PXL01 (ensereptide)_Dosage, benefits & legal status
Also known as ensereptide, PXL-01
A 25-residue piece of human lactoferrin, mixed into a hyaluronate gel and placed around a freshly repaired finger tendon to keep scar from gluing it to its sheath. It missed its primary endpoint at p=0.886, and its sponsor shut the program down in June 2023.
Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.
What is PXL01 (ensereptide)?
Plain language first. The technical label stays, but it never stands alone.Overview
After a cut flexor tendon in the hand is sewn back together, scar can stick the tendon to the sheath it slides through, and the finger never bends properly again; PXL01 was an attempt to prevent that in the operating room. In 138 patients it missed its primary endpoint: finger motion at 12 weeks was a median 121 degrees against 108 on placebo, p=0.886. Several six-month measures did favor it, including 60 against 41 degrees of motion at the end joint and 61% against 38% rated excellent or good, but only in the per-protocol set, with no adjustment for testing many outcomes, and against a saline placebo rather than the gel the peptide came in. A second randomized trial, in scar prevention, showed nothing; the sponsor stopped the compound on June 22, 2023 and the company went into liquidation that October.
PXL01 (INN ensereptide, INN list number 9579) is a 25-residue synthetic peptide, EATKCFQWQRNMRKVRGPPVSCIKR with a single disulfide between the cysteines at positions 5 and 22, taken from the cationic lactoferricin region near the start of human lactoferrin. It was given as a single intraoperative application of 0.5 mL containing 20 mg/mL of peptide in 15 mg/mL sodium hyaluronate, placed between a repaired flexor tendon and its sheath, with the aim of damping the inflammation that bridges scar across the gliding surface; the sponsor's proposed mechanism was increased expression of PRG4, or lubricin, and no receptor, molecular target or potency figure has ever been published. Pergamum AB sponsored the one randomized tendon trial, Promore Pharma carried the compound afterward, no regulator has ever approved it, and the planned phase 3 of 500 to 600 patients never enrolled anyone.
What it's used for
Nothing. It was given once during flexor tendon surgery in a 138-patient trial and tested on induced wounds in 24 volunteers, it has never been approved anywhere, it is not sold by research-peptide sellers, and the program was discontinued in 2023.
How does PXL01 (ensereptide) work?
What it does in the body, and where.PXL01 was stirred into a hyaluronate gel and laid around a freshly repaired tendon, to keep scar from sticking the tendon to the sheath it has to slide through.
- 01Where it comes fromThe 25 residues are a fragment of the cationic, antibacterial lactoferricin region near the start of human lactoferrin, an iron-binding protein found in neutrophil granules and in secretions such as tears and milk. Four arginines and three lysines against a single glutamate make the fragment strongly positively charged, as lactoferrin peptides generally are.
- 02What it was meant to doA repaired tendon heals inside a sheath it must glide through. Inflammation in the first weeks recruits fibroblasts that bridge scar between the two surfaces, and the finger stops bending. The peptide was meant to damp that response; the sponsor's proposed explanation was more PRG4, or lubricin, the boundary lubricant on gliding surfaces, shown in cell and animal work.
- 03What is not knownNo receptor, molecular target, selectivity or potency figure has ever been published, so the mechanism is phenotypic and inferred rather than defined. The hyaluronate carrier is a physical barrier in its own right, and since the trial's placebo was saline, the human data cannot say how much of any effect belonged to the peptide and how much to the gel.
What else is it used for?
Each group carries its own evidence level.Approved means regulators have cleared it for that purpose. Investigational means it is in trials. Early research means it is being studied and is not established.
The tendon trial's primary endpoint
tested-and-failed- Human trial138 patients at 15 sites in 3 countries: median TAM2 at 12 weeks 121 degrees (range 29 to 182) with PXL01 against 108 degrees (range 36 to 175) with placebo, ANCOVA p=0.886.
- No dataThe trial was powered at 110 patients to detect a 20 degree difference in TAM2, and 138 were enrolled to allow for withdrawals; only 50 and 51 patients had primary-endpoint data, and the registry notes the high dropout as a limit on the analysis.
- No dataThe publication reports that PXL01 values ran higher from 12 weeks onward without reaching significance under either a rank analysis or a mixed model, and gives no numbers for the primary endpoint in its text.
The secondary results, and what they rest on
Early research- Human trialAt 6 months in the per-protocol set: end-joint motion 60 against 41 degrees (p=0.016), excellent or good Strickland grade 61% against 38% (p=0.0499), tip-to-crease distance 5.0 against 15.5 mm (p=0.048). None of the three was significant in the full analysis set.
- Human trialIn patients with a complete digital nerve injury, 74% against 35% could feel the thinnest monofilaments at 12 weeks (p=0.021): the only reported finding significant in the full analysis set, and a subgroup of 36 patients.
- No dataNo multiplicity adjustment was made, the Strickland result lost significance under an alternative analysis, and the authors put the gap between analysis sets down partly to large visit-window deviations and partly to more multiple-digit and little-finger injuries in the PXL01 arm.
- No dataThe placebo was saline rather than the sodium hyaluronate vehicle, and the sponsor acknowledged the two solutions differed in viscosity, so the surgeon may have been unblinded.
The scar trial, and the end of the program
tested-and-failed- Human trialPHSU05: 24 healthy volunteers aged 18 to 40, each given six induced wounds, three per upper arm, randomized within each subject to ensereptide or placebo so every volunteer was his or her own control. Safety and tolerability, the primary objective, were met; neither scar rating scale showed a statistically verifiable difference and biopsies showed no clear treatment effect. No numbers or p values were released.
- RegulatoryThe sponsor's stated conclusion was that the results indicate no tangible treatment value in this indication, and it shut the project down on June 22, 2023.
- RegulatoryThe company resolved on voluntary liquidation on October 5, 2023, and the planned 500 to 600 patient phase 3 in the EU and India never enrolled a patient. Who owns the compound now is not on the public record.
Mechanism and animal work
Research only- Lab studyPXL01 in sodium hyaluronate raised PRG4, or lubricin, expression: the sponsor-side explanation for less adhesion. No receptor, molecular target or potency figure has been published.
- Animal studyIn rats, a lactoferrin peptide in sodium hyaluronate reduced adhesions after abdominal surgery.
- Animal studyIn rat sciatic nerve repair, a 2024 paper reported an altered macrophage response with no effect on axonal outgrowth or Schwann cells, and a 2025 paper reported effects on nerve regeneration in healthy and diabetic rats. Both are academic animal studies published after the program closed.
The summary that circulates, that several measures of hand recovery favored treatment at six months and particularly in the per-protocol analysis, is accurate and incomplete, and the omission changes the conclusion: the prespecified primary endpoint, finger motion at 12 weeks, was not met (p=0.886), all three favorable six-month measures were significant only in the per-protocol set, and nothing was adjusted for testing many outcomes. 'Larger confirmatory trials would be needed' is often presented as an open question. It is closed, but not by a confirmatory trial: the planned 500 to 600 patient phase 3 never enrolled anyone, the only later trial tested a different indication, skin scarring, in 24 volunteers and showed nothing, and the sponsor ended the compound on June 22, 2023 and liquidated the company that October. Calling the evidence stronger than that of most experimental repair peptides is fair, since BPC-157, TB-500 and PDA have no registered trial with posted results at all, and TP508, the nearest comparison here, reached a 503-patient phase 3 and missed its endpoint; stronger is not the same as positive. It has never been approved in Sweden, in Europe or anywhere else. It is also not LL-37: both peptides came from the same Swedish company with similar internal codes, and ropocamptide's positive leg-ulcer result belongs to that molecule, not this one. There is no dry-eye program, whatever a summary may say.
The published record
Papers and trials about PXL01 (ensereptide)
6 papers tagged human · 2 not reviews or lab · 1 clinical trial publications
2 registered trials · 1 with posted results
Furthest stage reached: Phase 2, results posted
Counted from Europe PMC indexing, not read by a person; a human tag can land on reviews, commentary or lab papers; clinical trial publications is the narrower count.
At a glance
Four things to know about PXL01 (ensereptide)
Evidence
Investigational
Category
Healing and recovery
Common vial
Varies
Half-life
Not established
How much, and do you cycle it?
The range, and whether you take breaks.10 mg in hyaluronate gel, placed around the repaired tendon (phase 2 trial), once, during the operation. A single application during the repair operation Trial dose
Both human trials gave it once. Nothing repeated, and nothing outside an operating room, was ever studied.
Not establishedNo figure
No human pharmacokinetic data have been published: no half-life, no Tmax, no bioavailability, no clearance pathway. The peptide was given once, locally, inside a surgical wound, and blood levels were never measured or reported. The FDA substance record does give a molecular weight, an estimated 3,020 Da, calculated from the sequence rather than measured.
You can compare this against the whole library to see where it sits.
How is it given?
Dosing context and source notes.Given in hospital from a prepared product, so there is nothing to mix.
Trial dose: 10 mg per dose. Wiig ME et al., PLoS ONE 2014;9(10):e110735
One dose, once, placed by the surgeon. The trial gave 0.5 mL containing PXL01 at 20 mg/mL in sodium hyaluronate at 15 mg/mL, a total of 10 mg, injected between the repaired flexor tendon and its sheath and around the sheath, after the repair and before the wound was closed. The product was made on site by dissolving PXL01 acetate in 0.9% saline to 50 mg/mL, filtering it, then mixing it with sodium hyaluronate supplied at 25 mg/mL. The placebo was 0.5 mL of 9 mg/mL sodium chloride, not the hyaluronate gel, so the peptide's own contribution was never isolated. There was no titration, no repeat dose and no kidney or liver adjustment, and no commercial presentation ever existed. The planned phase 3 was to compare two dose levels, never disclosed and never tested, so there is one trial dose here and nothing for a calculator to scale.
How do you store it?
Before mixing, and after.Given in a hospital or trial clinic, so the pharmacy stores it.
PXL01 (ensereptide) is prepared and given by hospital, clinic or trial staff, following the product label or the trial protocol. Some products like this arrive ready to use and others are mixed just before the dose, often with hours rather than weeks of shelf life once prepared. It is not a medicine people store at home.
What are the side effects and cautions?
Known cautions and warnings for this compound.Solubility, computed: 40% charged residues, 44% hydrophobic. Water usually sufficient.
A first-pass rule from peptide manufacturers' guidance. It does not account for disulfide bridges, salt form or how the powder was dried, and it predicts what should be easy rather than what will happen in your vial.
Who should avoid it
- Not studied in pregnancy or breastfeeding: no human data exist
- Not studied in young children: the tendon trial allowed ages 12 to 75 with a complete flexor digitorum profundus division in zone I or II of a finger, and the mean age enrolled was 36
- Not studied as a repeated dose: every patient received one application during the repair operation
- Not studied by any other route: it was never given under the skin, by mouth or into a vein
- Not studied in kidney or liver disease, and no human pharmacokinetic data exist
Stop and get help
- Sudden loss of finger bending after a repair, possible tendon rupture: ruptures occurred in both arms of the trial, 8% against 9%
- Spreading redness, swelling or pain at the surgical site, or signs of an allergic reaction
Common effects
- Any adverse event in 62% (73 events) against 57% (75 events) on placebo
- A serious adverse event in 15.4% (11 events) against 12.9% (9 events); 4 were judged possibly product-related and all 4 were tendon ruptures, 3 on PXL01 and 1 on placebo
- A severe adverse event in 11% against 1% on placebo, the one imbalance in the table and one the sponsor did not highlight
- Withdrawal for an adverse event in 9% (7 patients) against 11% (8 patients); in the 24-volunteer scar study there were no serious adverse events and local reactions matched placebo
Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.
Is PXL01 (ensereptide) approved?
And where the numbers on this page come from.No. PXL01 (ensereptide) was never approved, and its development has ended. There is no legal route to obtain it as a medicine.
- Approval statusInvestigational
- RouteApplied during surgery, around the repaired tendon
- Checked21 October 2026
- DoseFrom published clinical trials. Not approved by a regulator for this dose.
- Vial sizeFrom what vendors typically list; not a recommendation.
- SourcesFDA GSRS substance record, ensereptide (UNII SMV73KW49C)FDA GSRS codes record, ensereptideWiig ME et al., PLoS ONE 2014;9(10):e110735ClinicalTrials.gov, PXL01 in flexor tendon surgery (NCT01022242), posted resultsEU Clinical Trials Register, EudraCT 2009-012703-25Promore Pharma, outcome of the phase 2 ensereptide scar study (April 20, 2023)Promore Pharma, cost reduction announcement (June 22, 2023)Promore Pharma, voluntary liquidation notice (October 12, 2023)BioSpace, Promore Pharma adjusts North American plans (January 2, 2018)FierceBiotech, PharmaResearch spinal-surgery license (May 7, 2018)Promore Pharma AB, interim report January to March 2017Karolinska Development, formation of Pergamum AB (September 9, 2009)UniProt P02788, human lactotransferrinPXL01 in sodium hyaluronate raises PRG4 expression, Upsala Journal of Medical Sciences 2016
What has happened recently
No regulator has ever approved PXL01, and phase 2 was as far as it went. It came out of Karolinska Development's dermatology and wound-healing portfolio in Stockholm: Pergamum AB was formed on September 9, 2009 to hold the assets of five of those companies, with Karolinska Development owning 64%, and Pergamum sponsored the flexor tendon trial (NCT01022242, EudraCT 2009-012703-25) from December 2009. Lipopeptide AB, founded in 2002, began using the name Promore Pharma in the third quarter of 2016 with the formal change registered in January 2017, listed on Nasdaq First North in July 2017, and announced a term sheet with Cellastra Inc. on January 4, 2017 and signed a co-development agreement with it on March 17, 2017 for North American development; Cellastra's option to fund the US phase 3 expired unexercised on December 31, 2017 after it missed its fundraising goals. On May 7, 2018 Promore licensed the spinal-surgery indication globally to PharmaResearch Products of South Korea, keeping the tendon indication. A randomized, double-blind phase 3 of 500 to 600 patients at two doses was prepared for the EU and India, with an Indian application filed in May 2017, and it never enrolled a patient. On June 22, 2023, after the PHSU05 scar trial showed no clear effect, Promore shut the ensereptide project down; an extraordinary general meeting on October 5, 2023 resolved on voluntary liquidation, announced October 12, 2023. Who holds the ensereptide patents today is not known: the liquidation notice assigned the ropocamptide patents to a subsidiary and said nothing about ensereptide. No orphan, fast track or breakthrough designation has been found.
You can compare this against the whole library, or read how to check a seller.
What else is like PXL01 (ensereptide)?
Others in Healing and recovery, side by side.If you're weighing PXL01 (ensereptide), it's worth reading BPC-157, TB-500 / Thymosin Beta-4, and PDA (Pentadeca Arginate) in the same class.
A 25-residue piece of human lactoferrin, mixed into a hyaluronate gel and placed around a freshly repaired finger tendon to keep scar from gluing it to its sheath. It missed its primary endpoint at p=0.886, and its sponsor shut the program down in June 2023.
- Dose
- 10 mg in hyaluronate gel, placed around the repaired tendon (phase 2 trial)
- How often
- Once, during the operation
A popular healing peptide for injuries, gut, and joint or tendon pain.
- Dose
- 0.25 up to 0.5 mg per dose (start low, increase slowly)
- How often
- 1-2x daily
A recovery peptide for healing muscle and tendon, often paired with BPC-157.
- Dose
- 2 up to 2.5 mg per injection (start low, increase slowly)
- How often
- Twice a week
A newer, more stable cousin of BPC-157 for faster healing.
- Dose
- 0.25 up to 0.5 mg per day (start low, increase slowly)
- How often
- 1-2x daily
Guides for this compound
- How to Reconstitute a Peptide
Mix peptide powder with bacteriostatic water, step by step.
- How to Read an Insulin Syringe
Read the units, convert to millilitres, and draw the exact dose.
- mcg vs mg: The Peptide Dosing Mistake to Avoid
Your vial says mg and your protocol says mcg. Here is the conversion and how to check it.
- How to Read a Peptide COA
What the purity number does and does not tell you, and how to spot an edited report.
- How to Vet a Peptide Vendor
Independent COAs, HPLC purity, and the red flags that mean walk away.
Sources
- FDA GSRS substance record, ensereptide (UNII SMV73KW49C)(2026)25-residue sequence EATKCFQWQRNMRKVRGPPVSCIKR, one chain, one disulfide from cysteine 5 to cysteine 22; estimated molecular weight 3,020 Da, with the estimated formula C132H222N45O35S3.
- FDA GSRS codes record, ensereptide(2026)CAS 254433-51-7, INN number 9579, PubChem CID 49863418, NCI Thesaurus C169952 under the parent concept 'Immunotherapeutic Agent'.
- Wiig ME et al., PLoS ONE 2014;9(10):e110735(2014)The randomized flexor tendon trial: 10 mg in sodium hyaluronate against saline, per-protocol six-month results, the safety table, and Pergamum funding with the chief scientific officer as an author.
- ClinicalTrials.gov, PXL01 in flexor tendon surgery (NCT01022242), posted results(2014)Primary endpoint TAM2 at 12 weeks: median 121 degrees against 108, ANCOVA p=0.886; 138 enrolled at 15 sites in Germany, Sweden and Denmark; high dropout noted.
- EU Clinical Trials Register, EudraCT 2009-012703-25(2013)The same trial, sponsor Pergamum AB, completed in Sweden, Denmark and Germany; the register holds one PXL01 trial and no results.
- Promore Pharma, outcome of the phase 2 ensereptide scar study (April 20, 2023)(2023)24 healthy volunteers: safety and tolerability met, no statistically verifiable difference on either scar scale, no clear treatment effect on biopsies, no numbers released.
- Promore Pharma, cost reduction announcement (June 22, 2023)(2023)The ensereptide project was shut down and notice given to key personnel after the scar study showed no clear medical effect.
- Promore Pharma, voluntary liquidation notice (October 12, 2023)(2023)The October 5, 2023 meeting resolved on liquidation; ensereptide was dropped for insufficient effect, and the ropocamptide patents sat in a subsidiary.
- BioSpace, Promore Pharma adjusts North American plans (January 2, 2018)(2018)The Cellastra option expired on December 31, 2017; a phase 3 of 500 to 600 patients at two doses was planned for the EU and India, with the US trial postponed for funding.
- FierceBiotech, PharmaResearch spinal-surgery license (May 7, 2018)(2018)Global license to commercialize PXL01 for prevention of fibrosis after spinal surgery, with milestones and royalties and no amounts disclosed.
- Promore Pharma AB, interim report January to March 2017(2017)Lipopeptide AB, founded 2002, took the Promore Pharma name with the change registered in January 2017; an Indian phase 3 application was filed in May 2017.
- Karolinska Development, formation of Pergamum AB (September 9, 2009)(2009)Pergamum AB formed from the holdings of five dermatology and wound-healing companies, with Karolinska Development at 64%.
- UniProt P02788, human lactotransferrin(2026)The parent protein: a 710-residue precursor whose N-terminal lactoferricin region contains the PXL01 fragment.
- PXL01 in sodium hyaluronate raises PRG4 expression, Upsala Journal of Medical Sciences 2016(2016)The sponsor-side mechanism: more PRG4, or lubricin, as a proposed route to less adhesion.
Beyond these, 10 records are indexed. Browse the records