Maximizing Molecules and Medicines
From the discovery of new molecules to lifecycle management of our approved medicines, Horizon scientists and technical experts are relentlessly and compassionately exploring potential new treatments for patients with rare, autoimmune and severe inflammatory diseases.
Our team is committed to solving difficult problems and is not afraid to explore paths less taken to create the next generation of innovative therapies that serve patients around the world. We follow what the data tell us, resulting in a curated pipeline of targeted experimental medicines and novel mechanisms of action.
Watch to learn more about the Horizon research and development (R&D) team’s practical and creative approach to thinking differently about science:
Creative Approaches to Experimental Medicines
In this section, we explore how our scientists and technical experts are investigating targeted therapies to treat a variety of diseases. At the center of our scientific approach are premier pathways – those that have a central role in aggregating the many biological inputs that lead to disease and the transition from an early disease state to a more severe condition. First, we explain the origination and development of different diseases in the body. Then, we dive into the experimental medicines our team has developed as a potential solution. Take a look.

Plasmacytoid dendritic cells (pDCs) are present in high numbers in tissue and constantly activated in certain autoimmune diseases, which causes them to secrete large amounts of inflammatory molecules, especially Type 1 Interferons. This can lead to a variety of autoimmune conditions.

As a potential solution, daxdilimab (HZN-7734) is an anti-ILT7 human monoclonal antibody that has been shown to deplete plasmacytoid dendritic cells (pDCs) and reduce levels of these cells and Type 1 Interferons. Depleting these cells may interrupt the cycle of inflammation that causes tissue damage in diseases such as lupus, alopecia areata, discoid lupus erythematosus, dermatomyositis and lupus nephritis.

CD40 is a well-established receptor pathway that contributes to autoimmune and inflammatory disease when it binds to the CD40 ligand (CD40L) causing B cell and T cell interaction that creates inflammation and disease.

As a potential solution, dazodalibep (HZN-4920) is a novel, non-antibody fusion protein that blocks CD40L activity, that has been shown to reduce B cell activation and autoantibody production, potentially halting inflammation and autoimmunity and diseases such as Sjögren’s syndrome, rheumatoid arthritis, kidney transplant rejection and focal segmental glomerulosclerosis.

FLT3L drives the production and survival of plasmacytoid dendritic cells (pDCs) and conventional dendritic cells (cDCs), which contribute to inflammation in the body. Many autoimmune and inflammatory diseases have higher levels of circulating FLT3L levels which are thought to support the prolonged inflammation observed in these conditions.

As a potential solution, HZN-1116 is an anti-FLT3L human monoclonal antibody that binds and neutralizes the function of FLT3L and has been shown to reduce the levels of pDCs and cDCs, thereby decreasing the inflammatory molecules they produce, which could potentially reduce prolonged inflammation in a variety of diseases.
Overheard in the Lab
Our scientists are committed to working together to discover and develop novel treatments for patients in need. Watch as they take you behind the scenes.
Science Stories
Our scientific teams are exploring ways to bring novel small molecules, potential first-in-class biologics and new medicine administration options to patients.
'Premier Pathways' Are the Heart of Our R&D Strategy
At Horizon, our research and development (R&D) approach to scientific discovery is all about premier pathways that lead to a variety of diseases.
A New Approach to Target Dysregulated LPA Signaling
What if there was a way to target dysregulated signaling in one receptor while allowing five other receptors to continue normal activity?
Halting Inflammation Through CD40 Ligand
Our team is thinking differently about halting disease activity that leads to inflammation through CD40 ligand.
A Novel Approach to Target pDCs in the Body
Horizon scientists are exploring a new approach to reducing autoimmunity that leads to diseases like lupus.
People Behind the Science
Our work at Horizon is personal. Our R&D team is fueled by more than 300 scientific minds across the company.

Yaminah Leggett-Wells, M.S., MBA, senior director, alliance management, believes that when diverse mindsets from academia and biotechnology come together, it can create powerful partnerships that ultimately help patients. “Many diseases in our pipeline disproportionately affect people of diverse backgrounds - in order to accurately reflect these communities in our science work, we need to bring diverse perspectives to the table at the early stages of clinical development,” Leggett-Wells said. “Having thought leaders connect with our teams and potential partners, including those in international markets, helps us design better protocols for our clinical trials to ensure we’re meeting the needs of all people living with these diseases.”
At Horizon, Leggett-Wells and her team focus on advancing the company’s business development and scientific collaborations from early drug discovery to on-market medicines. She specifically focuses on seeking academic collaborations that will have a synergistic effect on advancing Horizon’s pipeline and providing new treatments to patients. “When we look for potential academic partners, we try to identify institutions that understand the biology behind the disease states we’re focused on and can help us bring targeted therapies for those patients,” Leggett-Wells said. “Having this kind of partner will make us more efficient in our work, allowing us to get therapies to patients sooner.”
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Sadiye Rieder, Ph.D., associate director and research scientist, spends her days in the lab asking questions about how autoimmunity develops in humans. As the leader of Horizon’s early preclinical programs, she builds research strategies to uncover new information about autoimmune diseases that have limited treatment options. She is specifically looking at T cells and the role they play in preventing these diseases. “If you understand the biology of how different cells work in the body, you can break down these disease processes and create targeted medicines that can help patients,” Rieder said.
Asking questions about scientific processes is what initially sparked Rieder to follow her career path. At a young age, she wanted to understand why people developed certain diseases. She credits several influential female mentors for empowering her to translate her autoimmune disease research into something meaningful for others. At Horizon, she aims to do the same with her female colleagues and those she mentors. “Knowing I can inspire young women to pursue a career in science by showing them that their work can ultimately turn into something life-changing for patients is what fuels me every day.”
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Bill Rees, Ph.D., Horizon’s leader in translational medicine, is focused on science that puts an emphasis on people as individuals rather than on the patient population as a whole, a discipline he calls “Big Science.” Rees leads toxicology, bioanalytic, pharmacology and translational medicine teams to produce the data needed to understand diseases. “Our team recognizes that one medicine isn’t going to fit all patients with the same disease, which is unique in biotech,” Rees said.
Rees and his team work closely with Horizon’s clinical development and medical affairs teams to examine and tell the story of how Horizon’s molecules interact with the human body. He is a strong believer in the benefit of collaboration to help break down barriers and spur growth. “True strength is not in white papers or guideline documents; it’s in the people and collaboration across all functions,” Rees said. He also looks across therapeutic areas to explore treatments to help patients manage their diseases. “Our goal is to bring the right medicine, right dose and right timing to the right patient.”
Read moreArticles and Publications
Our team’s discoveries and scientific findings extend beyond the lab. Review some of our scientific publications and articles below:
Preclinical Manuscripts
- B-cell depletion in vitro and in vivo with an afucosylated anti-CD19 antibody
- A glycoengineered anti-CD19 antibody with potent antibody-dependent cellular cytotoxicity activity in vitro and lymphoma growth inhibition in vivo
- Macrophage and NK-mediated killing of precursor-B acute lymphoblastic leukemia cells targeted with a-fucosylated anti-CD19 humanized antibodies
- Germinal center B cell depletion diminishes CD4+ follicular T helper cells in autoimmune mice
- Single dose of glycoengineered anti-CD19 antibody (MEDI551) disrupts experimental autoimmune encephalomyelitis by inhibiting pathogenic adaptive immune responses in the bone marrow and spinal cord while preserving peripheral regulatory mechanisms
- Autoreactive CD19+CD20- Plasma Cells Contribute to Disease Severity of Experimental Autoimmune Encephalomyelitis
- MEDI-551 Treatment Effectively Depletes B Cells and Reduces Serum Titers of Autoantibodies in Mice Transgenic for Sle1 and Human CD19
- Pharmacological profile of MEDI-551, a novel anti-CD19 antibody, in human CD19 transgenic mice
- IL-21 drives expansion and plasma cell differentiation of autoreactive CD11chiT-bet+ B cells in SLE
Clinical Manuscripts
- Suppression of T Cell Activation and Collagen Accumulation by an Anti-IFNAR1 mAb, Anifrolumab, in Adult Patients with Systemic Sclerosis
- Safety and tolerability of an anti-CD19 monoclonal antibody, MEDI-551, in subjects with systemic sclerosis: a phase I, randomized, placebo-controlled, escalating single-dose study
- Safety and tolerability of inebilizumab (MEDI-551), an anti-CD19 monoclonal antibody, in patients with relapsing forms of multiple sclerosis: Results from a phase 1 randomised, placebo-controlled, escalating intravenous and subcutaneous dose study
- Baseline Plasma Cell Gene Signature Predicts Improvement in Systemic Sclerosis Skin Scores Following Treatment With Inebilizumab (MEDI-551) and Correlates With Disease Activity in Systemic Lupus Erythematosus and Chronic Obstructive Pulmonary Disease
- Inebilizumab for the treatment of neuromyelitis optica spectrum disorder (N-MOmentum): a double-blind, randomised placebo-controlled phase 2/3 trial
- The MIDORA trial: a phase II, randomised, double-blind, placebo-controlled, mechanistic insight and dosage optimisation study of the efficacy and safety of dazodalibep in patients with rheumatoid arthritis
Review Articles
- B-cell targeted therapeutics in clinical development
- Statistical Considerations for an Adaptive Design for a Serious Rare Disease
- Placebo-controlled study in neuromyelitis optica-Ethical and design considerations
- Role of CD11c + Tbet + B cells in human health and disease
- Inebilizumab, a B Cell-Depleting Anti-CD19 Antibody for the Treatment of Autoimmune Neurological Diseases: Insights from Preclinical Studies
- B cell-based therapies in CNS autoimmunity: differentiating CD19 and CD20 as therapeutic targets
Molecules
Preclinical Manuscripts
- Autoimmune manifestations in aged mice arise from early-life immune dysregulation
- Requirement for CD40/CD40L Interactions for Development of Autoimmunity Differs Depending on Specific Checkpoint and Costimulatory Pathways