Melanotan I FDA Approved

What It Is

Melanotan I — generic name afamelanotide, originally coded CUV1647, marketed as Scenesse — is a synthetic analog of alpha-melanocyte-stimulating hormone (α-MSH). It is a linear 13-amino-acid peptide (Ac-Ser-Tyr-Ser-Nle-Glu-His-D-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH₂) differing from native α-MSH at positions 4 and 7: norleucine replaces methionine at position 4 (stabilizes against oxidation), and D-phenylalanine replaces L-phenylalanine at position 7 (resists proteolysis and dramatically increases receptor affinity). Molecular weight is 1,646.85 Da. The compound is alternatively abbreviated NDP-α-MSH in the mechanistic literature — "[Nle⁴,D-Phe⁷]-α-MSH."

Afamelanotide was synthesized in 1980 by Mac Hadley, Victor Hruby, and colleagues at the University of Arizona College of Pharmacy. The same group went on to design Melanotan II (a cyclic heptapeptide with pan-melanocortin activity) and, through Palatin Technologies, bremelanotide / PT-141 (an MC4R-biased analog approved in 2019 for hypoactive sexual desire disorder). Afamelanotide is the MC1R-selective member of this family — its receptor profile heavily favors MC1R activation in cutaneous melanocytes, with much weaker activity at the central MC3R/MC4R circuits responsible for MT-II's sexual-arousal and appetite effects.

The approved formulation is a bioresorbable poly-D,L-lactide-co-glycolide (PLGA) implant, 1.7 cm long by 1.5 mm diameter, containing 16 mg of afamelanotide. The implant is placed subcutaneously in the supra-iliac crest by a REMS-certified clinician every two months during periods of likely sun exposure. The implant slowly releases afamelanotide over approximately 48–72 hours; the peptide then distributes systemically and drives melanogenesis for the following ~60 days via the melanocytes it has already primed. This controlled-release PK is critical to the safety envelope: rapid injectable bolus dosing (the off-label research-peptide pattern) produces pharmacokinetics fundamentally different from the approved product.

Afamelanotide received its first national approval from the Italian Medicines Agency (AIFA) in 2010 for EPP under a compassionate-use framework. The European Medicines Agency granted a centralized authorization under "exceptional circumstances" in December 2014 (EU/1/14/969), citing the rarity of EPP and the compound's prior compassionate-use data. The US FDA approved Scenesse on October 8, 2019 (NDA 210797) — the first melanocortin agonist approved in the United States for any photoprotective indication. Australia's TGA (2020) and additional national approvals across Europe, Switzerland, and the Middle East followed.

CLINUVEL Pharmaceuticals (ASX: CUV; NASDAQ ADR: CLVLY), headquartered in Melbourne with operations in Europe, developed the product and holds the global rights. Beyond EPP, CLINUVEL has advanced afamelanotide into Phase II/III trials for vitiligo (in combination with narrow-band UVB phototherapy), variegate porphyria, and xeroderma pigmentosum, and into Phase II for hypopigmented skin conditions and post-ischemic stroke neuroprotection (via MC1R's documented cerebrovascular effects).

Mechanism of Action

Afamelanotide is a high-potency, high-selectivity MC1R agonist. Its biological effects follow from sustained MC1R activation in cutaneous melanocytes and extend to secondary anti-inflammatory and DNA-repair outputs in keratinocytes and other cell types.

• MC1R binding and cAMP signaling — Afamelanotide binds MC1R, a Gs-coupled seven-transmembrane receptor expressed on epidermal melanocytes, with affinity approximately 10–1,000× that of native α-MSH (depending on assay). Receptor activation stimulates adenylate cyclase, raising intracellular cAMP and activating protein kinase A (Abdel-Malek 2008).
• MITF transcriptional activation — cAMP/PKA signaling phosphorylates CREB, driving transcription of microphthalmia-associated transcription factor (MITF), the master regulator of the melanogenic program. MITF then transactivates tyrosinase (TYR), tyrosinase-related protein 1 (TYRP1), and dopachrome tautomerase (DCT/TYRP2) — the three enzymatic steps of melanin synthesis.
• Eumelanin-selective pigment shift — MC1R activation specifically biases melanin synthesis toward eumelanin (brown/black, UV-protective) rather than pheomelanin (red/yellow, pro-oxidant). Individuals with MC1R loss-of-function variants ("red hair" alleles) produce predominantly pheomelanin and have elevated melanoma risk. Afamelanotide's photoprotective rationale rests on pharmacologically overriding this phenotype to produce eumelanin across Fitzpatrick skin types.
• Nucleotide excision repair enhancement — α-MSH / MC1R signaling upregulates XPC, XPA, and other nucleotide-excision-repair pathway components. Cyclobutane pyrimidine dimers (CPDs) and 6,4-photoproducts generated by UV exposure are cleared more efficiently in afamelanotide-treated melanocytes (Böhm 2005). This DNA-repair enhancement is mechanistically distinct from pigment-mediated UV shielding and contributes independently to photoprotection.
• Oxidative stress attenuation — Increases cellular glutathione, reduces UV-induced reactive oxygen species, and limits apoptotic signaling in keratinocytes and melanocytes. Net effect is reduced UV-induced cell death and reduced sunburn inflammation at equivalent UV dose.
• Anti-inflammatory effects — MC1R is expressed on macrophages, keratinocytes, endothelial cells, and peripheral neurons. Receptor activation suppresses NF-κB signaling and pro-inflammatory cytokine release (TNF-α, IL-6, IL-1β). This underlies the symptom reduction seen in EPP (where photoactivated protoporphyrin drives a non-burning phototoxic pain syndrome) and supports the vitiligo / inflammatory-dermatosis applications under clinical investigation.
• Cerebrovascular / neuronal MC1R expression — MC1R is expressed on cerebral endothelium and peripheral neurons; Phase II CLINUVEL work has explored whether MC1R activation confers benefit in acute ischemic stroke via anti-inflammatory vasomodulation. This is an emerging, non-cutaneous mechanism beyond the approved indication.
• Pharmacokinetics of the implant — The 16 mg PLGA implant releases afamelanotide over approximately 48–72 hours after subcutaneous placement; peak plasma concentrations of ~1,800 pg/mL at 4–5 hours post-placement are reported, with a terminal half-life of 30 min for the free peptide once released. Pigmentation accumulates over the following 2–3 weeks and persists for approximately 2 months after implant placement before fading.
• MC1R selectivity vs MT-II — Afamelanotide is linear and extended from native α-MSH (13 aa); MT-II is cyclic and truncated (7 aa). The structural difference translates into dramatically lower MC3R/MC4R/MC5R activity for afamelanotide, which is why its clinical use lacks the central sexual-arousal, appetite-suppression, and sebaceous-activation signatures that dominate MT-II's community profile.

What the Research Shows

Afamelanotide has an unusually rigorous human evidence base for any melanocortin compound. The core dataset comes from CLINUVEL-sponsored Phase II and Phase III trials in EPP, with additional programs in vitiligo and other photosensitivity disorders.

• EPP pivotal trials — Langendonk et al., NEJM 2015 (PMID 26132941) — Two parallel randomized, placebo-controlled, double-blind Phase III trials (CUV029 European, CUV039 US) enrolled 93 and 74 adult EPP patients, respectively, with the 16 mg implant dosed every 60 days. Primary endpoint was total number of hours per day of pain-free time spent in direct sunlight between 10:00 and 18:00. In CUV029, median daily pain-free sun time was 6.0 hours on afamelanotide vs 0.75 hours on placebo; in CUV039, 6.1 vs 0.8 hours. Both trials met the primary endpoint; quality-of-life improvements were consistent.
• Biddolph 2020 observational disease registry — Analysis of EU Scenesse disease registry showed sustained benefit with repeated dosing over multiple years, with no new safety signals beyond those seen in the pivotal trials.
• Kim et al., Am J Clin Dermatol 2021 — real-world US post-approval — First US real-world outcomes from the REMS-enrolled patient population following 2019 approval. Demonstrated translation of pivotal-trial benefit into routine practice, with high patient retention and consistent dermatologic surveillance.
• Vitiligo Phase II — Lim et al., JAMA Dermatology 2015 (PMID 25587703) — Afamelanotide combined with narrowband UV-B phototherapy in generalized vitiligo showed faster and more complete repigmentation than NB-UVB alone. This was the first rigorous demonstration of MC1R stimulation beyond EPP.
• Vitiligo Phase II — Grimes et al. — Follow-up data in darker skin types (Fitzpatrick IV–VI) confirmed afamelanotide + NB-UVB superiority in repigmentation rate and extent.
• Xeroderma pigmentosum Phase II — CLINUVEL CUV151 study in XP patients (genetic nucleotide-excision-repair deficiency with severe UV sensitivity) documented safety and feasibility of afamelanotide in a dermatologic population at extreme melanoma risk.
• Solar urticaria — Case series and small trials in idiopathic solar urticaria; afamelanotide reduced urticarial responses to UVA/UVB provocation.
• Polymorphous light eruption (PLE) — Small clinical studies show reduction in PLE symptom frequency and severity during sun-exposure seasons.
• Stroke Phase II (CUV801) — under analysis — CLINUVEL's CUV801 proof-of-concept trial in acute arterial ischemic stroke is the first non-cutaneous major indication investigated; topline data reported preservation of cerebral vascular reactivity and acceptable safety.
• DNA repair / photoprotection mechanism work (Böhm et al., J Biol Chem 2005; PMID 15615718) — Foundational mechanistic paper showing α-MSH protects human melanocytes from UV-induced apoptosis and DNA damage via nucleotide-excision-repair enhancement. Underpins the photoprotective rationale beyond pigment.
• Receptor pharmacology (Abdel-Malek et al., Photochem Photobiol 2008; PMID 18248499) — MC1R biology review establishing the receptor's role in the UV response of human melanocytes and the translational rationale for MC1R-targeted photoprotection.

Human Data

Afamelanotide has the most robust human clinical dataset of any melanocortin agonist. Key trials:

• CUV029 (European Phase III EPP; Langendonk NEJM 2015; PMID 26132941) — Multicenter double-blind placebo-controlled trial; N=93; 16 mg implant every 60 days for 270 days. Primary endpoint of daily pain-free sun exposure met with large effect size.
• CUV039 (US Phase III EPP; Langendonk NEJM 2015) — Parallel US-based trial; N=74; same regimen. Met primary endpoint; formed basis of FDA NDA 210797.
• EU Scenesse disease registry (2014–2025) — Post-authorization observational registry documenting sustained benefit and real-world safety across repeat-implant cycles in EPP.
• US REMS registry (2019–2025) — US post-approval observational study; confirmed pivotal-trial benefit in routine clinical use.
• Lim 2015 vitiligo Phase II (JAMA Dermatology) — Afamelanotide plus NB-UVB superior to NB-UVB alone for repigmentation in generalized vitiligo.
• Grimes vitiligo follow-up — Confirmed repigmentation benefit in Fitzpatrick IV–VI skin types.
• CUV151 xeroderma pigmentosum Phase II — Safety and feasibility in UV-hypersensitive XP patients.
• Solar urticaria clinical series — Reduced urticarial threshold in refractory idiopathic solar urticaria.
• CUV801 acute stroke Phase II — Proof-of-concept trial in the cerebrovascular indication.
• CUV047 and related vitiligo programs — Ongoing CLINUVEL-sponsored trials extending repigmentation mechanism work.

Total afamelanotide human exposure as of 2026 exceeds 12,000 patient-years across approved use in EPP and investigational cohorts, making it one of the more thoroughly characterized peptide therapeutics in the dermatology armamentarium.

Dosing from the Literature

Approved dosing below refers specifically to the Scenesse 16 mg controlled-release implant. Injectable dosing patterns seen in research-peptide communities are presented for educational context and are not the approved regimen.

Reconstitution & Storage

The approved Scenesse product does not require reconstitution — it is a solid bioresorbable implant supplied in a foil-sealed single-use applicator. Research-peptide injectable formulations (lyophilized powder) follow standard peptide reconstitution practice.

• Implant storage — Refrigerate 2–8°C in original packaging; stable until labeled expiration. Do not freeze. Room-temperature excursions up to 25°C for up to 7 days are acceptable prior to placement.
• Implant placement — REMS-certified provider only. Placed via 14G applicator into supra-iliac subcutaneous fat after local anesthesia. Single-use; discard applicator after placement.
• Research-peptide reconstitution — Lyophilized powder reconstituted with bacteriostatic water (0.9% benzyl alcohol saline). Slow injection down vial wall; gentle swirl.
• Research-peptide storage — Unreconstituted powder: 2–8°C long-term. Reconstituted solution: 2–8°C, use within 21–28 days. Do not freeze.
• Injection sites (research-peptide) — SubQ abdomen or thigh; rotate sites. Not equivalent to implant placement.
• Inspection — Clear colorless solution when reconstituted; discard if cloudy or discolored.

→ Use the Kalios Peptide Calculator for exact syringe units

Side Effects & Risks

Scenesse's safety profile is well characterized from pivotal trials and subsequent registry data. The following is the approved-product safety envelope; injectable research-peptide use produces partially overlapping but not identical risk.

• Nausea — Most common adverse event in pivotal trials (~18% Scenesse vs ~6% placebo). Typically transient; resolves within hours of implant placement. More pronounced with injectable bolus dosing than with the controlled-release implant.
• Headache — Second most frequent adverse event (~18% Scenesse vs 17% placebo); usually mild. Often overlaps with infusion/implant-day stress.
• Implant-site reaction — Local pain, erythema, induration, or small hematoma at the supra-iliac placement site. Typically self-limited within 3–7 days. Rare infection or rejection requires implant removal.
• Flushing / facial warmth — Transient in the first 24 hours post-placement, reflecting peak peptide release.
• Fatigue — Reported in ~10% of users, typically on the day of placement.
• Skin hyperpigmentation (intended on-target effect) — Generalized darkening, darkening of freckles and nail beds, and darkened moles. Considered a pharmacological effect rather than an adverse event in the approved indication, but requires baseline dermatologic assessment and ongoing surveillance.
• New or changing nevi — MC1R activation can darken or enlarge existing nevi. The REMS program mandates twice-yearly full-skin examination by a dermatologist for any Scenesse-treated patient; any ABCDE change requires biopsy.
• Melanoma risk — Epidemiologic surveillance of the EPP registry has not detected increased melanoma incidence to date. Afamelanotide is contraindicated in patients with prior melanoma, current or prior non-melanoma skin cancer, or significant atypical nevus burden in the approved labeling.
• Mild dizziness, upper respiratory symptoms, respiratory tract infection — Reported at modest rates in both pivotal and registry populations; no causal attribution clearly established.
• Allergic reaction / hypersensitivity — Rare urticaria, angioedema, and anaphylactoid reactions; prior hypersensitivity to afamelanotide is a contraindication.
• Pregnancy and lactation — Insufficient human data; manufacturer advises avoidance where possible.
• Hepatic impairment — No dose adjustment needed; not hepatically cleared.
• Drug interactions — No significant clinically documented interactions. Concurrent use with photosensitizing medications warrants specialist discussion.
• Injectable research-peptide differences — Rapid bolus exposure produces acute peaks not seen with the implant and correlates with more frequent nausea, flushing, and headache reports in community settings. None of the approved-product safety claims have been validated in injectable off-label use.

Bloodwork & Monitoring

The approved Scenesse REMS program centers on dermatologic surveillance rather than laboratory monitoring. Key elements:

• Baseline full-body dermatologic examination — Required before first implant; ideally with dermoscopy and photographic documentation of all existing nevi. This is the single most important monitoring element.
• Semi-annual dermatologic re-examination — REMS mandates every 6 months during ongoing Scenesse treatment. Any ABCDE change in an existing nevus or any new pigmented lesion triggers biopsy.
• REMS enrollment and informed consent — US patients and prescribers must be REMS-enrolled. EU uses a parallel risk-management surveillance framework.
• CMP, CBC, LFTs — Reasonable but not required baseline. No specific signal anticipated; useful for baseline documentation in any complex multi-system patient.
• Vitamin D — Consider in patients avoiding sun chronically due to EPP; reduced endogenous vitamin D synthesis on afamelanotide is plausible given increased pigment shielding.
• Porphyrin labs (EPP indication) — Erythrocyte protoporphyrin levels track EPP disease activity; useful for clinical context rather than afamelanotide dosing.
• Blood pressure — Baseline; no specific BP signal but routine for any systemic peptide initiation.
• Research-peptide injectable users — Dermatologic surveillance analogous to the REMS protocol is the minimum defensible standard; lab monitoring remains the same as approved use.

Commonly Stacked With

Afamelanotide in approved use is typically monotherapy for EPP. Investigational combinations and related community stacks:

→ Check compound compatibility in the Stack Builder

Regulatory Status

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Next Steps

Key References

1. Langendonk JG, Balwani M, Anderson KE, Bonkovsky HL, Anstey AV, Bissell DM, Bloomer J, Edwards C, Neumann NJ, Parker C, Phillips JD, Lim HW, Hamzavi I, Deybach JC, Kauppinen R, Rhodes LE, Frank J, Murphy GM, Karstens FPJ, Sijbrands EJG, de Rooij FWM, Lebwohl M, Naik H, Goding CR, Wilson JHP, Desnick RJ. Afamelanotide for erythropoietic protoporphyria. N Engl J Med. 2015;373(1):48-59. PMID: 26132941. DOI: 10.1056/NEJMoa1411481.
2. Biolcati G, Marchesini E, Sorge F, Barbieri L, Schneider-Yin X, Minder EI. Long-term observational study of afamelanotide in 115 patients with erythropoietic protoporphyria. Br J Dermatol. 2015;172(6):1601-1612. PMID: 25494545.
3. Minder EI, Barman-Aksoezen J, Schneider-Yin X. Pharmacokinetics and pharmacodynamics of afamelanotide and its clinical use in treating dermatologic disorders. Clin Pharmacokinet. 2017;56(8):815-823. PMID: 28063036.
4. Böhm M, Wolff I, Scholzen TE, Robinson SJ, Healy E, Luger TA, Schwarz T, Schwarz A. Alpha-melanocyte-stimulating hormone protects from ultraviolet radiation-induced apoptosis and DNA damage. J Biol Chem. 2005;280(7):5795-5802. PMID: 15615718.
5. Abdel-Malek ZA, Knittel J, Kadekaro AL, Swope VB, Starner R. The melanocortin 1 receptor and the UV response of human melanocytes — a shift in paradigm. Photochem Photobiol. 2008;84(2):501-508. PMID: 18248499.
6. Lim HW, Grimes PE, Agbai O, Hamzavi I, Henderson M, Haddican M, Linkner RV, Lebwohl M. Afamelanotide and narrowband UV-B phototherapy for the treatment of vitiligo: a randomized multicenter trial. JAMA Dermatol. 2015;151(1):42-50. PMID: 25587703.
7. Grimes PE, Hamzavi I, Lebwohl M, Ortonne JP, Lim HW. The efficacy of afamelanotide and narrowband UV-B phototherapy for repigmentation of vitiligo. JAMA Dermatol. 2013;149(1):68-73. PMID: 23207610.
8. FDA. Scenesse (afamelanotide) prescribing information. NDA 210797. Approved October 8, 2019.
9. European Medicines Agency. Scenesse (afamelanotide) summary of product characteristics. EMA approval December 2014 (EU/1/14/969).
10. Hadley ME, Hruby VJ. Discovery and development of novel melanogenic drugs: melanotan-I and -II. In: Crommelin DJA, Sindelar RD, Meibohm B, editors. Pharmaceutical Biotechnology. 1992;1st ed.
11. Levine N, Sheftel SN, Eytan T, Dorr RT, Hadley ME, Weinrach JC, Ertl GA, Toth K, McGee DL, Hruby VJ. Induction of skin tanning by subcutaneous administration of a potent synthetic melanotropin. JAMA. 1991;266(19):2730-2736. PMID: 1658407.
12. Suzuki I, Cone RD, Im S, Nordlund J, Abdel-Malek ZA. Binding of melanotropic hormones to the melanocortin receptor MC1R on human melanocytes stimulates proliferation and melanogenesis. Endocrinology. 1996;137(5):1627-1633. PMID: 8612494.
13. Haylett AK, Nie Z, Brownrigg M, Taylor R, Rhodes LE. Systemic photoprotection in solar urticaria with α-melanocyte-stimulating hormone analogue [Nle⁴,D-Phe⁷]-α-MSH. Br J Dermatol. 2011;164(2):407-414. PMID: 21054334.
14. Kim CC, Levy A, Alizadeh V, Arora S, Jones J, Bodner R, Pfendler D, Schaffer JV, Lebwohl M, Honigman AD, Harrington MA, Bissonnette R, Desai S, Fernandez-Peñas P. US real-world experience with afamelanotide in erythropoietic protoporphyria. Am J Clin Dermatol. 2021;22(4):573-583.
15. Chen AC, Martin AJ, Choy B, Fernández-Peñas P, Dalziell RA, McKenzie CA, Scolyer RA, Dhillon HM, Vardy JL, Kricker A, St George G, Chinniah N, Halliday GM, Damian DL. A phase 3 randomized trial of nicotinamide for skin-cancer chemoprevention. N Engl J Med. 2015;373(17):1618-1626. PMID: 26488693. (Complementary photoprotection reference.)
16. CLINUVEL Pharmaceuticals. CUV801 acute arterial ischaemic stroke proof-of-concept — Phase II clinical program summary. ClinicalTrials.gov NCT05119296.
17. Falchi M, Bataille V, Hayward NK, Duffy DL, Bishop JA, Pastinen T, Cervino A, Zhao ZZ, Deloukas P, Soranzo N, Elder DE, Barrett JH, Martin NG, Bishop DT, Montgomery GW, Spector TD. Genome-wide association study identifies variants at 9p21 and 22q13 associated with development of cutaneous nevi. Nat Genet. 2009;41(8):915-919. PMID: 19578365.
18. Valverde P, Healy E, Jackson I, Rees JL, Thody AJ. Variants of the melanocyte-stimulating hormone receptor gene are associated with red hair and fair skin in humans. Nat Genet. 1995;11(3):328-330. PMID: 7581459.