Epkinly Side Effects: Everything You Should Know Before Starting Treatment

Epkinly (epcoritamab-bysp) marks a meaningful breakthrough in treating certain types of B-cell lymphomas, offering renewed hope to patients with diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma. While the promise of this innovative treatment is encouraging, it’s equally important to understand the potential side effects—both common and serious—that may occur during the course of therapy.

Being informed empowers you to manage expectations, detect symptoms early, and work closely with your care team to ensure the best possible outcome. This comprehensive guide covers what to expect, which side effects are manageable, and when to seek immediate help.

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Understanding Epkinly: What It Does and Why Side Effects Occur

Epkinly is an immunotherapy designed to help your body identify and destroy cancer cells more efficiently. It works by targeting specific proteins found on B-cell lymphoma cells, boosting the immune system’s ability to fight the disease.

Administered through injections, Epkinly is typically given in a step-up dosing schedule. This gradual approach helps the body adjust and reduces the likelihood of severe immune reactions early in treatment. While this methodical build-up can reduce risks, it doesn’t eliminate them—your immune system is still being activated in a powerful way, which is what causes many of the side effects.

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Common Side Effects by Cancer Type

Side effects from Epkinly can vary depending on the type of lymphoma being treated. Here’s a breakdown of the most common symptoms for patients with DLBCL and follicular lymphoma:

DLBCL Patients: What to Expect

1. Fatigue – Tiredness is almost universal. It can range from feeling mildly sluggish to being too drained for everyday tasks. This happens as your body channels energy into fighting cancer and adjusting to treatment.
2. Muscle and Bone Pain – Many people report aches that feel similar to flu symptoms. It’s your immune system doing extra work, and inflammation in joints and muscles is a typical side effect.
3. Injection Site Reactions – Redness, tenderness, or mild swelling where the shot is given are expected. These generally clear up within a few days.
4. Fever – A low-grade fever often signals that the immune system is reacting. While this is usually manageable, keep an eye on its duration and intensity.
5. Nausea & Diarrhea – Digestive disruptions can affect appetite and hydration. These symptoms often improve with supportive medications and dietary changes.

Follicular Lymphoma Patients: Additional Considerations

Patients with follicular lymphoma often experience the above symptoms along with:

• Upper Respiratory Infections – Sinus and cold-like symptoms may appear more frequently.
• Increased Risk of COVID-19 – Immune suppression can make patients more vulnerable.
• Skin Rashes – From mild irritation to more visible skin reactions, rashes can develop and typically respond to topical treatments.
• Cough and Headaches – Often linked to respiratory involvement or immune-related inflammation.

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Mild Side Effects That Still Deserve Attention

Though not considered serious, these symptoms can impact daily life if not managed properly:

Abdominal Discomfort

This can range from bloating to cramping, often tied to gastrointestinal inflammation. It might show up alongside nausea or diarrhea.

Constipation

A frustrating flip side to diarrhea, constipation can become chronic. Increasing fiber intake, drinking more fluids, and gentle physical activity can help ease symptoms.

Mild Respiratory Infections

Because Epkinly affects immune function, your body becomes more susceptible to common colds and other upper respiratory issues. Keep an eye on symptoms like congestion or a lingering cough.

Tip: While these symptoms often fade on their own, don’t let them linger without mentioning them to your care team—especially if they get worse or don’t improve after a few days.

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Serious Side Effects: What to Watch For

Some side effects go beyond discomfort and may pose a serious health risk if left unchecked.

1. Blood Cell Changes

Your bone marrow may produce fewer healthy blood cells, which can lead to:

• Low Platelets (Thrombocytopenia) – Easy bruising, bleeding gums, or blood in urine may be red flags.
• Low White Blood Cells (Neutropenia) – This reduces your body’s ability to fight infections, so even minor bugs can become serious.
• Low Red Blood Cells (Anemia) – Symptoms include fatigue, shortness of breath, or pale skin.

Note: These are monitored regularly through blood work. Your doctor may adjust your treatment if these levels dip too low.

2. Increased Risk of Infection

Because your immune system is suppressed, you’re at higher risk for:

• Pneumonia – Sometimes it’s subtle, without the usual symptoms like a deep cough.
• UTIs – If untreated, they can progress to kidney infections.
• COVID-19 Complications – Precautions like vaccinations and mask-wearing are highly advised.
• Sepsis – This life-threatening condition arises from an unchecked infection and requires emergency care.

3. Allergic Reactions

While rare, reactions can occur, especially after injections. Watch for:

• Hives, rash, or itching
• Difficulty breathing
• Swelling of lips, face, or tongue

Seek emergency care if any of these symptoms appear.

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FDA Boxed Warnings: Critical Safety Alerts You Should Know

Epkinly includes two boxed warnings, meaning the FDA has identified specific risks that are serious or potentially life-threatening.

Cytokine Release Syndrome (CRS)

This happens when your immune system overreacts and releases an excess of inflammatory proteins (cytokines). It’s the most frequently reported serious side effect.

Early Warning Signs of CRS

• Fever or chills
• Fast heartbeat or dizziness
• Confusion or difficulty concentrating
• Anxiety, agitation
• Balance issues or coordination problems
• Headaches or tremors

When It Happens: Most often after your first full dose, which is why patients are closely monitored in a hospital for at least 24 hours afterward.

Immune Effector Cell-Associated Neurotoxicity Syndrome (ICANS)

This condition affects the brain and nervous system, leading to potential neurological complications.

Watch for These ICANS Symptoms:

• Trouble speaking or writing
• Memory loss or confusion
• Muscle weakness (especially on one side)
• Tremors or twitching
• Seizures or unusual fatigue

While rare, ICANS demands immediate medical attention. It often develops within the first week of treatment, though late-onset cases are possible.

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Managing Common Side Effects: Practical Tips for Everyday Life

Relieving Muscle and Bone Pain

• OTC Pain Relievers: Acetaminophen is usually safe. Use ibuprofen only if approved by your doctor.
• Heat or Ice Packs: Ice reduces swelling, while heat eases stiffness.
• Low-Impact Activity: Gentle yoga or walking can prevent stiffness and improve mood.
• Alternative Options: Acupuncture or massage therapy may offer relief if approved.

Tackling Digestive Discomfort

• Eat Small Meals: Lighter meals more frequently can ease nausea.
• Stick to Bland Foods: Rice, applesauce, bananas, and toast are easy on the stomach.
• Stay Hydrated: Broths, electrolyte drinks, and water help replace lost fluids.
• Over-the-Counter Relief: Antacids or anti-nausea drugs may be helpful—ask your doctor first.

Handling Injection Site Reactions

• Cold Compresses: Apply immediately after injection.
• Avoid Tight Clothing: Let the area breathe and avoid friction.
• Gentle Massage: Around (not on) the injection site can boost circulation and ease soreness.

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When to Contact Your Healthcare Provider

Call Within 24–48 Hours If You Notice:

• Persistent fever over 100.4°F (38°C)
• Digestive symptoms lasting more than 3 days
• Fatigue that worsens or feels overwhelming
• New skin rashes or prolonged injection site pain

Seek Emergency Help If You Experience:

• High fever (101°F/38.3°C or higher) with chills
• Trouble breathing or chest pain
• Heavy or unusual bleeding
• Confusion, seizures, or tremors
• Symptoms suggestive of CRS or ICANS

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Ongoing Monitoring: The Key to Safe Treatment

1. Regular Blood Work

You’ll likely get blood tests every few weeks to monitor:

• White and red blood cell counts
• Platelet levels
• Kidney and liver function

2. Preventing Infections

• Wash hands frequently
• Avoid sick people and crowded places
• Stay up-to-date on recommended vaccines
• Use masks in high-risk areas (especially during cold and flu season)

3. Oral Care

Mouth sores or infections can become serious fast. Brush gently, avoid mouthwash with alcohol, and see a dentist regularly (inform them about your treatment).

4. Mental and Emotional Support

Side effects aren’t just physical. Join a support group, talk to a counselor, or share your journey with trusted friends and family.

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Weighing the Benefits vs. Risks of Epkinly

Epkinly offers real promise for patients with relapsed or refractory B-cell lymphoma. Its side effects are not to be taken lightly—but they are manageable in most cases, especially with proactive care and close medical supervision.

Here’s the bottom line:

• Most side effects are mild to moderate and fade over time.
• Serious complications, while possible, are rare and usually treatable if caught early.
• Your care team will monitor you closely, especially during the first month of therapy.
• Communication is crucial. Don’t wait to speak up about new or worsening symptoms.

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Final Thoughts

Deciding to begin treatment with Epkinly is a major step—but it doesn’t have to be a frightening one. Understanding the risks, warning signs, and available management tools ensures you’re not walking the journey alone or unprepared.

Talk openly with your oncologist, ask questions, and know your options. With a vigilant mindset and support from your care team, you can navigate side effects and focus on what really matters: healing.