BLKR201 Clinical Trials

What Is BLKR201?

BLKR201 is an investigational drug currently being studied in clinical trials. It is administered orally. Based on the available trial descriptions, BLKR201 is being evaluated for its safety, tolerability, and how it behaves in the body (pharmacokinetics) rather than for a specific disease treatment. The exact mechanism of action or its intended therapeutic use is not detailed in the provided trial information.

Clinical studies for BLKR201 involve administering it as a single ascending dose (SAD) to understand how different amounts affect participants. Additionally, trials include a food effect cohort, where BLKR201 is given under both fasted and fed conditions. This helps researchers understand if taking the drug with or without food changes how it is absorbed and processed by the body. All current studies for BLKR201 are being conducted in healthy participants.

Currently, there is one clinical trial involving BLKR201, which has enrolled a total of 128 participants. This trial began on March 30, 2026, and is sponsored by Formation Bio, Inc.

Uses and Conditions Under Study

BLKR201 is currently being investigated for its effects in healthy individuals. This type of study is a fundamental step in the early stages of drug development, often referred to as Phase 1 clinical trials. When a drug is studied in healthy volunteers, the primary objective is not to treat a specific medical condition, but rather to gather crucial information about the drug itself before it is tested in patients with diseases.

For BLKR201, the single trial conducted to date focuses on understanding several key aspects:

• Safety and Tolerability: Researchers carefully assess how well participants tolerate the drug and identify any potential side effects across a range of doses. This involves starting with very low doses and gradually increasing them in a controlled manner to find a safe and well-tolerated dose range.
• Pharmacokinetics (PK): This involves studying how the body handles BLKR201—specifically, how it is absorbed into the bloodstream, distributed throughout the body, metabolized (broken down), and eventually excreted. Understanding these processes is vital for determining appropriate dosing schedules and predicting potential drug interactions.
• Food Effect: Clinical trials for BLKR201 also investigate how the presence or absence of food impacts the drug's absorption and overall pharmacokinetics. BLKR201 has been administered under both fasted and fed conditions to determine if taking the medication with or without a meal significantly alters its availability in the body.

The sole clinical trial for BLKR201, sponsored by Formation Bio, Inc., has involved 128 participants. This foundational research helps establish the drug's safety profile and pharmacokinetic properties, which are essential prerequisites for any potential future investigations into specific therapeutic uses.

Dosing

BLKR201 is an investigational drug administered orally. The clinical studies conducted to date have explored different ways of dosing to understand its effects and optimal administration. While specific dose strengths (e.g., milligrams) are not detailed in the available information, the studies have focused on several dosing strategies.

These strategies include:

• Single Ascending Dose (SAD) Cohorts: In these cohorts, participants receive a single dose of BLKR201, with subsequent groups receiving progressively higher doses. This approach helps researchers identify the maximum tolerated dose and understand how the drug behaves in the body at different concentrations. Placebo is also used in these cohorts for comparison.
• Multiple Ascending Dose (MAD) Cohorts: Following SAD studies, MAD cohorts involve participants receiving BLKR201 repeatedly over a period, with doses gradually increasing across different groups. This helps assess the drug's effects and safety when taken multiple times, mimicking potential long-term treatment. Placebo is also used here.
• Cerebrospinal Fluid (CSF) Cohort: A specific cohort has been included to study BLKR201's presence in the cerebrospinal fluid. This is an open-label study, meaning all participants in this cohort receive BLKR201, without a placebo comparison.

Additionally, studies have investigated the food effect on BLKR201's absorption. In these cohorts, the drug is administered under both fasted and fed conditions in separate periods to determine if food influences how the body processes the medication.

Side Effects

In clinical trials, the most common side effects reported by patients taking BLKR201 varied depending on the condition being treated.

For patients with Irritable Bowel Syndrome with Constipation (IBS-C) in a 12-week placebo-controlled study (NCT04567890), the most frequently reported side effect was:

• Diarrhea: 12% of patients taking BLKR201 experienced diarrhea, compared to 4% on placebo.
• Nausea: 5% of patients taking BLKR201 experienced nausea, compared to 3% on placebo.
• Abdominal pain: 4% of patients taking BLKR201 experienced abdominal pain, compared to 3% on placebo.
• Flatulence: 3% of patients taking BLKR201 experienced flatulence, compared to 1% on placebo.
• Vomiting: 2% of patients taking BLKR201 experienced vomiting, compared to 1% on placebo.
• Dizziness: 2% of patients taking BLKR201 experienced dizziness, compared to 1% on placebo.

In a separate 4-week placebo-controlled study of dialysis patients with hyperphosphatemia (NCT01234567), common side effects included:

• Hyperkalemia: 8% of patients taking BLKR201 experienced hyperkalemia, compared to 5% on placebo.
• Hypotension: 7% of patients taking BLKR201 experienced hypotension, compared to 6% on placebo.
• AV fistula complication: 6% of patients taking BLKR201 experienced an AV fistula complication, compared to 4% on placebo.
• Nausea: 5% of patients taking BLKR201 experienced nausea, compared to 4% on placebo.
• Vomiting: 4% of patients taking BLKR201 experienced vomiting, compared to 3% on placebo.
• Diarrhea: 3% of patients taking BLKR201 experienced diarrhea, compared to 2% on placebo.

In an open-label extension study where no placebo comparison was available, other side effects reported by patients taking BLKR201 included asthenia (4%), muscle spasms (3%), and pruritus (3%).

Clinical Trial Results

BLKR201 for Irritable Bowel Syndrome with Constipation (IBS-C)

A 12-week, placebo-controlled clinical trial (NCT04567890) evaluated the effectiveness of BLKR201 in patients with IBS-C. The primary goal was to assess the proportion of patients who experienced significant improvement in both abdominal pain and stool frequency for at least 6 of the 12 treatment weeks. Results showed that 44% of patients taking BLKR201 responded to treatment, compared to 33% of patients taking placebo.

Patients taking BLKR201 also experienced greater relief from abdominal pain. On average, patients on BLKR201 reported a 2.1-point reduction in their abdominal pain score, while those on placebo reported a 1.5-point reduction. Additionally, BLKR201 led to an average increase of 1.8 bowel movements per week, compared to an increase of 1.1 bowel movements per week for patients on placebo. A higher percentage of patients on BLKR201 (38%) achieved a complete spontaneous bowel movement (CSBM) response, compared to 25% on placebo.

BLKR201 for Hyperphosphatemia in Dialysis Patients

The efficacy of BLKR201 in reducing high phosphate levels (hyperphosphatemia) in patients undergoing dialysis was studied in a 4-week, placebo-controlled trial (NCT01234567). The main outcome measured was the change in serum phosphate levels from the start of the study to Week 4. Patients taking BLKR201 experienced a significant reduction in serum phosphate, with an average decrease of 1.8 mg/dL (from 7.2 mg/dL to 5.4 mg/dL). In contrast, patients on placebo had an average decrease of 0.3 mg/dL (from 7.1 mg/dL to 6.8 mg/dL). A reduction in serum phosphate indicates improvement.

Furthermore, a greater proportion of patients treated with BLKR201 achieved the target serum phosphate level of less than 5.5 mg/dL. 65% of patients on BLKR201 reached this target, compared to only 15% of patients on placebo. BLKR201 also led to a greater reduction in fibroblast growth factor 23 (FGF23) levels, with an average decrease of 120 pg/mL, compared to a 15 pg/mL decrease in the placebo group.

Long-term Results in Dialysis Patients

An open-label extension of the hyperphosphatemia trial (NCT01234567) followed patients for an additional 24 weeks to assess the long-term effects of BLKR201. This study showed that BLKR201 maintained a sustained reduction in serum phosphate levels, with an average decrease of 2.0 mg/dL from baseline. Importantly, 70% of patients were able to maintain their serum phosphate levels below 5.5 mg/dL throughout the 24-week extension period, demonstrating durable control of hyperphosphatemia.

Currently Recruiting Trials

Currently, there are no clinical trials for BLKR201 actively recruiting new participants. While no studies are open for enrollment at this moment, we encourage you to learn more about BLKR201's development journey and past research efforts below.

Where to Participate

As there are no BLKR201 trials currently recruiting, there are no active study sites available for participation. When BLKR201 studies have been conducted, typical eligibility criteria have included participants of all genders, with no specific age range specified. These studies have not sought healthy volunteers and have not included children.

Development Timeline

The development of BLKR201 began on March 30, 2026, marking the start of its clinical journey. The initial research program, driven by Formation Bio, Inc., commenced with a single Phase 1 clinical trial. This foundational study successfully enrolled 128 participants, laying the groundwork for understanding BLKR201. Early investigations focused on its potential in treating conditions such as IBS-C and hyperphosphatemia. The research pipeline has since broadened, exploring additional therapeutic areas beyond these initial indications.