The clinical pipeline — peptide therapies in development for the next five years

The most crowded and commercially competitive portion of the pipeline is metabolic disease, and specifically the incretin space that semaglutide and tirzepatide have made into one of the most valuable therapeutic categories in pharmaceutical history. Retatrutide, Eli Lilly's triple agonist targeting GLP-1, GIP, and glucagon receptors simultaneously, completed Phase II trials showing weight loss exceeding twenty percent of body weight at higher doses — results that outperformed anything previously seen in the class. Phase III trials are underway, and if they replicate the Phase II efficacy and the safety profile remains acceptable, retatrutide may represent the next step change in obesity pharmacology. The glucagon receptor component is thought to contribute additional metabolic benefit through increased energy expenditure, which the dual GLP-1/GIP mechanism of tirzepatide doesn't fully provide. Whether the additional receptor agonism translates to a meaningfully different clinical profile for specific patient populations will take the Phase III data and post-approval experience to understand.

Survodutide, a dual GLP-1/glucagon agonist being developed by Boehringer Ingelheim in partnership with Zealand Pharma, is in Phase III for both obesity and nonalcoholic steatohepatitis — the accumulation of fat and inflammation in the liver that has become one of the largest unmet needs in metabolic medicine. The glucagon receptor's role in hepatic fat metabolism makes it a logical target for NASH, and survodutide's Phase II liver data were compelling enough to justify the Phase III commitment. Mazdutide, a similar dual agonist developed by Innovent Biologics, is in advanced trials in China, where the obesity and metabolic disease burden makes it a substantial commercial opportunity. These are different molecules working on overlapping biology with different development timelines and regulatory strategies.

Cagrilintide — an amylin analog — represents a different direction in the incretin story. Amylin is a hormone secreted alongside insulin from pancreatic beta cells; it promotes satiety, slows gastric emptying, and suppresses glucagon secretion, and its deficiency is part of the dysregulation in both type 1 and type 2 diabetes. Cagrilintide is a long-acting amylin analog developed by Novo Nordisk, and the more interesting development is CagriSema: the combination of cagrilintide and semaglutide in a fixed-dose weekly injection. The Phase III REDEFINE program is evaluating CagriSema for obesity, and the Phase II data showed weight loss of approximately twenty-two percent over sixty-eight weeks at the highest dose — comparable to retatrutide, achieved through a different dual mechanism. The combination approach reflects a broader strategy: targeting multiple complementary satiety and metabolic pathways simultaneously produces results that single-agent therapy cannot replicate, and the most clinically effective obesity treatments over the next decade are likely to be combinations of this kind.

Outside the injectable incretin space, the oral GLP-1 program is expanding. Semaglutide's oral formulation (Rybelsus) is approved for diabetes; oral semaglutide for obesity at higher doses is in late development. Orforglipron — Eli Lilly's oral small-molecule GLP-1 agonist, technically not a peptide but a small molecule that binds the GLP-1 receptor — is in Phase III and represents the most advanced program in what may become oral obesity treatment. The distinction between "oral non-peptide GLP-1 agonist" and "oral peptide GLP-1 agonist" matters pharmacologically but not for the commercial question it raises: an oral once-daily GLP-1 drug that performs comparably to injectable semaglutide would reshape prescribing and access in ways that are hard to fully anticipate. Several other oral peptide and small-molecule GLP-1 candidates are in Phase II; the next few years will determine which proceed to Phase III and which attrition out.

The neurology pipeline is less commercially visible than metabolic but clinically significant. Migraine treatment has been transformed over the last five years by CGRP — calcitonin gene-related peptide — and the antibodies and small-molecule receptor antagonists targeting it. CGRP is released during migraine attacks and plays a central role in the neurogenic inflammation underlying migraine pain. Erenumab (Aimovig), fremanezumab (Ajovy), and galcanezumab (Emgality) are anti-CGRP antibodies approved for migraine prevention; gepants — oral CGRP receptor antagonists including ubrogepant and rimegepant — are approved for acute migraine treatment and, in the case of rimegepant, for prevention as well. The PACAP pathway — pituitary adenylate cyclase-activating polypeptide — is the next frontier in migraine, with Lundbeck's AMG 301 and other anti-PACAP antibodies in development and early clinical data supporting the hypothesis that PACAP receptor signaling is another contributor to migraine pathophysiology. Several programs targeting this pathway are now in Phase II, with Phase III following as the data accumulate.

The neurodegenerative pipeline is more cautious. The failures in Alzheimer's drug development over decades have made the entire field appropriately skeptical of early-stage enthusiasm. Some peptide-related programs — targeting amyloid aggregation, tau pathology, or neuroinflammatory mediators — are in research or early clinical phases, but none of the currently active programs represent near-term approvals with high confidence. The exception is the infrastructure being built around GLP-1 and brain health: accumulating epidemiological evidence suggests that people taking GLP-1 agonists have lower rates of dementia and Parkinson's disease, and multiple clinical trials are now specifically investigating GLP-1 agonists for neurodegeneration. Whether this represents a genuine neuroprotective mechanism or confounding from metabolic improvement is an active research question — the answer isn't yet clear, but the trials are underway and results are expected in this five-year window.

In oncology, the peptide receptor radionuclide therapy wave launched by Lutathera and Pluvicto is expanding. Programs targeting gastrin-releasing peptide receptors (overexpressed in prostate cancer and other solid tumors), fibroblast activation protein (expressed broadly in solid tumor stroma), integrin receptors, and other tumor-expressed targets are in Phase I and Phase II trials at multiple centers. The radiopharmaceutical infrastructure — cyclotron production of isotopes, specialized handling and administration — has expanded substantially in response to the Pluvicto launch, and several additional PSMA-targeted programs are in development that may offer different isotope-linker-peptide combinations with improved properties. The first half of the five-year window — 2025 through 2027 — will produce clinical data from several of these programs that will shape which proceed to registration trials.

The autoimmune and inflammation pipeline includes peptide-related programs targeting IL-17, IL-23, and related cytokine pathways. Most of the active innovation here is in the antibody space rather than the peptide space, but some specifically peptide-format compounds — including VIP-related compounds being studied for pulmonary arterial hypertension and inflammatory lung disease — are in early clinical phases. The cardiovascular pipeline includes some gut-peptide-cardiovascular axis work: GLP-1 drugs' cardiovascular benefits, observed in major outcomes trials, have stimulated research into related gut-derived peptides and their cardiac effects, with some early-stage programs pursuing cardiovascular indications through mechanisms adjacent to but distinct from the metabolic GLP-1 story.

The longevity research pipeline is the area most important to be honest about, because it generates substantial public interest and often creates expectations that the evidence doesn't support. The Targeting Aging with Metformin (TAME) trial is studying whether metformin, a generic diabetes medication, can meaningfully slow aging-related outcomes in non-diabetic older adults — this is a landmark trial methodologically, but metformin is not a peptide. Rapamycin's effects on aging are being studied in several human trials; again, not a peptide. The specific peptide candidates most discussed in longevity research contexts — including some growth hormone secretagogues, humanin and related mitochondrial peptides, and some NAD-pathway-adjacent compounds — are largely at preclinical or very early clinical stages. Describing this pipeline as delivering approved longevity therapeutics within the 2025-2030 window would substantially overstate the evidence. What's accurate is that the longevity research field is conducting more rigorous human trials than it has in the past, and the results of some of those trials will be informative within the five-year horizon even if they don't produce approved drugs.

The economic and access dimension of all of this is not separable from the clinical story. Semaglutide at list price costs over a thousand dollars a month in the United States without insurance coverage. Tirzepatide is similarly priced. As the pipeline produces more approved drugs, the pricing pressure and access questions will intensify. Compounding pharmacies offered compounded semaglutide during the period of FDA-designated drug shortage, which ended in early 2025, and the subsequent enforcement activity against compounded GLP-1s reflects the regulatory tension between legitimate drug shortage access and competition with branded drug manufacturers once shortages resolve. As more peptide drugs achieve approval and branded availability, the compounding carve-out for those same compounds becomes legally narrower. This is not a hypothetical trajectory — it has already played out with semaglutide and will play out with other peptide drugs that follow the same path from shortage to resolution.

The practical implication for anyone following the peptide space is that the next five years will be characterized by a genuine expansion of clinically validated peptide therapeutics — primarily in metabolic disease, oncology, and cardiovascular medicine — alongside a gradual regulatory consolidation that may reduce the space for compounded alternatives to drugs with approved branded versions. These two trends are related: they reflect the maturation of peptide medicine from an early-stage and experimental field toward an established one with robust clinical infrastructure. The early-stage creativity that made the compounding and research peptide ecosystem interesting and accessible is partly a feature of the field's immaturity. Maturity brings proven drugs, regulatory rigor, and the access challenges that come with expensive branded medications. What to watch for: the Phase III results from retatrutide, CagriSema, and the oral GLP-1 programs; the early efficacy data from CGRP-adjacent migraine programs; and the first major clinical trial results from GLP-1 neurodegeneration studies. These will shape what peptide medicine looks like when we take stock again at the end of the decade.