Lumizyme: Package Insert and Label Information (Page 2 of 4)

5.4 Risk of Cardiac Arrhythmia and Sudden Cardiac Death during General Anesthesia for Central Venous Catheter Placement

Administration of general anesthesia can be complicated by the presence of severe cardiac and skeletal (including respiratory) muscle weakness. Therefore, caution should be used when administering general anesthesia. Ventricular arrhythmias and bradycardia, resulting in cardiac arrest or death, or requiring cardiac resuscitation or defibrillation have been observed in infantile-onset Pompe disease patients with cardiac hypertrophy during general anesthesia for central venous catheter placement.

5.5 Risk of Antibody Development

Patients with infantile-onset Pompe disease should have a cross-reactive immunologic material (CRIM) assessment early in their disease course and be managed by a clinical specialist knowledgeable in immune tolerance induction in Pompe disease to optimize treatment. Immune tolerance induction administered prior to and in conjunction with initiation of alglucosidase alfa has been reported to aide tolerability of alglucosidase alfa in CRIM-negative patients. CRIM status has been shown to be associated with immunogenicity and patients’ responses to enzyme replacement therapies. CRIM-negative infants with infantile-onset Pompe disease treated with alglucosidase alfa have shown poorer clinical response in the presence of high sustained IgG antibody titers and positive inhibitory antibodies compared to CRIM-positive infants [see Adverse Reactions (6.2)].

In clinical studies, the majority of patients developed IgG antibodies to alglucosidase alfa, typically within 3 months of treatment. There is evidence to suggest that some patients who develop high and sustained IgG antibody titers, including CRIM-negative patients (i.e., patients in whom no endogenous GAA protein was detected by Western blot analysis and/or predicted based on the genotype), may experience reduced clinical alglucosidase alfa treatment efficacy, such as loss of motor function, ventilator dependence, or death.

5.6 Monitoring: Laboratory Tests

Patients should be monitored for IgG antibody formation every 3 months for 2 years and then annually thereafter. Testing for IgG titers may also be considered if patients develop hypersensitivity reactions, other immune-mediated reactions, or lose clinical response. Patients who experience reduced clinical response may also be tested for inhibitory antibody activity. Patients who experience anaphylactic or hypersensitivity reactions may also be tested for IgE antibodies to alglucosidase alfa and other mediators of anaphylaxis [see Adverse Reactions (6.2)].

Testing services for antibodies against alglucosidase alfa are available through Genzyme Corporation. Contact Genzyme Corporation at 1-800-745-4447 for information on testing.

6 ADVERSE REACTIONS

6.1 Clinical Trials 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 clinical practice.

The following serious adverse reactions are described below and elsewhere in the labeling:

In clinical trials, the most common adverse reactions (≥5%) following alglucosidase alfa treatment were hypersensitivity reactions, and included anaphylaxis, rash, pyrexia, flushing/feeling hot, urticaria, headache, hyperhidrosis, nausea, cough, decreased oxygen saturation, tachycardia, tachypnea, chest discomfort, dizziness, muscle twitching, agitation, cyanosis, erythema, hypertension/increased blood pressure, pallor, rigors, tremor, vomiting, fatigue, and myalgia.

Clinical Trials in Infantile-Onset and Juvenile-Onset Pompe Disease

Two multicenter, open-label clinical trials were conducted in 39 infantile-onset Pompe disease patients, ages 1 month to 3.5 years old. Approximately half of the patients (54%) were male. Patients were treated with alglucosidase alfa 20 or 40 mg/kg every other week for periods ranging from 1 to 106 weeks (mean: 61 weeks).

The most serious adverse reactions reported with alglucosidase alfa treatment included anaphylaxis and acute cardiorespiratory failure.

The most common adverse reactions requiring intervention in clinical trials were hypersensitivity reactions, occurring in 20 of 39 (51%) patients treated with alglucosidase alfa, and included rash, pyrexia, urticaria, flushing, decreased oxygen saturation, cough, tachypnea, tachycardia, hypertension/increased blood pressure, pallor, rigors, vomiting, cyanosis, agitation, and tremor. These reactions were more likely to occur with higher infusion rates. Some patients who were pretreated with antihistamines, antipyretics and/or corticosteroids still experienced hypersensitivity reactions.

Table 2 summarizes all adverse reactions occurring in ≥5% of patients (2 or more patients) treated with alglucosidase alfa in clinical trials described above.

Table 2: Adverse Reactions that Occurred in at Least 5% of Infantile-Onset Patients Treated with Alglucosidase Alfa in Clinical Trials
Number of Patients(N=39)n (%)
Adverse Reaction 20 (51)
Rash (including rash erythematous, rash macular and maculopapular) 7 (18)
Pyrexia 6 (15)
Urticaria 5 (13)
Flushing 5 (13)
Hypertension/Increased Blood Pressure 4 (10)
Decreased Oxygen Saturation 3 (8)
Cough 3 (8)
Tachypnea 3 (8)
Tachycardia 3 (8)
Erythema 2 (5)
Vomiting 2 (5)
Rigors 2 (5)
Pallor 2 (5)
Cyanosis 2 (5)
Agitation 2 (5)
Tremor 2 (5)

An open-label, single-center trial was conducted in 18 treatment-naive infantile-onset Pompe disease patients who were treated exclusively with alglucosidase alfa. Adverse reactions observed in these patients were similar to infantile-onset Pompe disease patients who received alglucosidase alfa in other clinical trials.

Additional hypersensitivity reactions observed in infantile-onset Pompe disease patients treated in other clinical trials and expanded access programs with alglucosidase alfa included livedo reticularis, irritability, retching, increased lacrimation, ventricular extrasystoles, nodal rhythm, rales, respiratory tract irritation, and cold sweat.

Safety was also evaluated in 99 patients (51 male, 48 females) with Pompe disease in an ongoing, open-label, prospective study in patients 12 months of age and older who were previously treated with the 160 L scale of alglucosidase alfa and switched to the 4000 L scale of alglucosidase alfa. Patients were aged 1 to 18 years with a median duration of treatment of 437 days (range 13 to 466 days). No new safety findings were observed following the switch to 4000 L scale of alglucosidase alfa.

Clinical Trials in Late-Onset Pompe Disease

Assessment of adverse reactions in patients with late-onset Pompe disease is based on the exposure of 90 patients (45 male, 45 female), aged 10 to 70 years, to 20 mg/kg alglucosidase alfa or placebo in a randomized, double-blind, placebo-controlled trial. The youngest alglucosidase alfa-treated patient was 16 years of age, and the youngest placebo-treated patient was 10 years of age. All patients were naive to enzyme replacement therapy. Patients were randomized in a 2:1 ratio and received alglucosidase alfa or placebo every other week for 78 weeks (18 months). The study population included 34 males and 26 females (n=60) in the alglucosidase alfa group and 11 males and 19 females (n=30) in the placebo group. Two patients receiving alglucosidase alfa discontinued the trial due to anaphylactic reactions.

Serious adverse reactions reported with alglucosidase alfa included anaphylaxis, which presented as angioedema, throat tightness and chest pain/discomfort. One patient with a history of Wolff-Parkinson-White syndrome experienced a serious adverse reaction of supraventricular tachycardia.

The most common adverse reactions (≥3%; 2 or more patients) observed in alglucosidase alfa-treated patients were hypersensitivity reactions and included anaphylaxis, headache, nausea, urticaria, dizziness, chest discomfort, vomiting, hyperhidrosis, flushing/feeling hot, increased blood pressure, paresthesia, pyrexia, local swelling, diarrhea, pruritus, rash, and throat tightness.

Delayed-onset reactions, defined as adverse reactions occurring 2 to 48 hours after completion of alglucosidase alfa infusion, that were observed in ≥3% more patients in the alglucosidase alfa-treated group compared to patients in the placebo-treated group in the controlled trial, included hyperhidrosis. Additional delayed-onset reactions occurring in alglucosidase alfa-treated patients included fatigue, myalgia, and nausea. Patients should be counseled about the possibility of delayed-onset hypersensitivity reactions and given proper follow-up instructions.

Table 3 summarizes the most common adverse reactions that occurred in at least 3% of alglucosidase alfa-treated patients and with a higher incidence than the placebo-treated patients during the randomized, double-blind, placebo-controlled study described above.

Table 3: Adverse Reactions Occurring in at Least 3% of Alglucosidase Alfa-Treated Late-Onset Patients and with a Higher Incidence than the Placebo-Treated Patients
Adverse Reaction Alglucosidase Alfan=60N (%) Placebon=30N (%)
Hyperhidrosis 5 (8.3) 0 (0)
Urticaria 5 (8.3) 0 (0)
Anaphylaxis 4 (6.7) 0 (0)
Chest Discomfort 4 (6.7) 1 (3.3)
Muscle Twitching 4 (6.7) 1 (3.3)
Myalgia 3 (5.0) 1 (3.3)
Flushing/Feeling Hot 3 (5.0) 0 (0)
Increased Blood Pressure 3 (5.0) 0 (0)
Vomiting 3 (5.0) 0 (0)
Edema, Peripheral 2 (3.3) 0 (0)
Pruritus 2 (3.3) 0 (0)
Rash Papular 2 (3.3) 0 (0)
Throat Tightness 2 (3.3) 0 (0)

In clinical trials, anaphylaxis and hypersensitivity reactions were managed with infusion interruption, decreased infusion rate, administration of antihistamines, corticosteroids, intravenous fluids, and/or oxygen, when clinically indicated. In some cases of anaphylactic reactions, epinephrine was administered. Patients who have experienced anaphylaxis or hypersensitivity reactions should be treated with caution when they are readministered alglucosidase alfa.

6.2 Immunogenicity

As with all therapeutic proteins, there is potential for immunogenicity. The detection of antibody formation is highly dependent on the sensitivity and specificity of the assay. Additionally, the observed incidence of antibody (including neutralizing antibody) positivity in an assay may be influenced by several factors including assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease. For these reasons, comparison of the incidence of antibodies in the studies described below with the incidence of antibodies in other studies or to other alglucosidase alfa products may be misleading.

In the two clinical trials in infantile-onset patients, the majority of patients (34 of 38; 89%) tested positive for IgG antibodies to alglucosidase alfa. There is evidence to suggest that some patients who develop high sustained titers of anti-alglucosidase alfa antibodies may experience reduced clinical efficacy to alglucosidase alfa treatment [see Warnings and Precautions (5.5)]. Some IgG-positive patients in clinical trials who were retrospectively evaluated for the presence of inhibitory antibodies tested positive for inhibition of enzyme activity and/or uptake in in vitro assays. Furthermore, CRIM-negative infants have shown reduced clinical effect in the presence of high sustained IgG antibody titers with inhibitory activity [see Warnings and Precautions (5.5)]. Alglucosidase alfa-treated patients who experience a decrease in motor function should be tested for the presence of inhibitory antibodies that neutralize enzyme uptake or activity.

Immunogenicity data from clinical trials and published literature in CRIM-negative, infantile-onset Pompe disease patients suggest that the administration of an immune tolerance induction regimen individualized to alglucosidase alfa–naive patients may be effective in preventing or reducing the development of high sustained antibody titer against alglucosidase alfa.

In the randomized, double-blind, placebo-controlled trial in late-onset patients, all alglucosidase alfa-treated patients with available samples (N=59, 100%) developed IgG antibodies to alglucosidase alfa. These patients were all CRIM positive, consistent with late-onset Pompe disease. Most patients who developed IgG antibodies did so within the first 3 months of exposure (median time to seroconversion was 4 weeks). There was no apparent association between mean or peak IgG antibody titers and the occurrence of adverse reactions.

None of the 59 evaluable patients tested positive for inhibition of enzyme activity. Antibody titers for cellular uptake inhibition were present in 18 of 59 (31%) patients by Week 78. All other patients tested negative for inhibition of cellular uptake. Patients who tested positive for uptake inhibition tended to have higher IgG titers than patients who tested negative for uptake inhibition. Among the 32 patients with evaluable pharmacokinetic (PK) samples, 5 patients tested positive for uptake inhibition. The clinical relevance of this in vitro inhibition is not fully understood. The clearance values for 4 of these 5 patients were approximately 1.2-fold to 1.8-fold greater in the presence of inhibitory antibodies (Week 52) as compared to in the absence of inhibitory antibodies (Week 0) [see Clinical Pharmacology (12.3)].

Some patients in the clinical studies or in the postmarketing setting have undergone testing for alglucosidase alfa-specific IgE antibodies. Testing was performed in patients who experienced moderate to severe or recurrent hypersensitivity reactions, for which mast-cell activation was suspected. Some of the patients who tested positive for alglucosidase alfa-specific IgE antibodies experienced anaphylactic reactions [see Boxed Warning and Warnings and Precautions (5.1)].

Some patients who tested positive for alglucosidase alfa-specific IgE antibodies and experienced hypersensitivity reactions were able to be rechallenged with alglucosidase alfa using a slower infusion rate at lower starting doses and have continued to receive treatment under close clinical supervision [see Warnings and Precautions (5.1)]. Since patients who develop IgE antibodies to alglucosidase alfa appear to be at a higher risk for developing anaphylaxis and hypersensitivity reactions, these patients should be monitored more closely during administration of alglucosidase alfa.

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