Palynziq Drug Information

PALYNZIQ is indicated to reduce blood phenylalanine concentrations in adult and pediatric patients 12 years of age and older with phenylketonuria (PKU) who have uncontrolled blood phenylalanine concentrations greater than 600 micromol/L on existing management.

Important Recommendation Prior to PALYNZIQ Treatment Treatment with PALYNZIQ should be managed by a healthcare provider experienced in the management of PKU. Obtain baseline blood phenylalanine concentration before initiating treatment. Consider premedication with an H 1 -receptor antagonist, H 2 -receptor antagonist, and/or antipyretic based upon individual patient tolerability.

Recommended Dosage and Administration Induction

The recommended initial induction dosage for PALYNZIQ is 2.5 mg subcutaneously once weekly for 4 weeks. Administer the initial dose under the supervision of a healthcare provider. Titration Titrate the PALYNZIQ dosage in a step-wise manner, based on tolerability, over at least 5 weeks, to achieve a dosage of 20 mg subcutaneously once daily according to Table 1.

Maintenance Therapeutic response may not be achieved until the patient is titrated to an effective maintenance dosage of PALYNZIQ. Use the lowest effective and tolerated dosage of PALYNZIQ. Assess patient tolerability, blood phenylalanine concentrations, and dietary protein and phenylalanine intake throughout treatment.

Individualize the maintenance dosage to achieve blood phenylalanine control (blood phenylalanine concentrations less than or equal to 600 micromol/L), taking into account patient tolerability to PALYNZIQ and dietary protein and phenylalanine intake (see Table 1 ). Maintain the PALYNZIQ dosage at 20 mg once daily for at least 24 weeks. Consider increasing the PALYNZIQ dosage to a maximum of 60 mg once daily in patients who have been on 40 mg once daily continuously for at least 16 weeks without achieving blood phenylalanine control.

Discontinuation Discontinue PALYNZIQ in patients who have not achieved an adequate response after 16 weeks of continuous treatment with the maximum dosage of Maintenance Individualize treatment to the lowest effective and tolerated dosage. Consider increasing to a maximum of 60 mg once daily in patients who have not achieved a response with Dose Reduction During titration and maintenance of PALYNZIQ treatment, patients may experience blood phenylalanine concentrations below 30 micromol/L. For blood phenylalanine concentrations below 30 micromol/L, the dosage of PALYNZIQ may be reduced and/or dietary protein and phenylalanine intake may be modified to maintain blood phenylalanine concentrations within a clinically acceptable range and above 30 micromol/L.

Missed Dose If a dose is missed, instruct patients to take their next dose as scheduled and to not take two doses of PALYNZIQ to make up for the missed dose.

Subsequent dose titration should be based on patient tolerability and therapeutic response.

Blood Phenylalanine Monitoring and Diet

After initiating treatment with PALYNZIQ, obtain blood phenylalanine concentrations every 4 weeks until a maintenance dosage is established. After a maintenance dosage is established, periodic blood phenylalanine monitoring is recommended to assess blood phenylalanine control. Frequent blood Phe monitoring is recommended in the pediatric population.

Monitor patients' dietary protein and phenylalanine intake throughout treatment with PALYNZIQ and counsel them on how to adjust their dietary protein and phenylalanine intake, as needed, based on blood phenylalanine concentrations.

Administration Instructions

Each prefilled syringe of PALYNZIQ is intended for use as a single subcutaneous injection. Inspect PALYNZIQ visually for particulate matter and discoloration prior to administration. PALYNZIQ is a clear to slightly opalescent, colorless to pale yellow solution.

Discard if discolored, cloudy, or if particulate matter is present. Prior to first dose of PALYNZIQ, prescribe epinephrine, and instruct the patient and observer (if applicable) on how to recognize the signs and symptoms of anaphylaxis, how to properly administer epinephrine, and to seek immediate medical care upon its use. Perform initial administration(s) and/or readministration after an anaphylaxis episode under the supervision of a healthcare provider equipped to manage anaphylaxis, and closely observe patients for at least 60 minutes following injection.

Prior to self-injection, confirm patient competency with self-administration using aseptic technique. Discard after use. Consider having an adult observer for patients who may need assistance in recognizing and managing anaphylaxis during PALYNZIQ treatment.

If an adult observer is needed, the observer should be present during and for at least 60 minutes after each PALYNZIQ administration, should be able to administer epinephrine, and call for emergency medical support upon its use. The recommended injection sites for PALYNZIQ are: the front middle of thighs and the abdomen at least 2 inches (five centimeters) away from the navel. If a caregiver is giving the injection, the top of the buttocks and the back of the upper arms are also appropriate injection sites.

Do not inject PALYNZIQ into moles, scars, birthmarks, bruises, rashes, or areas where the skin is hard, tender, red, damaged, burned, inflamed, or tattooed. Check the injection site for redness, swelling, or tenderness. Rotate sites for subcutaneous injections of PALYNZIQ.

If more than one injection is needed for a single dose of PALYNZIQ, the injection sites should be at least 2 inches away from each other. The second injection site can be on the same part of the body or a different part of the body.

Clinical Trial Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Twelve patients aged 16-17 years at enrollment received PALYNZIQ as part of the overall induction/titration/maintenance population and are included in this analysis. The most common adverse reactions (at least 20% of patients in either treatment phase) were injection site reactions, arthralgia, hypersensitivity reactions, headache, generalized skin reactions lasting at least 14 days, nausea, abdominal pain, vomiting, cough, oropharyngeal pain, pruritus, diarrhea, nasal congestion, fatigue, dizziness, and anxiety.

Of the 285 patients exposed to PALYNZIQ from the pooled safety analysis, 44 (15%) patients discontinued treatment due to adverse reactions. Table 2 lists adverse reactions reported in at least 15% of patients treated with PALYNZIQ in an induction/titration/maintenance dosage regimen in clinical trials and illustrates the adverse reaction rates over time by treatment phase. Table 3 lists laboratory abnormalities reported in at least 10% of patients treated with PALYNZIQ in this pooled safety analysis.

For these analyses, the induction/titration phase was defined as the time prior to reaching a stable dose (completing an 8-week phase at the same dose level). Once a stable dosage was reached, patients were considered to be in the maintenance phase thereafter. Safety data for patients who reached the maintenance phase are included within either the induction/titration or maintenance phases depending on the onset date of the adverse reaction.

Safety data for patients who did not reach the maintenance phase are included within the induction/titration phase. The maintenance phase includes data for patients who were previously on PALYNZIQ and transitioned to placebo during the randomized withdrawal period of Study 3. Rates of adverse reactions (adjusted for duration of exposure) generally decreased over time and for some stayed relatively stable.

In the maintenance phase, the rate of adverse reactions (adjusted for duration of exposure) in patients who reached the maintenance phase was comparable across dosages evaluated. The types and rate of adverse reactions reported during the maintenance phase in patients who received 20 mg once daily, 40 mg once daily, and 60 mg once daily were similar. During long-term treatment (greater than 36 months), the exposure-adjusted rates of adverse reactions decreased.

Rates of laboratory abnormalities (adjusted for duration of exposure) stayed relatively stable over time, except for complement C4 below lower limit of normal (LLN) and high sensitivity-C Reactive Protein (hs-CRP) above 0.287 mg/dL over a 6-month period (both decreased over time) and hypophenylalaninemia (blood phenylalanine concentration below 30 micromol/L) on a single measurement (increased over time). There were no dose-related trends in type or rate of laboratory abnormalities (adjusted for duration of exposure) reported during the maintenance phase in patients receiving 20 mg once daily, 40 mg once daily, or 60 mg once daily. Arthralgia episodes were more frequent during the induction/titration phase (7.4 episodes/patient-year) and decreased over time (1.4 episodes/patient-year in the maintenance phase).

Arthralgia occurred as early as after the first dose of PALYNZIQ and occurred at any time during treatment. Severe arthralgia (severe pain limiting self-care activities of daily living) was reported by 11 (4%) patients. Arthralgia episodes were managed with medications (e.g., nonsteroidal anti-inflammatory drugs, glucocorticoids, and acetaminophen), PALYNZIQ dosage reduction (4% of episodes), PALYNZIQ interruption (4% of episodes), or PALYNZIQ withdrawal (0.6% of episodes). 97% of arthralgia episodes were reported as resolved at the time of last observation (up to 77 months of follow-up).

Injection site reactions were more frequent during the induction/titration phase (21 episodes/patient-years) and decreased over time (3 episodes/patient-years in the maintenance phase). Three injection site reactions consistent with granulomatous skin lesions were reported (each reaction occurring in one patient): granulomatous dermatitis (occurred after 464 days of PALYNZIQ treatment and lasted 16 days), xanthogranuloma (occurred after 378 days of PALYNZIQ treatment and lasted 638 days) was treated with a topical antihistamine, corticosteroid, and PALYNZIQ treatment was discontinued, and necrobiosis lipoidica diabeticorum (occurred after 281 days of PALYNZIQ treatment and lasted 281 days). Necrobiosis lipoidica diabeticorum was treated with steroid injections and complicated by Pseudomonas infection.

All three injection site reactions resolved. One patient reported soft tissue infection (occurred after 196 days of PALYNZIQ treatment and lasted 8 days) associated with mesenteric panniculitis treated with antibiotics which resulted in treatment discontinuation. Generalized skin reactions were more frequent during the induction/titration phase (0.7 episodes/patient-years) and decreased over time (0.3 episodes/patient-years in the maintenance phase).

Angioedema In clinical trials, 22 out of 285 (8%) patients experienced 45 episodes of angioedema (symptoms included: pharyngeal edema, swollen tongue, lip swelling, mouth swelling, eyelid edema and face edema) occurring independent of anaphylaxis. Angioedema (included under Hypersensitivity in Table 2) was more frequent during the induction/titration phase (0.14 episodes/patient-year) and decreased over time (0.04 episodes/patient-year in the maintenance phase). Three patients discontinued treatment.

All episodes resolved. Angioedema can present as a symptom of anaphylaxis. Serum Sickness In clinical trials, serum sickness was reported in 7 out of 285 (2%) patients.

Serum sickness episodes were more frequent during the induction/titration phase (0.04 episodes/patient-year) and decreased over time (less than 0.01 episodes/patient-year during the maintenance phase). All serum sickness reactions resolved without sequelae (duration of serum sickness ranged from 1 to 8 days). Out of the 7 patients who experienced serum sickness, 5 patients continued treatment without a recurrence and managed serum sickness with drug interruption, dosage reduction and/or concomitant medication.

Two patients discontinued treatment. Patients were randomized in a 2:1 ratio to receive PALYNZIQ in an induction/titration/maintenance regimen or to continue dietary management only for 72 weeks. Of the 36 patients, anaphylaxis was reported in discontinued from the study due to anaphylaxis.

A total of 19 (53%) patients reported dose interruption and the most common adverse reactions leading to dose interruption were arthralgia (n=8) and headache (n=4). Dose reductions were reported in 9 (25%) patients and was most commonly due to arthralgia (n=4) and hypophenylalaninemia (n=3). The most common adverse reactions in patients who are 12 to less than 18 years of age (at least 20% and greater than in control) were injection site reactions, arthralgia, headache, pyrexia, hypersensitivity reactions, dizziness, nausea, vomiting, fatigue, and pain in extremity.

Table 4 lists the adverse reactions that were reported in at least 15% of patients treated with PALYNZIQ and greater than that of the diet-only arm in Study 4. Creatine Phosphokinase (CPK) Elevation: In Study 4, 14% of patients in the PALYNZIQ-treated group experienced CPK level greater than 3 times the ULN compared to 0% of patients in the diet-only group.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of PALYNZIQ. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Administration site conditions: injection site infection, cellulitis, necrosis, and abscess.

Effect of PALYNZIQ on Other PEGylated Products In a single dose study of PALYNZIQ in adult patients with PKU, two patients receiving concomitant injections of medroxyprogesterone acetate suspension (a formulation containing PEG 3350) experienced a hypersensitivity reaction. One of the two patients experienced a hypersensitivity reaction on day 15 after a single PALYNZIQ dosage of 0.67 mg within 15 minutes following medroxyprogesterone acetate injectable suspension, and subsequently experienced anaphylaxis on day 89 within 30 minutes after the next dose of medroxyprogesterone acetate injectable suspension. The other patient experienced a hypersensitivity reaction on day 40 after a single PALYNZIQ dosage of 0.08 mg within 10 minutes following medroxyprogesterone acetate injectable suspension.

Both patients had high anti-PEG IgG antibody titers at or around the time of the hypersensitivity reactions. In PALYNZIQ clinical trials, the majority of patients developed anti-PEG IgM and IgG antibodies after treatment with PALYNZIQ. The clinical effects of concomitant treatment with different PEGylated products is unknown.

Monitor patients treated with PALYNZIQ and concomitantly with other PEGylated products for hypersensitivity reactions including anaphylaxis.

Pregnancy Risk Summary Available data from pharmacovigilance and published literature with pegvaliase-pqpz use in pregnant women have not identified a clear association with major birth defects, miscarriage or other adverse maternal or fetal outcomes (see Data ). There are risks to the fetus associated with poorly controlled phenylalanine concentrations in women with PKU during pregnancy including increased risk for miscarriage, major birth defects (including microcephaly and major cardiac malformations), intrauterine fetal growth retardation, and future intellectual disability with low IQ; therefore, phenylalanine concentrations should be closely monitored in women with PKU during pregnancy (see Clinical Considerations and Data ). Advise pregnant women of the potential risks to the fetus.

A reproduction study in pregnant rabbits without PKU treated with pegvaliase-pqpz demonstrated a high incidence of fetal malformations throughout the skeletal system, and in kidneys, lungs, and eyes. Embryo-fetal toxicity (increased resorptions and reduced fetal weight) was also observed. These effects occurred at 5 times the maximum recommended daily dose and were associated with strong signs of maternal toxicity, including marked reductions in weight gain and food consumption, and death.

A reproduction study in pregnant rats without PKU treated with pegvaliase-pqpz demonstrated an increase in skeletal variations with no malformations observed. The effects in rats occurred at 2.8 times the maximum recommended daily dose. In a pre-/post-natal development study in rats, pegvaliase-pqpz produced reduced survival of offspring during lactation, decreases in pup weight and litter size, and delayed sexual maturation of offspring when administered daily at 13 times the maximum recommended daily dose.

Observed embryofetal and postnatal findings could be attributable to maternal toxicity. All pregnancies have a background risk of major birth defects, pregnancy loss, or other adverse pregnancy outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is respectively.

The estimated background risk of major birth defects and miscarriage in pregnant women with PKU who maintain blood phenylalanine concentrations greater than 600 micromol/L during pregnancy is 12-73% and 24%, respectively. There is a pregnancy surveillance program for PALYNZIQ. If PALYNZIQ is administered during pregnancy, or if a patient becomes pregnant while receiving PALYNZIQ or within one month following the last dose of PALYNZIQ, healthcare providers should report PALYNZIQ exposure by calling 1-866-906-6100.

Clinical Considerations Disease-Associated Maternal and/or Embryo-Fetal Risk Uncontrolled blood phenylalanine concentrations above 600 micromol/L before and during pregnancy are associated with an increased risk of adverse pregnancy outcomes and fetal adverse effects, including increased risk for miscarriage, major birth defects (including microcephaly and major cardiac malformations), intrauterine fetal growth retardation, and future intellectual disability with low IQ (see Data ). To reduce the risk of hyperphenylalaninemia-induced fetal adverse effects, blood phenylalanine concentrations should be maintained between 120 and 360 micromol/L during pregnancy and during the 3 months before conception. Dose Adjustments During Pregnancy and the Postpartum Period Phenylalanine concentrations below 30 micromol/L in pregnant women with PKU treated with PALYNZIQ may be associated with adverse fetal outcomes.

Monitor blood phenylalanine concentrations during pregnancy. Adjust the dosage of PALYNZIQ or modify dietary protein and phenylalanine intake to avoid blood phenylalanine concentrations below 30 micromol/L. Data Human Data Uncontrolled Maternal PKU: Available data from the Maternal Phenylketonuria Collaborative Study on 468 pregnancies and 331 live births in pregnant women with PKU demonstrated that uncontrolled phenylalanine concentrations above 600 micromol/L are associated with an increased risk for miscarriage, major birth defects (including microcephaly and major cardiac malformations), intrauterine fetal growth retardation, and future intellectual disability with low IQ.

Animal Data All developmental toxicity studies were conducted in animals (rats and rabbits) without PKU, in which treatment with pegvaliase-pqpz produced a dose-dependent reduction in maternal blood phenylalanine concentrations. At doses that produced maternal toxicity and/or effects on embryo-fetal development, the maternal plasma phenylalanine concentrations were markedly reduced compared to the control group. The contribution of maternal phenylalanine depletion to the incidence of embryo-fetal developmental effects was not evaluated.

Subcutaneous administration of 5 mg/kg/day pegvaliase-pqpz (5 times the maximum recommended daily dose based on bodyweight ) in pregnant rabbits during the period of organogenesis produced embryo-lethality (increased resorptions), marked reduction in fetal weight, and fetal malformations. The malformations included multiple external abnormalities of the head, body and limbs, multiple soft tissue malformations (reduced size or absence of kidneys, diaphragmatic hernia, corneal opacity, discoloration or reduced size of eyes, and reduced size of lungs) and multiple skeletal malformations of the craniofacial bones, vertebrae, sternebrae, ribs, pelvis, limbs, and digits. An increase in variations and delayed ossification was also observed in all skeletal regions.

The adverse developmental effects were associated with maternal toxicity, as indicated by marked impairment of weight gain and food consumption. Deaths associated with weight loss and abortion occurred in 8% of the pregnant rabbits treated with 5 mg/kg/day pegvaliase-pqpz. Subcutaneous administration of 2 mg/kg/day pegvaliase-pqpz (2 times the maximum recommended daily dose based on bodyweight ) in pregnant rabbits had no adverse effects on embryo-fetal development.

Systemic exposure to pegvaliase-pqpz was detected in fetuses from rabbits treated with 2 or 5 mg/kg/day. Pegvaliase-pqpz increased fetal alterations when administered daily in pregnant rats at doses of 8 mg/kg subcutaneously and higher (2.8 times the human steady-state area under the curve at the maximum recommended daily dose) during a 28-day premating period, mating, and through the period of organogenesis. The fetal alterations were limited to skeletal variations such as cervical ribs, bifid centra of lumbar and thoracic vertebrae, and incomplete ossification of squamosal bones, frontal bones, lumbar vertebra arch, and ribs.

Daily administration of 20 mg/kg subcutaneously (13 times the human steady-state AUC at the recommended maximum daily dose) to pregnant rats produced reductions in litter sizes and fetal weights, which was associated with maternal toxicity (decreased body weight, ovarian weight, and food consumption). The decrease in litter sizes at 20 mg/kg subcutaneously was secondary to reductions in corpora lutea and implantations. Systemic exposure to pegvaliase-pqpz was detected in fetuses from rats treated with 20 mg/kg of pegvaliase-pqpz (13 times the human steady-state AUC at the recommended maximum daily dose).

Subcutaneous administration of 2 mg/kg/day pegvaliase-pqpz (less than the human steady state AUC at the maximum recommended daily dose) in pregnant rats had no adverse effects on embryo-fetal development. Pegvaliase-pqpz decreased pup weight, litter size, and survival of offspring during lactation, and delayed sexual maturation of offspring when administered daily in rats at 20 mg/kg subcutaneously (13 times the human steady-state AUC at the recommended maximum daily dose), with dosing starting before mating and continuing through lactation. The effects in offspring were associated with maternal toxicity.

No effects in offspring were observed at 8 mg/kg/day subcutaneously (2.8 times the human steady-state AUC at the recommended maximum daily dose). A follow-up study of the same design evaluated additional parameters of physical and neurobehavioral development in offsprings; No effects of pegvaliase-pqpz were noted at the maternal NOAEL dose of 8 mg/kg/day.

Pediatric Use The safety and effectiveness of PALYNZIQ to reduce blood phenylalanine concentrations have been established in pediatric patients 12 years and older with PKU who have uncontrolled blood phenylalanine concentrations greater than 600 micromol/L on existing management. Use of PALYNZIQ for this indication is supported by evidence from Study 4, an open label randomized 2-arm study in patients who are 12 to less than 18 years of age. Incidence of eosinophil levels higher than upper limit of normal was more frequent during the induction/titration phase and decreased during the maintenance phase.

The safety and effectiveness of PALYNZIQ in pediatric patients younger than 12 years of age have not been established.