RARE DISEASE
Erythropoietic porphyria
Erythropoietic porphyria
Erythropoietic porphyria
Synonyms: EPP
Synonyms: EPP
Synonyms: EPP
Drug discovery
2
drugs
With orphan designations
Overview
Erythropoietic protoporphyria (EPP) is a rare inherited metabolic disorder caused by ferrochelatase (FECH) deficiency or ALAS2 mutations (X-linked), leading to protoporphyrin IX accumulation. Patients experience severe phototoxicity with burning pain, erythema, and edema within minutes of sunlight/visible light exposure. Complications include hepatobiliary disease (5-10% develop liver cirrhosis/failure) and protoporphyrin gallstones. Diagnosis requires elevated free erythrocyte protoporphyrin (>80% in EPP; zinc-protoporphyrin predominant in XLP) and genetic confirmation [1][6][9].
Population
Therapies
Photoprotection: Sun avoidance, UV-blocking window films, physical barriers (clothing) [6][17]
Pharmacologic: Afamelanotide (melanocortin-1 agonist implant, improves light tolerance) [9][13], beta-carotene (antioxidant) [6][17]
Monitoring/Advanced Care: Biannual liver function tests, hepatology referral for cholestasis; liver transplant ± bone marrow transplant for end-stage disease [3][7][9]
Categories: rare genetic diseases, rare inborn errors of metabolism, rare renal diseases, rare skin diseases
Research Papers
255 drug discovery papers about Erythropoietic porphyria, with 3 first-in-class and 4 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
255 drug discovery papers about Erythropoietic porphyria, with 3 first-in-class and 4 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
2026-03-26 | New and currently investigated pharmacotherapies for the erythropoietic protoporphyrias: spotlight on dersimelagon and bitopertin.
The erythropoietic protoporphyrias (EPP) are ultra-rare inborn errors of the heme biosynthesis characterized by painful and debilitating phototoxic reactions in the blood vessels upon exposure to visible light. Afamelanotide is the only approved treatment for EPP and effectively prevents pain and prolongs the time patients can spend in sunlight. However, afamelanotide does not address the underlying disease mechanism and is currently only approved for use in adult patients, leaving children and adolescents without a treatment option. The two investigational pharmacotherapies, dersimelagon and bitopertin, could offer benefits such as treatment options for children and prevention of some of the associated disease complications. This narrative review (using Pubmed and trial databases) aims to provide an overview of the status of development of dersimelagon and bitopertin, with a focus on the prevention of phototoxicity. The currently available trial data on dersimelagon and bitopertin suggests treatment effects in EPP as compared to placebo control groups. However, safety and efficacy of dersimelagon and bitopertin need to be further characterized. Moreover, to ensure benefit for patients and access to therapy after regulatory approval, it also would be important to generate data on the relative safety and efficacy as compared to afamelanotide.
2026-03-12 | Hematopoietic stem cell transplantation for erythropoietic porphyria-induced acute liver failure: a case report and literature review.
Protoporphyrias are rare genetic disorders in heme biosynthesis, causing protoporphyrin IX accumulation with progressive liver injury. Liver transplantation has traditionally treated protoporphyria-induced liver injury but does not correct the underlying hematopoietic defect. We present a 16-year-old male with painful cutaneous photosensitivity who developed cholestatic liver dysfunction and severe abdominal pain. After plasmapheresis, red blood cell (RBC) transfusions, and intravenous hemin, he had transient improvement and subsequently underwent hematopoietic stem cell transplantation (HSCT) without liver transplantation, which normalized his protoporphyrin levels, liver function, and symptoms. This case underscores HSCT as a disease-modifying therapy that may prevent liver transplantation when performed before irreversible hepatic damage.
2025-12-31 | Congenital Erythropoietic Porphyria with Persistent Severe Biochemical Abnormalities and a Non-Mutilating Clinical Course: A Case Report
Congenital erythropoietic porphyria (CEP), also known as Günther disease, is a rare autosomal recessive porphyria caused by deficiency of uroporphyrinogen III synthase, leading to accumulation of phototoxic type I porphyrins. CEP classically presents in infancy with severe photosensitivity, blistering, scarring, and hemolytic anemia; however, significant phenotypic variability has increasingly been recognized. We report 32-year-old women diagnosed with CEP in early infancy who demonstrated persistently and profoundly elevated erythrocyte porphyrin levels over more than a decade yet followed a relatively non-mutilating clinical course. Genetic testing identified a low penetrance intronic UROS variant typically associated with erythropoietic protoporphyria, underscoring diagnostic challenges and genotype-phenotype discordance. The patient experienced marked improvement in photosensitivity and burning pain after initiation of afamelanotide, without need for transfusion therapy or stem cell transplantation. This case highlights the heterogeneity of CEP, the importance of long-term biochemical follow up, and the potential role of afamelanotide in improving quality of life for selected patients with CEP.
2025-12-30 | New pharmacotherapies for the erythropoietic protoporphyrias: an analysis of trial protocols from a patient perspective.
BACKGROUND: The erythropoietic protoporphyrias (EPP) are a group of ultra-rare (1:100.000) inborn errors of the heme biosynthesis characterised by painful phototoxic reactions in tissue exposed to visible light. Afamelanotide is the only approved treatment for EPP and effectively prevents phototoxic reactions and improves the quality of life of the patients. In the past years, several new potential treatment options for EPP have been identified, some of which are currently under investigation in clinical trials. While these developments could improve patient care, it is important to know how safety and efficacy of drug candidates compare to the existing treatment, i.e. afamelanotide. METHODS: We identified pharmacotherapies (leaving out, for example, topical applications such as sunscreens or supplements such as iron) which are currently (that is, within the last 5 years) evaluated for EPP from clinical trial registries and investigated whether the trial designs allow a comparison of their treatment effects with each other and with afamelanotide. Therefore, we analysed the clinical trial protocols with emphasis on their trial designs, efficacy outcome measures, inclusion and exclusion criteria, safety aspects and, if available, published results. RESULTS: Our search in the clinical trials registries retrieved 29 trials that included patients with EPP. From these, we identified 16 clinical trials evaluating afamelanotide and three new pharmacotherapies, i.e., dersimelagon, bitopertin and cimetidine. Safety and efficacy of all new pharmacotherapies are currently being investigated against placebo-control groups or against baseline. Because of differences in the outcome measures and included patient populations, the results of the trials cannot be directly compared. Moreover, methodically challenging aspects and ethical issues were identified in some of the trial protocols. CONCLUSION: Efficacy and safety of currently investigated treatments for EPP are not directly comparable. We wrote this manuscript as a call to action to Principal Investigators, Ethical Review Boards, Regulatory Authorities and the sponsors of trials because we are convinced that trials directly assessing new pharmacotherapies against afamelanotide would be the more informative, and methodological and ethically sounder trial design. CLINICAL TRIAL NUMBER: Not applicable.
2025-12-14 | Bitopertin shows efficacy in patients with erythropoietic protoporphyria: Results from the randomized, double-blind, placebo-controlled AURORA trial.
Erythropoietic protoporphyria is a rare genetic disorder of heme biosynthesis characterized by protoporphyrin-IX accumulation, painful phototoxic reactions, and hepatobiliary disease, for which no disease-modifying therapies are approved. To evaluate the efficacy and safety of bitopertin, an inhibitor of glycine transporter 1, in adults with erythropoietic protoporphyria. In this randomized, double-blind, phase 2 study, patients received once-daily oral bitopertin 20 mg, bitopertin 60 mg, or placebo for 17 weeks. The primary endpoint was percentage change from baseline in whole-blood metal-free protoporphyrin-IX levels at day 121. Patients received bitopertin 20 mg (n = 26), 60 mg (n = 25), or placebo (n = 24). At day 121, the percentage change from baseline in whole-blood metal-free protoporphyrin-IX versus placebo was -29.6% (P = .004) with bitopertin 20 mg and -49.8% (P < .001) with bitopertin 60 mg. Bitopertin was associated with a reduced incidence of phototoxic reactions. Bitopertin was well tolerated with no notable safety concerns identified. Small sample size, short follow-up period, and no formal adjustments for between-group multiple-pairwise comparisons. Bitopertin significantly reduced protoporphyrin-IX levels, showed improved measures of sunlight tolerance, and had a favorable safety profile in patients with erythropoietic protoporphyria.
2026-03-26 | New and currently investigated pharmacotherapies for the erythropoietic protoporphyrias: spotlight on dersimelagon and bitopertin.
The erythropoietic protoporphyrias (EPP) are ultra-rare inborn errors of the heme biosynthesis characterized by painful and debilitating phototoxic reactions in the blood vessels upon exposure to visible light. Afamelanotide is the only approved treatment for EPP and effectively prevents pain and prolongs the time patients can spend in sunlight. However, afamelanotide does not address the underlying disease mechanism and is currently only approved for use in adult patients, leaving children and adolescents without a treatment option. The two investigational pharmacotherapies, dersimelagon and bitopertin, could offer benefits such as treatment options for children and prevention of some of the associated disease complications. This narrative review (using Pubmed and trial databases) aims to provide an overview of the status of development of dersimelagon and bitopertin, with a focus on the prevention of phototoxicity. The currently available trial data on dersimelagon and bitopertin suggests treatment effects in EPP as compared to placebo control groups. However, safety and efficacy of dersimelagon and bitopertin need to be further characterized. Moreover, to ensure benefit for patients and access to therapy after regulatory approval, it also would be important to generate data on the relative safety and efficacy as compared to afamelanotide.
2026-03-12 | Hematopoietic stem cell transplantation for erythropoietic porphyria-induced acute liver failure: a case report and literature review.
Protoporphyrias are rare genetic disorders in heme biosynthesis, causing protoporphyrin IX accumulation with progressive liver injury. Liver transplantation has traditionally treated protoporphyria-induced liver injury but does not correct the underlying hematopoietic defect. We present a 16-year-old male with painful cutaneous photosensitivity who developed cholestatic liver dysfunction and severe abdominal pain. After plasmapheresis, red blood cell (RBC) transfusions, and intravenous hemin, he had transient improvement and subsequently underwent hematopoietic stem cell transplantation (HSCT) without liver transplantation, which normalized his protoporphyrin levels, liver function, and symptoms. This case underscores HSCT as a disease-modifying therapy that may prevent liver transplantation when performed before irreversible hepatic damage.
2025-12-31 | Congenital Erythropoietic Porphyria with Persistent Severe Biochemical Abnormalities and a Non-Mutilating Clinical Course: A Case Report
Congenital erythropoietic porphyria (CEP), also known as Günther disease, is a rare autosomal recessive porphyria caused by deficiency of uroporphyrinogen III synthase, leading to accumulation of phototoxic type I porphyrins. CEP classically presents in infancy with severe photosensitivity, blistering, scarring, and hemolytic anemia; however, significant phenotypic variability has increasingly been recognized. We report 32-year-old women diagnosed with CEP in early infancy who demonstrated persistently and profoundly elevated erythrocyte porphyrin levels over more than a decade yet followed a relatively non-mutilating clinical course. Genetic testing identified a low penetrance intronic UROS variant typically associated with erythropoietic protoporphyria, underscoring diagnostic challenges and genotype-phenotype discordance. The patient experienced marked improvement in photosensitivity and burning pain after initiation of afamelanotide, without need for transfusion therapy or stem cell transplantation. This case highlights the heterogeneity of CEP, the importance of long-term biochemical follow up, and the potential role of afamelanotide in improving quality of life for selected patients with CEP.
2025-12-30 | New pharmacotherapies for the erythropoietic protoporphyrias: an analysis of trial protocols from a patient perspective.
BACKGROUND: The erythropoietic protoporphyrias (EPP) are a group of ultra-rare (1:100.000) inborn errors of the heme biosynthesis characterised by painful phototoxic reactions in tissue exposed to visible light. Afamelanotide is the only approved treatment for EPP and effectively prevents phototoxic reactions and improves the quality of life of the patients. In the past years, several new potential treatment options for EPP have been identified, some of which are currently under investigation in clinical trials. While these developments could improve patient care, it is important to know how safety and efficacy of drug candidates compare to the existing treatment, i.e. afamelanotide. METHODS: We identified pharmacotherapies (leaving out, for example, topical applications such as sunscreens or supplements such as iron) which are currently (that is, within the last 5 years) evaluated for EPP from clinical trial registries and investigated whether the trial designs allow a comparison of their treatment effects with each other and with afamelanotide. Therefore, we analysed the clinical trial protocols with emphasis on their trial designs, efficacy outcome measures, inclusion and exclusion criteria, safety aspects and, if available, published results. RESULTS: Our search in the clinical trials registries retrieved 29 trials that included patients with EPP. From these, we identified 16 clinical trials evaluating afamelanotide and three new pharmacotherapies, i.e., dersimelagon, bitopertin and cimetidine. Safety and efficacy of all new pharmacotherapies are currently being investigated against placebo-control groups or against baseline. Because of differences in the outcome measures and included patient populations, the results of the trials cannot be directly compared. Moreover, methodically challenging aspects and ethical issues were identified in some of the trial protocols. CONCLUSION: Efficacy and safety of currently investigated treatments for EPP are not directly comparable. We wrote this manuscript as a call to action to Principal Investigators, Ethical Review Boards, Regulatory Authorities and the sponsors of trials because we are convinced that trials directly assessing new pharmacotherapies against afamelanotide would be the more informative, and methodological and ethically sounder trial design. CLINICAL TRIAL NUMBER: Not applicable.
2025-12-14 | Bitopertin shows efficacy in patients with erythropoietic protoporphyria: Results from the randomized, double-blind, placebo-controlled AURORA trial.
Erythropoietic protoporphyria is a rare genetic disorder of heme biosynthesis characterized by protoporphyrin-IX accumulation, painful phototoxic reactions, and hepatobiliary disease, for which no disease-modifying therapies are approved. To evaluate the efficacy and safety of bitopertin, an inhibitor of glycine transporter 1, in adults with erythropoietic protoporphyria. In this randomized, double-blind, phase 2 study, patients received once-daily oral bitopertin 20 mg, bitopertin 60 mg, or placebo for 17 weeks. The primary endpoint was percentage change from baseline in whole-blood metal-free protoporphyrin-IX levels at day 121. Patients received bitopertin 20 mg (n = 26), 60 mg (n = 25), or placebo (n = 24). At day 121, the percentage change from baseline in whole-blood metal-free protoporphyrin-IX versus placebo was -29.6% (P = .004) with bitopertin 20 mg and -49.8% (P < .001) with bitopertin 60 mg. Bitopertin was associated with a reduced incidence of phototoxic reactions. Bitopertin was well tolerated with no notable safety concerns identified. Small sample size, short follow-up period, and no formal adjustments for between-group multiple-pairwise comparisons. Bitopertin significantly reduced protoporphyrin-IX levels, showed improved measures of sunlight tolerance, and had a favorable safety profile in patients with erythropoietic protoporphyria.
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Drug Discovery Landscape
2 orphan drug designations for Erythropoietic porphyria, including 1 approved therapy.
2 orphan drug designations for Erythropoietic porphyria, including 1 approved therapy.
Drug | Therapy type | Regulator | Orphan designation | Approval | Sponsor |
|---|---|---|---|---|---|
bitopertin | small molecules | FDA | 2022-12-22 | — | Disc Medicine |
Afamelanotide [Scenesse] | peptides | EMA | 2008-05-08 | 2014-12-29 | Clinuvel Europe Limited |
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