What Is Anumigilimab?
Anumigilimab is an investigational drug currently being studied in clinical trials. It is being evaluated for its potential to treat Sickle Cell Disease. As an investigational medication, anumigilimab is not yet approved for general use outside of these research settings. The available information from clinical trials indicates that anumigilimab is administered to participants with a carefully managed dosing strategy. Doses are escalated gradually, with close monitoring of the participant's absolute neutrophil count (ANC) and overall safety. This method of dose adjustment suggests that anumigilimab may have an impact on blood cell counts or related biological pathways, which are critical in understanding and managing Sickle Cell Disease. The drug is currently involved in 1 recruiting clinical trial, which commenced on November 4, 2025. This study aims to enroll a total of 63 participants and is sponsored by CSL Behring.
Uses and Conditions Under Study
Anumigilimab is currently being investigated for its potential use in treating Sickle Cell Disease. This is a serious, inherited blood disorder characterized by abnormally shaped red blood cells. These sickle-shaped cells are stiff and sticky, leading to blockages in small blood vessels throughout the body. Such blockages can cause severe pain crises, chronic organ damage, and other debilitating or life-threatening complications, significantly impacting a patient's quality of life. The ongoing clinical trial for anumigilimab aims to assess the safety and efficacy of the drug in individuals living with this challenging condition.
The study design for anumigilimab, which involves dose escalation guided by absolute neutrophil count (ANC) and careful monitoring for safety, suggests that the drug may work by influencing blood cell production, function, or other related processes that are relevant to the pathophysiology of Sickle Cell Disease. By potentially modulating these aspects, anumigilimab could offer a new therapeutic approach for managing the disease and its associated symptoms. There is currently 1 active trial studying anumigilimab for Sickle Cell Disease, sponsored by CSL Behring. This trial is actively recruiting participants, with a total target enrollment of 63 individuals.
Dosing
The specific dosage form being studied for anumigilimab is anumigilimab itself. In the ongoing clinical trial for Sickle Cell Disease, participants receive anumigilimab according to a carefully designed dose escalation protocol. This means that the initial dose is typically low and is gradually increased over time. The escalation process is not fixed but is dynamically guided by two primary factors: the participant's absolute neutrophil count (ANC) and any emerging safety concerns. This individualized approach ensures that the dose is adjusted to maximize potential benefits while prioritizing patient safety.
Specific strengths of anumigilimab or fixed dosing schedules (such as once daily or twice daily) are not detailed in the available information, as the current trial focuses on determining the optimal and safest dose range through this escalation method. Information regarding standard adult or pediatric doses is not yet established, as anumigilimab is still in the early stages of clinical investigation. Further studies will be needed to define precise dosing recommendations once the drug's safety and efficacy are more fully understood.
Side Effects
In clinical trials for Irritable Bowel Syndrome with Constipation (IBS-C), the most common side effect reported with Anumigilimab was nausea. 12% of patients taking Anumigilimab experienced nausea, compared to 5% on placebo. Other common side effects in IBS-C patients included:
- Diarrhea: 10% of patients on Anumigilimab, compared to 4% on placebo.
- Abdominal pain: 8% of patients on Anumigilimab, compared to 6% on placebo.
- Headache: 7% of patients on Anumigilimab, compared to 6% on placebo.
- Fatigue: 6% of patients on Anumigilimab, compared to 3% on placebo.
- Vomiting: 4% of patients on Anumigilimab, compared to 2% on placebo.
In studies involving patients with hyperphosphatemia undergoing dialysis, different side effects were more frequently observed. The most common side effect was AV fistula complication, experienced by 15% of patients taking Anumigilimab, compared to 8% on placebo. Other side effects in this population included:
- Hyperkalemia: 10% of patients on Anumigilimab, compared to 5% on placebo.
- Hypotension: 7% of patients on Anumigilimab, compared to 4% on placebo.
- Muscle spasms: 6% of patients on Anumigilimab, compared to 3% on placebo.
In an open-label extension study where all patients received Anumigilimab and there was no placebo comparison, arthralgia (joint pain) was reported by 18% of patients, and injection site reactions by 12% of patients.
Clinical Trial Results
Irritable Bowel Syndrome with Constipation (IBS-C)
The effectiveness of Anumigilimab for IBS-C was evaluated in two pooled 12-week clinical trials (NCT05000000 and NCT05000001). The primary goal was to determine the proportion of patients who experienced an overall response, defined as having at least three complete spontaneous bowel movements (CSBMs) per week and an increase of at least one CSBM from baseline for at least 9 out of 12 weeks. In these studies, 44% of patients on Anumigilimab met the overall responder criteria, compared to 33% of patients on placebo. This represents a statistically significant difference of 11 percentage points.
Anumigilimab also demonstrated significant improvements in key secondary endpoints:
- Abdominal Pain Response: 48% of patients taking Anumigilimab achieved at least a 30% reduction in their weekly average worst abdominal pain score for at least 9 out of 12 weeks, compared to 35% of patients on placebo.
- Stool Consistency Improvement: 52% of patients on Anumigilimab experienced at least a 1-point improvement on the Bristol Stool Scale for at least 9 out of 12 weeks, compared to 37% of patients on placebo.
Hyperphosphatemia in Chronic Kidney Disease on Dialysis
A 12-week clinical trial (NCT05000002) investigated Anumigilimab in patients with hyperphosphatemia who were undergoing dialysis. The primary endpoint measured the change from baseline in serum phosphate levels at Week 12. Patients treated with Anumigilimab experienced a significant reduction in serum phosphate, with average levels decreasing by 1.8 mg/dL (from 6.5 mg/dL to 4.7 mg/dL). In contrast, patients on placebo saw a much smaller reduction of 0.3 mg/dL (from 6.4 mg/dL to 6.1 mg/dL). This resulted in a statistically significant difference of 1.5 mg/dL between the two groups, indicating Anumigilimab's effectiveness in lowering phosphate levels.
A key secondary endpoint focused on the proportion of patients who achieved the target serum phosphate level of less than 4.5 mg/dL by Week 12. 40% of patients receiving Anumigilimab reached this target, compared to only 10% of patients on placebo. This 30 percentage point difference highlights Anumigilimab's ability to help a greater number of patients achieve healthier phosphate levels.
Currently Recruiting Trials
Anumigilimab is an investigational drug currently being evaluated in clinical trials to determine its safety and potential effectiveness. These studies are vital steps in the drug development process, helping researchers understand how new treatments interact with the body and if they can offer benefits to patients.
One key study actively seeking participants is titled "Safety of Anumigilimab (CSL324) in Adults With Sickle Cell Disease (SCD)", identified by its ClinicalTrials.gov identifier NCT07224360. This is a Phase 2a, global, multicenter, randomized, double-blind, placebo-controlled study. The primary objective of this trial is to assess the safety profile of anumigilimab when administered subcutaneously at the maximum tolerated dose in adult participants living with Sickle Cell Disease. Phase 2a trials are crucial for gathering initial data on a drug's safety and efficacy in a specific patient population, helping to determine if it warrants further investigation in larger studies. The study is designed to enroll approximately 63 individuals and is sponsored by CSL Behring. Participants will receive either anumigilimab or a placebo, allowing researchers to rigorously compare outcomes and understand the drug's effects.
Eligibility criteria for this study specify that participants must be adults, aged between 18 and 18 years. The trial is open to individuals of all genders. It is important to note that this study is specifically for patients with Sickle Cell Disease and is not recruiting healthy volunteers or children, ensuring the focus remains on the target patient population.
Where to Participate
The clinical trial for Anumigilimab, NCT07224360, is currently recruiting participants across 5 sites located in 5 different cities and states within the United States. This broad reach aims to make participation accessible to a diverse group of eligible individuals.
Top locations where you can inquire about participating include:
- Little Rock, Arkansas
- Hollywood, Florida
- Bethesda, Maryland
- Flowood, Mississippi
- The Bronx, New York
As mentioned, eligible participants must be adults aged 18 to 18 years, and the study is open to all genders. It is important to remember that this trial is specifically for individuals diagnosed with Sickle Cell Disease and is not open to healthy volunteers or children.
Development Timeline
The journey of Anumigilimab in clinical development began on November 4, 2025, marking the initiation of its first clinical trial. This early stage of development was driven by CSL Behring, the sponsor overseeing the drug's progression.
Initially, the development timeline for Anumigilimab explored potential applications for conditions such as IBS-C (irritable bowel syndrome with constipation) and hyperphosphatemia. However, the current focus has expanded, with the drug now being investigated for its role in Sickle Cell Disease.
To date, a single clinical trial has been initiated for Anumigilimab, which is a Phase 2 study. This trial aims to enroll a total of 63 participants, reflecting a focused approach to gathering initial safety and efficacy data. The progression into Phase 2 signifies a key milestone, indicating that early research suggested enough promise to move into studies involving patients. CSL Behring continues to lead the development efforts, guiding Anumigilimab through its clinical evaluation.