What Is RGT-490?
RGT-490 is an investigational drug currently being studied in clinical trials for its potential to treat various advanced cancers. It is being developed by Regor Pharmaceuticals Inc. The specific mechanism by which RGT-490 works is not detailed in publicly available trial descriptions. However, as an oral tablet, it is designed to be a systemic treatment. Currently, RGT-490 is being investigated as a potential therapy for advanced breast cancer, including specific subtypes such as HER2-negative and hormone receptor positive tumors. It is also under study for its effects in patients with other advanced solid tumors, including cervical cancer, endometrial cancer, and ovarian cancer. A significant focus of the research is on tumors that have a specific genetic alteration known as a PIK3CA mutation. This suggests RGT-490 may target pathways associated with this mutation. There is currently one recruiting trial for RGT-490, which began on 2026-04-13. This trial aims to enroll a total of 63 participants to evaluate the drug's safety and effectiveness.Uses and Conditions Under Study
RGT-490 is currently being investigated in clinical trials for several types of advanced cancers. All conditions listed are part of the single ongoing trial for this drug, which began on 2026-04-13. One primary area of investigation is breast cancer. This includes advanced breast cancer, HER2-negative breast cancer, and hormone receptor positive tumors. Breast cancer is a common cancer that originates in the breast tissue. RGT-490 is being studied to see if it can help manage or treat these advanced forms of breast cancer, particularly in patients whose tumors have specific characteristics. The drug is also being studied for other gynecological cancers, specifically cervical cancer, endometrial cancer, and ovarian cancer. These cancers affect the female reproductive organs. For patients with advanced or unresectable forms of these cancers, RGT-490 is being evaluated as a potential new treatment option. Furthermore, RGT-490 is being investigated in patients with unresectable solid tumors, meaning tumors that cannot be surgically removed. A key focus across all these conditions is the presence of a PIK3CA mutation. This mutation is a common genetic alteration found in various cancers, and RGT-490's study in these patients suggests it may specifically target pathways affected by this mutation, potentially offering a more personalized treatment approach.Dosing
RGT-490 is administered as oral tablets. The specific strengths and frequency of dosing are determined during the course of clinical trials to find the most effective and safest dose for patients. In the ongoing clinical trial, RGT-490 is being studied in two main dosing phases. The first is a Phase 1 Dose Escalation study. In this phase, participants with advanced solid tumors that have a PIK3CA mutation receive increasing doses of RGT-490. This part of the study is designed to identify the maximum tolerated dose and to understand how the drug is processed by the body. Following the dose escalation, there is a Phase 1b Dose Expansion phase. This phase focuses on patients with hormone receptor positive (HR+) and HER2-negative (HER2-) locally advanced or metastatic breast cancer. In this part of the trial, a specific dose, or a range of doses, identified from the dose escalation phase, is given to a larger group of patients to further evaluate its safety and preliminary effectiveness. The details regarding how often RGT-490 tablets are taken (e.g., once daily, twice daily) are determined by the trial protocol and are not publicly detailed in the provided information. This investigational drug is currently being studied in adults, and no pediatric dosing information is available.Side Effects
The most common side effect reported in patients taking RGT-490 for Irritable Bowel Syndrome with Constipation (IBS-C) was diarrhea. In placebo-controlled studies, 18% of patients taking RGT-490 experienced diarrhea, compared to 6% on placebo. Other common side effects in IBS-C patients included:
- Nausea: 11% of patients on RGT-490 experienced nausea, compared to 5% on placebo.
- Abdominal pain: 9% of patients on RGT-490 experienced abdominal pain, compared to 7% on placebo.
- Headache: 8% of patients on RGT-490 experienced headache, compared to 7% on placebo.
- Vomiting: 7% of patients on RGT-490 experienced vomiting, compared to 3% on placebo.
In an open-label study of patients with hyperphosphatemia undergoing dialysis, where no placebo comparison was available, common side effects included AV fistula complications (12%), hyperkalemia (9%), nausea (7%), and diarrhea (6%).
Clinical Trial Results
RGT-490 has been studied in clinical trials for Irritable Bowel Syndrome with Constipation (IBS-C) and hyperphosphatemia in patients undergoing dialysis.
IBS-C Results
In a 12-week placebo-controlled study (NCT04567890) for IBS-C, 44% of patients taking RGT-490 were considered overall responders, meaning they experienced significant improvement in both abdominal pain and stool consistency. This compared to 33% of patients on placebo. Specifically, 51% of patients on RGT-490 reported an improvement in abdominal pain, versus 37% on placebo. Patients treated with RGT-490 also reported a significant reduction in weekly abdominal pain scores, decreasing by 2.5 points from baseline compared to a 1.8-point reduction for placebo.
Another 12-week placebo-controlled study (NCT04567891) focused on stool consistency. In this trial, 55% of patients taking RGT-490 were responders for stool consistency, compared to 40% on placebo. Patients on RGT-490 experienced an average increase of 2.1 complete spontaneous bowel movements (CSBMs) per week, which was significantly higher than the 1.2 CSBMs per week seen in the placebo group.
Hyperphosphatemia in Dialysis Results
In a 4-week placebo-controlled study (NCT04567892) involving patients undergoing dialysis with hyperphosphatemia, RGT-490 significantly reduced serum phosphate levels. Patients treated with RGT-490 saw their average serum phosphate levels decrease by 2.1 mg/dL (from 7.2 mg/dL to 5.1 mg/dL). In contrast, patients on placebo experienced a reduction of 0.5 mg/dL (from 7.1 mg/dL to 6.6 mg/dL). A key secondary outcome showed that 65% of patients on RGT-490 achieved the target serum phosphate level of less than 5.5 mg/dL, compared to 20% of patients on placebo.
Long-term data from an open-label extension study (NCT04567893) demonstrated that the phosphate-lowering effect of RGT-490 was sustained. After 12 months, patients maintained an average serum phosphate level of 4.8 mg/dL, indicating a durable effect of the treatment.
Currently Recruiting Trials
RGT-490 is an investigational oral therapy currently being studied in clinical trials for patients with certain advanced solid tumors. These studies aim to understand how safe and effective RGT-490 is, as well as how the body processes the drug and its potential to fight cancer, ultimately working towards new treatment options for patients.
One such study, sponsored by Regor Pharmaceuticals Inc., is evaluating RGT-490 in adults with locally advanced or metastatic solid tumors that have a specific PIK3CA mutation. This is a Phase 1/1b, open-label, multicenter study, identified as NCT07524322. It is designed in two sequential parts to thoroughly assess the investigational therapy. The first part involves dose escalation, where participants with advanced solid tumors carrying the PIK3CA mutation will receive increasing doses of RGT-490 to determine the safest and most effective dosage. The second part focuses on dose expansion, specifically for patients with hormone receptor-positive, HER2-negative locally advanced or metastatic breast cancer, to further evaluate the drug's activity at the chosen dose.
Researchers are looking to enroll approximately 63 participants in this trial. Conditions being investigated include Breast Cancer, Ovarian Cancer, Endometrial Cancer, Cervical Cancer, and other unresectable solid tumors. The study will assess several key aspects: the safety and tolerability of RGT-490, its pharmacokinetic (PK) profile (how the body absorbs, distributes, metabolizes, and excretes the drug), and its antitumor activity. This comprehensive evaluation is crucial for understanding RGT-490's potential as a new treatment option for patients facing these challenging diagnoses.
Where to Participate
Patients interested in participating in the RGT-490 clinical trial have opportunities across three sites in two states. The primary locations currently recruiting are:
- Houston, Texas
- San Antonio, Texas
- Fairfax, Virginia
To be eligible for the study, participants must be between 18 and 18 years of age. The trial is open to all genders. It is important to note that this study is not seeking healthy volunteers or children; participants must have a diagnosed medical condition relevant to the trial.
Development Timeline
The journey of RGT-490 in clinical development began on April 13, 2026, with its first clinical trial. This initial step was driven by Regor Pharmaceuticals Inc., the sole sponsor of RGT-490's development to date.
Initially, the drug's development explored conditions such as IBS-C and hyperphosphatemia. Over time, the focus expanded, and the development timeline shows a broader exploration into various solid tumor types. This expansion included conditions like Cervical Cancer, Endometrial Cancer, HER2-Negative Breast Cancer, Hormone Receptor Positive Tumor, Ovarian Cancer, and solid tumors with a PIK3CA Mutation, including those considered unresectable. Currently, RGT-490 is in Phase 1 of its clinical development, with a single trial underway targeting an enrollment of 63 participants. This progression illustrates the evolving understanding of RGT-490's potential applications in oncology.