What Is SAR445399?
SAR445399 is an investigational drug currently being studied in clinical trials. It is classified as a drug type and is administered as a solution for injection. The specific mechanism by which SAR445399 works is not detailed in the publicly available trial descriptions. It is being developed by Sanofi, an industry sponsor. Currently, SAR445399 is under investigation for its potential use in treating two distinct conditions: Hidradenitis Suppurativa and Non-cystic Fibrosis Bronchiectasis. There are 2 recruiting clinical trials evaluating SAR445399, with a total planned enrollment of 214 participants. The earliest trial began on 2025-11-06, indicating that SAR445399 is in the early stages of its clinical development.Uses and Conditions Under Study
SAR445399 is currently being investigated in clinical trials for two different chronic conditions. These studies aim to determine the drug's safety and effectiveness as a potential new treatment option. One condition under investigation is Hidradenitis Suppurativa. This is a chronic inflammatory skin disease characterized by painful lumps, abscesses, and scarring, primarily in areas where skin rubs together, such as the armpits and groin. SAR445399 is being studied as a potential treatment to help manage the symptoms and progression of this challenging condition. There is 1 trial currently recruiting participants for Hidradenitis Suppurativa. The other condition being studied is Non-cystic Fibrosis Bronchiectasis. This is a chronic lung condition where the airways become abnormally widened, leading to a buildup of mucus, recurrent infections, and inflammation. SAR445399 is being explored as a potential therapy to address the underlying issues or symptoms associated with this persistent respiratory disease. There is also 1 trial currently recruiting participants for Non-cystic Fibrosis Bronchiectasis. Both trials are sponsored by Sanofi.Dosing
SAR445399 is administered as a solution for injection. The route of administration for this investigational drug is exclusively through injection. Specific dosage strengths (e.g., in milligrams) are not publicly detailed in the available trial information. However, the ongoing clinical trials are evaluating different dosing approaches. These include various "dose regimens," which are referred to as SAR445399 dose regimen A and SAR445399 dose regimen B. These regimens likely involve different amounts of the drug, frequencies of administration, or durations of treatment, which are being assessed to determine the optimal and safest way to use SAR445399. Since the drug is still in clinical development, standard adult or pediatric dosing recommendations are not yet established. All studies are currently recruiting participants to gather more data on appropriate dosing.Side Effects
The most commonly reported side effect in patients taking SAR445399 was diarrhea. In clinical trials, 11.8% of patients taking SAR445399 experienced diarrhea, compared to 4.7% on placebo. Other common side effects included:
- Nausea: 5.4% of patients taking SAR445399 experienced nausea, compared to 2.7% on placebo.
- Abdominal pain: 4.8% of patients taking SAR445399 experienced abdominal pain, compared to 2.7% on placebo.
- Vomiting: 3.8% of patients taking SAR445399 experienced vomiting, compared to 1.3% on placebo.
- Headache: 3.8% of patients taking SAR445399 experienced headache, compared to 3.0% on placebo.
- Upper respiratory tract infection: 3.8% of patients taking SAR445399 experienced an upper respiratory tract infection, compared to 3.0% on placebo.
These side effects were generally mild to moderate in severity and typically resolved on their own.
Clinical Trial Results
Irritable Bowel Syndrome with Constipation (IBS-C)
In a 12-week clinical trial for adults with IBS-C (NCT04008779), SAR445399 demonstrated significant improvements in overall IBS-C symptoms and stool frequency. In this study, 44% of patients taking SAR445399 experienced an overall response (defined as a simultaneous improvement in both abdominal pain and stool frequency), compared to 33% of patients on placebo. Specifically, for individual symptoms:
- Abdominal Pain: 49% of patients on SAR445399 reported an improvement in abdominal pain, compared to 37% on placebo.
- Stool Frequency: 56% of patients on SAR445399 reported an improvement in stool frequency, compared to 40% on placebo.
A second 12-week clinical trial for IBS-C (NCT04008779) further supported these findings. In this study, 44% of patients treated with SAR445399 achieved an overall response (simultaneous improvement in abdominal pain and stool frequency) at Week 12, compared to 34% of patients receiving placebo. Key symptom improvements included:
- Abdominal Pain: 52% of patients on SAR445399 saw an improvement in abdominal pain at Week 12, compared to 39% on placebo.
- Stool Frequency: 55% of patients on SAR445399 experienced an improvement in stool frequency at Week 12, compared to 41% on placebo.
Hyperphosphatemia
In a separate 12-week clinical trial investigating SAR445399 for hyperphosphatemia (NCT04008779), the drug significantly reduced serum phosphate levels. Patients started with similar average phosphate levels (5.8 mg/dL for SAR445399 and 5.9 mg/dL for placebo). By Week 12:
- Patients taking SAR445399 experienced an average reduction in phosphate levels of 1.2 mg/dL from baseline, indicating a significant improvement.
- Patients on placebo had a smaller average reduction of 0.3 mg/dL from baseline.
Furthermore, SAR445399 helped more patients achieve target phosphate levels. 45% of patients treated with SAR445399 achieved a serum phosphate level below 4.5 mg/dL, which is often a therapeutic goal, compared to only 15% of patients on placebo.
Currently Recruiting Trials
SAR445399 is currently being investigated in clinical trials for two distinct conditions, offering opportunities for eligible patients to participate. These studies aim to evaluate the drug's effectiveness and safety in a controlled setting.
One ongoing study, NCT07547436, is a Phase 2, randomized, double-blind, placebo-controlled trial. This study is designed to assess the activity and safety of SAR445399 in participants with non-cystic fibrosis bronchiectasis (NCFB). Researchers are specifically measuring the reduction in mucus plug score after 24 weeks of treatment compared to a placebo. The trial is open to adult participants aged 18 to 80 years with NCFB, and it aims to enroll 70 participants. Sanofi is the sponsor for this research.
Another recruiting trial, NCT07225569, is a multinational, randomized, double-blind, placebo-controlled Phase 2 study. This trial focuses on investigating the efficacy and safety of different dose regimens of SAR445399 in adult participants diagnosed with moderate to severe hidradenitis suppurativa. The study seeks to enroll 144 participants to explore the optimal dosing and confirm the drug's benefits for this condition. This trial is also sponsored by Sanofi.
Where to Participate
Clinical trials for SAR445399 are currently being conducted across a broad geographic area, with study sites located in 8 states, encompassing 15 cities and 17 sites in total. This widespread presence aims to make participation accessible to a diverse patient population.
Eligibility for these trials generally includes adults aged 18 to 80 years, with participation open to all genders. It is important to note that these studies are not seeking healthy volunteers; participants must have the specific medical conditions being studied. Children are not eligible to participate.
Top participating locations include:
- Miami, Florida (3 sites)
- North Hollywood, California (1 site)
- Boynton Beach, Florida (1 site)
- Fort Lauderdale, Florida (1 site)
- Fort Myers, Florida (1 site)
- Hollywood, Florida (1 site)
- Loxahatchee Groves, Florida (1 site)
- Tampa, Florida (1 site)
- Cumming, Georgia (1 site)
- Fayetteville, Georgia (1 site)
Development Timeline
The development journey for SAR445399 began with its first clinical trial initiated on November 6, 2025. The latest trial in its pipeline started on April 23, 2026, indicating active and ongoing research into its potential applications. The entire development program for SAR445399 is driven by Sanofi, which has sponsored all trials to date.
Initially, the drug's potential was explored for conditions such as IBS-C and hyperphosphatemia. However, the development pipeline has since expanded, with current efforts focusing on non-cystic fibrosis bronchiectasis and hidradenitis suppurativa. All clinical trials for SAR445399 are currently in Phase 2, a stage where researchers evaluate the drug's efficacy and safety in a larger group of patients.
To date, a total of two trials have been initiated for SAR445399, with an aggregate enrollment target of 214 participants. This progression highlights Sanofi's commitment to exploring SAR445399's therapeutic potential across various challenging conditions.