Vestibular Hypofunction Screening in Older Cochlear Implant Candidates

OBJECTIVE

Vestibular loss is associated with increasing age and hearing loss. Cochlear implantation (CI) may be performed in these patients; however, CI can induce vestibular hypofunction (VH) postoperatively. If CI is performed in the "better balancing ear," patients may experience vestibulopathy from new bilateral VH. The objective of this study was to evaluate the rates of VH in older CI candidates, thereby helping to identify patients at increased risk for bilateral VH after CI.

STUDY DESIGN

Retrospective cohort study from 2019 to 2022 of patients age 60 to 80 years old who underwent videonystagmography (VNG).

SETTING

Tertiary care neurotology practice.

METHODS

VNG, including spontaneous nystagmus, cervical vestibular evoked myogenic potential (cVEMP), caloric stimulation, and rotary chair, was reviewed and stratified by CI candidacy. Patients with prior CI or known vestibular diagnosis were excluded.

RESULTS

Thirty-three patients were CI candidates and 184 patients were controls. cVEMP demonstrated a significantly greater rate of unilateral VH in CI candidates (P = .018). Caloric stimulation demonstrated an elevated rate of bilateral VH and presbyvestibulopathy in CI candidates (P = .057 and P = .036, respectively). Rotary chair demonstrated a significantly higher rate of bilateral VH and incomplete vestibular compensation based on reduced gain and gain asymmetry, respectively, in CI candidates (P < .001 and P = .043, respectively). Mean bithermal slow phase velocity sum and rotary chair gain were significantly lower in the CI candidate group (P = .002 and P < .001, respectively). Preoperative identification of VH determined the side of implantation in 4 patients (15%).

CONCLUSION

VH and incomplete vestibular compensation are common and more frequently seen in CI candidates compared to age-matched controls. Vestibular screening can play a role in surgical counseling and planning, and should be considered in older patients undergoing CI.

Posterior Nasal Nerve Ablation as a Viable Treatment Option for the Primary Symptom of Postnasal Drip

BACKGROUND

Postnasal drip (PND) syndrome is a prevalent complaint encountered in otolaryngology practices. PND may be refractory to medical therapy, and surgical treatments are complicated by side effects.

OBJECTIVE

While posterior nasal nerve (PNN) ablation has demonstrated efficacy for chronic rhinitis overall, we sought to examine the effect of PNN ablation for patients with PND as their primary complaint.

METHODS

This is a retrospective case series study of 40 chronic rhinitis (CR) patients with a primary complaint of PND. Included patients had to have failed medical therapy such as anti-cholinergic nasal sprays, reflux treatments, and/or nasal steroids. Primary outcome measures included 22 item Sino-Nasal Outcome Test (SNOT-22) PND component and Total Nasal Symptom Score. Secondary outcome measure was subjective improvement, defined as a  > 30% improvement in PND symptoms.

RESULTS

Median follow-up was 138 days (interquartile range: 72-193). 72.5% (29/40) of patients reported at least a 30% improvement in PND symptoms. Mean PND SNOT-22 scores were 4.2/5 (SD = 0.8) pre-procedure versus 1.9/5 (SD = 1.3) post-procedure (P = .001). PNN ablation response did not correlate to ipratropium bromide nasal spray response, although younger and non-smoker patients had better response rates.

CONCLUSION

This exploratory study of PNN ablation for the primary symptom of PND demonstrates efficacy as assessed by the PND component of SNOT-22 and subjective improvement. These results can be useful in guiding physician-patient discussions in determining treatment options for medically refractory PND.

Modified technique improves efficacy for in-office posterior nasal nerve ablation

Objectives

Posterior nasal nerve (PNN) ablation is a minimally invasive treatment option for patients with chronic rhinitis. Recent evidence shows that parasympathetic innervation of the nasal cavity is more extensive and there are many fibers posterior to the lateral attachment of the middle turbinate. We describe a modified ablative technique that targets the extensive innervation of the posterior nasal nerves.

Methods

Description of the technique and retrospective cohort analysis. In addition to the traditional radiofrequency and cryoablation targets, three additional treatment sites posterior to the middle turbinate were targeted using radiofrequency ablation, as well as one focused treatment posteroinferior to the middle turbinate attachment using cryotherapy ablation. The primary outcome collected was a 30% improvement in overall rhinitis symptoms.

Results

Forty-five patients received treatment and completed 3-month follow-up using the modified technique for radiofrequency and cryotherapy PNN ablation. Previously, our institution documented a 64.5% responder rate at 3 months. After introducing the modified technique, the response rate at 3 months significantly improved (64.5% vs. 91.1%, p = .004).

Conclusions

This report suggests improved efficacy with implementation of the modified technique for in-office PNN ablation. Given the extensive nature of the post-ganglionic parasympathetic fibers of the nasal cavity which often emerge posterior to the middle turbinate attachment, a modified technique to target these branches should be considered. Prospective randomized studies comparing this modified technique to the traditional technique are needed.

Level of Evidence

III.

Isolated Fracture of the Malleus: An Overlooked Cause of Conductive Hearing Loss?

OBJECTIVE

To report the largest case series of isolated malleus fractures with systematic review to characterize the disease's presentation and natural history, and provide suggestions for management.

DATA SOURCES

PubMed, Embase, Cochrane Library.

REVIEW METHODS

Retrospective cohort study was performed on 12 patients with isolated malleus fractures. History, physical exam, pre- and post-treatment audiograms, and imaging were obtained. Systematic review of the literature was performed.

RESULTS

Including the cases herein, 58 isolated malleus fractures were identified, the majority of which were published in the 21st century. Mean time to presentation after injury was 34.4 months. Most common etiology was external auditory canal (EAC) manipulation. Physical exam and imaging did not identify any abnormality at presentation in 16% and 21% of cases, respectively. The majority of fractures involved the manubrium. Air-bone gap (ABG) at initial presentation ranged from 16 to 26 dB, and was greater at higher frequencies. Thirty-six cases underwent surgery. ABG improvement was greater at all frequencies for those who underwent surgery. Final ABG was significantly less than initial ABG at nearly every frequency for those who underwent surgery (p < 0.05), while not at any frequency for those who were observed.

CONCLUSIONS

Isolated malleus fractures may occur more often than historical data suggests, and are perhaps underdiagnosed. Abrupt removal of a finger from the EAC with pain and hearing loss is nearly pathognomonic. Conductive hearing loss with ABG greater at higher frequencies is most often observed. Observation is unlikely to produce spontaneous improvements in hearing, while surgery demonstrates reliable decreases in ABG. Laryngoscope, 134:1032-1041, 2024.

Outcomes for COVID-19 Patients Undergoing Tracheostomy With or Without Extracorporeal Membrane Oxygenation (ECMO)

Introduction The coronavirus disease 2019 (COVID-19) pandemic led to the more common use of venovenous (VV) extracorporeal membrane oxygenation (ECMO) for adults with acute respiratory distress syndrome (ARDS). While tracheostomy is generally understood to decrease the risks of prolonged endotracheal intubation, there is conflicting data regarding the benefit of tracheostomy in patients on ECMO. The purpose of this study is to determine whether ECMO cannulation before tracheostomy impacted patient outcomes. Methods This is a retrospective chart review of patients who underwent tracheostomy for COVID-19-related ARDS at a tertiary academic center from March 2020 through March 2022. Patients were separated into two groups based on whether they were cannulated for ECMO prior to tracheostomy. Fisher's exact test or Wilcoxon rank sum test was used to compare the two groups. Results A total of 24 patients were included in the study, with 13 in the ECMO group and 11 in the non-ECMO group. There was no significant difference in age, comorbidities, race, or gender between the groups. Patients on ECMO had a longer time from admission to intubation (seven days vs. three days, p=.002), were more likely to have multiple intubations (54% vs 9%, p= .033), had increased rates of postoperative bleeding (62% vs. 18%, p = .047), and had a higher mortality rate (39% vs. 0%, p= .041). Conclusions ECMO cannulation prior to tracheostomy for COVID-19-related ARDS is associated with poorer outcomes. It is unclear whether this is related to a more severe disease burden in these patients. Further study is needed to evaluate this and guide future management.

Postnasal drip and chronic cough in patients with chronic rhinitis treated with temperature-controlled radiofrequency neurolysis

OBJECTIVE

To evaluate the contribution of postnasal drip (PND) and chronic cough (CC) to symptoms of patients with chronic rhinitis treated with temperature-controlled radiofrequency (TCRF) neurolysis of the posterior nasal nerve (PNN), and correlate PND and CC scores with components of the reflective total nasal symptom score (rTNSS).

METHODS

Pooled data from three prospective studies: two single-arm studies and the index active treatment arm of a randomized controlled trial. Adult patients with baseline rTNSS ≥6 were treated with TCRF neurolysis at nonoverlapping regions of the PNN. PND and CC symptoms were evaluated on a 0 (none) to 3 (severe) scale.

RESULTS

Data from 228 patients (57.9% women, 42.1% men) were included. The mean baseline rTNSS was 8.1 (95% confidence interval [CI], 7.8-8.3), which decreased to 3.2 (95% CI, 2.9-3.5) at 6 months. At baseline, 97.4% of patients had PND and 80.3% had CC. Median baseline PND and CC symptom scores were 3 (interquartile range [IQR], 2-3) and 2 (IQR, 1-2), respectively. At 6 months, this decreased to 1 (IQR, 0-2) and 0 (IQR, 0-1), respectively, showing significant improvement from baseline (both p < 0.001). Spearman correlation coefficients with components of rTNSS (rhinorrhea, congestion, itching, sneezing) were 0.16 to 0.22 for CC and 0.19 to 0.46 for PND, indicating only a weak to moderate correlation.

CONCLUSION

PND and CC contribute to the symptomatology of chronic rhinitis and are significantly improved after TCRF neurolysis of the PNN. The inclusion of PND and CC symptoms in a chronic rhinitis assessment instrument could provide important additional information for the characterization of the disease state and outcomes after any therapeutic treatment.

Recurrent Respiratory Papillomatosis With Complete Response to Systemic Bevacizumab Therapy

Recurrent respiratory papillomatosis is a condition caused by human papilloma virus, usually sub types 6 and 11. Papillomas are benign neoplasms that are most commonly found on the larynx and can be often associated with significant airway involvement. Frequency of episodes varies among patients as do the clinical symptoms. Patients often present with symptoms such as hoarseness but there is potential for respiratory compromise and even complete airway obstruction.

New Medical Device and Therapeutic Approvals in Otolaryngology: State of the Art Review of 2022

Objective

To review new drugs and devices relevant to otolaryngology approved by the Food and Drug Administration (FDA) in 2022.

Data Sources

Publicly available FDA data on drugs and devices approved in 2022.

Review Methods

A preliminary screen was conducted to identify drugs and devices relevant to otolaryngology. A secondary screen by members of the American Academy of Otolaryngology-Head and Neck Surgery's (AAO-HNS) Medical Devices and Drugs Committee differentiated between minor updates and new approvals. The final list of drugs and devices was sent to members of each subspecialty for review and analysis.

Conclusion

A total of 1251 devices and 37 drugs were identified on preliminary screening. Of these, 329 devices and 5 drugs were sent to subspecialists for further review, from which 37 devices and 2 novel drugs were selected for further analysis. The newly approved devices spanned all subspecialties within otolaryngology. Many of the newly approved devices aimed to enhance patient experience, including over-the-counter hearing aids, sleep monitoring devices, and refined CPAP devices. Other advances aimed to improve surgical access, convenience, or comfort in the operating room and clinic.

Implications for Practice

Many new devices and drugs are approved each year to improve patient care and care delivery. By staying up to date with these advances, otolaryngologists can leverage new innovations to improve the safety and quality of care. Given the recent approval of these devices, further studies are needed to assess long-term impact within the field of otolaryngology.

GPT-4 accuracy and completeness against International Consensus Statement on Allergy and Rhinology: Rhinosinusitis

KEY POINTS

GPT-4 is an AI language model that can answer basic questions about rhinologic disease. Vetting is needed before AI models can be safely integrated into otolarygologic patient care.

Confirmatory Auditory Brainstem Responses Testing Results in Discordant Outcomes: Implications for Timely Care

OBJECTIVES

The purpose of this study is to evaluate for discrepancies in diagnostic auditory brainstem responses (ABR) between Children's National Hospital (CNH), a pediatric medical center, and outside facilities (OSF) that referred patients to CNH for confirmatory evaluation. Such discrepancies impact early hearing detection and intervention (EHDI) timelines.

METHODS

A retrospective chart review was conducted from an internal database of patients who underwent diagnostic ABR from 2017 to 2021. Only patients with ABR results from both CNH and OSF were analyzed. Demographic data, external and internal test results, and intervention data were obtained. Hearing loss (HL) severity was graded on a scale of 0 to 8, where 0 indicated normal hearing and 8 indicated profound. Each ear was analyzed separately.

RESULTS

Forty-nine patients met the inclusion criteria, and each ear was evaluated separately. Median HL severity was 1.0 [0.0, 4.3] at CNH compared to 3.0 [1.8, 6] at OSF (p = 0.004). Forty-seven ears (48.0%) showed lower severity at CNH. Twenty-seven patients (55%) received hearing amplification devices. The median age at time of hearing intervention was 220 days.

CONCLUSION

Our results showed statistical significance in the median severity of HL between CNH and OSF. A substantial proportion (70%) of children in our dataset who received amplification via cochlear implant or hearing aids were shown to have discrepancies in ABR findings from CNH and OSF. These findings have implications with regards to the appropriate usage of health care resources and maintaining EDHI timelines.

LEVEL OF EVIDENCE

4 (Retrospective Cohort Study) Laryngoscope, 133:3571-3574, 2023.

Single-port transoral robotic surgery for a rare tonsil mass

Squamous cell carcinoma predominates as the most common malignant lesion of the oropharynx with human papilloma virus-associated disease now predominant over tobacco-related oropharynx cancer. Other rare malignant pathologies can manifest as visible neoplasms in these anatomic sites with varying degrees of symptoms such as dysphagia, odynophagia, otalgia, aspiration, hemorrhage, weight loss and dyspnea. We present a case of a rarely encountered primary oropharyngeal sarcoma managed by single-port transoral robotic resection and a selective cervical lymph node dissection followed by adjuvant radiotherapy.

New Medical Device and Therapeutic Approvals in Otolaryngology: State of the Art Review of 2021

Objective

To evaluate new medical devices and drugs pertinent to otolaryngology–head and neck surgery that were approved by the Food and Drug Administration (FDA) in 2021.

Data Sources

Publicly available FDA device and drug approvals from ENT (ear, nose, and throat), anesthesia, neurosurgery, plastic surgery, and general surgery FDA committees.

Review Methods

FDA device and therapeutic approvals were identified and reviewed by members of the American Academy of Otolaryngology–Head and Neck Surgery’s Medical Devices and Drugs Committee. Two independent reviewers assessed the relevance of devices and drugs to otolaryngologists. Medical devices and drugs were then allocated to their respective subspecialty fields for critical review based on available scientific literature.

Conclusions

The Medical Devices and Drugs Committee reviewed 1153 devices and 52 novel drugs that received FDA approval in 2021 (67 ENT, 106 anesthesia, 618 general surgery and plastic surgery, 362 neurosurgery). Twenty-three devices and 1 therapeutic agent relevant to otolaryngology were included in the state of the art review. Advances spanned all subspecialties, including over-the-counter hearing aid options in otology, expanding treatment options for rhinitis in rhinology, innovative laser-safe endotracheal tubes in laryngology, novel facial rejuvenation and implant technology in facial plastic surgery, and advances in noninvasive and surgical treatment options for obstructive sleep apnea.

Implications for Practice

FDA approvals for new technology and pharmaceuticals present new opportunities across subspecialties in otolaryngology. Clinicians’ nuanced understanding of the safety, advantages, and limitations of these innovations ensures ongoing progress in patient care.

Barriers to Pediatric Osseointegrated Bone-Conduction Hearing Devices

OBJECTIVE

To identify social, demographic, and clinical barriers for implantation with Osseointegrated Bone Conduction Devices (OBCD) in pediatric candidates.

STUDY DESIGN

Retrospective cohort study of 94 children who met standard OBCD implantation criteria.

SETTING

Tertiary stand-alone children's hospital.

MATERIALS AND METHODS

Retrospective chart review comparing demographic (age, race, state of residence, and insurance) and clinical (severity and etiology of hearing loss, medical comorbidities, and early intervention) factors impacting implantation. Members of the existing cohort were then contacted to obtain a better understanding of qualitative factors impacting surgical decision.

RESULTS

Of the identified 94 surgical candidates, 47 (50%) underwent OBCD implantation. State of residence significantly impacted implantation rates, with children from the District of Columbia and Virginia being less likely to receive an implant than those from Maryland. Private insurance, race, and ethnicity did not impact rate of implantation (OR 2.8 [95% CI 0.78-10]; 1.34 [95% CI 0.44-3.68]; and 1.0 [95% CI 0.42-2.43], respectively). Children with anotia or microtia and children younger than 10 years old were less likely to have an implant (OR 10.6 (95% CI 1.74-65). Thirty-nine children participated in the qualitative portion. Themes that emerged as reasons to forgo implantation included a child's young age, planned reconstruction for microtia or atresia, and overall device functionality and usage. Thirtyseven children (39%) of the cohort declined surgery and currently wear a nonsurgical bone conduction aid regularly.

CONCLUSION

Despite known benefits of implantation, only one-half of children who were candidates underwent OBCD. Unlike cochlear implantation, where insurance status is a major risk factor for implantation delay and underperformance, for OBCD, implantation barriers appear to be more multifactorial and include medical, demographic, and social factors.

Diagnostic performance of the second-generation molecular tests in the assessment of indeterminate thyroid nodules: A systematic review and meta-analysis

OBJECTIVE

The objective of this systematic review and meta-analysis was to evaluate the diagnostic performance of the second-generation molecular tests in the diagnosis of thyroid nodules with indeterminate fine-needle aspiration biopsy results.

METHODS

We searched PubMed, Google Scholar, Scopus, and Cochrane Library for studies published between January 2017 and March 2021. Inclusion criteria were indeterminate thyroid results from fine-needle aspiration (FNA) that included Bethesda categories III and IV, use of Afirma GSC, Thyroseq v3, and ThyGeNext as an index test, and conclusive histopathological results. Studies with no post-surgical diagnoses were excluded. For each included study, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were obtained. Sensitivity and specificity were pooled jointly using a bivariate binomial random-effects model. Statistical significance was indicated at p-value less than 0.05.

RESULTS

Our search yielded 431 non-duplicate articles, of which 15 were included in the study (7 GSC, 6 Thyroseq v3, and 2 ThyGeNext). ThyGeNext studies were excluded from the meta-analysis due to the small sample size. Pooled data for GSC studies on 472 thyroid nodules showed a sensitivity of 96.6 (95% confidence interval: 89.7-98.9%), specificity of 52.9% (23.4-80.5%), PPV of 63% (51-74%), and NPV of 96% (94-98%). Pooled data for ThyroSeq studies on 530 thyroid nodules showed a sensitivity of 95.1% (91.1-97.4%), specificity of 49.6% (29.3-70.1%), PPV of 70% (55-83%), and NPV of 92% (86-97%). There was no statistically significant difference in diagnostic performances of the two tests (p-values for sensitivity = 0.89, specificity = 0.82, PPV = 0.43, NPV = 0.17).

CONCLUSION

High sensitivity and high NPV in GSC and Thyroseq v3 have potential to help rule out malignancy among thyroid nodules with indeterminate cytology results. There was no difference in diagnostic performances between the two molecular tests indicating that either test is appropriate to determine the malignancy of thyroid nodules. Further long-term outcome data are warranted to make a clear recommendation.

Swallowing Function Following Neoadjuvant Chemotherapy and Transoral Robotic Surgery for Oropharyngeal Carcinoma: A 2-Year Follow-up

OBJECTIVE

To evaluate 2-year follow-up swallowing function in patients with human papillomavirus-related oropharyngeal squamous cell carcinoma (HPV+ OPSCC) who completed neoadjuvant chemotherapy and transoral robotic surgery (NAC+S).

STUDY DESIGN

Retrospective analysis of patients with OPSCC treated with NAC+S between 2010 and 2021.

SETTING

A single academic institution.

METHODS

This is a cross-sectional study of patient-reported swallowing function, assessed with the MD Anderson Dysphagia Inventory (MDADI) at least 2 years after completion of treatment. The inclusion criteria are patients with HPV+ OPSCC who underwent NAC+S at least 2 years ago. Those requiring adjuvant radiation or chemoradiation or experiencing relapse were excluded from the study.

RESULTS

Completed MDADIs were received from 37 patients at a median 3.8 years posttreatment (interquartile range, 2.0-8.6 years). Of those, 94.6% (n = 35) were male and 81.1% (n = 30) were White. The median age at OPSCC diagnosis was 59.0 years (interquartile range, 41-80 years). The most frequent primary subsite of OPSCC was the base of the tongue (n = 20, 54.1%), followed by the tonsils (n = 16, 43.2%). In addition, 75.7% (n = 28) had stage IVa disease (TNM seventh edition), and 29 (78.4%) had scores ≥80, classified as optimal function. When compared with patients who received bilateral neck dissection, patients who received unilateral neck dissection were associated with an age <65 years old (P = .036) and lower clinical TNM stage (P = .04), as well as higher composite, emotional, functional, and physical MDADI scores (P = .017, .046, .013, and .05, respectively).

CONCLUSION

Patients with OPSCC who were treated with NAC+S achieved satisfactory long-term swallowing outcomes. Unilateral neck dissection was significantly associated with higher MDADI scores in this patient cohort.

Expression of the muscle-associated gene MYF6 in hairy cell leukemia

Hairy cell leukemia (HCL) is a purine analog-responsive B-cell malignancy containing the BRAF V600E mutation, expressing CD22, CD11c, CD103, tartrate resistant acid phosphatase (TRAP) CD25, CD123, and annexin 1A. BRAF V600E and the latter 4 markers are usually absent in the more aggressive and chemoresistant variant HCLv. To evaluate differences between HCL and HCLv, expression microarrays comparing HCL with HCLv were performed for 24694 genes using 47323 probes. Microarray data from 35 HCL and 27 HCLv purified samples showed the greatest HCL-HCLv difference in the muscle-associated gene MYF6, expressed by its 2 probes 18.5- and 10.8-fold higher in HCL than HCLv (p<0.0001). By real-time quantitative PCR (RQ-PCR), 100% of 152 classic HCL samples were MYF6-positive, vs 5 (6%) of 90 blood donors. MYF6-expression was also detected in 18 (35%) of 51 with HCLv, 11 (92%) of 12 with HCL expressing unmutated IGHV4-34, 35 (73%) of 48 with chronic lymphocytic leukemia (CLL), and 1 (8%) of 12 with mantle cell lymphoma. Hypomethylation status of MYF6 supported expression in HCL more than HCLv. Posttreatment blood samples becoming negative by flow cytometry remained MYF6+ by RQ-PCR in 42 (48%) of 87 HCL patients, and MYF6 RQ-PCR could detect 1 HCL in 10⁵ normal cells. MYF6, universally expressed in HCL and in most CLL samples, may be a useful biomarker for these leukemias. Further studies are underway to determine the role of MYF6 in HCL.

Site-selective redox isomerizations of furanosides using a combined arylboronic acid/photoredox catalyst system

In the presence of an arylboronic acid and a hydrogen atom transfer mediator under photoredox conditions, furanoside derivatives undergo site-selective redox isomerizations to 2-keto-3-deoxyfuranosides. Experimental evidence and computational modeling suggest that the transformation takes place by abstraction of the hydrogen atom from the 2-position of the furanoside-derived arylboronic ester, followed by C3-O bond cleavage via spin-center shift. This mechanism is reminiscent of the currently accepted pathway for the formation of 3'-ketodeoxynucleotides by ribonucleotide reductase enzymes.

Abstract CN07-03: Recombinant immunotoxins for hematologic malignancies

Recombinant immunotoxins are composed of fragments of monoclonal antibodies (Mabs) and protein toxins, enabling the toxin to bind to a target cell recognized by the antibody, and the toxin to kill the cell after internalization. Recombinant immunotoxins are similar to but distinct from growth-factor fusions toxins like denileukin diftitox and Tagraxofusp, FDA-approved in 1999 and 2018, respectively. Unlike chemical conjugates, Recombinant immunotoxins have a peptide that links the cell-binding to the toxin domains. After proteolytic cleavage, the toxin separates from the binding domain, undergoes intracellular trafficking and enters the cytosol, resulting in apoptotic cell death. Recombinant immunotoxins containing Pseudomonas exotoxin A contain an Fv or Fab fragment of a Mab replacing the native cell-binding toxin domain. The first recombinant immunotoxin we made contained an anti-CD25 single-chain Fv fused to a 38 kDa fragment of Pseudomonas exotoxin called PE38. Anti-CD25 recombinant immunotoxin LMB-2 was active in several hematologic malignancies, notably hairy cell leukemia (HCL) and adult T-cell leukemia (ATL). LMB-2 achieved a high complete remission (CR) rate in ATL when combined with chemotherapy to reduce immunogenicity and progression between cycles. Improved targeting of HCL was achieved with anti-CD22 recombinant immunotoxin Moxetumomab Pasudotox (Moxe) that was stabilized with a disulfide bond in the Fv and has a high affinity for CD22. Moxe achieved investigator-assessed CR rates of 51-64% in relapsed/refractory HCL in Phase 1 and 3 trials, leading to FDA-approval in 2018. Minimal residual disease (MRD) was negative in most CRs. On the phase I trial, which had adequate follow-up, MRD eradication by the most sensitive standard assay, flow cytometry of the bone marrow aspirate (BMA), was associated with longer CR duration. Extra or ‘consolidation’ cycles past documentation of CR was also associated with longer CR duration. To detect MRD with higher sensitivity, patient specific immunoglobulin heavy chain (IgH) rearrangements were cloned and real-time quantitative PCR (RQ-PCR) performed. Using patient-specific primers and probe, 1 HCL cell could be detected in 106 normal cells. We found that phase 1-3 patients achieving MRD-free CR by blood RQ-PCR had significantly prolonged CR duration (p&lt;0.0001) compared to those remaining blood RQ-PCR+. Both BMA flow cytometry and RQ-PCR were associated with prolonged CR duration if negative, but blood flow cytometry was not helpful since only one patient with CR remained flow-positive. Molecular remissions assessed by blood analysis may be useful to determine the number of cycles of Moxe to administer to achieve long-term CR or possibly cure. To achieve molecular remissions with fewer cycles, Moxe is being tested with rituximab to facilitate tumor reduction and decrease anti-drug antibody formation.

Citation Format: Robert Kreitman, Daniel Gorelik, Maryalice Stetler-Stevenson, Constance M Yuan, Hao-Wei Wang, Hong Zhou, Katherine Potocka, Erin Fykes, Evgeny Arons, Ira Pastan. Recombinant immunotoxins for hematologic malignancies [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr CN07-03. doi:10.1158/1535-7163.TARG-19-CN07-03

Diarylborinic Acid-Catalyzed, Site-Selective Sulfation of Carbohydrate Derivatives

Sulfated carbohydrates have been implicated in diverse biological processes, with the position and extent of sulfation of a glycoside often playing important roles in determining the affinity and specificity of its binding to a biomolecular partner. Methods for the site-selective introduction of sulfate groups to carbohydrates are thus of interest. Here, we describe the development of a diarylborinic acid-catalyzed protocol for selective sulfation of pyranoside derivatives at the equatorial position of a cis-1,2-diol group. This method, which employs the sulfur trioxide-trimethylamine complex as the electrophile, has been employed for installation of a sulfate group at the 3-position of a range of galacto- and mannopyranosides, including substrates having a free primary OH group. By using a full equivalent of the diarylborinic acid, selective syntheses of more complex monosulfated glycosides, namely, a 3'-sulfolactose derivative and 3'-sulfo-β-galactosylceramide, have been accomplished. Preliminary kinetics experiments suggested that the catalyst resting state is a tetracoordinate diarylborinic ester that reacts with the SO₃ complex in the turnover-limiting step. Catalyst inhibition by the pyranoside sulfate product and trialkylamine byproduct of the reaction was demonstrated.