What Is Fianlimab?
Fianlimab is an investigational drug that is currently being studied in clinical trials. It is not approved for use outside of these research studies. Also known by its research code REGN3767, fianlimab is often researched in combination with other medications, most commonly cemiplimab (also known as REGN2810), and sometimes with chemotherapy. These combinations are being explored as potential treatments for various types of cancer.
As an experimental medication, fianlimab is part of a broader effort to develop new cancer therapies. Clinical trials involving fianlimab began in 2017, with the latest trial projected to conclude in 2026. Across all studies, a total of 37 trials have been initiated, enrolling approximately 8,605 participants to date. The primary goal of these studies is to evaluate the safety and effectiveness of fianlimab, often as a component of combination therapy, in treating different cancers.
Uses and Conditions Under Study
Fianlimab is being investigated as a treatment for several types of cancer, often in combination with other drugs like cemiplimab or chemotherapy. The clinical trials aim to understand how fianlimab can help patients with these conditions.
- Melanoma: This is a serious type of skin cancer. Fianlimab is being studied in 6 clinical trials for melanoma, including those for advanced or refractory forms of the disease. Researchers are exploring its use alone and in combination with other immunotherapies to improve patient outcomes.
- Lung Cancer: Specifically, fianlimab is under investigation for non-small cell lung cancer, a common type of lung malignancy. There are 2 trials exploring its potential role in treating this condition, often as part of a multi-drug regimen.
- Gynecological Cancers: Fianlimab is being studied across several cancers affecting the female reproductive system. This includes 2 trials for fallopian tube cancer, 2 trials for primary peritoneal cancer, and 2 trials for ovarian cancer. These conditions often present treatment challenges, and fianlimab is being evaluated as a new therapeutic option.
- Gastrointestinal Cancers: The drug is also being researched for its potential in treating cancers of the digestive system. There are a total of 3 trials focused on colorectal cancer, which affects the colon or rectum.
- Liver Cancer: Hepatocellular carcinoma, a common type of liver cancer, is another condition where fianlimab is being investigated. There are 2 trials currently studying its effectiveness in this setting.
- Kidney Cancer: Fianlimab is being explored for clear cell renal cell carcinoma (ccRCC), which is the most common type of kidney cancer. A total of 2 trials are looking into fianlimab as a potential treatment for this disease.
Dosing
Fianlimab is administered intravenously (IV), meaning it is given directly into a vein. The specific dosage and frequency of administration can vary depending on the particular clinical trial and the combination of drugs being studied.
In some studies, fianlimab has been administered as a single agent at a dose of 350 mg via IV. More commonly, it is studied as part of a combination therapy. One specific combination being investigated involves fianlimab 1600 mg alongside cemiplimab 350 mg, often given as a fixed-dose combination (FDC).
Clinical trials are exploring various dosing strategies, including:
- Different numbers of doses, such as 3, 6, or 8 doses in neoadjuvant settings (treatment given before the main treatment).
- Combinations with other immunotherapies like cemiplimab, ipilimumab, or nivolumab.
- Combinations with chemotherapy agents, such as oxaliplatin or gemcitabine/cisplatin.
- Exploration of both high dose (HD) and low dose (LD) fianlimab when combined with cemiplimab.
The duration of treatment can also vary, with some regimens involving treatment for up to 1 year. All dosing regimens are carefully determined by the study protocol to assess safety and efficacy in adult participants, as no specific pediatric doses have been detailed in the available trial information.
Side Effects
In a study of patients with irritable bowel syndrome with constipation (IBS-C) (NCT05018619), the most common side effect reported was nausea. 16% of patients taking Fianlimab experienced nausea, compared to 10% on placebo. Other common side effects included:
- Diarrhea: 13% of patients on Fianlimab, compared to 7% on placebo.
- Headache: 11% of patients on Fianlimab, compared to 9% on placebo.
- Abdominal pain: 9% of patients on Fianlimab, compared to 8% on placebo.
- Fatigue: 7% of patients on Fianlimab, compared to 5% on placebo.
- Vomiting: 6% of patients on Fianlimab, compared to 3% on placebo.
In a separate study of patients with hyperphosphatemia undergoing hemodialysis (NCT04533031), side effects observed with Fianlimab included AV fistula complication (10% of patients on Fianlimab, compared to 0% on placebo), hyperkalemia (7% of patients on Fianlimab, compared to 0% on placebo), and hypotension (7% of patients on Fianlimab, compared to 0% on placebo). Nausea was also reported by 7% of Fianlimab patients in this population, compared to 0% on placebo.
In an open-label extension of the hyperphosphatemia study, where all patients received Fianlimab and no placebo comparison was available, hypertension was reported by 15% of patients. Anemia, peripheral edema, and muscle spasms were each reported by 10% of patients.
Clinical Trial Results
IBS-C Trial Results (NCT05018619)
A 12-week study evaluated Fianlimab in patients with irritable bowel syndrome with constipation (IBS-C). The primary goal was to determine the overall responder rate, defined as a significant reduction in both weekly average stool frequency and abdominal pain for at least 6 of 12 weeks. In this study, 44% of patients on Fianlimab met the criteria for an overall responder, compared to 33% of patients on placebo. This represented a statistically significant difference of 11 percentage points.
Patients taking Fianlimab also experienced greater improvements in key symptoms compared to placebo. On average, patients on Fianlimab reported a reduction of 2.5 stools per week from baseline, compared to a reduction of 1.8 stools per week for those on placebo. Abdominal pain scores, measured on a 0-10 scale, decreased by 2.1 points for Fianlimab patients, versus a 1.6-point decrease for placebo patients. Additionally, patients on Fianlimab experienced an average increase of 1.2 complete spontaneous bowel movements per week, compared to an increase of 0.8 per week for placebo. Quality of life, as measured by the IBS-QoL score (where higher scores indicate better quality of life), improved by 15 points for Fianlimab patients, compared to a 10-point improvement for placebo patients.
Hyperphosphatemia Trial Results (NCT04533031)
A study investigated Fianlimab in patients with hyperphosphatemia (high phosphate levels) who were undergoing hemodialysis. The first part of the study was a 4-week, randomized, placebo-controlled trial. At Week 4, patients treated with Fianlimab experienced an average reduction in serum phosphate levels of 2.0 mg/dL from baseline, which is a clinically meaningful improvement. In contrast, patients on placebo had an average reduction of 0.5 mg/dL. This significant difference of 1.5 mg/dL demonstrates Fianlimab's effectiveness in lowering phosphate levels.
Furthermore, 60% of patients receiving Fianlimab achieved the target phosphate level of less than 5.5 mg/dL by Week 4, compared to only 13% of patients on placebo. In an open-label extension of this study, where patients continued to receive Fianlimab for up to 24 weeks, the mean phosphate reduction was maintained at 2.2 mg/dL from baseline. By Week 24, 70% of these patients achieved the target phosphate level of less than 5.5 mg/dL, indicating sustained efficacy over a longer period.
Currently Recruiting Trials
Fianlimab is an investigational drug currently being studied in clinical trials for various types of cancer, often in combination with cemiplimab or other therapies. These studies aim to understand its safety and effectiveness in treating different advanced or metastatic cancers.
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A Phase 2 trial, NCT07188896, is recruiting up to 120 participants with advanced or metastatic clear cell renal cell carcinoma (aRCC, mRCC, ccRCC). This randomized study compares fianlimab, cemiplimab, and ipilimumab against fianlimab and cemiplimab, or the standard combination of nivolumab and ipilimumab as a first-line treatment.
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For recurrent or metastatic head and neck squamous cell carcinoma (HNSCC), a Phase 2 study, NCT06769698, is enrolling up to 120 participants. It investigates whether fianlimab combined with cemiplimab is more effective than cemiplimab alone.
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The safety and effects of cemiplimab with or without fianlimab after stereotactic body radiotherapy in patients with oligometastatic clear cell renal cell carcinoma are being tested in a Phase 2 trial, NCT07223541, targeting 72 participants.
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A translational study, NCT07223411, is examining immune responses in 20 participants with unresectable or metastatic melanoma, comparing Opdualag to cemiplimab and fianlimab as first-line therapy.
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In localized muscle-invasive bladder cancer, the NeoSTOP-IT Phase 2 trial, NCT06571708, aims to enroll 36 participants to evaluate gemcitabine/cisplatin plus cemiplimab with or without fianlimab.
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A Phase 2 study, NCT06865339, is recruiting 76 participants with locally advanced non-small cell lung cancer (LA-NSCLC) to determine the anti-tumor efficacy of cemiplimab and fianlimab combined with thoracic radiotherapy.
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For patients with BRAF mutant melanoma and symptomatic brain metastases, a Phase 2 trial, NCT06887088, plans to enroll 33 participants to study encorafenib and binimetinib followed by cemiplimab and fianlimab.
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An investigation into ubamatamab combination therapy in adult participants with platinum-resistant ovarian cancer, Fallopian tube cancer, or primary peritoneal cancer is underway in a Phase 2 study, NCT06787612, with an enrollment target of 220 participants.
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The Mayo Clinic is sponsoring a Phase 2 trial, NCT06918132, for 60 participants with stage IB-IIIB non-small cell lung cancer, testing cemiplimab and fianlimab before surgery.
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A long-term follow-up study, NCT06848088, is enrolling 48 participants who previously received fianlimab and cemiplimab for advanced melanoma to learn about their long-term health.
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A Phase 2 feasibility study, NCT06699602, is recruiting 10 participants with clear cell renal cell carcinoma to assess giving cemiplimab and fianlimab before nephrectomy.
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For advanced melanoma, a Phase 2 study, NCT06594991, aims to enroll 88 participants to test the safety and effectiveness of fianlimab, cemiplimab, and ipilimumab in refractory cases.
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A large Phase 3 study, NCT06246916, known as Harmony Head-to-Head, is recruiting 560 participants with advanced or metastatic melanoma to compare fianlimab and cemiplimab against relatlimab and nivolumab.
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In older patients with localized or locally advanced MSI-H colorectal cancer, a Phase 2 study, NCT06205836, is evaluating cemiplimab with or without fianlimab in 44 participants.
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A Phase 2 non-randomized study, NCT05929664, is recruiting 70 participants with locally advanced head and neck basal cell carcinoma to receive cemiplimab or cemiplimab plus fianlimab before surgery.
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A Phase 1 study, NCT05137054, is exploring linvoseltamab in combination with various other cancer treatments, including fianlimab, for 317 participants with multiple myeloma that is resistant to current standard treatments.
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For newly diagnosed, high-risk prostate cancer, a Phase 1/Phase 2 study, NCT04989946, is enrolling 60 participants to examine androgen deprivation, with or without a vaccine (pTVG-AR), and with or without T-cell checkpoint blockade, including cemiplimab and fianlimab.
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A Phase 1/Phase 2 study, NCT04590326, is investigating the safety and efficacy of REGN5668 alone or in combination with cemiplimab, cemiplimab and fianlimab, or ubamatamab, for 612 participants with ovarian, Fallopian tube, primary peritoneal, or endometrial cancer.
Where to Participate
Clinical trials for fianlimab are currently active across a wide geographic area, with 173 sites in 117 cities and 40 states. This broad reach aims to make participation accessible to more patients.
The top locations with the most recruiting sites include:
- New York, New York (6 sites)
- Detroit, Michigan (6 sites)
- Nashville, Tennessee (5 sites)
- Boston, Massachusetts (4 sites)
- Los Angeles, California (4 sites)
- Seattle, Washington (4 sites)
- Dallas, Texas (4 sites)
- Pittsburgh, Pennsylvania (3 sites)
- St Louis, Missouri (3 sites)
- Aurora, Colorado (3 sites)
To be eligible for these studies, participants must be between 18 and 18 years of age. All genders are welcome, but healthy volunteers and children are not being recruited for these trials.
Development Timeline
The development journey for fianlimab began on July 28, 2017, with its first clinical trial. Initially, investigations included conditions such as IBS-C and hyperphosphatemia, before the focus expanded significantly into a broad range of oncology indications. Regeneron Pharmaceuticals has been a primary driver of this research, sponsoring 15 of the 37 total trials conducted to date.
Over time, the pipeline expanded to include various cancers, such as Fallopian Tube Cancer, Hepatocellular Carcinoma, Primary Peritoneal Cancer, Colorectal Cancer, Ovarian Cancer, and Clear Cell Renal Cell Carcinoma. Further expansion covered Head and Neck Squamous Cell Carcinoma, Locally Advanced Basal Cell Carcinoma, Melanoma, Multiple Myeloma, and Non-Small Cell Lung Cancer, among many others.
Fianlimab's development has progressed through different phases, with the majority of trials, 26, currently in Phase 2. There are also 3 trials in Phase 1 and 3 in Phase 3, indicating a steady advancement through the clinical research process. The latest trial is projected to conclude by April 14, 2026, reflecting ongoing commitment to understanding fianlimab's potential.