Adipotide, also known by the abbreviation FTPP, is a synthetic molecule built from two parts: an “address” that sticks to the blood vessels of white adipose tissue, and a “payload” that kills the cell from inside. The idea runs opposite to classical obesity drugs: rather than suppressing appetite, cut off the blood supply to fat. In obese monkeys this worked fast — they lost 7.4 to 14.7% of body weight in four weeks — but at the doses that produced that effect, injury to the renal tubules appeared. The only human trial opened in 2012 and closed after four patients, with no results published. Adipotide is not part of the SWISS LAB range, and we set out the reasons plainly below.
What adipotide is
Its full chemical name, CKGGRAKDC-GG-D(KLAKLAK)2, describes the structure well. The first fragment, CKGGRAKDC, is a nine-letter “address” fished out in 2004 by screening peptide libraries in live animals. It sticks to prohibitin — a multifunctional membrane protein that is especially abundant in the vasculature of white adipose tissue. The second fragment, D(KLAKLAK)2, is the “payload”: a short sequence that is harmless outside the cell but, once internalised, disrupts mitochondrial membranes and triggers cell death. The idea of joining an address to a payload was first described in 1999, in work on targeting tumour vessels.
How it works — “address and payload” in plain terms
Adipose tissue, like any other, needs vessels. Adipotide does not attack fat cells; it attacks the endothelium, the cell layer lining the small vessels that feed that fat. The address guides the molecule to fat vessels, the payload kills their cells, the fat loses its blood supply and is resorbed. The distinction matters, because it explains both the efficacy and the risk: the mechanism is cell killing, and its safety rests entirely on the accuracy of the address. Prohibitin, moreover, is not a protein found only in fat vessels — it is multifunctional and present in other tissues too.
What was studied — rodents
In the 2004 paper, delivering the payload to prohibitin led in mice to resorption of established white adipose tissue, normalisation of metabolism and rapid reversal of obesity — with, as the authors wrote at the time, no detectable adverse effects. That last part is worth remembering: the renal signal only appeared in monkeys.
The second important thread is metabolism. In a 2012 paper, obese mice on a high-fat diet received either the pro-apoptotic peptide or vehicle, while a third group was pair-fed to the treated group (given the same amount of food). Glucose tolerance improved rapidly and independently of body weight and of food intake, insulin and triglycerides fell, and gene-expression analysis in adipose tissue showed that diet-induced changes in mitochondrial pathways and in branched-chain amino acid degradation were reversed.
The third point comes from an independent centre. In 2013 a Japanese team compared adipotide with a prohibitin-targeted nanoparticle carrying the same payload. At a low dose it was the nanoparticle, not adipotide, that reduced body weight — so the efficacy of the bioconjugate itself proved dose-dependent and inferior to the newer construct.
The pivotal study — obese monkeys (2011)
This is the only study in primates and at the same time the source of every figure later repeated online. In its main part, 15 spontaneously obese rhesus macaques (5 controls, 10 treated) received a previously established dose of 0.43 mg/kg subcutaneously every day for four weeks, followed by four weeks of observation. At the end of treatment the treated monkeys had lost between 7.4 and 14.7% of their pretreatment body weight, while the controls changed by +1.0 to -3.5%. The insulinogenic index — a measure of insulin resistance — fell by a mean of 48.5% in the treated group and rose by 33.8% in the controls (p = 0.006). Magnetic resonance imaging and densitometry confirmed a marked loss of white adipose tissue.
The same paper, however, carries two caveats that the authors themselves flagged. First: the weight loss went hand in hand with reduced food intake. Second: lean monkeys given the therapeutic dose did not lose weight at all. A year later the same journal published a comment whose author argued that the observed weight loss might simply reflect eating less, rather than vessel death. The mouse study with a pair-fed group shows that at least the improvement in glucose tolerance is not explained by food intake — but the dispute over the mechanism of weight loss was never settled.
The kidneys — why development stalled
Kidneys filter blood, and molecules of this size pass through the renal tubules. In monkeys, serum creatinine rose in a dose-dependent way at subcutaneous doses above 0.25 mg/kg, urine volume increased, and at the highest doses there were signs of mild dehydration. Urine contained sugar and protein, while serum phosphorus and potassium fell — the pattern typical of disturbed proximal tubule function.
The strongest data come from a formal safety study run to GLP standard: 15 lean macaques received one of three dose levels — 0.25, 0.43 or 0.75 mg/kg — every day for 28 days. In animals examined 24 hours after the last dose, kidney lesions were found that were dose-dependent and absent from the control group: single-cell necrosis plus reactive and regenerative changes in the tubules. They were scored minimal to mild in the lowest-dose group, minimal to mild in most animals of the middle group, and minimal to moderate in the highest. In the highest-dose group creatinine peaked at the end of dosing and remained slightly elevated after the recovery period, and minimal tubular degeneration persisted in one monkey from the middle group and two from the highest-dose group.
The authors summarised this as relatively mild, predictable and reversible injury. A different observation is the crucial one, though: histological lesions occurred at all three dose levels, including the lowest — that is, below the 0.43 mg/kg dose that produced weight loss in obese monkeys. Efficacy and the renal signal do not separate, they overlap, and that is the gravest charge against this molecule.
Human data — the trial that never happened
PubMed holds not a single paper in which adipotide was given to a human being. The ClinicalTrials.gov registry, however, holds one entry worth knowing: NCT01262664, “A First-in-Man, Phase I Evaluation of A Single Cycle of Prohibitin Targeting Peptide 1 in Patients With Metastatic Prostate Cancer and Obesity”, run at the MD Anderson Cancer Center, with the molecule listed there as Prohibitin-TP01. The study set out to find the highest tolerated dose in obese men with metastatic prostate cancer. It began in May 2012, carries the status of terminated with the note “Terminated per PI's request”, its actual enrolment was 4, and no results were posted; the record was last updated in January 2019.
Hence a conclusion more precise than the popular “it never entered human trials”: it did enter, at one centre, and ended there — after four patients, with no publication and no disclosed results. So about the action of adipotide in a human being we know nothing: neither how long it persists, nor what dose is tolerable, nor what it does to human kidneys.
Safety and the limits of the evidence
Let us gather what is missing. No published human pharmacokinetic, efficacy or safety data of any kind. No animal data beyond 28 days of dosing. No proof that renal tubular changes resolve in humans — in monkeys they mostly did, but not in every animal within the recovery period. The molecule's payload is a membrane-destroying sequence with no tissue selectivity of its own, so all protection of healthy tissue rests on the accuracy of the address, and the address protein, prohibitin, is not reserved for fat vessels. We deliberately give no methods of use and no doses; the figures above describe what was done to animals in studies and are guidance to nobody.
Why it is not part of our range
First reason: in primates the effective dose and the dose that injures renal tubules fall in the same range — there is no margin anyone could call safe, because no such margin was ever demonstrated. Second: the only human trial closed after four patients without publication, so a human dose scale simply does not exist. Third: the mechanism is cell killing and its safety rests solely on the selectivity of the address — an entirely different category of risk from compounds that modulate a signal. Fourth: even the weight-loss effect has a published alternative explanation (eating less) that was never refuted. For someone looking for a way to lose weight, that is the worst possible combination: real renal risk and uncertain benefit.
The wider context — where obesity pharmacology went
Adipotide was conceived when obesity drugs were being withdrawn one after another and targeting fat vasculature looked like a way around central side effects. Today the niche looks different: the field has been taken over by incretin peptides, tested in large trials with thousands of participants — we cover them in our pieces on semaglutide and on the metabolic peptides of GLP-1, GIP and glucagon. The difference is not that those are “natural” and adipotide “synthetic”. It is that those have data from tens of thousands of people, and adipotide from four whose results were never published.
Summary
Adipotide is a well-documented idea with one clear result in primates: rapid fat loss and improved insulin resistance in obese macaques. The same experiment also showed dose-dependent renal tubular injury within the effective dose range, and a fall in food intake whose contribution to the effect was never excluded. Development ended with a single phase 1 trial, terminated after four patients. The state of the evidence: a rich animal literature, zero published human data, and a renal signal nobody managed to separate from efficacy.
Sources
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- Kolonin MG, Saha PK, Chan L, Pasqualini R, Arap W. Reversal of obesity by targeted ablation of adipose tissue. Nature Medicine. 2004;10(6):625-632. PMID: 15133506. DOI: 10.1038/nm1048. pubmed.ncbi.nlm.nih.gov/15133506
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- Hossen N, Kajimoto K, Akita H, Hyodo M, Harashima H. A comparative study between nanoparticle-targeted therapeutics and bioconjugates as obesity medication. Journal of Controlled Release. 2013;171(2):104-112. PMID: 23871959. DOI: 10.1016/j.jconrel.2013.07.013. pubmed.ncbi.nlm.nih.gov/23871959
- Ellerby HM, Arap W, Ellerby LM, et al. Anti-cancer activity of targeted pro-apoptotic peptides. Nature Medicine. 1999;5(9):1032-1038. PMID: 10470080. DOI: 10.1038/12469. pubmed.ncbi.nlm.nih.gov/10470080
- Criscione L. Comment on "A peptidomimetic targeting white fat causes weight loss and improved insulin resistance in obese monkeys". Science Translational Medicine. 2012;4(131):131le2. PMID: 22539771. DOI: 10.1126/scitranslmed.3003760. pubmed.ncbi.nlm.nih.gov/22539771
For in-vitro laboratory research only. It is not a human medicine and is not for treatment.