Delandistrogene Moxeparvovec-Rokl

For single-dose intravenous infusion only. ELEVIDYS is for single-dose intravenous infusion only. Select patients for treatment with ELEVIDYS with anti-AAVrh74 total binding antibody titers <1:400, as measured by an FDA authorized test. ( 2.1 ) Postpone in patients with active or recent (within 4 weeks) infections. ( 2.1 ) Assess liver function, platelet counts and troponin-I before ELEVIDYS infusion. ( 2.1 ) Recommended dosage: 10 to 70 kg: 1.33 × 10 14 vector genomes (vg) per kg of body weight; 70 kg or greater: 9.31 × 10 15 vg. ( 2.2 ) One day prior to infusion, initiate a corticosteroid regimen for a minimum of 60 days. Recommend modifying corticosteroid dose for patients with liver function abnormalities. ( 2.2 ) Administer as an intravenous infusion over 1-2 hours. Infuse at a rate of less than 10 mL/kg/hour. ( 2.4 )

2.1 Critical Dosing Information Instruct patients to maintain proximity to an appropriate healthcare facility, as determined by the healthcare provider, for at least 2 months following ELEVIDYS infusion. Prior to ELEVIDYS infusion: Select patients for treatment with ELEVIDYS with anti-AAVrh74 total binding antibody titers <1:400, as measured by an FDA authorized test. Information on FDA authorized tests is available at http://www.fda.gov/companiondiagnostics. Do not administer ELEVIDYS to patients with elevated anti-AAVrh74 total binding antibody titers (≥1:400) [Clinical Pharmacology ( 12.6 )] . Due to the increased risk of serious systemic immune response, postpone ELEVIDYS in patients with active or recent (within 4 weeks) infections [see Warnings and Precautions ( 5.2 )]. Assess liver function (clinical examination and laboratory testing including aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), albumin, activated partial thromboplastin time (aPTT), international normalized ratio (INR), and total bilirubin) [see Dosage and Administration ( 2.4 ), Warnings and Precautions ( 5.1 ), Use in Specific Populations ( 8.6 )] . Obtain platelet count and troponin-I levels [see Dosage and Administration ( 2.4 ), Warnings and Precautions ( 5.3 )] . Do not re-administer ELEVIDYS.

2.2 Recommended Dose The recommended dose of ELEVIDYS is 1.33 × 10 14 vector genomes per kilogram (vg/kg) of body weight (or 10 mL/kg body weight) for patients weighing less than 70 kg or 9.31 × 10 15 vg total fixed dose for patients weighing 70 kg or greater. For the number of vials required, refer to Table 10 [see How Supplied/Storage and Handling ( 16.1 )] . Calculate the dose as follows: ELEVIDYS dose (in mL) = patient body weight (rounded to the nearest kilogram) x 10 The multiplication factor 10 represents the per kilogram dose (1.33 × 10 14 vg/kg) divided by the amount of vector genome copies per mL of the ELEVIDYS suspension (1.33 × 10 13 vg/mL). Number of ELEVIDYS vials needed = ELEVIDYS dose (in mL) divided by 10. Example: Calculation of volume needed for a 19.5 kg patient 19.5 kg rounded to the nearest kilogram = 20 kg 20 kg × 10 = 200 mL Number of ELEVIDYS vials needed = 200 divided by 10, rounded to the nearest number of vials = 20 vials Administer corticosteroids to reduce the risk of immune responses to the AAVrh74 vector after administration of ELEVIDYS [see Clinical Pharmacology ( 12.6 )] . Start corticosteroids 1 day prior to ELEVIDYS infusion based on the schedule outlined in Table 1 below. Continue this regimen for a minimum of 60 days after the infusion, unless earlier tapering is clinically indicated. Table 1: Recommended pre- and post-infusion oral corticosteroid dosing a Patient continues to receive this dose b Corticosteroids other than prednisone and prednisolone have not been studied for use as a peri-ELEVIDYS infusion corticosteroid Baseline corticosteroid dosing a Peri-ELEVIDYS infusion corticosteroid dose (prednisone equivalent) b Recommended maximum total daily oral dose (prednisone equivalent) b Daily or intermittent dose Start 1 day prior to infusion: 1 mg/kg/day (and continue baseline dose) 60 mg/day High dose for 2 days per week Start 1 day prior to infusion: 1 mg/kg/day taken on days without high-dose corticosteroid treatment (and continue baseline dose) 60 mg/day Not on corticosteroids Start 1 week prior to infusion: 1.5 mg/kg/day 60 mg/day Modify oral corticosteroid doses according to Table 2 for patients with liver function abnormalities (e.g., GGT >= 3 times baseline, total bilirubin > ULN) following ELEVIDYS infusion. Consider IV bolus corticosteroids instead of oral corticosteroids for GGT or bilirubin elevations that do not respond after 1 week of increased oral corticosteroids. Consult with a specialist experienced in immunosuppressive therapy for additional interventions as needed. Obtain prompt consultation with a specialist (e.g., gastroenterologist or hepatologist) if acute serious liver injury or impending acute liver failure is suspected. Taper the additional peri-ELEVIDYS corticosteroids for patients previously taking corticosteroids at baseline back to baseline dose over 2 weeks, or longer as needed. Taper the peri-ELEVIDYS corticosteroids for patients not previously taking corticosteroids at baseline back to no corticosteroids over 4 weeks, or longer as needed. Do not stop corticosteroids abruptly. Table 2: Recommended oral corticosteroid regimen dose modification for liver function abnormalities following ELEVIDYS infusion a Peri-ELEVIDYS infusion corticosteroid dosing Modified oral corticosteroid dose following ELEVIDYS infusion (prednisone equivalent) b c Recommended maximum total daily oral dose (prednisone equivalent) b c a GGT >= 3 times baseline and/or other clinically significant liver function abnormalities (e.g., total bilirubin > ULN) following infusion. b Consider IV bolus corticosteroids instead of oral corticosteroids for GGT or bilirubin elevations that do not respond after 1 week of increased oral corticosteroids. Consult with a specialist experienced in immunosuppressive therapy for additional interventions as needed. c Corticosteroids other than prednisone and prednisolone have not been studied for use as a peri-ELEVIDYS infusion corticosteroid. Baseline + 1 mg/kg/day Increase to 2 mg/kg/day (and continue baseline dose) 120 mg/day Baseline + 1 mg/kg/day taken on days without high-dose corticosteroid treatment Increase to 2 mg/kg/day taken on days without high-dose corticosteroid treatment (and continue baseline dose) 120 mg/day 1.5 mg/kg/day Increase from 1.5 mg/kg/day to 2.5 mg/kg/day 120 mg/day 2.3 Preparation General precautions Prepare ELEVIDYS using aseptic technique. Verify the required dose of ELEVIDYS based on the patient's body weight. Confirm that the kit contains sufficient number of vials to prepare the ELEVIDYS infusion for the patient. Visually inspect parenteral drug products for particulate matter and discoloration prior to administration, whenever suspension and container permit. ELEVIDYS may contain white to off-white particles. Recommended supplies and materials: 60 mL siliconized polypropylene syringes 21-gauge maximum or smaller stainless steel needles Preparing ELEVIDYS infusion Thaw ELEVIDYS before use. When thawed in the refrigerator, ELEVIDYS vials are stable for up to 14 days in the refrigerator (2°C to 8°C [36º F to 46º F]) when stored in the upright position. Frozen ELEVIDYS vials will thaw in approximately 2 hours when placed at room temperature (up to 25°C [77ºF]) when removed from original packaging. Thawed ELEVIDYS is stable for up to 24 hours at room temperature (up to 25°C [77ºF]). Inspect vials to ensure no ice crystals are present prior to preparation. When thawed, swirl gently. Do not shake. Do not refreeze. Do not place back in the refrigerator. Visually inspect each vial of ELEVIDYS. ELEVIDYS is a clear, colorless liquid that may have some opalescence. ELEVIDYS may contain white to off-white particles. Do not use if the suspension in the vials is cloudy or discolored. Remove the plastic flip-off cap from the vials and disinfect the rubber stopper with a sterilizing agent (e.g., alcohol wipes). Withdraw 10 mL of ELEVIDYS from each vial provided in the customized ELEVIDYS kit (refer to Table 10 ). Do not use filter needles during preparation of ELEVIDYS. Multiple syringes will be required to withdraw the required volume. Remove air from the syringes and cap the syringes. Maintain syringes at room temperature prior to and during administration.

2.4 Administration Recommended supplies and materials: Syringe infusion pump 0.2-micron PES* in-line filter with a large surface area. To avoid the risk of occlusions, the use of smaller pediatric in-line filters (e.g., less than 10 cm 2 surface area) is not recommended. PVC* (non-DEHP*) IV infusion tubing, and polyurethane catheter *PVC = Polyvinyl chloride, DEHP = Di(2-ethylhexyl) phthalate, PES = Polyether sulfone Administer ELEVIDYS as a single-dose intravenous infusion through a peripheral venous catheter: ELEVIDYS should be administered in a setting where treatment for infusion-related reactions is immediately available [see Warnings and Precautions ( 5.4 )] . Do not infuse ELEVIDYS at a rate of 10 mL/kg/hour or faster. Consider application of a topical anesthetic to the infusion site prior to administration of IV insertion. Recommend inserting a back-up catheter. Flush the intravenous access line with 0.9% Sodium Chloride Injection prior to the ELEVIDYS infusion at the same infusion rate. Administer ELEVIDYS via intravenous infusion using a syringe infusion pump with an in-line 0.2-micron filter at a duration of approximately 1 to 2 hours, or longer at care team discretion, through a peripheral limb vein. Infuse at a rate of less than 10 mL/kg/hour. Do not administer ELEVIDYS as an intravenous push. Do not infuse ELEVIDYS in the same intravenous access line with any other product. Use ELEVIDYS within 12 hours after drawing into syringe. Discard the ELEVIDYS-containing syringe(s) if infusion of the drug has not been completed within the 12-hour timeframe. In the event of an infusion-related reaction during administration [see Warnings and Precautions ( 5.4 )]: Slow or stop the infusion based on patient's clinical presentation. Discontinue infusion for anaphylaxis. Administer treatment as needed to manage infusion-related reaction. ELEVIDYS infusion may be restarted at a lower rate after the infusion-related reaction has resolved at the discretion of the physician, based on severity of patient's clinical presentation. If the ELEVIDYS infusion needs to be stopped and restarted, ELEVIDYS should be infused within 12 hours after drawing into the syringe [see How Supplied/Storage and Handling ( 16.2 )] . Flush the intravenous access line with 0.9% Sodium Chloride Injection after the ELEVIDYS infusion. Discard unused ELEVIDYS [see How Supplied/Storage and Handling ( 16.2 )]. Dispose of the needle and syringe [see How Supplied/Storage and Handling ( 16.2 )]. Monitoring Post-ELEVIDYS Administration Assess liver function (clinical exam, AST, ALT, GGT, albumin, aPTT, INR, and total bilirubin) weekly for the first 3 months. Continue monitoring if clinically indicated, until results are unremarkable (e.g., normal clinical exam, GGT and total bilirubin levels return to near baseline levels) [see Warnings and Precautions ( 5.1 ), Specific Populations ( 8.6 )] . Obtain platelet counts weekly for the first two weeks [see Adverse Reactions ( 6.1 )] . Continue monitoring if clinically indicated. Measure troponin-I weekly for the first month [see Warnings and Precautions ( 5.3 )] . Continue monitoring if clinically indicated, until results return to near baseline levels or stabilize.

5 WARNINGS AND PRECAUTIONS Serious Infections: Serious infections with fatal outcomes may occur due to concomitant administration of corticosteroids, additional immunosuppressants, and ELEVIDYS. Monitor patients for signs and symptoms of infection; treat appropriately. ( 5.2 ) Myocarditis: Acute, serious, life-threatening myocarditis and troponin-I elevations have been observed. Monitor troponin-I before ELEVIDYS infusion, and weekly for the first month after ELEVIDYS infusion. ( 5.3 ) Infusion-related Reactions: Infusion-related reactions, including hypersensitivity reactions and anaphylaxis, have occurred. Monitor during administration and for at least 3 hours after end of infusion. If symptoms occur, slow or stop the infusion and give appropriate treatment. Once symptoms resolve, restart infusion at a slower infusion rate. Discontinue infusion for anaphylaxis. ( 2.4 , 5.4 ) Immune-mediated Myositis: Severe to life-threatening immune-mediated myositis has been reported with ELEVIDYS in patients with deletions including portions of exons 1 to 17 and /or exons 59 to 71 of the DMD gene. Consider additional immunomodulatory treatment if symptoms of myositis occur (e.g., unexplained increased muscle pain, tenderness, or weakness). ( 5.5 ) Pre-existing Immunity against AAVrh74: Perform baseline testing for presence of anti-AAVrh74 total binding antibodies prior to ELEVIDYS administration. ( 5.6 )

5.1 Acute Serious Liver Injury and Acute Liver Failure Acute serious liver injury marked by elevations of liver enzymes (e.g., GGT, ALT) and total bilirubin and acute liver failure, has occurred with ELEVIDYS. Onset of the liver injury typically begins within 8 weeks after administration of ELEVIDYS. In non-ambulatory patients treated with ELEVIDYS, acute liver failure with fatal outcome has occurred in the clinical and post-marketing settings. Life-threatening mesenteric vein thrombosis, complicated by bowel ischemia and necrosis, and portal hypertension have been reported following acute liver injury associated with ELEVIDYS in a non-ambulatory patient [see Adverse Reactions ( 6.2 )] . Patients with preexisting liver impairment, chronic hepatic condition, or acute liver disease (e.g., acute hepatic viral infection) may be at higher risk of acute serious liver injury or acute liver failure. Postpone ELEVIDYS administration in patients with acute liver disease until resolved or controlled. Patients with hepatic impairment, acute liver disease, chronic hepatic condition or elevated GGT have not been studied in clinical trials with ELEVIDYS [see Specific Populations ( 8.6 )] . In clinical studies, liver function test increased (including increases in GGT, ALT, AST, or total bilirubin) was commonly reported typically within 8 weeks following ELEVIDYS infusion, with the majority of cases being asymptomatic [see Adverse Reactions ( 6.1 )] . Most cases resolved spontaneously or with systemic corticosteroids and resolved without clinical sequelae within 2 months. Prior to ELEVIDYS administration, perform liver enzyme test [see Dosage and Administration ( 2.1 )] . Monitor liver function (clinical examination, AST, ALT, GGT, albumin, aPTT, INR, and total bilirubin) weekly for the first 3 months following ELEVIDYS infusion. Continue monitoring if clinically indicated, until results are unremarkable (e.g., normal clinical exam, GGT and total bilirubin levels return to near baseline levels) [see Dosage and Administration ( 2.4 )] . Systemic corticosteroid treatment is recommended for patients before and after ELEVIDYS infusion [see Dosage and Administration ( 2.2 )] . Adjust corticosteroid regimen when indicated [see Dosage and Administration ( 2.2 )] . Obtain prompt consultation with a specialist (e.g., gastroenterologist or hepatologist) if acute serious liver injury or impending acute liver failure is suspected.

5.2 Serious Infections Increased susceptibility to serious infections may occur due to concomitant administration of corticosteroid regimen and additional immunosuppressants, and ELEVIDYS. Serious respiratory infections, including with fatal outcomes, have occurred in patients taking immunosuppressant corticosteroids required for ELEVIDYS administration [see Adverse Reactions ( 6.2 )] . Monitor patients for signs and symptoms of infection before and after ELEVIDYS administration and treat appropriately. Administer immunizations according to best clinical practices and immunization guidelines prior to initiation of the corticosteroid regimen required before ELEVIDYS infusion [see Drug Interactions ( 7 )] . Avoid administration of ELEVIDYS to patients with active infections.

5.3 Myocarditis Acute, serious, life-threatening myocarditis and troponin-I elevations have been observed within 24 hours to more than 1 year following ELEVIDYS infusion [see Adverse Reactions ( 6.1 ) ]. If a patient experiences myocarditis, those with pre-existing left ventricle ejection fraction (LVEF) impairment may be at higher risk of adverse outcomes. Patients with moderate to severe LVEF impairment have not been studied in clinical trials with ELEVIDYS. Monitor troponin-I before ELEVIDYS infusion and weekly for the first month following infusion [see Dosage and Administration ( 2.4 )] . Continue monitoring if clinically indicated, until results return to near baseline levels or stabilize. More frequent monitoring may be warranted in the presence of cardiac symptoms, such as chest pain or shortness of breath. Advise patients to contact a physician immediately if they experience cardiac symptoms.

5.4 Infusion-related Reactions Infusion-related reactions, including hypersensitivity reactions and anaphylaxis, have occurred during or up to several hours following ELEVIDYS administration. Closely monitor patients during and for at least 3 hours after the end of infusion for signs and symptoms of infusion-related reactions including tachycardia, tachypnea, lip swelling, difficulty breathing, nasal flaring, urticaria, flushing, lip pruritus, rash, cheilitis, vomiting, nausea, rigors and pyrexia. ELEVIDYS should be administered in a setting where treatment for infusion-related reactions is immediately available. In the event of an infusion-related reaction, administration of ELEVIDYS may be slowed or stopped based on the severity of the patient's clinical presentation. Administer treatment as needed to manage infusion-related reactions based on the severity of patient's signs and symptoms. [see Dosage and Administration ( 2.4 )] . If the infusion was stopped, ELEVIDYS infusion may be restarted at a lower rate once patient's symptoms have resolved, at the discretion of the physician. Discontinue infusion for anaphylaxis.

5.5 Immune-mediated Myositis Immune-mediated myositis, including serious and life-threatening events, has occurred approximately 1 month following ELEVIDYS infusion [see Adverse Reactions ( 6 ) ]. Signs and symptoms include severe muscle weakness, including dysphagia, dyspnea, dysphonia, and hypophonia. These immune reactions may be due to a T-cell based response against specific regions of the micro-dystrophin transgenic protein. Severe to life-threatening immune-mediated myositis has been reported in patients with deletions including portions of exons 1-17 and/or exons 59-71 of the DMD gene. ELEVIDYS is contraindicated in patients with any deletion in exon 8 and/or exon 9, including a deletion of any portion or the entirety of these exons, in the DMD gene due to the increased risk for a severe immune-mediated myositis reaction [see Contraindications ( 4 )] . Regardless of genetic mutation, advise patients to contact a physician immediately if they experience any unexplained increased muscle pain, tenderness, or weakness, including dysphagia, dyspnea, dysphonia, or hypophonia as these may be symptoms of myositis. Consider additional immunomodulatory treatment based on patient's clinical presentation and medical history if these symptoms occur.

5.6 Pre-existing Immunity against AAVrh74 In AAV-vector based gene therapies, preexisting anti-AAV antibodies may impede transgene expression at desired therapeutic levels. Following treatment with ELEVIDYS all patients developed anti-AAVrh74 antibodies. Perform baseline testing for the presence of anti-AAVrh74 total binding antibodies prior to ELEVIDYS administration [see Dosage and Administration ( 2.1 )] . ELEVIDYS administration is not recommended in patients with elevated anti-AAVrh74 total binding antibody titers (≥1:400).

12.1 Mechanism of Action ELEVIDYS is the recombinant gene therapy product that is comprised of a non-replicating, recombinant, adeno-associated virus (AAV) serotype rh74 (AAVrh74) capsid and a single-stranded DNA expression cassette flanked by inverted terminal repeats (ITRs) derived from AAV2. The cassette contains: 1) an MHCK7 gene regulatory component comprising a creatine kinase 7 promoter and an α-myosin heavy chain enhancer, and 2) the DNA transgene encoding the engineered micro-dystrophin protein. Vector/Capsid: Clinical and nonclinical studies have demonstrated AAVrh74 serotype transduction in skeletal muscle cells. Additionally, in nonclinical studies, AAVrh74 serotype transduction has been demonstrated in cardiac and diaphragm muscle cells. Promoter: The MHCK7 promoter/enhancer drives transgene expression and has been shown in animal models to drive transgenic micro-dystrophin protein expression predominantly in skeletal muscle (including diaphragm) and cardiac muscle. In clinical studies, muscle biopsy analyses have confirmed micro-dystrophin expression in skeletal muscle. Transgene: DMD is caused by a mutation in the DMD gene resulting in lack of functional dystrophin protein. ELEVIDYS carries a transgene encoding a micro-dystrophin protein consisting of selected domains of dystrophin expressed in normal muscle cells. ELEVIDYS micro-dystrophin has been demonstrated to localize to the sarcolemma.

12.2 Pharmacodynamics In 92 patients who received ELEVIDYS in clinical studies, micro-dystrophin protein expression from muscle biopsies (gastrocnemius or biceps brachii) was quantified by western blot and localized by immunofluorescence staining (fiber intensity and percentage micro-dystrophin). Micro-dystrophin expression (expressed as change from baseline) in ELEVIDYS-treated patients as measured by western blot was the primary objective of Study 1 and Study 2, and a key secondary objective for Study 3. Muscle biopsies were obtained at baseline prior to ELEVIDYS infusion and at Week 12 after ELEVIDYS infusion in all patients. The absolute quantity of micro-dystrophin was measured by western blot assay, adjusted by muscle content and expressed as a percent of control (levels of wild-type dystrophin in patients without DMD or Becker muscular dystrophy) in muscle biopsy samples. Study 1 and 2 results of patients receiving 1.33 × 10 14 vg/kg ELEVIDYS are presented in Table 5 . Table 5. Micro-Dystrophin Expression in Study 1 and Study 2 at Week 12 from Baseline (Western Blot Assay) abc Western blot (% of micro-dystrophin compared to control) Study 1 Part 1 (n=6) Study 1 Part 2 (n=21) Study 2 Ambulatory (n=40) a All patients received 1.33 x 10 14 vg/kg, as measured by ddPCR b Change from baseline was statistically significant c Adjusted for muscle content. Control was level of wild-type (normal) dystrophin in normal muscle. Mean change from baseline (SD) 43.4 (48.6) 40.7 (32.3) 51.0 (47) Median change from baseline (Min, Max) 24.3 (1.6, 116.3) 40.8 (0.0, 92.0) 46.9 (1.9, 197.3) In Study 3 Part 1, muscle biopsies were obtained at Week 12 in 31 patients. For the ELEVIDYS-treated patients, the mean micro-dystrophin expression at Week 12 was 34.3% (N=17, SD: 41.0%), compared to placebo patients of 0% (N=14, SD: 0%). Assessment of micro-dystrophin levels can be meaningfully influenced by differences in sample processing, analytical technique, reference materials, and quantitation methodologies. Therefore, valid comparisons of micro-dystrophin measurements obtained from different assays cannot be made.

12.3 Pharmacokinetics Vector Distribution and Vector Shedding Nonclinical Data Biodistribution of ELEVIDYS was evaluated in tissue samples collected from healthy mice and DMD mdx mice following intravenous administration in toxicology studies. At 12 weeks following ELEVIDYS administration at dose levels of 1.33 ×10 14 to 4.02 ×10 14 vg/kg, vector DNA was detected in all major organs with the highest quantities detected in the liver, followed by lower levels in the heart, adrenal glands, skeletal muscle, and aorta. ELEVIDYS was also detected at low levels in the spinal cord, sciatic nerve and gonads (testis). Protein expression of micro-dystrophin was highest in cardiac tissue, exceeding physiologic dystrophin expression levels in healthy mice, with lower levels in the skeletal muscle and diaphragm. In some studies, micro-dystrophin was also detected at low levels in the liver. Clinical Data Following IV administration, ELEVIDYS vector genome undergoes distribution via systemic circulation and distributes into target muscle tissues followed by elimination in the urine and feces. ELEVIDYS biodistribution and tissue transduction are detected in the target muscle tissue groups and quantified in the gastrocnemius or biceps femoris biopsies obtained from patients with mutations in the DMD gene. Evaluation of ELEVIDYS vector genome exposure in clinical muscle biopsies at Week 12 post-dose expressed as copies per nucleus revealed ELEVIDYS drug distribution and transduction with a mean change from baseline of 2.91 and 3.44 copies per nucleus at the recommended dose of 1.33 × 10 14 vg/kg for Study 1 and Study 2 Cohort 1, respectively. In Study 2 Cohorts 1-3, the biodistribution and vector shedding of ELEVIDYS in the serum and excreta were quantified, respectively. The mean maximum concentration (C max ) in the serum was 0.0055 × 10 13 copies/mL and 2.78 × 10 6 copies/mL in the urine, 7.86 × 10 7 copies/mL in the saliva, and 4.87 × 10 7 copies/μg in the feces. The median time to achieve maximum concentration (T max ) was 5.8 hours post-dose in the serum, followed by 6.7 hours, 6.5 hours and 13 days post-dose in the saliva, urine, and feces, respectively. The median time to achieve first below limit of quantification (BLOQ) sample followed by 2 consecutive BLOQ samples was 55 days post-dose for serum. The median time to achieve complete elimination as the first below limit of detection (BLOD) sample followed by 2 consecutive BLOD samples were 49.8 days, 78 days and 162 days post-dose for saliva, urine and feces, respectively. The estimated elimination half-life of ELEVIDYS vector genome in the serum is approximately 12 hours, and the majority of the drug is expected to be cleared from the serum by 1-week post-dose. In the excreta, the estimated elimination half-life of ELEVIDYS vector genome is approximately 40 hours, 55 hours, and 60 hours in the urine, feces, and saliva, respectively. As an AAV-based gene therapy that consists of a protein capsid containing the transgene DNA genome of interest, ELEVIDYS capsid proteins are broken down through proteasomal degradation following AAV entry into target cells. As such, ELEVIDYS is not likely to exhibit the drug-drug interaction potential mediated by known drug metabolizing enzymes (cytochrome P450-based) and drug transporters.

12.6 Immunogenicity The observed incidence of anti-AAVrh74 antibodies is highly dependent on the sensitivity and specificity of the assay. Differences in assay methods preclude meaningful comparisons of the incidence of anti-AAVrh74 antibodies in the studies described below with the incidence of anti-AAVrh74 antibodies in other studies. In ELEVIDYS clinical studies, patients were required to have baseline anti-AAVrh74 total binding antibodies of <1:400, measured using an investigational total binding antibody enzyme-linked immunosorbent assay (ELISA), and only patients with baseline anti-AAVrh74 total binding antibodies <1:400 were enrolled in those studies. Across clinical studies evaluating a total of 156 patients, elevated anti-AAVrh74 total binding antibodies titers were observed in all patients following a one-time ELEVIDYS infusion. Anti-AAVrh74 total binding antibody titers reached at least 1:3200 in every patient, and the maximum titers exceeded 1:26,214,400 in certain patients. The safety of re-administration of ELEVIDYS or any other AAVrh74 vector-based gene therapy in the presence of high anti-AAVrh74 total binding antibody titer has not been evaluated in humans [see Warnings and Precautions ( 5.6 )] . There is insufficient data to assess whether the observed anti-AAVrh74 antibodies titers have clinically significant effect on pharmacokinetics, pharmacodynamics, safety, and efficacy of ELEVIDYS.