Papzimeos

Papzimeos is used to treat recurrent respiratory papillomatosis (RRP) in adults. This gene therapy is the first non-replicating adenoviral vector-based immunotherapy approved for RRP treatment. Papzimeos is given by subcutaneous injection 4 times over a 12-week interval.

RRP is a rare, life-threatening infection caused by human papillomavirus (HPV) types 6 and 11, resulting in voice problems, airway obstruction, and pneumonia.

Papzimeos (zopapogene imadenovec-drba) gained FDA approval on August 14, 2025.

Approval was supported by the PRGN-2012-201 clinical trial ( NCT04724980 ), which demonstrated that 51% (18/35) of study participants achieved a complete response, with no surgeries needed for 12 months; 15 maintained response at 24 months.

Mechanism

Papzimeos works in RRP by using selected parts of HPV 6 and HPV 11 proteins as a fusion antigen, training the immune system to recognize and attack cells infected with these viruses.

Papzimeos is administered by a health professional by subcutaneous (under the skin) injection, into the outer, upper arm or outer, upper thigh.

• Before administering Papzimeos, your healthcare provider will remove as much of the visible papilloma as possible. This is called surgical debulking.
• This may be repeated before the third and fourth treatment of Papzimeos if necessary.
• Avoid direct contact with the injection site (such as touching or scratching) and dressings for at least 24 hours following treatment.

You and your healthcare provider should treat any material associated with the Papzimeos injection as contaminated.

• This includes the needle and syringe containing Papzimeos and any dressings.
• Place these in a sealable bag and dispose of them in your regular trash.
• Follow these precautions for 1-2 weeks after the injection.
• All caregivers should practice proper hand hygiene, such as hand washing when coming into direct contact with a patient's body waste.

Common side effects

The most common side effects of Papzimeos are:

• Injection site reactions
• Fatigue
• Chills
• Pyrexia (fever)
• Myalgia (muscle aches)
• Nausea.

Serious side effects and warnings

Papzimeos may cause the following serious side effects:

Injection site reactions. These have occurred after an injection of Papzimeos, and some may be severe. Signs and symptoms may include redness, pain, swelling, itching, or warmth at the injection site. Your healthcare provider will monitor you for these for at least 30 minutes after the initial treatment. Manage symptoms with a cold compress, over-the-counter pain relievers, or antihistamines if needed. Seek urgent medical attention if symptoms worsen or are accompanied by signs of a systemic allergic reaction (such as difficulty breathing, widespread rash, or facial swelling) or an infection

Thrombotic events. These may occur after a Papzimeos injection and symptoms may include shortness of breath, chest pain, leg swelling, persistent abdominal pain, or neurological symptoms (including severe or persistent headaches or blurred vision). Seek urgent medical attention if you develop any of these symptoms.

These are not all the side effects of Papzimeos. See the Papzimeos Prescribing Information for a list of side effects. To report suspected adverse reactions, contact Precigen Inc. at 855-743-6777, and [email protected] or the FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Dose of Papzimeos for Recurrent Respiratory Papillomatosis (RRP) in Adults

• 5 x 1011 particle units (PU) subcutaneously (SC).
• Administer four times over a 12-week interval (at 0, 2, 6, and 12 weeks)

Papzimeos requires storage at -60°C (-76°F) or less.

When ready to administer, remove Papzimeos from the freezer and thaw immediately in a 37°C (98.6°F) water bath or dry bead bath until there are no visible ice crystals in the vial, for a time of less than or equal to 5 minutes.

• Do not hold Papzimeos at room temperature for more than 60 minutes after thawing. Do not store thawed Papzimeos.

Treat any Papzimeos spills with a virucidal agent (eg, sodium hypochlorite with 0.5% active chlorine or 6% hydrogen peroxide) for 15 minutes.

Dispose of any unused product or waste materials as per facility biohazard waste disposal procedure.

Active ingredient: zopapogene imadenovec-drba 5 x 1011 PU/1 mL

Excipients: Tris base (10 mM), sodium chloride (75 mM), magnesium chloride hexahydrate (1 mM), polysorbate 80 (0.019 mM), and trehalose dihydrate (146 mM).

Supplied as a sterile, frozen suspension that has been aseptically filled into single-dose vials fitted with a rubber stopper and aluminum flip-cap seal.

Papzimeos is manufactured by Precigen Inc., 20358 Senecca Meadows Parkway, Germantown, MD 20876 USA. U.S. Licence No. 2364.