Abstracts / Toxicon 123 (2016) S2eS90 studied. One patient had received onabotulinumtoxinA (ONA) only; 3 had received abobotulinumtoxinA (ABO) only; 3 had received ABO and then ONA; and 1 had received rimabotulinumtoxinB (RIMA) and then ONA before ABTF with maximal BTAB titers occurred. All BTAB titers had dropped to insignificant levels before BT therapy was restarted with INCO. Results: Treatment parameters before and after restart were as follows: single dose, 191.5 ± 55.2 mouse units (MU) vs 259.0 ± 100.6 MU; interinjection interval (days), 116.7 ± 20.9 vs 104.5 ± 14.7 MU; cumulative dose, 1903.8 ± 1168.6 MU vs 5130.4 ± 3602.5 MU; and treatment time (days), 954.1 ± 512.9 vs 1895.4 ± 1211.4. Repeated BTAB measurements and clinical examination did not reveal any signs of ABTF after restart. Conclusions: Even when INCO is given at higher single doses, shorter injection intervals, and higher cumulative doses, it does not produce ABTF. INCO offers a new, long-term opportunity for ABTF patients when BTAB titers have dropped. This observation supports the prediction that INCO has a lower antigenicity than do conventional BT drugs. Keywords: Botulinum toxin; Botulinum toxin antibody titers; IncobotulinumtoxinA, restart; Therapy failure 58. COMPARING INCOBOTULINUMTOXINA (XEOMIN) AND ONABOTULINUMTOXINA (BOTOX): IDENTICAL POTENCY LABELING IN THE HEMIDIAPHRAGM ASSAY Dirk Dressler a, *, Hans Bigalke b. a Movement Disorders Section, Department of Neurology, Hannover Medical School, Hannover, Germany; b Toxogen, Hannover, Germany * Corresponding author: Movement Disorders Section, Department of Neurology, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625, Hannover, Germany. E-mail address:dressler.dirk@mh-hannover.de. Introduction and objectives: To compare the potency labeling of incobotulinumtoxinA (Xeomin) and onabotulinumtoxinA (Botox) using doseeffect curves in the mouse hemidiaphragm assay (HDA). Methods: We measured HDA half-paresis times using 20, 60, 100, and 140 mouse units (MU) of either Xeomin or Botox. Botulinum toxin came from several different and unexpired batches. Reconstitution was performed with 2.5 mL of 0.9% NaCl/H2O immediately before the experiments. Results: Half-paresis times for 20 MU were 132.3±1.5 min (Xeomin) and 169.7±28.9 min (Botox); for 60 MU, 84.7±4.2 min (Xeomin) and 105.3±10.1 min (Botox); for 100 MU, 66.0±7.0 min (Xeomin) and 69.7±1.5 min (Botox); and for 140 MU, 62.3±2.1 min (Xeomin), and 74.7±0.6 min (Botox) (overall Xeomin vs Botox, P¼0.238). Conclusions: These results do not reveal differences in potency labeling between Xeomin and Botox even when the full range of therapeutic doses is examined. The data confirm previous reports of identical potency labeling of Xeomin and Botox. Keywords: Dose-effect curves; Hemidiaphragm assay; IncobotulinumtoxinA; OnabotulinumtoxinA; Potency labelling 59. COMPLEXING PROTEINS: ARE THEY NECESSARY FOR MECHANICAL STABILITY OF BOTULINUM TOXIN DRUGS? Dirk Dressler a,*, Hans Bigalke b. Movement Disorders Section, Department of Neurology, Hannover Medical School, Hannover, Germany; b Toxogen, Hannover, Germany a * Corresponding author: Movement Disorders Section, Department of Neurology, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625, Hannover, Germany. E-mail address:dressler.dirk@mh-hannover.de. Objective: To study whether complexing proteins (CP) are necessary for mechanical stability of botulinum toxin (BT) drugs. Methods: A previously published paradigm to provoke mechanical inactivation of BT drugs by repeated aspiration through thin needles and violent shaking of the reconstituted drug was used to compare the halfparalysis time in the mouse hemidiaphragm assay of incobotulinumtoxinA (INCO, containing no CP, 5 unexpired 100-mouse unit (MU) vials each) and onabotulinumtoxinA (ONA, containing CP, 3 unexpired 100-MU vials each) as a potency parameter for BT drugs. S23 Results: Half-paralysis time for INCO increased from 66.0±7.0 min to 76.1±1.0 min and for ONA from 75.8±10.3 min to 106.0±16.0 min. Based on calibration curves this equals a potency drop from 100 MU to 82.7 MU (-17.3%) for INCO and from 100 MU to 63.3 MU (-36.7%) for ONA. Conclusions: The presence of CP does not increase the mechanical stability of BT drugs confirming other observations that they are not necessary for therapeutic use of BT. Keywords: Complexing proteins; Hemidiaphragm assay; IncobotulinumtoxinA; OnabotulinumtoxinA; Mechanical stability; Potency measurements 60. RECONSTITUTING BOTULINUM TOXIN DRUGS: SHAKING, STIRRING OR WHAT? Dirk Dressler a, *, Hans Bigalke b. a Movement Disorders Section, Department of Neurology, Hannover Medical School, Hannover, Germany; b Toxogen, Hannover, Germany * Corresponding author: Movement Disorders Section, Department of Neurology, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625, Hannover, Germany. E-mail address:dressler.dirk@mh-hannover.de. Objective: To study whether botulinum neurotoxin (BNT), the therapeutically active ingredient and a fragile double-stranded protein, can be inactivated during reconstitution when mechanical stress is applied. Methods: In this study, 100 mouse units (MU) onabotulinumtoxinA (Botox, Irvine, CA, USA) was reconstituted with 2.0 mL of NaCl/H2O. Gentle reconstitution was performed with a 5-mL syringe, a 0.90 x 70-mm injection needle, 1 cycle of injection-aspiration-injection and 2 gentle shakes of the vial. Aggressive reconstitution (AR) was performed with a 5-mL syringe, a 0.40 x 40-mm injection needle, 10 injection-aspiration-injection cycles and 30 seconds of continuous shaking of the vial. Results: AR increased the half paralysis time in the mouse hemidiaphragm assay from 72.0±4.6 min to 106.0±16.0 min (P¼ 0.002, two-tailed t-test after Kolmogorov-Smirnov test with Lilliefors correction for normal distribution). Construction of a calibration curve revealed that the increase in the time to paralysis was correlated with a loss of potency of from 100 MU to 58 MU (e42%). Conclusions: For reconstitution of BNT drugs, large-diameter injection needles and 2-3 injection-aspiration-injection cycles should be used. Shaking the vials a few times to rinse the entire glass wall also seems safe. Aggressive reconstitution with small diameter needles, prolonged injection-aspiration-injection, and violent shaking should be avoided. 61. ABOBOTULINUMTOXINA (DYSPORT) INJECTION DOSES PER MUSCLE IN PEDIATRIC PATIENTS WITH LOWER LIMB SPASTICITY Nigar Dursun a, Ann Tilton b, Mark Gormley c, Marcin Bonikowski d, Juan Carlos Velez e, Maria Luisa Rodriguez f, Philippe Picaut f, Anne-Sophie Grandoulier f, Mauricio R. Delgado g, *. a Kocaeli University Medical Faculty, Izmit, Turkey; b Louisiana State University Health Center and Children’s Hospital New Orleans, New Orleans, LA, USA; c Gillette Children’s Specialty Healthcare, St Paul, MN, rze n, Warsaw, Poland; USA; d Mazovian Neuropsychiatry Center, Zago e Club De Leones Cruz Del Sur Rehabilitation Center, Punta Arenas, Chile; f Ipsen Pharma, Les Ulis, France; g Texas Scottish Rite Hospital for Children, Dallas, TX, USA * Corresponding author: Texas Scottish Rite Hospital Neurology, 2222 Welborn St, Dallas, TX 75219, USA. E-mail address:mauricio.delgado@tsrh.org. Introduction and objectives: The efficacy and safety of BoNT-A for the treatment of children with spastic cerebral palsy (CP) has been previously demonstrated. However, there is little guidance on dosing per muscle for this population. Methods: We present the doses per muscle used from a multicenter, repeated-treatment, open-label study of abobotulinumtoxinA (AboBoNTA; Dysport) injections into the gastrocsoleus complex (GSC). Subsequent injections allowed injections into the hamstrings and other leg muscles during the later treatment cycles, in children with lower limb spasticity