GondolaBio has reported positive results from its Phase IIa GATEWAY study of PORT-77, an investigational oral ABCG2 inhibitor, which aims to treat erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP).
The company announced the results on behalf of its affiliate Portal Therapeutics.
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The blinded, placebo-controlled, crossover, randomised trial evaluated PORT-77 in adults with EPP, focusing on the reduction of plasma protoporphyrin IX (PPIX), a key factor in these genetic disorders characterised by photosensitivity and liver complications.
In the study, 19 participants received either a placebo followed by 180mg PORT-77 once daily (QD) or 300mg twice daily (BID) for four days.
Presented at the European Hematology Association 2026 Congress in Stockholm, Sweden, the results indicate PORT-77 was well tolerated, with no serious adverse events or treatment discontinuations.
Key findings show a mean 79% decrease in plasma PPIX among participants who received 300mg BID and 63% for those on 180mg QD.
Both dose groups experienced rapid reductions in plasma PPIX, observed within hours, with no rebound effect after treatment cessation. Efficacy was consistent across a wide range of baseline PPIX levels (8µg/dL–121µg/dL).
Following these results and discussions at the end-of-Phase II meeting with the US Food and Drug Administration (FDA), GondolaBio plans to start the global Phase IIb/III PATHWAY trial of PORT-77 in EPP and XLP in the third quarter (Q3) of 2026.
The stEPP global observational study is also progressing to further characterise disease burden and PPIX variability.
Portal Therapeutics chief medical officer Pete Schmidt said: “These data represent an important milestone, highlighting PORT-77’s potential to be a disease-modifying therapy by significantly reducing PPIX in plasma, the most physiologically relevant blood component for these conditions, which may address the significant unmet need in people living with EPP and XLP.
“Notably, these results demonstrate PORT-77’s potential for leading efficacy, safety, and speed to onset, with rapid and profound reductions in plasma PPIX within hours of dosing. We are encouraged by the magnitude and speed of these reductions, which may translate to patients tolerating more time in the sun and improved quality of life.”
