Complexing Protein-Free Botulinum Neurotoxin A Formulations: Implications of Excipients for Immunogenicity.

The formation of neutralizing antibodies is a growing concern in the use of botulinum neurotoxin A (BoNT/A) as it may result in secondary treatment failure. Differences in the immunogenicity of BoNT/A formulations have been attributed to the presence of pharmacologically unnecessary bacterial components. Reportedly, the rate of antibody-mediated secondary non-response is lowest in complexing protein-free (CF) IncobotulinumtoxinA (INCO). Here, the published data and literature on the composition and properties of the three commercially available CF-BoNT/A formulations, namely, INCO, Coretox® (CORE), and DaxibotulinumtoxinA (DAXI), are reviewed to elucidate the implications for their potential immunogenicity. While all three BoNT/A formulations are free of complexing proteins and contain the core BoNT/A molecule as the active pharmaceutical ingredient, they differ in their production protocols and excipients, which may affect their immunogenicity. INCO contains only two immunologically inconspicuous excipients, namely, human serum albumin and sucrose, and has demonstrated low immunogenicity in daily practice and clinical studies for more than ten years. DAXI contains four excipients, namely, L-histidine, trehalosedihydrate, polysorbate 20, and the highly charged RTP004 peptide, of which the latter two may increase the immunogenicity of BoNT/A by introducing neo-epitopes. In early clinical studies with DAXI, antibodies against BoNT/A and RTP004 were found at low frequencies; however, the follow-up period was critically short, with a maximum of three injections. CORE contains four excipients: L-methionine, sucrose, NaCl, and polysorbate 20. Presently, no data are available on the immunogenicity of CORE in human beings. It remains to be seen whether all three CF BoNT/A formulations demonstrate the same low immunogenicity in patients over a long period of time.

Addressing the Real-World Challenges of Immunoresistance to Botulinum Neurotoxin A in Aesthetic Practice: Insights and Recommendations from a Panel Discussion in Hong Kong.

With increasing off-label aesthetic indications using higher botulinum neurotoxin A (BoNT-A) doses and individuals starting treatment at a younger age, particularly in Asia, there is a greater risk of developing immunoresistance to BoNT-A. This warrants more in-depth discussions by aesthetic practitioners to inform patients and guide shared decision-making. A panel comprising international experts and experienced aesthetic practitioners in Hong Kong discussed the implications and impact of immunoresistance to BoNT-A in contemporary aesthetic practice, along with practical strategies for risk management. Following discussions on a clinical case example and the results of an Asia-Pacific consumer study, the panel concurred that it is a priority to raise awareness of the possibility and long-term implications of secondary non-response due to immunoresistance to BoNT-A. Where efficacy and safety are comparable, a formulation with the lowest immunogenicity is preferred. The panel also strongly favored a thorough initial consultation to establish the patient's treatment history, explain treatment side effects, including the causes and consequences of immunoresistance, and discuss treatment goals. Patients look to aesthetic practitioners for guidance, placing an important responsibility on practitioners to adopt risk-mitigating strategies and adequately communicate important risks to patients to support informed and prudent BoNT-A treatment decisions.

Kidney transplantation in a patient with absent right common iliac artery and congenital renal abnormalities.

INTRODUCTION: Congenital atresia of the common and external iliac arteries is a rare vascular anomaly that may be associated with congenital renal or genitourinary malformations. In ESRD patients, its presence may pose potential problems during renal transplantation. CASE PRESENTATION: We report a rare case of kidney transplantation in a patient with VACTERL syndrome who was found to have absent right common and external iliac arteries during pre-operative imaging. Vascular supply to the right lower limb is derived from an anomalous branch from the left internal iliac artery which takes on a convoluted course across the pelvis. Kidney transplantation was performed successfully with implantation performed on the left side. DISCUSSION: Isolated cases of congenital iliac artery atresia have been described in association with urological abnormalities but no clear association has yet been established. However, we feel that it may be useful to perform routine angiographic evaluation for ESRD patients with congenital genitourinary abnormalities being planned for kidney transplantation. While most cases of congenital iliac artery anomalies are symptomatic with claudication, some remain asymptomatic with normal physical examination findings. There is some evidence in literature suggesting the usefulness of routine pre-operative CT in a selective group of patients. CONCLUSION: Kidney transplantation in such cases is safe and we recommend routine pre-operative imaging of patients known to have congenital genitourniary abnormalities. The kidney should be implanted heterotopically to the contralateral side of the vascular anomaly and care must be taken to preserve vascular supply to the lower limbs.

Diagnosis and management of pancreaticopleural fistula.

Pancreaticopleural fistula is a rare diagnosis requiring a high index of clinical suspicion due to the predominant manifestation of thoracic symptoms. The current literature suggests that confirmation of elevated pleural fluid amylase is the most important diagnostic test. Magnetic resonance cholangiopancreatography is the recommended imaging modality to visualise the fistula, as it is superior to both computed tomography and endoscopic retrograde cholangiopancreatography (ERCP) in delineating the tract within the pancreatic region. It is also less invasive than ERCP. While a trial of medical regimen has traditionally been the first-line treatment, failure would result in higher rates of complications. Hence, it is suggested that management strategies be planned based on pancreatic ductal imaging, with patients having poor chances of spontaneous closure undergoing either endoscopic or surgical intervention. We also briefly describe a case of pancreaticopleural fistula in a patient who was treated using a modified Puestow procedure after failed endoscopic treatment.

KIT gene mutation analysis in solid tumours: biology, clincial applications and trends in diagnostic reporting.

Gain-of-function mutations involving c-kit protein, a cell-surface transmembrane receptor for stem cell factor, have been identified as a key oncogenic driver in a variety of solid tumours. Coupled with the development of tyrosine kinase inhibitors such as imatinib, c-kit has emerged as a viable drug target in what seems to be a validated therapeutic concept. This review will focus on gastrointestinal stromal tumours and melanomas, two types of solid tumours most closely associated with KIT gene mutations. The biology of KIT mutations in both conditions, as well as the value of KIT mutation testing in predicting disease and treatment outcomes are discussed. Since initial response to imatinib is largely influenced by mutation status, genotyping these tumours serves to facilitate personalised oncology. We also summarise our experience with diagnostic reporting of KIT mutation analysis over a period of 3 years, and briefly survey future developments in treatment, which indeed look very promising.

Perforated early gastric cancer: uncommon and easily missed a case report and review of literature.

Gastric carcinoma rarely presents as a perforation, but when it does, is perceived as advanced disease. The majority of such perforations are Stage III/IV disease. A T1 gastric carcinoma has never been reported to perforate spontaneously in English literature. We present a 56 year-old Chinese male who presented with a perforated gastric ulcer. Intra-operatively, there was no suspicion of malignancy. At operation, an open omental patch repair was performed. Post-operative endoscopy revealed a macroscopic Type 0~III tumour and from the ulcer edge biopsy was reported as adenocarcinoma. Subsequently, the patient underwent open subtotal gastrectomy and formal D2 lymphadenectomy. The final histopathology report confirms T1b N0 disease. The occurrence of a perforated early gastric cancer re-emphasises the need for vigilance, including intra-operative frozen section and/or biopsy, as well as routine post-operative endoscopy for all patients.

Gianotti-Crosti syndrome: case report of a pruritic acral exanthema in a child.

Gianotti-Crosti syndrome (GCS) is a sporadic dermatosis affecting mainly children. It is characterized by multiple, confluent, monomorphic and pruritic pink to red-brown papules or papulovesicles, distributed symmetrically on the face, extensor surfaces of the extremities and buttocks, commonly sparing the trunk, palms and soles. This can be preceded by a viral infection, and may be accompanied by fever, hepatosplenomegaly, or lymphadenopathy. Personal and family history of atopy appears to be a risk factor in the subsequent development of GCS, thus frequently diagnosed as atopic dermatitis. We report a case of a 4-year-old boy from our institution with generalized, pruritic, papulovesicular rashes on the face and extremities for one month. He was diagnosed to have atopic dermatitis and treated as such, before presentation to our institution. As the signs and symptoms in GCS are similar to atopic dermatitis, we suggest that this diagnosis be considered when presented with a similar case.