. A modified human peptide given repeatedly can be immunogenic, and the immune response can produce hypersensitivity independent of whether the drug is still lowering glucose. Whether the antibodies also reduced efficacy over time was not established in the published trials, which ran 24 to 52 weeks. Half-life and molecular weight were not retrievable from a primary source and are not given.
Human evidence
A large randomised phase 3 programme: three published trials totalling 2,181 people over 24 weeks with 52 week extensions, and at least three further phase 3 trials totalling 3,946 people that completed and were never published or posted. All sponsored by Roche. The published trials met their efficacy endpoints; the programme was halted for tolerability and hypersensitivity.
- T-emerge 2, 1,189 people, open-label against exenatide: HbA1c fell 0.26 to 0.33 points more than exenatide; weight loss at 10 mg was less than exenatide; nausea 53 to 59 percent against 35; vomiting 33 to 37 percent against 16; antibodies in 49 percent.
- T-emerge 4, 666 people, double-blind against sitagliptin and placebo: HbA1c fell 0.34 to 0.41 points more than sitagliptin; weight fell 1.8 to 2.6 kg against 0.9; antibodies in 46 percent; higher discontinuation for adverse events.
- T-emerge 3, 326 people, double-blind against placebo on metformin plus pioglitazone: HbA1c fell about 0.9 points more than placebo; nausea 35 to 44 percent against 10; injection site reactions 24 percent against 5.
- NCT01051011, 370 people against insulin glargine: terminated by the sponsor for high discontinuation rates mainly from gastrointestinal intolerance and a hypersensitivity risk mitigation plan.
- Unreported: 2,118 people with cardiovascular disease (NCT01018173), 1,072 against glargine (NCT00755287), 756 against pioglitazone (NCT00909597), all completed 2010 to 2011 with no results posted.
What this does not tell you: The published trials are 24 weeks with extensions to 52, so nothing is known about longer use, and the largest trials never reported at all, which means the tolerability and hypersensitivity picture across the full programme is only partly public. The exenatide comparison was open-label. Whether the anti-drug antibodies reduced efficacy over time was not established. The sponsor's stated reason for stopping is the only primary account of the decision, and it does not quantify the hypersensitivity reactions.
Reading the research record
Taspoglutide is the case that separates two questions this site keeps apart: did the drug do what it was meant to, and could it be developed. On the first, the answer from three randomised phase 3 trials is yes: it lowered HbA1c more than exenatide, more than sitagliptin and much more than placebo. On the second, the answer from the sponsor's own registry entry is no: too many people stopped taking it because of nausea and vomiting, and hypersensitivity reactions were frequent enough to require a formal risk mitigation plan. Roche halted the programme in 2010 and the compound has not been heard of since.
Two features of the record deserve attention. First, immunogenicity: 46 to 49 percent of participants developed antibodies to taspoglutide. Modified peptides given repeatedly can provoke antibodies and, in some people, systemic allergic reactions, and that risk is rarely discussed in consumer material about peptides bought outside the regulated system, where nobody measures antibodies at all. Second, unreported trials: at least 3,946 people were randomised in phase 3 trials that completed and never appeared in a journal or on the registry. Those participants' data exist and are not public. The reason the programme stopped is documented; the full extent of what it found is not.
The evidence, charted
Fig. 1 · evidence composition
7of 7 citations (100%) are in people
Every citation cited here is Human work; no other study type is cited on this page. This count is of our own citation list and understates any literature larger than the sources we cite.
Fig. 2 · evidence over time
Evidence spans 4 distinct years, 2010 to 2013, counted from the citation list on this page. The newest citation on file is from 2013, more than five years ago; the published record may have gone quiet.
Fig. 3 · legal status at a glance
US
Not approved
UK
Approved
AU
Approved
CA
Not approved
Approved in 2 of 4, prescription route in 0, not approved in 2. A jurisdiction's classification is a regulatory fact, not a verdict on the science; see Legal status below for the full text and any notes.
Key studies & citations
- Human2013
The fate of taspoglutide, a weekly GLP-1 receptor agonist, versus twice-daily exenatide for type 2 diabetes: the T-emerge 2 trial
1,189 overweight adults with type 2 diabetes on metformin randomised open-label to taspoglutide 10 mg weekly (399), 20 mg weekly (398) or exenatide 10 mcg twice daily (392), 24 weeks. HbA1c minus 1.24 and minus 1.31 percentage points against minus 0.98 (P below 0.0001 for both). Weight minus 1.6 and minus 2.3 kg against minus 2.3 kg. Nausea 53, 59 and 35 percent; vomiting 33, 37 and 16 percent; more allergic and injection site reactions and more discontinuations with taspoglutide; anti-drug antibodies in 49 percent. Sponsor funded (registry NCT00717457).
Diabetes Care - Human2012
Efficacy and safety of taspoglutide versus sitagliptin for type 2 diabetes mellitus (T-emerge 4 trial)
666 people on metformin randomised double-blind to taspoglutide 10 mg (190) or 20 mg (198) weekly, sitagliptin 100 mg daily (185) or placebo (93), 24 weeks. HbA1c minus 1.23 and minus 1.30 points against minus 0.89 (sitagliptin) and minus 0.10 (placebo); weight minus 1.8 and minus 2.6 kg against minus 0.9 and minus 0.5 kg. Gastrointestinal, allergic and injection site reactions higher with taspoglutide with higher discontinuation; antibodies confirmed in 46 percent. The authors state the safety profile led to discontinuation of dosing. Sponsor funded.
Diabetes Therapy - Human2012
Efficacy and safety of taspoglutide in patients with type 2 diabetes inadequately controlled with metformin plus pioglitazone over 24 weeks: T-Emerge 3 trial
326 people randomised double-blind to taspoglutide 10 mg, 20 mg or placebo weekly for 24 weeks. HbA1c minus 1.35 and minus 1.40 points against minus 0.45 (P below 0.0001); HbA1c at or below 7 percent in 69.8 and 76.1 percent against 35.1; weight minus 0.64 and minus 1.04 kg against plus 0.59 kg. Nausea 35, 44 and 10 percent; vomiting 21, 24 and 2 percent; injection site reactions 24, 24 and 5 percent. Sponsor funded.
Journal of Clinical Endocrinology and Metabolism - Human2010
A Study to Compare Taspoglutide and Insulin Glargine in Insulin-Naive Patients With Type 2 Diabetes Mellitus Inadequately Controlled on Metformin and Sulfonylurea Combination Therapy
Phase 3, 370 participants, sponsor Hoffmann-La Roche, TERMINATED. Sponsor's why-stopped text: high discontinuation rates mainly due to GI tolerability and implementation of risk mitigation plan to address hypersensitivity reactions. The primary source for why the programme ended.
ClinicalTrials.gov - Human2011
A Study of Taspoglutide in Patients With Inadequately Controlled Diabetes Mellitus Type 2 and Cardiovascular Disease
Phase 3, 2,118 participants, sponsor Hoffmann-La Roche, listed as COMPLETED with primary completion January 2011. No results posted and no publication located as of 11 September 2026. The largest trial in the programme is unreported.
ClinicalTrials.gov - Human2010
A Study of the Safety, Tolerability and Effect on Glycemic Control of Taspoglutide Versus Insulin Glargine in Insulin Naive Type 2 Diabetic Patients Inadequately Controlled With Metformin Plus Sulphonylurea
Phase 3, 1,072 participants, completed December 2010, no results posted and no publication located. A 756 person comparison against pioglitazone (NCT00909597) is in the same position.
ClinicalTrials.gov - Human2011
A Study of Taspoglutide Versus Exenatide for the Treatment of Patients With Type 2 Diabetes Mellitus Inadequately Controlled With Metformin, Thiazolidinedione or a Combination of Both (T-emerge 2)
Phase 3, 1,189 participants, completed March 2011. The registration for the published T-emerge 2 trial; no results posted on the registry.
ClinicalTrials.gov
Frequently asked questions
Why was taspoglutide abandoned if it lowered blood sugar better than exenatide?
Because of how people tolerated it. The sponsor's own entry on ClinicalTrials.gov for a terminated phase 3 trial gives the reason as high discontinuation rates mainly due to gastrointestinal tolerability and implementation of a risk mitigation plan to address hypersensitivity reactions. In the published trials, 53 to 59 percent had nausea and 33 to 37 percent vomited, and 46 to 49 percent developed antibodies to the drug.
What did the phase 3 trials show?
In T-emerge 2, 1,189 people were randomised to weekly taspoglutide or twice-daily exenatide for 24 weeks; taspoglutide lowered HbA1c by 1.24 to 1.31 percentage points against 0.98 for exenatide. In T-emerge 4, 666 people, it beat sitagliptin by 0.34 to 0.41 points. In T-emerge 3, 326 people, it beat placebo by about 0.9 points. Weight loss was modest, 1 to 2.6 kg. All three were funded by Roche.
What does 49 percent antibody positivity mean?
That about half of participants developed an immune response to the drug. Anti-drug antibodies can be harmless, can neutralise a drug's effect, or can be associated with allergic reactions. The trials showed more systemic allergic and injection site reactions with taspoglutide than with comparators, and the sponsor introduced a hypersensitivity risk plan, but the published papers do not report whether the antibodies reduced glucose lowering over time.
Were all the trials published?
No. Three published phase 3 trials cover 2,181 people. At least three more that completed in 2010 and 2011, totalling 3,946 people including 2,118 with cardiovascular disease, have no results posted on ClinicalTrials.gov and no located publication.