Lapemelanotide zapixetan (VMT01)_Dosage, benefits & legal status
Also known as VMT01, [212Pb]VMT01, 212Pb-VMT01, Pb-212 VMT01, lapemelanotide zapixetar, lead (212Pb) lapemelanotide zapixetan, 203Pb-VMT01, [203Pb]VMT01
An alpha-emitting melanoma drug whose own maker misspells its approved generic name.
Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.
What is Lapemelanotide zapixetan (VMT01)?
Plain language first. The technical label stays, but it never stands alone.Overview
This is a hospital cancer treatment for advanced melanoma, not anything that can be bought. The idea is worth understanding because it is elegant. Melanoma cells tend to carry a lot of one particular receptor on their surface. Take a tiny peptide that latches onto that receptor, bolt a radioactive atom to the other end, and inject it. The peptide finds the tumor and the radiation does its damage from a cell or two away instead of from a machine outside the body. Two details make this version distinctive. The radioactive atom emits alpha particles, heavier and far more destructive over a much shorter distance than the beta particles used by the older drugs of this type. The same peptide can also be loaded with a different, harmless isotope first, so a scan shows whether a given person's tumor actually grabs the drug before they are given the radioactive version. As of a September 2026 data cut, twenty people had received at least one dose.
Lapemelanotide zapixetan is a peptide radioligand therapy. A small synthetic peptide binds melanocortin 1 receptor, a protein carried in excess on many metastatic melanoma cells, and a chelator cage welded to that peptide holds an atom of lead-212. Lead-212 is an alpha generator, so the peptide delivers alpha radiation from inside the tumor. The same targeting peptide is labeled with lead-203 for SPECT imaging, and a related agent called VMT02 is labeled with gallium-68 for PET, so a scan decides who is eligible before anyone is treated. It is in one trial, NCT05655312, as monotherapy and in combination with nivolumab, and it is approved in no country.
What it's used for
Tested in previously treated unresectable or metastatic melanoma, in people whose tumors take up the matching imaging agent. Approved in no country and available only inside one clinical trial.
How does Lapemelanotide zapixetan (VMT01) work?
What it does in the body, and where.Three things distinguish this from the radioligands already covered here: the receptor it aims at, the kind of radiation it delivers, and the fact that a scan decides who gets it.
- 01The peptide is the postcode, not the drugMelanocortin 1 receptor sits on the surface of pigment-producing cells and is carried in excess by many metastatic melanomas. A short synthetic peptide binds it, the receptor pulls the peptide inside, and whatever is attached to the peptide comes along. The peptide itself does almost nothing therapeutically. Perspective has not published its sequence, describing it only as a proprietary low molecular weight peptide, so the delivery vehicle on this page is a known shape with an unpublished spelling.
- 02Lead-212 is the payload, and it is a generator rather than an emitterLead-212 is not itself an alpha emitter. It decays by beta emission to bismuth-212, and the alpha particle arrives one step later, from bismuth-212 by way of either polonium-212 or thallium-208. That matters for a practical reason: the chelator has to hold on to the daughter atom after the first decay, or the radioactivity wanders off to wherever that loose atom goes. Alpha particles deposit far more energy over a far shorter range than the beta particles used by the older lutetium-177 drugs. That concentration is the case for using them, and the short range is why delivery accuracy matters more here than it does with beta emitters.
- 03The same peptide, loaded with a harmless isotope, picks the patientsLead-203 behaves chemically like lead-212 and emits gamma rays suitable for a SPECT scan, so the identical molecule can be imaged before it is used as a treatment. A separate agent, VMT02, carries gallium-68 for PET. Eligibility for the trial requires uptake on one of those scans. This is the part a reader should take from the page even if the drug never reaches approval: the selection step means the reported results describe people already known to have the target, not melanoma patients in general.
- 04What the chelator is, and a disagreement about itThe company says the cage is its own lead-specific chelator, abbreviated PSC, built to hold lead and its decay daughter. One third-party radiopharmacy reference instead names the compound as a DOTA conjugate. The company is the stronger source on the composition of its own molecule, and the FDA registry entry describes a chelator architecture that is not plain DOTA, so the DOTA naming looks like an older or generic description carried forward.
A schematic of the compound's mechanism, not a diagnostic image.
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 November 2026 interim monotherapy readout
Investigational- human-earlyTwenty patients had received at least one monotherapy treatment at the September 18, 2026 data cut, across three cohorts at 1.5, 3.0 and 5.0 mCi per treatment.
- human-earlyIn the eight-patient 3.0 mCi cohort, two had objective partial responses and the disease control rate was 75%, including two patients with long-lasting stabilization.
- human-earlyOne partial response was still ongoing about 40 weeks after the first treatment. Duration is what a response rate cannot tell you, so that is the single most informative number in the readout.
- No dataThe eighth patient in that cohort had not yet reached a first tumor assessment, so the 75% figure rests on seven assessable patients at most.
Safety as reported, and what a single arm cannot show
Investigational- human-earlyNo dose-limiting toxicities, no treatment-related serious adverse events and no discontinuations for adverse events across all 20 monotherapy patients.
- human-earlyGrade 3 or worse adverse events in 5 of 20 patients, 25%, none assessed by the company as treatment-related.
- No dataAttribution of adverse events in an open-label single-arm trial is the sponsor's judgment call, not a measurement. A 25% rate of severe events with none attributed to the drug is a claim about causation from a design that cannot test causation.
Regulatory position
Investigational- RegulatoryFDA granted Fast Track designation in September 2024, covering both diagnosis and treatment of melanocortin 1 receptor positive melanoma. Fast Track speeds up interaction with the agency and implies nothing about whether the drug works.
- RegulatoryThe trial has run since June 1, 2023, lists 300 estimated participants across 16 US sites, and gives an estimated primary completion of December 31, 2027.
- RegulatoryApproved in no country, and no marketing application anywhere is on the public record.
The name, and why two spellings are in circulation
none- lab-analysisThe FDA substance registry carries three records under this name, for the unlabeled peptide and the lead-203 and lead-212 forms, and the entry flagged as the international nonproprietary name ends in zapixetan.
- No dataPerspective's own press releases spell it zapixetar, with an r, consistently. The November 6, 2026 release uses that spelling three times.
- lab-analysisThe ending points the same way. Three chelator-carrying generic names end in xetan and all three sit in the FDA registry: this one, navoxetan in the company's other program, and tiuxetan in the approved ibritumomab tiuxetan.
The first error is the name, and it starts with the company. Perspective's own releases call the drug lapemelanotide zapixetar. The FDA substance registry and the WHO nonproprietary name both end in zapixetan, and the registry entry carrying that spelling is the one flagged as the international nonproprietary name. A reader searching the company's spelling will find press coverage and miss the regulatory records. Both spellings are carried as search aliases on this page for that reason. The second error is reading the 75% disease control rate as a response rate. Disease control counts tumors that shrank and tumors that merely stopped growing, and in this cohort the responses were two. The third is quoting the figure without its denominator of eight, one of whom had no tumor assessment yet. The fourth is treating Fast Track designation as a signal that the drug works, when it concerns the speed of the agency's engagement and nothing else. The fifth is confusing the three isotopes. Lead-212 is the treatment, lead-203 is a SPECT imaging label on the same molecule, and gallium-68 sits on a different molecule called VMT02. One housekeeping note: lead-212 is described everywhere as an alpha therapy, and it is, but lead-212 itself decays by beta emission. The alpha comes from bismuth-212 one step down the chain.
The published record
Papers about Lapemelanotide zapixetan (VMT01)
Searched: lapemelanotide zapixetan, lapemelanotide zapixetar, VMT01, 212Pb-VMT01, 203Pb-VMT01.
Left out: bamzireotide navoxetan (THE critical rejection. The SAME company's other lead program, the SAME lead-212 isotope and the SAME proprietary chelator, aimed at a DIFFERENT receptor (SSTR2) in a DIFFERENT disease (neuroendocrine tumors). Added to this site in the same batch under its own slug. Their INN numbers are consecutive, 13291 here and 13292 there, and their CAS numbers are adjacent, 2941523-46-0 and 2941523-47-1, so registry searches return both and any platform-level search returns both); VMT-alpha-NET (the development code for that sibling program); VMT02 (a DIFFERENT molecule, not a different label of this one. It is the gallium-68 PET imaging agent used alongside lead-203 VMT01 for patient selection, and the company names it separately); PSV359 (the company's THIRD program, lead-212 against fibroblast activation protein alpha in solid tumors, on no page here. Held back deliberately: phase 1/2a NCT06710756, first patient April 2025, cohort 2 at 5.0 mCi from October 2025, and NO efficacy data published. The threshold that would earn it a card is a first reported efficacy or safety readout, or an INN appearing in the FDA registry); PSV377 (the gallium-68 imaging label for PSV359, a different molecule again); melanotan II (a melanocortin agonist already on this site, sold gray market for tanning. It hits melanocortin receptors including MC1R, so every receptor-level keyword search returns it, and it has nothing to do with cancer therapy); melanotan I (the same problem, and it is the one melanocortin agonist with a real approval, which makes conflation worse rather than better); PL8177 (the OTHER MC1R agonist carried here, a cyclic heptapeptide with a colon-release formulation for inflammatory disease. Same receptor, opposite purpose, and it is the nearest neighbor a reader could mistake this for); MC1R (the receptor class term, returning the pigmentation and inflammation literature in full); melanocortin (broader still, returning every melanocortin receptor subtype and all four peptides already on this site); lead-212 (the isotope, returning this company's whole platform and every other 212Pb program anywhere); targeted alpha therapy (the class term, returning actinium-225, radium-223, astatine-211 and lead-212 programs together); melanoma (vastly too broad, and the disease term returns the checkpoint-inhibitor literature); nivolumab (the combination partner, an approved antibody with an enormous literature of its own and no page here).
2 papers tagged human · 2 not reviews or lab · 0 clinical trial publications
Furthest stage reached: No clinical trial on record
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. A preprint and its journal version count once.
At a glance
Four things to know about Lapemelanotide zapixetan (VMT01)
Evidence
Investigational
Category
Sexual and hormonal
Common vial
Varies
Half-life
Lead-212 decays over about 10.6 hours; no human blood half-life published for this drug
How much, and do you cycle it?
The range, and whether you take breaks.1.5 to 5.0 mCi per treatment in dose finding, up to three treatments, every 8 weeks, up to three times. Up to three treatments about 8 weeks apart, then stop Trial dose
A finite course rather than ongoing treatment. The limit is cumulative radiation dose to kidney and marrow, and the 8-week spacing exists to let both recover.
How long does it stay in the body?
The half-life, and where the figure comes from.Lead-212 decays over about 10.6 hours; no human blood half-life published for this drugNo figure
Two separate clocks, often merged. The isotope's physical half-life is about 10.6 hours and that is fixed physics. How long the peptide circulates in a person is a different measurement and none has been published for this drug. The short physical half-life has a consequence a reader can act on: a vial loses most of its activity within a day, so the drug has to be made close to where it is given, and the company has built its own generator network to do that. The 10.6-hour figure is quoted in a 2022 preclinical dosimetry paper on this compound and was read through a reproduction of that paper's abstract, not opened at source.
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 range: 1.5 up to 5 mCi per dose. ClinicalTrials.gov record NCT05655312
Prepared and infused by licensed staff in a nuclear medicine unit, so no vial draw exists and the reconstitution calculator does not apply. Three monotherapy cohorts ran at 1.5, 3.0 and 5.0 mCi per treatment, three treatments each about 8 weeks apart. The company reports those same cohorts as cumulative totals of up to 4.5, 9 and 15 mCi. Both sets of figures get quoted interchangeably, so check which one a given number is. The 3.0 mCi level is the one the company calls its focus dose. In the combination arms nivolumab is given at 480 mg into a vein every 4 weeks.
How do you store it?
Before mixing, and after.Given in a hospital or trial clinic, so the pharmacy stores it.
Lapemelanotide zapixetan (VMT01) goes into a vein and is prepared by hospital, clinic or trial pharmacy staff, following the product label or the trial protocol. Some products like this are ready-made solutions and others are powders mixed just before use, 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.Who should avoid it
- Any expectation of access outside a trial, since the drug is approved nowhere and lead-212 decays with a half-life measured in hours, so a vial cannot be shipped or stored
- Reading the imaging agents as treatments. Lead-203 VMT01 and gallium-68 VMT02 exist to select patients and measure dose, and neither is therapeutic
- Treating the 75% disease control rate as a response rate, since the two measure different things and the figure comes from eight patients
- Assuming the company's spelling of the generic name is the official one, since searching zapixetar will miss the FDA and WHO records filed under zapixetan
Stop and get help
- Given in a nuclear medicine unit under specialist supervision, so there is no self-administered dose to stop
- Falling urine output, new swelling or breathlessness between treatments, all needing same-day assessment for kidney injury
- Fever, unusual bruising or bleeding between treatments, all needing urgent blood counts for marrow suppression
Common effects
- No per-event breakdown has been published. The company has reported only the absence of dose-limiting toxicities and the 25% rate of grade 3 or worse events, so there is no list of common effects to give.
Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.
Is Lapemelanotide zapixetan (VMT01) approved?
And where the numbers on this page come from.No. Lapemelanotide zapixetan (VMT01) is not approved anywhere and is currently in company-run clinical trials. There is no legal route to obtain it outside a trial.
- Approval statusInvestigational
- RouteInto a vein, in a nuclear medicine unit, about every 8 weeks for up to three doses
- Checked8 November 2026
- DoseFrom published clinical trials. Not approved by a regulator for this dose.
- Vial sizeFrom what vendors typically list; not a recommendation.
- SourcesPerspective Therapeutics, interim monotherapy results presented at SITC 2026, filed with the SECClinicalTrials.gov record NCT05655312FDA Global Substance Registration System, lead-212 formNCI Thesaurus concept C211712Perspective Therapeutics, FDA Fast Track designation announcementPerspective Therapeutics, SITC 2026 presentation detailsPerspective Therapeutics, VMT01 and VMT02 program pageMolecules, preclinical dosimetry of the lead-212 compound
What has happened recently
Approved in no country. FDA granted Fast Track designation in September 2024 for the diagnosis and treatment of melanocortin 1 receptor positive melanoma, a designation that affects how closely the agency works with the sponsor and says nothing about efficacy. The only trial is NCT05655312, phase 1/2a, recruiting, 300 estimated participants at 16 US sites, started June 1, 2023, with estimated primary completion December 31, 2027. Interim monotherapy results were presented at the SITC annual meeting on November 6, 2026, from a September 18, 2026 data cut. No orphan designation for this generic name was found in the FDA orphan drug database, and that database declined to run a query in this session, so the absence is unconfirmed rather than established. The sponsor is Perspective Therapeutics, Inc., Seattle, listed on NYSE American as CATX.
You can compare this against the whole library, or read how to check a seller.
What else is like Lapemelanotide zapixetan (VMT01)?
Others in Sexual and hormonal, side by side.If you're weighing Lapemelanotide zapixetan (VMT01), it's worth reading Leuprolide (Lupron), Lutetium-177 dotatate (Lutathera), and Lutetium-177 edotreotide (ITM-11) in the same class.
An alpha-emitting melanoma drug whose own maker misspells its approved generic name.
- Dose
- 1.5 to 5.0 mCi per treatment in dose finding, up to three treatments
- How often
- Every 8 weeks, up to three times
The GnRH agonist that shuts hormones down by overstimulating them first.
- Dose
- Set by the label and the depot formulation
- How often
- Monthly to six-monthly depot
A peptide used as a delivery van: it finds tumor cells with somatostatin receptors and irradiates them from the inside.
- Dose
- 7.4 GBq every 8 weeks, 4 doses (label)
- How often
- Every 8 weeks, for 4 doses
A near-identical twin of Lutathera that the FDA has not approved.
- Dose
- 7.5 GBq per cycle, four cycles, in the phase 3
- How often
- Once every 90 days, four times
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
- Perspective Therapeutics, interim monotherapy results presented at SITC 2026, filed with the SEC(2026)Press release dated November 6, 2026, filed as an exhibit. Twenty patients had received at least one monotherapy treatment at the September 18, 2026 data cut. Three cohorts at cumulative doses of up to 4.5, 9 and 15 mCi, given as three treatments of 1.5, 3.0 and 5.0 mCi every eight weeks. In the eight-patient 3.0 mCi cohort, two objective partial responses, one ongoing at about 40 weeks, and a 75% disease control rate, with the eighth patient not yet eligible for a first tumor assessment. No dose-limiting toxicities, no treatment-related serious adverse events and no discontinuations for adverse events across all 20. Grade 3 or worse events in five patients, 25%, none assessed as treatment-related. The release does not call the compound a peptide and does not give a sequence. It spells the generic name zapixetar.
- ClinicalTrials.gov record NCT05655312(2026)Phase 1/2, recruiting, sponsor Perspective Therapeutics, 300 estimated participants at 16 US sites. Actual start June 1, 2023; estimated primary completion December 31, 2027; last update posted October 13, 2026. Interventions are the lead-212 therapeutic, the lead-203 imaging surrogate for dosimetry, and nivolumab at 480 mg into a vein every four weeks in the combination arms only. Conditions are recurrent cutaneous melanoma, metastatic melanoma and stage III or IV melanoma. The registry describes the agent as a lead-212-labeled peptide radiopharmaceutical, so the peptide identity comes from the registry rather than from the November press release. Eligibility requires uptake on imaging with lead-203 VMT01 by SPECT or gallium-68 VMT02 by PET.
- FDA Global Substance Registration System, lead-212 form(2026)UNII GJE2VT7WLR, substance class chemical, formula C79H117N25O18 with one lead atom, molecular weight 1916.926. Two moieties: the ligand C79H117N25O18 at 1704.9341 with charge minus two, and the lead-212 ion at 211.9919 with charge plus two. CAS 2941523-46-0, INN 13291, NCI Thesaurus C211712, PubChem 172866299. The only name flagged with name organization INN is the one ending in zapixetan. No protein block exists; a validation note on the record observes that the substance could also be represented as a protein with a partial sequence, and none is stored.
- NCI Thesaurus concept C211712(2026)Preferred name Lead Pb 212 Lapemelanotide Zapixetan, with the FDA entry for UNII GJE2VT7WLR as the source of the synonym. Carries no development code name, so this record does not by itself connect the generic name to VMT01, and it is not independent of the FDA record it cites.
- Perspective Therapeutics, FDA Fast Track designation announcement(2024)Fast Track designation for the development of lead-212 VMT01 for the diagnosis and treatment of patients with unresectable or metastatic melanoma who have demonstrated melanocortin 1 receptor tumor expression. The same release describes the company's platform as delivering lead-212 by way of specialized targeting peptides. That is the company calling the targeting molecule a peptide.
- Perspective Therapeutics, SITC 2026 presentation details(2026)Abstract 571, poster presentation dated Friday, November 6, 2026, presented by Matthew Block of the Department of Oncology, Mayo Clinic. Describes the trial as a multi-center open-label dose escalation and dose expansion study in patients with histologically confirmed melanoma and melanocortin 1 receptor positive imaging scans, and states no dose-limiting toxicities, no discontinuations due to adverse events and no grade 4 or grade 5 treatment-emergent adverse events.
- Perspective Therapeutics, VMT01 and VMT02 program page(2026)States that the agent uses the company's proprietary chelator, abbreviated PSC, to bind lead-203 for SPECT imaging and lead-212 for alpha particle therapy. Records first patient dosed in the nivolumab combination arm in March 2025, dose finding at 3.0 mCi for both monotherapy and combination, and a separate phase 1 imaging study at Mayo Clinic supporting patient selection with lead-203 VMT01 and gallium-68 VMT02.
- Molecules, preclinical dosimetry of the lead-212 compound(2022)Estimates human tissue absorbed doses from mouse biodistribution data and examines what happens to the thallium-208 that is set free when bismuth-212 decays by the alpha branch. Gives the lead-212 physical half-life as 10.64 hours and reports that the bismuth-212 daughter stays inside the chelator in human serum stability work. Sourcing tier: read through a reproduction of the abstract in a search result, not opened at source, because the article host does not render for this session's fetch tool. No DOI is given here, because the one query that could have confirmed it returned unrelated records.
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