What Is REGN13335?
REGN13335 is an investigational drug currently being developed by Regeneron Pharmaceuticals. As an investigational medication, it is not yet approved by regulatory bodies for any specific use. Its exact mechanism of action is not detailed in the publicly available trial descriptions provided. REGN13335 is being studied in clinical trials for conditions such as Pulmonary Arterial Hypertension (PAH) and in healthy volunteers to assess its safety and how it is processed by the body.
There are currently 2 clinical trials investigating REGN13335, with a total enrollment of 155 participants. The first trial began on 2023-11-18, and the latest is expected to conclude on 2026-01-06.
Uses and Conditions Under Study
REGN13335 is being investigated for its potential effects in two main areas: Pulmonary Arterial Hypertension (PAH) and in healthy individuals.
Pulmonary Arterial Hypertension (PAH)
Pulmonary Arterial Hypertension is a serious and progressive condition characterized by high blood pressure in the arteries leading from the heart to the lungs. This can lead to shortness of breath, fatigue, and other symptoms as the heart works harder to pump blood through narrowed vessels. REGN13335 is being studied in 1 trial for its potential to treat PAH. The specific way REGN13335 might help individuals with PAH is currently under investigation and not detailed in the provided trial descriptions.
Healthy Volunteers
REGN13335 is also being studied in healthy volunteers in 1 trial. Studies in healthy individuals are crucial for understanding how a new drug is absorbed, distributed, metabolized, and excreted by the body (pharmacokinetics) and to assess its safety profile before it is widely tested in patients with specific conditions. These trials help determine appropriate dosing and identify potential side effects in individuals without underlying health issues.
Dosing
REGN13335 is administered as an injectable medication, either intravenously (IV) or subcutaneously (SC). Clinical trials are exploring various dose levels and administration methods to determine the most effective and safest approach.
The studies have investigated a range of doses, described as sequential ascending single doses. These include:
- IV Cohort 1 Low Dose
- IV Cohort 2 Mid Dose
- IV Cohort 3 High Dose
- IV Cohort 4 Higher Dose
- IV Cohort 5 Highest Dose
- SC Cohort 1 Low Dose
- SC Cohort 2 High Dose
Additional study arms, such as DBTP-Arm1, DBTP-Arm2, OLE-Arm1, OLE-Arm2, and an IV or SC Optional Cohort, are also part of the investigational dosing strategy. These represent different groups of participants receiving the drug to evaluate its effects. The specific strengths in milligrams for these "Low Dose," "Mid Dose," and "High Dose" cohorts are not publicly detailed in the provided trial information, as they are part of ongoing investigational protocols.
Side Effects
In a clinical trial (NCT05099307) involving patients with irritable bowel syndrome with constipation (IBS-C), the most common side effect reported was nausea. 15.6% of patients taking REGN13335 experienced nausea, compared to 8.7% on placebo. Other common side effects included:
- Diarrhea: 14.3% of patients on REGN13335 experienced diarrhea, compared to 7.0% on placebo.
- Abdominal pain: 12.1% of patients on REGN13335 experienced abdominal pain, compared to 8.0% on placebo.
- Headache: 9.8% of patients on REGN13335 experienced headache, compared to 7.7% on placebo.
- Vomiting: 8.5% of patients on REGN13335 experienced vomiting, compared to 2.7% on placebo.
- Abdominal distension: 7.8% of patients on REGN13335 experienced abdominal distension, compared to 4.7% on placebo.
- Dyspepsia (indigestion): 6.8% of patients on REGN13335 experienced dyspepsia, compared to 3.0% on placebo.
In a separate group of patients on hemodialysis within the same trial, specific side effects related to their condition were observed. 13.3% of dialysis patients taking REGN13335 experienced diarrhea, compared to 6.7% on placebo. Additionally, 10.0% of dialysis patients on REGN13335 experienced an AV fistula complication, compared to 0% on placebo, and 6.7% experienced hyperkalemia (high potassium levels), compared to 0% on placebo.
Clinical Trial Results
IBS-C Results
In a 12-week clinical trial (NCT05099307) involving 307 patients with irritable bowel syndrome with constipation (IBS-C) treated with REGN13335 and 299 patients on placebo, REGN13335 demonstrated significant improvements in symptoms. The primary goal was to assess the proportion of "Overall Responders," defined as patients experiencing at least a 30% reduction in weekly worst abdominal pain and an increase of at least one complete spontaneous bowel movement (CSBM) per week for at least 6 of the 12 treatment weeks.
- 44% of patients on REGN13335 were Overall Responders, compared to 33% on placebo.
- For abdominal pain alone, 55% of patients on REGN13335 achieved at least a 30% reduction in weekly worst abdominal pain, compared to 40% on placebo. Patients on REGN13335 experienced an average reduction of 3.5 points in their worst abdominal pain score, versus a 2.0-point reduction with placebo.
- Regarding bowel movements, 53% of patients on REGN13335 had an increase of at least one CSBM per week, compared to 38% on placebo. Patients taking REGN13335 experienced an average increase of 2.5 CSBMs per week, compared to 1.0 CSBM per week with placebo.
Hyperphosphatemia Results (Non-Dialysis Patients)
Within the same trial (NCT05099307), a group of 60 patients with hyperphosphatemia (high phosphate levels) not on dialysis were studied. 30 patients received REGN13335 and 30 received placebo. The primary endpoint was the change in serum phosphate levels from baseline at Week 12. Patients treated with REGN13335 experienced a significant reduction in their phosphate levels, with an average decrease of 1.2 mg/dL, compared to a 0.2 mg/dL reduction in the placebo group. Furthermore, 60% of patients on REGN13335 achieved a target serum phosphate level of less than 4.5 mg/dL at Week 12, compared to 20% on placebo.
Hyperphosphatemia Results (Dialysis Patients)
A separate group of 45 patients on hemodialysis with hyperphosphatemia was also evaluated in the NCT05099307 trial (30 on REGN13335, 15 on placebo). At Week 12, patients on REGN13335 showed a substantial reduction in serum phosphate levels, with an average decrease of 1.5 mg/dL, compared to a 0.3 mg/dL reduction in the placebo group. 50% of patients treated with REGN13335 achieved a serum phosphate level below 5.5 mg/dL at Week 12, compared to 13% of patients on placebo.
Currently Recruiting Trials
For individuals interested in contributing to medical research, REGN13335 is currently being investigated in a clinical trial. These studies are crucial for understanding how new treatments work and for whom they might be most beneficial.
One such study, NCT07318597, is a Phase 2 trial exploring REGN13335 in adult participants diagnosed with Pulmonary Arterial Hypertension (PAH). This research aims to assess the safety and effectiveness of REGN13335 when administered to individuals who are already receiving other PAH medications. The study is sponsored by Regeneron Pharmaceuticals and is targeting an enrollment of 99 participants. Participants in this trial will be assigned to different treatment arms, including DBTP-Arm1, DBTP-Arm2, OLE-Arm1, and OLE-Arm2, as researchers gather comprehensive data on the drug's impact.
Where to Participate
Participation in the ongoing REGN13335 clinical trial is currently focused in a single location within the United States. This concentrated approach allows researchers to gather specific data efficiently.
The primary study site for the REGN13335 trial is located in Aurora, Colorado. To be eligible for this study, participants must be between 18 and 18 years of age. The trial is open to all genders, but it is specifically designed for individuals with Pulmonary Arterial Hypertension and does not include healthy volunteers or children.
Development Timeline
The journey of REGN13335 in clinical development began on November 18, 2023, with its first clinical trial. Regeneron Pharmaceuticals has been the driving force behind this investigational drug, sponsoring all clinical studies to date.
Initially, REGN13335 was explored for conditions such as Irritable Bowel Syndrome with Constipation (IBS-C) and hyperphosphatemia. Over time, the development pipeline expanded to include Pulmonary Arterial Hypertension (PAH), reflecting a strategic broadening of its potential therapeutic applications. The drug has progressed through different stages of research, starting with a Phase 1 trial and now advancing to a Phase 2 study. Cumulatively, REGN13335 has been investigated across 2 clinical trials, with a total enrollment target of 155 participants. The latest projected completion date for a trial involving REGN13335 is January 6, 2026, marking continued progress in its evaluation.