CSL Behring (CSL Limited) / Calimmune, Inc.

Sickle Cell Disease

Disease Overview

Sickle cell disease is an inherited red blood cell disorder caused by mutation in the beta-globin gene that causes hemoglobin to polymerize and red cells to sickle, leading to vaso-occlusion, chronic hemolytic anemia, organ damage and recurrent pain crises. The disease disproportionately affects people of African ancestry and historically had limited disease-modifying options beyond hydroxyurea and chronic transfusion. Beta-thalassemia, a related hemoglobinopathy, leaves patients transfusion-dependent for life.

Competitive Landscape

At deal time (Aug 2017), the SCD treatment landscape was dominated by hydroxyurea and supportive care; Endari (L-glutamine, Emmaus) had just received FDA approval (July 2017) and Adakveo (crizanlizumab) and Oxbryta (voxelotor) were still pre-approval. The transformative therapeutic horizon was lentiviral and CRISPR gene therapy: bluebird bio's LentiGlobin (later Zynteglo/Lyfgenia) was the most advanced ex vivo lentiviral program for SCD and beta-thalassemia, with Sangamo/Bioverativ pursuing zinc-finger BCL11A approaches and CRISPR Therapeutics/Vertex (CTX001, later Casgevy) emerging. Calimmune's preclinical CAL-H gave CSL Behring an entry alongside the Select+ enrichment and Cytegrity manufacturing platforms — directly addressing the scale-up bottleneck that would later constrain commercial gene therapy launches. CSL framed the deal as complementary to its plasma-based hemophilia franchise (Hemgenix later validated CSL's commitment to gene therapy), but the ex vivo lentiviral approach proved harder than expected: CSL ultimately paused its lentiviral SCD program and shut its Pasadena cell-and-gene therapy hub in 2024, while the post-deal market was won by Casgevy and Lyfgenia (FDA-approved December 2023, priced $2.2M and $3.1M respectively per Fierce Pharma). [https://www.fiercebiotech.com/biotech/csl-behring-buys-calimmune-for-early-stem-cell-gene-therapy-boost]