Paroxysmal nocturnal hemoglobinuria (PNH)

What changes during this transition

Paroxysmal nocturnal hemoglobinuria is an acquired clonal hematopoietic stem cell disorder — somatic PIGA mutations cause loss of GPI-anchor biosynthesis in the affected clone, leaving its surface deficient in the GPI-anchored complement regulators CD55 (decay-accelerating factor) and CD59 (membrane inhibitor of reactive lysis), and producing uncontrolled complement-mediated intravascular hemolysis. The three load-bearing clinical features: intravascular hemolysis (LDH often >1.5x ULN, haptoglobin suppressed, indirect hyperbilirubinemia, reticulocytosis), thrombosis (the dominant morbidity-mortality driver in the pre-eculizumab era; venous predominant with characteristic hepatic vein / Budd-Chiari syndrome, cerebral venous sinus thrombosis, splanchnic vein, dermal vein, DVT/PE distribution), and bone marrow failure with substantial overlap with aplastic anemia and MDS — AA-PNH syndrome is a recognized bidirectional entity. Diagnosis is high-sensitivity flow cytometry per ICCS 2010/2018 (FLAER + CD55 + CD59 on RBCs and granulocytes/monocytes; FLAER preferred on WBCs for clone-size quantification since the RBC clone is depleted by hemolysis); the older Ham and sucrose lysis tests are obsolete. Clone-size categorization (classical hemolytic PNH >50%, AA-PNH overlap, subclinical) drives the treatment conversation. Standard-of-care has been transformed by complement-pathway inhibitors across three molecular targets: ECULIZUMAB (Soliris, Alexion/AstraZeneca) anti-C5 mAb FDA-approved March 2007 — the first complement inhibitor approved for any disease — based on TRIUMPH and SHEPHERD trials; transformed median survival from ~10-15 years to near-normal life expectancy; IV every 2 weeks after loading. RAVULIZUMAB (Ultomiris, Alexion/AstraZeneca) long-acting anti-C5 mAb FDA-approved December 2018 for PNH; engineered eculizumab variant with FcRn-modified half-life; IV Q8wk; non-inferior to eculizumab in Studies 301 and 302; SC formulation FDA-approved March 2024. PEGCETACOPLAN (Empaveli in US, Aspaveli in EU, Apellis) pegylated C3 inhibitor FDA-approved May 2021 — addresses C3-mediated extravascular hemolysis that anti-C5 doesn't block; PEGASUS Phase 3 superior to eculizumab in transfusion-dependent suboptimal responders; SC twice-weekly. IPTACOPAN (Fabhalta, Novartis) ORAL factor B inhibitor FDA-approved December 2023 — first oral complement inhibitor for PNH; APPLY-PNH + APPOINT-PNH Phase 3; twice-daily capsule. DANICOPAN (Voydeya, AstraZeneca/Alexion) ORAL factor D inhibitor ADD-ON to eculizumab/ravulizumab FDA-approved March 2024 — for clinically significant extravascular hemolysis on anti-C5; ALPHA Phase 3; oral TID. CROVALIMAB (PiaSky, Roche) anti-C5 mAb with SMART-Ig recycling FDA-approved June 2024; SC Q4wk; COMMODORE 1/2/3 program. Meningococcal vaccination (MenACWY + MenB) at least 2 weeks before any complement inhibitor with antibiotic-prophylaxis-window coverage is load-bearing precondition per CDC/ACIP/REMS programs. Allogeneic HSCT remains the only curative option for selected patients (severe AA-PNH overlap, complement-inhibitor failure, evolution to MDS/AML); the risk-benefit calculus has been reshaped by the complement-inhibitor era. Multi-jurisdictional disease — European, Japanese, Korean, and Chinese hematology programs run substantial cohorts and contribute to IPIG consensus literature; access disparities for the newer agents are editorial reality. No peptide in the Juno library has a discovery-card-defensible PNH case. The drafted substrate entries exist for honest /ask answers when users probe specific compounds: BPC-157's pro-angiogenic VEGF/eNOS mechanism is mechanistically problematic in a disease where Budd-Chiari and cerebral venous sinus thrombosis are central morbidity drivers, AND the SC injection itself is a bleed-risk event in patients on complement inhibitors with often low platelets from underlying bone marrow failure or AA-PNH overlap; NMN reaches the population through the aging-PNH-cohort-emerged-from-complement-inhibitor-era frame with no PNH-specific evidence; the GH-axis trio (CJC-1295 + ipamorelin + tesamorelin) raises SC injection-frequency consideration in hemolytic + thrombotic disease, with Rule 6 non-propagation sharpest for tesamorelin (HIV-LD label does NOT extend to PNH); semaglutide is the coordination-of-care conversation for weight loss in an aging PNH population on complement inhibitors. Eighty-third deliberate non-elevation of community peptides.