Background and Significance

In sickle cell disease (SCD), a single point mutation in the beta-globin gene results in hemoglobin S (HbS) production, which can polymerize upon deoxygenation. Polymerization distorts the red blood cell (RBC) membrane and generates sickled RBCs, contributing to microvascular occlusions, which may present as acute, painful vaso-occlusive episodes (VOEs). For patients (pts) with SCD, 70% of emergency department visits and 90% of hospitalizations are VOE-related. 1,2 Despite existing treatments for VOE prevention, considerable morbidity and mortality remain; acute VOE treatment is limited to supportive care due to a lack of targeted therapies.

Accumulating nonclinical data suggest a multimodal role for complement dysregulation in SCD pathophysiology, including in vaso-occlusion, hemolysis, inflammation, thrombogenicity, endothelial activation, and end-organ damage. 3 Crovalimab is a novel, engineered, anti-complement C5 monoclonal antibody that allows for small-volume subcutaneous (SC) injection after an initial intravenous (IV) loading dose. 4 Here, we describe two randomized, double-blind, placebo-controlled trials evaluating crovalimab in pts with SCD: CROSSWALK-a (Phase 1b; NCT04912869) and CROSSWALK-c (Phase 2a; NCT05075824).

Study Design and Methods

CROSSWALK-a evaluates the safety of crovalimab in managing acute uncomplicated VOEs. CROSSWALK-c evaluates the efficacy and safety of crovalimab as adjunct therapy in preventing VOEs.

Pts 12-55 years old, weighing ≥40 kg with a confirmed diagnosis of sickle cell anemia (homozygous HbSS or heterozygous HbS/β 0 thalassemia) and vaccinated against N. meningitidis, H. influenzae type B and S. pneumoniae are eligible (Fig. 1 and 2). Concurrent SCD-directed therapies are allowed.

CROSSWALK-a

Pts must present with an acute uncomplicated VOE requiring hospitalization and parenteral opioid analgesics, and have had ≤10 VOEs in the 12 months prior to randomization. Eligible pts will be randomized 2:1 to receive a single IV weight-based tiered dose of crovalimab or placebo, and monitored during hospitalization and in an 84-day observational period followed by a safety follow-up period for a total study duration of 322 days (10.5 months).

The primary objective of CROSSWALK-a is to evaluate safety up to Day 84, including:

  • Incidence and severity of adverse events

  • Incidence and severity of infusion-related reactions and hypersensitivity

  • Change from baseline in targeted vital signs and clinical laboratory test results

Efficacy, pharmacokinetic (PK), pharmacodynamic (PD), immunogenicity, and exploratory biomarker endpoints will also be evaluated.

CROSSWALK-c

Pts with 2-10 VOEs in the 12 months prior to randomization are eligible. Eligible pts will be randomized 1:1 to receive weight-based tiered doses of crovalimab or placebo, consisting of initial loading doses (IV: Day 1; SC: Day 2 and weekly for Weeks 2-4) and monthly maintenance SC doses Weeks 5-49 for 48 weeks of treatment.

The primary objective of CROSSWALK-c is to evaluate crovalimab efficacy vs placebo up to 48 weeks, on the basis of:

  • The annualized rate of medical facility VOEs

Key secondary efficacy objectives are:

  • Annualized rate of home VOEs

  • Annualized rate of acute chest syndrome

  • Annualized rate of days hospitalized for medical facility VOEs

  • Pt-reported fatigue in adults

Safety, PK, PD, immunogenicity, and exploratory biomarker endpoints will also be evaluated.

Primary results will be published upon trial readout.

References

1. Ballas et al, Am J Hematol 2005; 79:17-25.

2. Lanzkron et al , Am J Hematol 2010; 85:797-799.

3. Roumenina et al, Am J Hematol 2020; 95:456-464.

4. Röth et al, Blood 2020; 135:912-920.

Salvino:F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Research Funding, Speakers Bureau; OrphanDrugs: Consultancy; Abbvie: Consultancy, Honoraria, Speakers Bureau; Amgen: Consultancy; Pfizer: Consultancy, Honoraria, Research Funding, Speakers Bureau; MSD: Consultancy, Honoraria, Speakers Bureau; Gilead: Honoraria, Speakers Bureau; ABHH: Membership on an entity's Board of Directors or advisory committees; SBTMO: Membership on an entity's Board of Directors or advisory committees. Chite Asirwa:MSD: Consultancy, Honoraria; F. Hoffman-La Roche: Honoraria, Research Funding; GBT: Research Funding; Pfizer: Research Funding; Genentech Inc.: Honoraria, Research Funding; Bausch: Research Funding; Celgene: Research Funding; Millennium: Honoraria; AstraZeneca: Honoraria; Merck: Honoraria; Novartis: Honoraria; ASCO: Membership on an entity's Board of Directors or advisory committees; ESMO: Membership on an entity's Board of Directors or advisory committees; ECSACO: Membership on an entity's Board of Directors or advisory committees. Chonat:Amgen: Consultancy, Research Funding; Roche/Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda Pharmaceuticals: Consultancy, Research Funding; GBT/Pfizer: Consultancy, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Agios: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Alexion: Consultancy, Other, Research Funding. De Franceschi:Agios: Research Funding; Bristol Myers Squibb: Research Funding; F. Hoffmann-La Roche Ltd, Basel: Membership on an entity's Board of Directors or advisory committees. Eleftheriou:Pfizer: Honoraria; GBT: Honoraria; Alexion: Honoraria; Forma Therapeutics: Honoraria; Agios: Honoraria. Mahlangu:Roche: Research Funding; Pfizer: Research Funding; Spark Therapeutics: Research Funding; Catalyst: Research Funding; Sanofi: Research Funding; Sandoz: Research Funding; Novo Nordisk: Research Funding; BioMarin Pharmaceutical Inc.: Research Funding. Nur:VERTEX: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Novartis: Consultancy, Research Funding, Speakers Bureau. Charania:F. Hoffmann-La Roche Ltd, Basel: Current Employment. Gradinaru:F. Hoffmann-La Roche Ltd, Basel: Current Employment, Current equity holder in publicly-traded company. Hsia:Genentech Inc.: Current Employment. Luder:F. Hoffmann-La Roche Ltd, Basel: Current Employment. Perretti:F. Hoffmann-La Roche Ltd, Basel: Current Employment. Srekovic:F. Hoffmann-La Roche Ltd, Basel: Current equity holder in publicly-traded company, Ended employment in the past 24 months; Genentech Inc.: Current Employment, Current equity holder in publicly-traded company. Bartolucci:Addmedica: Consultancy, Membership on an entity's Board of Directors or advisory committees; INNOVHEM: Current equity holder in private company; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bluebird: Consultancy; Roche: Consultancy; Emmaus: Consultancy; GBT: Consultancy; Jazz Pharma: Consultancy.

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