Producing high-quantity and high-quality recombinant adeno-associated virus by low-cis triple transfection

Recombinant adeno-associated virus (rAAV)-based gene therapy is entering clinical and commercial stages at an unprecedented pace. Triple transfection of HEK293 cells is currently the most widely used platform for rAAV manufacturing. Here, we develop low-cis triple transfection that decreases transgene plasmid use by 10- to 100-fold and overcomes several major limitations associated with standard triple transfection. This new method improves packaging of yield-inhibiting transgenes by up to 10-fold, and generates rAAV batches with reduced plasmid backbone contamination that otherwise cannot be eliminated in downstream processing. When tested in mice and compared with rAAV produced by standard triple transfection, low-cis rAAV shows comparable or superior potency and results in diminished plasmid backbone DNA and RNA persistence in tissue. Mechanistically, low-cis triple transfection relies on the extensive replication of transgene cassette (i.e., inverted terminal repeat-flanked vector DNA) in HEK293 cells during production phase. This cost-effective method can be easily implemented and is widely applicable to producing rAAV of high quantity, purity, and potency.

RADT-15. FIRST EXPERIENCE WITH MAXIMAL SAFE RESECTION AND GAMMATILE BRACHYTHERAPY AS TREATMENT FOR RECURRENT GLIOBLASTOMA

INTRODUCTION

Gammatile (GT) is a recently FDA-cleared brachytherapy platform with 131Cs seeds imbedded into a resorbable collagen carrier for surgically targeted radiation delivery. We report the first experience for recurrent glioblastoma patients who underwent GT treatment following surgical resection.

METHODS

Twenty-two consecutive patients with 23 isocitrate dehydrogenase (IDH) wild-type glioblastomas (14 second; eight third recurrence) who underwent intra-operative MRI/5-ALA guided maximal safe resection followed by GT placement were prospectively followed. There were 6 methylguanine-DNA-methyltransferase promoter methylated (MGMTm) and 17 unmethylated (MGMTu) glioblastomas.

RESULTS

The median hospital stay was one day (range:1-15 days). There was one 30-day readmission (4.5%) for a cerebrospinal fluid leak from the incision site, which resolved with lumbar drainage. There were no other wound complications. One patient (4.5%) suffered new post-operative seizure. Eight patients experienced worsened neurological deficit (8/22 or 36%). While all deficits improved by the 30-day follow-up, 7 of these 8 patients suffered KPS decline due to persistent deficits. There was one 30-day mortality (4.5%) from intracranial hemorrhage secondary to heparinization for an ischemic limb. The median follow-up after GT placement for the remaining 21 patients was 296 days (range:111-931 days). Six months local control (LC) was achieved in ~75% of the patients irrespective of MGMT status. Median overall survival (OS) was 715 days for the MGMTu patients, and not reached (>1000 days) for MGMTm patients. These outcomes compared favorably to the published literature (LC: 3-49%; OS MGMTu: 135-285 days; OS MGMTm: 174-564 days) and an age, KPS, extent of resection matched glioblastoma cohort who underwent maximal safe resection without GT at our institution (LC: 52%; OS MGMTu: 462 days; OS MGMTm: 821 days; p=0.0089 and p=0.0271, respectively when compared to the GT treated patients).

CONCLUSION

This clinical experience supports the safety and efficacy of GT brachytherapy as a treatment option for recurrent glioblastomas.

Case report: cranial angiosarcoma with multiple hemorrhagic brain metastasis in a child

BACKGROUND AND IMPORTANCE

Angiosarcoma is a rare malignant tumor with an aggressive course and poor prognosis. It is typically seen in adults but very rarely seen in children. Angiosarcoma of the skull with brain metastasis is exceptionally rare. Due to the rare nature of these tumors, much is left unknown about clinical progression and treatment guidelines are not well established.

CLINICAL PRESENTATION AND COURSE

A 14-year-old male patient presented with an enlarging mass on the parietal region of the head. Further investigations revealed a mass lesion involving scalp and skull tissue. Biopsy result showed angiosarcoma and the patient underwent multiple surgical interventions including scalp excision, craniectomy on tumor site, and excision of brain metastases. He also received chemotherapy and radiation therapy. Despite aggressive treatment, disease progression could not be controlled.

CONCLUSION

Here we report a pediatric patient with intracranially invasive angiosarcoma of the scalp and skull, with recurrent hemorrhagic metastases to the brain. This is a very rare case in pediatric age group with very poor prognosis. Our patient had impressively longer survival than those reported in the literature despite multiple hemorrhagic brain metastasis and this is most likely related to our aggressive treatment strategy that includes multiple craniotomies for metastatic tumor resection in addition to neoadjuvant chemotherapy and radiation therapy. We believe optimal treatment of skull angiosarcoma in children should aim gross total resection of the skull tumor including involving scalp and dura as well as neoadjuvant chemotherapy and radiation therapy, and the patient should be followed closely with repeated brain MRI studies to pursue additional surgeries to remove brain metastasis if feasible.

Cognitive and emotional impairments underpinning suicidal activity in patients with mood disorders: an fMRI study

OBJECTIVE

Mood disorders are strongly associated with suicide, the prevention of which is predicated on timely detection of suicidal activity (ideation, behaviour). Building on our previous work, we sought to determine the nature of neural responses to an emotional-cognitive task in patients with varying degrees of suicidal activity.

METHOD

Seventy-nine patients with mood disorders were assessed clinically and scanned using fMRI. Neural responses to an Emotional Face-Word Stroop task were compared with 66 healthy controls. We identified regions of interest from seven key networks and examined responses to incongruent stimuli (Happy face-'Sad' word; Sad face-'Happy' word).

RESULTS

In comparison with healthy controls, patients had differential activity during both incongruent conditions. When examining for associations with suicidal activity within the patient group, those with higher scores had decreased default mode network activity for Happy face-'Sad' word manipulation, and increased basal ganglia network activity for Sad face-'Happy' word manipulation, after controlling for patient characteristics.

CONCLUSION

The fMRI findings suggest that suicidal activity in patients with mood disorders may be underpinned by cognitive-emotional deficits. These findings have implications for future suicide research and for achieving a deeper understanding of suicidal activity that may ultimately inform clinical detection and management.

What is it like to work for a big five consulting firm? Interview by Barbara J. Linney

Is consulting for a big five a career direction you've thought about pursuing? In this column, Barbara Linney interviews physician executive Don Gessler, MD, MBA, CPE, FACPE, to talk about his experience in working for a big five consulting firm. He discusses how he got his position at ABC Consulting Firm, the nature of the work, the rigorous travel schedule, the pluses, and the type of physician executive that is satisfied in this environment. He describes some of the projects and tasks he has been involved in as a consultant. He emphasizes that if physicians don't like to do selling, consulting is not a place for them to be and that it is a very team-based structure.