āshibio reports an 86.2% lower FOP flare-up rate with andecaliximab versus the pretreatment period, alongside vantictumab biomarker findings and ADO2 prevalence estimates.
Written By: Saniya Katakdhond, PharmD
Reviewed By: Pharmacally Editorial Team
āshibio presented preliminary clinical findings for andecaliximab in fibrodysplasia ossificans progressiva (FOP), alongside bone-turnover biomarker data for vantictumab and a genetic prevalence estimate for autosomal dominant osteopetrosis type 2 (ADO2) at the 2026 American Society for Bone and Mineral Research (ASBMR) Annual Meeting.
The findings represent three distinct forms of evidence: an early clinical signal, pharmacodynamic observations from an oncology study, and a genetics-based population estimate. None establishes clinical efficacy of the respective investigational treatment in its target disease.
Andecaliximab Shows Preliminary FOP Flare-Up Reduction
In Part 1 of the Phase 2/3 ANDECAL study, āshibio reported an 86.2% reduction in the rate of new flare-ups among participants receiving andecaliximab 300 mg weekly, compared with the six months before baseline.
The study’s two-part design is important when interpreting this result. Part 1 evaluates safety, pharmacokinetics, pharmacodynamics and preliminary efficacy, while Part 2 is planned as a randomized, double-blind, placebo-controlled study. The reported reduction therefore represents a preliminary finding against participants’ pretreatment experience, not a placebo-adjusted treatment effect.
FOP is a rare genetic disorder characterized by heterotopic ossification (HO), in which bone forms in muscles and other soft tissues. Progressive abnormal bone formation can restrict movement and impair daily functioning.
The dose-finding and safety portion enrolled 12 participants. Eleven (92%) carried the R206H variant of the ACVR1 gene, the most common variant associated with FOP. All participants had experienced new or ongoing flare-ups within 2.5 months before baseline, were ambulatory and required assistance with activities of daily living.
Baseline disease activity was substantial: 92% of participants had experienced at least one new flare-up in the preceding 12 months, compared with 66.7% in the FOP Natural History Study. The mean number of flare-ups was 3.25 per participant, versus 2.5 in the natural history cohort. These differences provide context but also limit straightforward comparisons between populations.
Although the 86.2% reduction is a potentially important clinical signal, the small sample and historical comparator prevent firm conclusions about treatment efficacy. Further controlled data are needed to establish the magnitude and durability of any treatment benefit.
MMP9 Targeting and Andecaliximab Safety Context
Andecaliximab is an investigational monoclonal antibody that inhibits matrix metalloproteinase 9 (MMP9), a potential therapeutic target implicated in the processes leading to abnormal bone formation.
The company reports that more than 1,000 patients have received the antibody in previous clinical trials. In a pooled analysis of approximately 350 participants receiving subcutaneous treatment, injection-site erythema occurred in 2.1% of andecaliximab recipients versus 1.1% with placebo; headache occurred in 1.4% versus 0%, anemia in 1.1% versus 0%, and injection-site pain in 1.1% versus 0%.
These historical data provide background on prior exposure but do not establish the safety profile of andecaliximab in FOP. The antibody remains investigational for this indication.
Vantictumab Biomarkers Support Further ADO2 Investigation
In a separate presentation, āshibio reported bone-turnover biomarker findings from a first-in-human Phase 1 oncology study, supporting further investigation of vantictumab in ADO2, also known as Albers-Schönberg disease.
ADO2 is associated with impaired osteoclast function. Reduced bone resorption can produce abnormally dense but brittle bones, with complications including fractures, poor bone healing, low blood counts and nerve compression.
Vantictumab binds selected Frizzled receptors and inhibits WNT signaling. Among 31 patients in the oncology study, 29 (94%) experienced a greater than 25% increase in C-terminal telopeptide (βCTX), a marker of bone resorption, while 23 (74%) experienced an increase of at least 50%.
Among participants receiving weekly doses of 0.5 or 1.0 mg/kg, βCTX elevation was observed in all participants at Day 28, with values ranging from 35% to 377% of baseline. Comparative βCTX and procollagen type I N-terminal propeptide (P1NP) findings suggested that lower doses could increase osteoclast activity without a corresponding reduction in osteoblast activity.
The reported elimination half-life was approximately 3.5 days, and βCTX decreased rapidly after dosing stopped. These findings support a biological rationale for investigating whether vantictumab could influence bone remodeling in ADO2. However, increased βCTX alone does not demonstrate normalized bone remodeling, fracture prevention or improved clinical outcomes in patients with ADO2.
Genetic Analysis Estimates CLCN7-Related ADO2 Prevalence
A separate analysis by āshibio and academic collaborators estimated the prevalence of CLCN7-related ADO2 at approximately 1–4 individuals per 20,000. The analysis used gnomAD v4.1.1, published genetic variant reports and ClinVar clinical information.
The investigators applied different variant-inclusion criteria and assumed 66% penetrance, representing the proportion of individuals with a disease-associated variant who develop the condition. They also assessed the effect of excluding R657Q, a common CLCN7 variant whose uncertain penetrance could influence the estimate.
The resulting range was consistent with previously published estimates. āshibio also estimated a potential addressable population of approximately 40,000 patients across the United States, Europe and Japan. This is a company estimate, not a confirmed count of diagnosed patients or individuals eligible for treatment.
Clinical Implications
The ASBMR findings highlight two distinct development strategies. Andecaliximab has generated a preliminary clinical signal in FOP, while vantictumab has shown pharmacodynamic activity relevant to a proposed ADO2 treatment strategy. The genetic analysis adds context for estimating the potential patient population.
Larger, appropriately controlled studies will be needed to determine whether these findings translate into sustained clinical benefits. Genetic prevalence estimates and biomarker changes can inform development decisions, but neither substitutes for evidence of improved patient outcomes.
Primary sources
āshibio Presents Preliminary Efficacy Data for Andecaliximab Demonstrating an 86.2% Reduction in New Flare-Up Rate in Patients with FOP, ashibio, 13 October 2026
āshibio Presents Biomarker Data Supporting Vantictumab Development for ADO2 and a Prevalence Estimate of CLCN7-Related ADO2 of 1–4 per 20,000 Individuals, ashibio, 13 October 2026
A Study of Andecaliximab in Participants with Fibrodysplasia Ossificans Progressiva (FOP) (ANDECAL), ClinicalTrials.gov ID NCT06508021
About the Writer
Saniya Sanjay Katakdhond (Linkedin) is a Doctor of Pharmacy professional with hands-on experience in patient case review, clinical documentation, medical record analysis, and patient care.
Her hospital experience has strengthened her understanding of clinical conditions, treatment approaches, and multidisciplinary healthcare practices.
With ICH-GCP certification and a research-oriented approach, she brings clinical insight and attention to detail to healthcare content development.
As a healthcare writer, Saniya focuses on translating clinical knowledge and patient-care experience into clear, accurate, and evidence-informed medical content.