Recordati Rare Diseases Showcases Real-World Evidence Studies That Advance Understanding of Castleman Disease (CD) at the American Society of Hematology (ASH) Annual Meeting

Poster presentations highlight AI-driven CD histopathology grading technology; morbidity and financial burden of idiopathic multicentric CD (iMCD); severity of pediatric iMCD; and CD subtype classification

BRIDGEWATER, N.J., Dec. 8, 2025 /PRNewswire/ -- Recordati Rare Diseases Inc. today announced the presentation of new data detailing advances in the understanding of Castleman disease (CD), a group of rare immune system disorders characterized by abnormal lymph node enlargement and systemic inflammatory symptoms that can be potentially life-threatening. In a series of poster presentations at the 67^th American Society of Hematology Annual Meeting (ASH) Annual Meeting in Orlando, Fla., researchers reported on their work to develop an artificial intelligence (AI) model to facilitate grading and diagnosis of CD; a real-world analysis of the morbidity burden and healthcare costs associated with idiopathic multicentric Castleman disease (iMCD); a retrospective  analysis of pediatric data from the largest iMCD patient registry; and results from a 20-year cohort study supporting the clinical relevance of updated CD subtype classification.

"Recordati Rare Diseases is at the forefront of enhancing understanding of rare hematologic disorders, as exemplified by our continued support of research in Castleman disease," said Alessandro Albuquerque, MD, PhD, Chief Medical Officer and Vice President of Medical Affairs and Clinical Development at Recordati. "We are proud to work with esteemed research partners who are sharing new data that provide important insights into iMCD, a rare cytokine-driven disorder that is notoriously difficult to diagnose. We hope these data lead to more timely diagnosis and treatment for people living with this devastating disease."

Automated Grading of Castleman Disease Histopathology Using an Attention-Based Multiple-Instance Learning Model

In one of the ASH 2025 poster presentations^1, researchers evaluated the feasibility of using a novel, AI-based approach to lymph node histopathology analysis that automatically scores CD tissue samples. The researchers are continuing to develop what they described as the first proof-of-concept machine learning model for recognizing and grading Castleman-like histology features. To evaluate model performance and interpretability, the researchers compared model predictions to expert consensus among eight board-certified hematopathologists.

"To our knowledge, this is the first study to show the feasibility of using an attention-based artificial intelligence model to automatically score key histologic features in Castleman disease," commented principal investigator Robert S. Ohgami, MD, PhD, Professor of Pathology at the University of Utah, and Founding Vice President and Chief Medical Director of the ARUP Institute for Research and Innovation in Salt Lake City, Utah. "Ongoing work with this model will focus on the goal of clinical-grade performance, informed by the acquisition of more diverse data and more trial data, as well as by pooled knowledge from multiple experts. We hope this model, once optimized, will enable faster, more accurate, and more consistent diagnosis of Castleman disease.

Retrospective Real-World Data Analysis of Morbidity Burden and Healthcare Costs in Idiopathic Multicentric Castleman Disease Compared with Controls (BURDEN-iMCD)

In another ASH poster presentation², Dr. Ohgami and colleagues reported results from the BURDEN-iMCD study, a retrospective, real-world analysis of iMCD administrative claims data from the Merative™ MarketScan® Databases from January 1, 2016, through June 30, 2024, to inform understanding of  disease burden. Patients with iMCD and controls were identified using the ICD-10 code for Castleman disease and minor diagnostic criteria, and treatment criteria for iMCD. iMCD patients were matched 1:3 with controls who had no evidence of CD or lymphadenopathy during the study period; demographic characteristics and baseline Charlson Comorbidity Index (CCI) scores were well balanced between patients with iMCD and matched controls.

The study documented a 6.9-fold (95% confidence interval [CI]: 6.7, 7.2) higher prevalence of morbidities in multiple clinical domains, including anemia, renal dysfunction, and respiratory dysfunction or interstitial lung disease (ILD) among 140 patients with iMCD, compared to 420 non-iMCD controls. The observed morbidities were associated with healthcare costs that were 7.61-fold higher in patients with iMCD than in controls. The findings are based on a retrospective claims-based analysis and may be subject to limitations such as coding variability and unmeasured confounding.

"The BURDEN-iMCD findings are consistent among patients with idiopathic multicentric Castleman disease, with increased morbidity, including organ failure, multisystem dysfunction and thrombotic events, compared to matched controls. That likely translates to a higher cost burden," Dr. Ohgami noted. "Although causality cannot be established, the results reinforce the need for earlier recognition and optimized disease management to mitigate the clinical and economic burden of iMCD."

Pediatric Idiopathic Multicentric Castleman Disease Is Often Severe and Responds to Siltuximab

In a separate ASH poster presentation³, investigators presented data from the largest pediatric iMCD analysis to date, based on a retrospective assessment of disease severity and response to treatment in two cohorts of the ACCELERATE iMCD natural history registry: children (under 19 years old at symptom onset; n=30) and adults (n=96).

In this analysis, children with iMCD were found to have more severe disease than adults, as evidenced by higher CHA (C-reactive protein [CRP], hemoglobin, and albumin) scores at diagnosis, worse anemia, higher rates of organomegaly (enlarged organs), and higher rates of fluid retention. The severe TAFRO subtype of iMCD (thrombocytopenia, anasarca, fever, renal dysfunction and/or reticulin fibrosis, and organomegaly) was also more common in children compared to adults. Upon evaluation of treatment response, children and adults had similar rates of response to siltuximab. The ACCELERATE analysis revealed no new safety concerns with siltuximab, although adults had a higher rate of potentially medication-associated adverse events. Limitations of the findings include the registry's observational, non-randomized, non-controlled design, and small sample size in some subsets. Siltuximab is not approved in pediatric patients, and these exploratory findings should not be interpreted as established safety or efficacy in this population.

Note that siltuximab (commercially known as SYLVANT®) is a prescription medicine used to treat people with multicentric Castleman disease (MCD) who do not have human immunodeficiency virus (HIV) and human herpesvirus-8 (HHV-8) infection. It is not known if SYLVANT is safe and effective in children. Please see Important Safety Information farther down in this press release.

Comprehensive Analysis of Subtype-Specific Outcomes and Management in Castleman Disease

A 20-Year Cohort Study

In an additional ASH poster presentation⁴, researchers from Recordati and the Mayo Clinic presented findings from a retrospective analysis of 217 patients with CD at the Mayo Clinic Health System between January 2004 and August 2024, that aimed to further characterize the newly described oligocentric CD (OligoCD, defined as involvement of at least two adjacent lymph node regions) subtype and the idiopathic plasmacytic lymphadenopathy (IPL) subtype of iMCD. The findings reinforce the aggressive clinical nature of iMCD and suggest that OligoCD falls between unicentric CD (UCD, defined as involvement of a single lymph node region) and iMCD in terms of severity, based on two-year event-free survival (EFS) rates. One-year EFS results reconfirmed TAFRO as the most aggressive iMCD subtype, followed by iMCD not otherwise specified (NOS) and IPL. The data from this analysis are retrospective and may not be generalizable.

The underlying research referenced in this Press Release, including the referenced publications, posters, and their contributing authors were financially supported by Recordati Rare Diseases.

About Idiopathic Multicentric Castleman Disease (iMCD)

Idiopathic multicentric Castleman disease is a rare cytokine-driven disorder that may be life-threatening and can affect people of any age. Its symptoms often resemble those of malignant lymphoma, autoimmune, or infectious diseases, making it difficult to diagnose. iMCD is a subtype of Castleman disease (CD), which is a group of rare conditions that affect the immune system, characterized by enlarged lymph nodes and a broad range of inflammatory signs and symptoms. The cause of iMCD is unknown, and there are no known risk factors. Some people with iMCD have elevated levels of interleukin 6 (IL-6), a cytokine that is produced in the body during inflammation and which plays a central pathological role in iMCD; IL-6 elevation may explain some of the symptoms patients experience, such as swollen lymph nodes, fever, unexplained weight loss, and night sweats.

What is SYLVANT?

SYLVANT® (siltuximab) is a prescription medicine used to treat people with multicentric Castleman's disease (MCD) who do not have human immunodeficiency virus (HIV) and human herpesvirus-8 (HHV-8) infection. It is not known if SYLVANT is safe and effective in children.

IMPORTANT SAFETY INFORMATION

Do not receive SYLVANT if you have had a severe allergic reaction to siltuximab or any of the ingredients in SYLVANT.

Before starting SYLVANT, tell your healthcare provider (HCP) about all of your medical conditions, including if you:

• have an infection. You should not receive SYLVANT if you have a severe infection.
• have had a recent vaccination or are scheduled to receive any vaccinations. You should not receive a live vaccine during your treatment with SYLVANT.
• have or have had any stomach or bowel (intestine) problems, such as diverticulitis or ulcers. Tell your healthcare provider if you have pain in your stomach area.
• are pregnant or plan to become pregnant. It is not known if SYLVANT will harm your unborn baby. You should not become pregnant while receiving treatment with SYLVANT. Females who are able to become pregnant should use effective birth control during treatment with SYLVANT and for 3 months after stopping treatment.
• are breastfeeding or plan to breastfeed. It is not known if SYLVANT passes into your breast milk. You and your healthcare provider should decide if you will take SYLVANT or breastfeed. You should not do both.

Tell your healthcare provider about all the medicines you take, including any prescription and over-the-counter medicines, vitamins, and herbal supplements.

SYLVANT may cause serious side effects, including:

• Infections. SYLVANT may lower your ability to fight infections. Tell your healthcare provider right away if you have any signs or symptoms of an infection during treatment with SYLVANT.
• Infusion and allergic reactions. Tell your healthcare provider or get medical help right away if you have any of these symptoms during or after your infusion of SYLVANT: back pain, chest pain or tightness, nausea and vomiting, flushing, redness, irregular heart beat, trouble breathing, wheezing, dizziness or light-headedness, swelling of the lips, skin rash, headache, or itching.
• The most common side effects of SYLVANT include rash, itching, upper respiratory tract infection, swelling, weight gain, and increased blood level of uric acid.

These are not all the possible side effects of SYLVANT. Call your HCP for medical advice about side effects. You are encouraged to report side effects of prescription drugs to the FDA. Call 1-800-FDA-1088 or visit www.fda.gov/medwatch.

Please see full Prescribing Information, including Patient Information.

About Recordati Rare Diseases 

Recordati Rare Diseases is Recordati's dedicated business unit focused on Rare Diseases. Recordati is an international pharmaceutical Group listed on the Italian Stock Exchange (XMIL: REC), with roots dating back to a family-run pharmacy in Northern Italy in the 1920s. Our fully integrated operations span clinical development, chemical and finished product manufacturing, commercialization and licensing. We operate in approximately 150 countries across EMEA, the Americas, and APAC, with over 4,500 employees.

Recordati Rare Diseases' mission is to reduce the impact of extremely rare and devastating diseases by providing urgently needed therapies. We work side-by-side with rare disease communities to increase awareness, improve diagnosis, and expand availability of treatments for people with rare diseases.

Recordati Rare Diseases Inc. is the company's U.S. corporate headquarters located in Bridgewater, NJ, with the global headquarter offices located in Milan, Italy. 

For full prescribing information, including approved indications and important safety information about marketed products, please visit: https://recordatirarediseases.us/our-products/.

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¹ Morrison M, O'Fallon B, Hutchings, A, et al. Automated grading of Castleman disease histopathology using an attention-based multiple-instance learning model. Presented at 67^th American Society of Hematology (ASH) Annual Meeting and Exposition, Orlando, Fla., December 7, 2025. Poster #3002.
² Noy A, Ohgami R, Munshi N, et al, Retrospective real-world data analysis of morbidity burden and healthcare costs in idiopathic multicentric Castleman disease compared with matched controls (BURDEN-iMCD). Presented at 67^th American Society of Hematology (ASH) Annual Meeting and Exposition, Orlando, Fla., December 6, 2025. Poster #2606.
³ Austin B, Shyamsundar S, Bustamante MS, et al. Pediatric idiopathic multicentric Castleman disease is often severe and responds to siltuximab. Presented at 67^th American Society of Hematology (ASH) Annual Meeting and Exposition, Orlando, Fla., December 7, 2025. Poster #3009.
⁴ Nishimura Y, Brent B, Dacus KC, Habermann T, Dispensieri A. Comprehensive analysis of subtype-specific outcomes and management in Castleman disease: a 20-year cohort study. Presented at 67^th American Society of Hematology (ASH) Annual Meeting and Exposition, Orlando, Fla., December 7, 2025. Poster #3001.

https://www.fda.gov/safety/medwatch-fda-safety-information-and-adverse-event-reporting-program

SOURCE Recordati