In short
Camostat mesilate (also known as camostat mesylate) is a serine protease inhibitor that has gained significant attention in recent clinical research, particularly during the COVID-19 pandemic. Originally approved in Japan for treating conditions like chronic pancreatitis and reflux esophagitis, this drug has shown promise in preventing viral entry of SARS-CoV-2 into human cells by inhibiting the host cell serine protease TMPRSS2. This article explores the ongoing clinical trials investigating camostat mesilate across various conditions, with a primary focus on its potential as a treatment for COVID-19 and other medical conditions.
Key points
- Camostat mesilate, a serine protease inhibitor with a long history of safe use in Japan, has emerged as a potential treatment for COVID-19 by blocking the TMPRSS2 enzyme needed for SARS-CoV-2 viral entry into cells. Multiple clinical trials are investigating its efficacy in different patient populations, with most studies administering 600-800 mg daily for 5-14 days. Primary outcomes focus on viral load reduction, preventing disease progression, and shortening recovery time. Beyond COVID-19, camostat is also being studied for conditions like protein-losing enteropathy and kidney protection in chronic kidney disease. Trial designs vary from outpatient to inpatient settings, sometimes combining camostat with other medications to potentially enhance therapeutic effects.
At a glance
- Primary Uses in COVID-19 Trials
- - Reducing viral load in respiratory samples; - Preventing disease progression in early/mild COVID-19; - Reducing hospitalization rates; - Shortening time to clinical improvement; - Treating COVID-19 outpatients with risk factors
- Common Dosage Regimens
- - 200 mg three to four times daily (600-800 mg total daily dose); - Treatment durations from 5-14 days; - Administered as oral tablets; - Some trials using 100 mg tablets, 2-3 per dose
- Mechanism of Action
- - Inhibits host cell serine protease TMPRSS2; - Blocks SARS-CoV-2 viral entry into cells; - May reduce viral replication; - Demonstrated in vitro inhibition of SARS-CoV-2
- Non-COVID Applications
- - Protein-losing enteropathy after Fontan operation; - Kidney protection in chronic kidney disease patients with proteinuria; - Historical use in Japan for chronic pancreatitis; - Treatment of postoperative reflux esophagitis
- Trial Designs
- - Randomized, double-blind, placebo-controlled studies; - Phase II and III trials; - Both inpatient and outpatient settings; - Some trials combining camostat with other treatments; - Follow-up periods typically 14-90 days
- Combination Therapies
- - Camostat + hydroxychloroquine; - Camostat + bicalutamide; - Camostat + niclosamide; - Comparison with other COVID-19 treatments
- Safety Monitoring
- - Adverse events and serious adverse events; - Liver function tests (AST, ALT, ALP, GGT); - Kidney function (creatinine, GFR); - Blood parameters (platelets, potassium); - Vital signs and ECG monitoring
What is Camostat Mesilate?
Camostat mesilate (also known as camostat mesylate or by the brand name Foipan®) is a medication that belongs to a class of drugs called serine protease inhibitors. It has been used clinically in Japan since 1985 for treating conditions such as chronic pancreatitis (inflammation of the pancreas) and postoperative reflux esophagitis (inflammation of the esophagus after surgery). The drug has a well-established safety record with more than 15 years of clinical experience in Japan.
Camostat mesilate may also be referred to by several synonyms including:
- Camostat mesylate
- Foipan® (brand name in Japan)
- FOY-305 (research designation)
How Does Camostat Mesilate Work?
Camostat mesilate works by inhibiting certain enzymes called serine proteases. These enzymes are involved in various biological processes in the body. Specifically, camostat inhibits:
- Pancreatic enzymes: In chronic pancreatitis, camostat reduces the activity of digestive enzymes that can damage the pancreas.
- TMPRSS2: This is a serine protease found on the surface of certain cells. It has gained attention because it is needed for some viruses, including SARS-CoV-2 (the virus that causes COVID-19), to enter cells.
By blocking these enzymes, camostat mesilate can help reduce inflammation in the pancreas and potentially prevent certain viral infections by blocking their entry into cells.
Current Medical Uses
Camostat mesilate has been approved and used in Japan for several conditions:
- Chronic pancreatitis: To treat pain and inflammation associated with ongoing inflammation of the pancreas.
- Postoperative reflux esophagitis: To treat inflammation of the esophagus that can occur after surgery.
- Acute exacerbations of chronic pancreatitis: To manage flare-ups of chronic pancreatic inflammation.
It's important to note that while camostat mesilate is widely used in Japan, it may not be approved for these uses in other countries. Clinical trials are currently investigating its potential for other medical conditions.
Potential Use in COVID-19
One of the most actively researched potential applications for camostat mesilate is in the treatment of COVID-19. Here's why researchers are interested in this drug for COVID-19 treatment:
- Mechanism against viral entry: SARS-CoV-2, the virus that causes COVID-19, needs to bind to a receptor called ACE2 on human cells to gain entry. This process requires a serine protease called TMPRSS2. Camostat mesilate can inhibit TMPRSS2, potentially blocking viral entry into cells.
- Laboratory evidence: Studies have shown that camostat mesilate can inhibit SARS-CoV-2 replication in laboratory settings (in vitro). Additionally, in previous research on related coronaviruses like SARS-CoV, camostat mesilate showed protective effects in mouse models, reducing mortality from 100% to 30-35%.
- Clinical trials: Multiple clinical trials have been conducted to evaluate camostat mesilate's effectiveness against COVID-19 in humans, both in hospitalized patients and outpatients with mild to moderate disease.
Clinical trials have investigated different aspects of camostat mesilate in COVID-19 treatment, including:
- Reduction of viral load (amount of virus in the body)
- Shortening the duration of symptoms
- Preventing progression to severe disease requiring hospitalization
- Reducing COVID-19-associated blood clotting problems (coagulopathy)
- Combination therapy with other medications like hydroxychloroquine or bicalutamide
While research continues, it's important to understand that camostat mesilate is still considered investigational for COVID-19 treatment and has not been approved by regulatory agencies like the FDA for this purpose.
Dosage and Administration
The dosage of camostat mesilate varies depending on the condition being treated and the clinical trial protocol. Based on the available information from clinical studies:
- For COVID-19 clinical trials: Various dosing regimens have been studied, including:
- 200 mg taken orally 3-4 times daily (600-800 mg total daily dose)
- Treatment duration typically ranging from 5 to 14 days
- For chronic pancreatitis (in Japan): The typical dosage is 100 mg taken orally 3 times daily.
Camostat mesilate is typically administered as oral tablets. It's important to note that dosing should always be determined by a healthcare provider, and patients should never self-medicate with camostat mesilate or adjust their dosage without medical supervision.
Safety Profile and Side Effects
Camostat mesilate has been used in Japan for several decades and generally has a good safety profile. However, like all medications, it can cause side effects in some people.
Common side effects may include:
- Gastrointestinal symptoms (nausea, vomiting, diarrhea)
- Skin reactions
- Headache
- Fatigue
In clinical trials for COVID-19, researchers carefully monitored participants for adverse events. The CLOCC trial, for example, was designed to evaluate both the efficacy and safety of hydroxychloroquine-camostat combination therapy compared to hydroxychloroquine plus placebo in hospitalized patients with moderate COVID-19 infection.
Several studies have collected safety data by monitoring:
- Laboratory tests including liver function, kidney function, and blood counts
- ECG parameters to check for heart-related side effects
- Vital signs including blood pressure and oxygen saturation
It's important to discuss potential risks and benefits with your healthcare provider before starting any new medication, including camostat mesilate.
Ongoing Research
Research on camostat mesilate continues to evolve, particularly in the context of COVID-19 treatment. Several large-scale clinical trials have been conducted or are in progress:
- The ACTIV-2 trial: A large platform trial testing multiple potential COVID-19 treatments, including camostat mesilate, in outpatients.
- The CLOCC trial: Evaluated the efficacy and safety of hydroxychloroquine-camostat combination therapy compared to hydroxychloroquine plus placebo in hospitalized patients with moderate COVID-19.
- The CAMOVID trial: A multicenter randomized trial to evaluate the efficacy and safety of camostat mesilate for the treatment of SARS-CoV-2 infection in ambulatory adult patients.
- The COMBO trial: Studying camostat in combination with bicalutamide for COVID-19 treatment.
These studies are helping researchers better understand the potential benefits and limitations of camostat mesilate in COVID-19 treatment, as well as optimal dosing strategies and patient populations who might benefit most from this therapy.
Other Potential Applications
Beyond its established uses and COVID-19 research, camostat mesilate is being investigated for other medical conditions:
- Protein-losing enteropathy after Fontan operation: A phase 2 clinical trial is evaluating camostat mesilate for treating protein-losing enteropathy (a condition where protein leaks from the intestines) in patients who have undergone a specific heart surgery called the Fontan operation.
- Chronic kidney disease (CKD): Researchers are studying whether camostat mesilate might help protect kidney function in patients with chronic kidney disease and proteinuria (protein in the urine). By inhibiting serine protease activity and tubular complement activation, camostat may potentially mitigate progressive kidney injury.
These investigations highlight the versatility of camostat mesilate as a serine protease inhibitor with potential applications across multiple medical conditions.