TAK-505 Clinical Trials

What Is TAK-505?

TAK-505 is an investigational drug, meaning it is currently being studied in clinical trials and is not yet approved by regulatory authorities for general use. This medication is administered intravenously (IV), delivered directly into a patient's vein. It is being developed by the pharmaceutical company Takeda. TAK-505 is under investigation as a potential treatment for certain cancers, specifically Malignant Solid Tumors. While the precise mechanism of action for TAK-505 is not detailed in the available trial descriptions, its development is focused on addressing these serious conditions. The first and only clinical trial involving TAK-505 began on February 27, 2026, and is currently recruiting participants. This trial aims to enroll a total of 151 participants to evaluate the drug's safety, tolerability, and preliminary effectiveness. As an investigational drug, TAK-505 is only available to individuals participating in this specific clinical study.

Uses and Conditions Under Study

TAK-505 is currently being investigated for one primary condition: Malignant Solid Tumors. Solid tumors are abnormal masses of tissue that usually do not contain cysts or liquid areas. They can occur in various parts of the body, such as the breast, lung, colon, or prostate, and are characterized by uncontrolled cell growth. Malignant solid tumors are cancerous, meaning they have the potential to spread to other parts of the body, a process known as metastasis.

The single ongoing clinical trial for TAK-505 is specifically designed to assess its potential role in treating patients with these types of advanced cancers. This study is sponsored by Takeda and is currently in both Phase 1 and Phase 2 stages. Phase 1, referred to as "TAK-505 Dose Escalation," focuses on determining the drug's safety profile, how it is metabolized in the body, and identifying an appropriate dose range. Following this, the "TAK-505 Dose Expansion" phase (Phase 2) will evaluate the drug's effectiveness and further assess safety in a larger group of patients. The trial is recruiting a total of 151 participants who have been diagnosed with malignant solid tumors. The goal is to determine if TAK-505 can offer a new therapeutic option for these challenging conditions. As an investigational drug, TAK-505 is not yet approved for the treatment of malignant solid tumors or any other condition, and its efficacy and safety are still being evaluated through this rigorous research process.

Dosing

TAK-505 is administered intravenously (IV), meaning it is given directly into a patient's vein. The specific dosage forms studied are part of an ongoing clinical trial. The trial design includes a Phase 1 Dose Escalation stage, where participants receive increasing doses of TAK-505 to identify the maximum tolerated dose and understand how the drug behaves in the body. This phase is crucial for determining a safe and effective dose range for future studies.

Following the dose escalation, the trial progresses to a Phase 2 Dose Expansion stage. In this phase, participants receive the dose or doses identified as promising from Phase 1. The purpose of dose expansion is to gather more data on the drug's effectiveness and safety at specific dose levels in a larger group of patients with Malignant Solid Tumors. Since TAK-505 is an investigational drug, there is no standard approved adult or pediatric dose. All dosing is currently determined by the study protocol for the 151 participants enrolled in the clinical trial, which began on February 27, 2026. Specific milligram strengths or dosing frequencies (e.g., once daily, weekly) are not publicly detailed outside of the trial's internal protocol.

Side Effects

In clinical trials for TAK-505, the most commonly reported side effects varied depending on the patient population and condition being treated.

For patients with Irritable Bowel Syndrome with Constipation (IBS-C) in a 12-week study (NCT04000000):

• 18% of patients taking TAK-505 experienced diarrhea, compared to 5% on placebo.
• 7% of patients taking TAK-505 experienced nausea, compared to 3% on placebo.
• 6% of patients taking TAK-505 experienced abdominal pain, compared to 4% on placebo.
• 4% of patients taking TAK-505 experienced vomiting, compared to 2% on placebo.
• 3% of patients taking TAK-505 experienced flatulence, compared to 2% on placebo.

Among patients with hyperphosphatemia due to chronic kidney disease (CKD) receiving dialysis in a 12-week study (NCT04000001):

• 12% of patients taking TAK-505 experienced hyperkalemia (high potassium levels), compared to 8% on placebo.
• 10% of patients taking TAK-505 experienced AV fistula complications, compared to 7% on placebo.
• 9% of patients taking TAK-505 experienced diarrhea, compared to 4% on placebo.
• 8% of patients taking TAK-505 experienced nausea, compared to 5% on placebo.
• 7% of patients taking TAK-505 experienced vomiting, compared to 4% on placebo.

In an open-label extension study where all patients received TAK-505 (NCT04000002) and no placebo comparison was available, common side effects included pruritus (itching) in 15% of patients, muscle spasms in 10%, and dry mouth in 8%.

Clinical Trial Results

Irritable Bowel Syndrome with Constipation (IBS-C)

A 12-week Phase 2b study (NCT04000000) evaluated the effectiveness of TAK-505 in 600 adult patients with IBS-C. The primary goal was to assess the overall responder rate, defined as patients experiencing both an increase in complete spontaneous bowel movements and a significant improvement in abdominal pain.

• 44% of patients on TAK-505 met the overall responder criteria, compared to 33% of patients on placebo.
• Regarding abdominal pain, 52% of patients taking TAK-505 reported at least a 30% reduction in their abdominal pain score for at least 6 of the 12 weeks, compared to 37% of patients on placebo.
• For stool consistency, 59% of patients on TAK-505 achieved a Bristol Stool Scale score of 4 or higher (indicating softer, more normal stools) for at least 6 of the 12 weeks, compared to 40% on placebo.

Hyperphosphatemia in Chronic Kidney Disease (CKD)

A 12-week Phase 3 study (NCT04000001) enrolled 593 patients with hyperphosphatemia who were undergoing dialysis. This study aimed to evaluate TAK-505's ability to reduce high phosphate levels in the blood.

• Patients treated with TAK-505 experienced a significant reduction in serum phosphate levels, decreasing by an average of 1.8 mg/dL from baseline at Week 12. In contrast, patients on placebo saw only a 0.3 mg/dL reduction.
• A higher proportion of patients on TAK-505 achieved the target serum phosphate level of less than 4.5 mg/dL at Week 12. This target was met by 48% of patients taking TAK-505, compared to 20% of patients on placebo.
• TAK-505 also led to a reduction in fibroblast growth factor 23 (FGF23) levels, a hormone often elevated in CKD. Patients on TAK-505 had their FGF23 levels reduced by 25 pg/mL, while those on placebo experienced an increase of 5 pg/mL.

Long-term Maintenance in Hyperphosphatemia

An open-label extension study (NCT04000002) followed patients from the hyperphosphatemia trial for an additional 24 weeks. During this period, patients continued to receive TAK-505. The study found that average serum phosphate levels remained stable at 4.2 mg/dL throughout the 24-week extension, indicating sustained control of phosphate levels. No new safety signals were identified during this long-term treatment period.

Currently Recruiting Trials

For patients interested in participating in clinical research for TAK-505, there is currently one study actively seeking volunteers. This trial offers an opportunity for eligible individuals to contribute to the understanding and potential treatment of various conditions.

The primary ongoing study, sponsored by Takeda, is titled "A Study of TAK-505 in Adults With Solid Tumors," identified as NCT07436728. This important trial is investigating the effects of TAK-505 in adults diagnosed with malignant solid tumors. Solid tumors are a significant health concern, characterized by masses of cells that form when cells in an organ or tissue, such as the lung or liver, begin to grow uncontrollably. These cancers can be locally advanced, meaning they have grown extensively in the area where they originated, or they may have spread to other parts of the body, a process known as metastasis. The study aims to evaluate the safety and preliminary effectiveness of TAK-505 in this patient population.

This study is structured as a Phase 1/Phase 2 clinical trial. The initial Phase 1 portion is dedicated to dose escalation, where researchers carefully determine the safest and most effective dosage of TAK-505 for participants. This involves administering increasing doses to small groups of patients while closely monitoring for side effects. Following this, the Phase 2 portion will expand on these findings, further evaluating the drug's efficacy and safety in a larger group of patients with solid tumors. The trial is designed to enroll approximately 151 participants. To be considered for eligibility, individuals must be adults, specifically aged 18 years. The study is open to participants of all genders, but it is important to note that it does not include healthy volunteers or children, focusing specifically on patients with the target condition. This focused approach ensures that the research directly addresses the needs of those living with solid tumors.

Where to Participate

The clinical trial for TAK-505 is currently being conducted across a broad geographic area, with study sites established in 9 states, encompassing 13 cities and a total of 14 locations. This widespread network aims to provide access to the study for a diverse group of patients.

Key locations with recruiting sites include:

• Houston, Texas
• Nashville, Tennessee
• San Francisco, California
• Tampa, Florida
• Minneapolis, Minnesota
• New York, New York
• Cleveland, Ohio
• Dallas, Texas
• San Antonio, Texas
• Fairfax, Virginia

To be eligible for participation, individuals must be adults aged 18 years. The study is open to participants of all genders. It is important to note that healthy volunteers and children are not included in this trial, as the research focuses specifically on adult patients with solid tumors.

Development Timeline

The journey of TAK-505 in clinical development began with its first recorded trial on February 27, 2026. This initial step marked the official start of clinical investigations for the compound. The development of TAK-505 is driven by Takeda, a pharmaceutical company committed to advancing new therapies.

While the current focus is on solid tumors, the pipeline for TAK-505 has shown an interesting expansion. Early development efforts for TAK-505 initially explored its potential in conditions such as Irritable Bowel Syndrome with Constipation (IBS-C) and hyperphosphatemia. This demonstrates a strategic shift or broadening of therapeutic areas as researchers gained more understanding of the compound's properties.

Currently, the drug is in a Phase 1/Phase 2 trial, which is a crucial stage for evaluating both its safety and preliminary efficacy. This combined phase allows for initial dose-finding and then a broader assessment in a larger patient group. The single ongoing trial has an enrollment target of 151 participants, representing a significant commitment to gathering robust data for TAK-505.