Cat Allergen Relief: Regeneron vs. Pacagen’s New Approach

Allergies can disrupt a peaceful night’s sleep, stop you from cuddling with your beloved pets, and turn daily life into continuous discomfort. 

In fact, nearly 1 in 3 people worldwide are affected by pet and dust allergies. In the U.S., over 90% of homes carry multiple allergens, which cause allergic reactions.

Allergens are invisible particles or proteins in your environment, and they are harmless until your immune system mistakes them as a threat. This false alarm sets off a cascade of immune reactions, resulting in allergy flare-ups. Those tiny allergens cling to everything - carpets, furniture and even your clothes - making them impossible to escape.

For decades, the best solutions have remained the same. They simply manage the symptoms of allergies (e.g., sneezing, runny nose, itchy eyes, etc.) but don’t target the allergens that cause allergies in the first place. For example, taking pills (e.g., antihistamines) or getting allergy shots, and a never-ending cycle of cleaning have been offering relief. However, these strategies address your flare-ups by reducing immune reactions or slowly retraining your immune system to change their response. Ultimately, for the individuals, these gold-standard solutions are underwhelming, time-consuming, and often come with side effects, ranging from drowsiness to swelling.

What if we tell you there is a new story appearing in the world of allergy relief? One that tackles the root cause in a completely different way?

One Shared Goal, Two Paths to Relief 

Recently, Regeneron, a pharmaceutical company, developed a new therapy that masks allergens within the body. This block describes the similarities between Regeneron’s shots, and Pacagen’s next-gen environmental mitigation approach.

Regeneron’s Antibody Therapy

Regeneron has developed a therapy that uses specially engineered antibodies - immune proteins that latch onto a cat allergen (in this case Fel d 1, the cause of over 90% cat allergies) directly inside the body to stop it from triggering allergy symptoms. Their goal is to stop the allergen after it is already in your body by masking it from your immune system. 

Regeneron recently reported their Phase 3 trials for cat allergies. They reported promising results, notably:

• People with cat allergies saw a 52% drop in itchy eyes compared to a placebo. Redness and skin reactions improved as well.
• Benefits appeared within a week after a single dose.

This marks a big step beyond antihistamines or traditional allergy shots, which require very long treatment regimens (~3 years). As a prescription drug, Regeneron’s therapy will likely be expensive, and needs to be injected into the bloodstream - it only works after allergens have entered the body.

How does it work? 

Fel d 1, the major cat allergen, originates from cat dander and saliva. As cats groom themselves and roam around the home, Fel d 1 disperses in massive quantities into the environment. 

Structurally, Fel d 1 exists as a tetramer - it is a dimer of 2 identical units/heterodimers. Once it comes into contact with immune cells in your body, it will bind to IgE antibodies on the surface of these cells, causing them to crosslink. This act of cross-linking is very important! It acts as a “switch” to activate your immune cells, setting off the release of histamine and other chemicals that drive allergy symptoms!

Regeneron’s antibodies were specifically engineered to interrupt this cascade. After being injected into your body, these antibodies seek out and bind to Fel d 1. By locking onto the allergen, they block Fel d 1’s ability to connect with IgE antibodies, stopping the chain reaction that would normally trigger histamine release. 

What makes these antibodies especially powerful is their persistence. They can remain active in the body for more than three weeks, continuously neutralizing Fel d 1 and protecting you against allergic flare-ups. In clinical trials, this durability translated into meaningful relief - many patients reported protection lasting as long as 85 days after a single injection.

Environmental Mitigation with Pacagen

Pacagen takes an entirely different approach. We asked the question: what if allergens could be stopped before they ever reached you?

Rather than waiting until allergens enter your body, our strategy is to eliminate them right at the source, directly in your home. Using an alpaca’s immune system as inspiration, we engineered our own proprietary protein, WhiskerBlock™ for a singular purpose: to target and neutralize allergens in the environment before they can cause harm to you.

How does it work?

Like Regeneron’s antibodies that target Fel d 1 inside the body, WhiskerBlock™-alpha are designed to precisely latch onto Fel d 1, but directly in your environment. By binding and neutralizing these allergens outside of the body, WhiskerBlock™ stops the allergic chain reaction at its origin, long before it even reaches you.

What makes it different from Regeneron’s antibody

Both Regeneron’s antibodies and WhiskerBlock™ share the same mission: stopping Fel d 1. Yet the way they achieve this is quite different.

Inside the body: 

Regeneron’s antibodies are injected as a drug. Once in circulation, they attach to Fel d 1 and block its ability to connect with IgE antibodies. This halts the allergic chain reaction - but only temporarily. As the antibodies are gradually cleared from the body, Fel d 1 can once again bind to IgE, and symptoms may return. 

Because these are therapeutic antibodies, they typically require a prescription, are likely expensive/may not be covered by insurance, and may involve recurring clinic visits similar to allergy shots. Like many antibody drugs, they may also cause side effects such as headaches, nausea, and fatigue.

Outside the body: 

WhiskerBlock™ works at the source - neutralizing allergens in your home before they ever reach your immune system. 

Unlike antibody drugs, WhiskerBlock™ doesn’t simply block Fel d 1/IgE binding. It was designed to break down Fel d 1’s tetrameric structure, breaking it into harmless fragments that are unable to be cross-linked by IgE. 

Additionally, WhiskerBlock™ is much smaller in size (~25% size of Fel d 1 dimer, and ~7% size of the Regeneron antibodies), granting it more flexibility and stability. Bolstered by this small size, this strategy provides not only fast and efficient neutralization but also lasting Fel d 1 breakdown. 

Importantly, WhiskerBlock™ is not a drug. It does not go into your body. Instead, it eliminates allergens in your home environment. It is an engineered protein packaged into safe, food-grade products - available as a home spray, food topper, or cat health supplement - requiring no prescription and designed for everyday use. 

Because WhiskerBlock™ acts outside the body, it delivers effective, durable relief with a significantly low risk of side effects, and creates a safe, hypoallergenic environment for the entire household.

Our rigorous laboratory studies and customers surveys have shown that: 

• WhiskerBlock™ begins binding allergens on contact, breaking down to 98% of them within minutes.
• Safe for children, adults, and pets based on thousands of data points from dozens of safety studies and further validated by independent third-party research organizations. 
• Over 80% of customers noticed improvements within the first week.
• 97% of customers reported significant relief after four weeks. 

Beyond individual benefits, one of the greatest strengths of Pacagen’s approach is its shared impact. By minimizing allergen levels in the home, our products create a safer, more comfortable environment for the entire family, restoring peace of mind and making your home a haven again.

Summary of How They Differ

What They Share

Despite taking very different paths, we and Regeneron share an important common ground: we are both built on advanced biotechnology engineered to deliver safe and effective solutions for cat allergies.

At the core, both approaches were designed to bind Fel d 1, the dominant cat allergen, and stop it from triggering your immune system. The way it does that is what differs. The WhiskerBlockTM proteins break down allergens in the environment while the Regeneron antibodies prevent false immune activations in your body. Whether neutralizing Fel d 1 inside the body or in the surrounding environment, these strategies go far beyond masking symptoms like sneezing, itchy eyes, or congestion. They target the root cause of allergic reactions.

Unlike traditional pills or shots that provide only temporary relief, both Regeneron antibodies and WhiskerBlock™ aim for lasting protection, reducing flare-ups in a way that can meaningfully improve daily life. 

Precision is key: both are designed to act only on the allergen itself. This stands in contrast to conventional antihistamines, which broadly suppress histamine activity throughout the body. Because histamine regulates many functions including the sleep - wake cycle, such non-specific treatments often come with side effects like drowsiness.

By focusing directly on the allergen in your environment, our approach sets a new standard: targeted relief, greater safety, and the peace of mind that comes with breathing freely, without the burden of unwanted side effects.

Bottom Line

You shouldn't have to choose between living your life and managing your allergies. Constant cleaning, daily medications, and repeated clinic visits shouldn't define your routine. You deserve something easier, gentler, and more comforting. Because your well-being isn't just important, it's everything.

Allergy relief doesn’t have to be one-size-fits-all. Whether it’s advanced medicine working inside your body or proactive care within your environment, both approaches strive toward the same goal: better sleep, fewer symptoms, and the freedom to fully enjoy life with the people and pets you love.

Regeneron is leading the way on the clinical front with antibody therapy that works from within. By masking allergens like Fel d 1 from your immune system, their Phase 3 trials have shown real hope for those suffering from severe cat allergies.

At Pacagen, we're reimagining the fight against allergies from outside your body.
Our WhiskerBlock™ proteins work before allergens even reach you, neutralizing them right in your home environment. No pills, no injections, no long-term medical regimens, WhiskerBlockTM is a safe, science-backed solution designed for everyday comfort. 

• Gentle enough for pets and people. 
• Powerful enough to change how you live.
• Because you weren’t meant to fight allergies alone.

You were meant to breathe freely, rest deeply, and love fully without holding back.
That’s the future Pacagen is building.

Learn more about Pacagen

Take a look at how we discovered WhiskerBlock and validated its efficacy and safety! Development of high-affinity, single-domain protein binders for neutralizing household allergens