Progression-Free Survival in Patients with WHO-2 Meningioma Undergoing Active Surveillance Based on DOTATATE PET Evidence of Gross Total Resection: Prospective Observational Study

PURPOSE/OBJECTIVE(S)

MRI is the standard of care for meningioma radiotherapy planning, but lacks sensitivity for postoperative small volume disease and osseous or parenchymal invasion. NRG-BN003 (NCT03180268) randomizes patients with WHO-2 meningiomas and MRI-determined gross total resection (GTR) to observation or 60 Gy IMRT to the resection bed. More sensitive and specific imaging biomarkers than MRI may improve clinical outcomes in meningioma by limiting unnecessary irradiation of normal tissues and improving radiotherapy targeting. [68Ga]-DOTATATE, a PET radiotracer targeting somatostatin receptor 2 (SSTR2) is a highly sensitive and specific meningioma biomarker. Our dedicated DOTATATE brain PET/MRI and PET/CT protocol allows meningioma differentiation from post-treatment change, using SUV analysis and Patlak modeling. Our prospective IRB-approved observational trial (NCT04081701) has imaged >100 patients with meningioma. In the sub-analysis presented here, we prospectively evaluated PFS in patients with WHO-2 tumors and postoperative GTR as determined by [68Ga]-DOTATATE brain PET/MRI or PET/CT who were managed solely with active surveillance. We hypothesized that the PFS of patients with GTR by PET managed with active surveillance would be higher than reported PFS data for patients with MRI-determined GTR, using NRG-BN003's observation arm (randomized trial comparing observation to fractionated RT) as a reference standard.

MATERIALS/METHODS

From the cohort of >100 patients with SSTR2-positive brain neoplasms enrolled between 9/2019 and 10/2022 and imaged according to our previously published protocol, a sub-cohort of patients were selected with WHO-2 meningioma, postoperative findings of GTR, and postoperative active surveillance with periodic MRI every 3-6 months. Kaplan-Meier survival analysis was performed.

RESULTS

A total of 12 patients met inclusion criteria. Mean patient age was 64 years and 5 (42%) were female. Mean follow up period was 23.4 months (range: 7-38). 83% (10/12) patients underwent postoperative PET/MRI and 17% (2/12) underwent PET/CT. 2 patients (17%) progressed, at 22 and 34 months, respectively; the remainder remain progression-free. Both patients who had progression were successfully salvaged with focal fractionated radiosurgery. Kaplan-Meier analysis demonstrated PFS at almost 3 years to be 75%, which is substantially higher than the reported 3-year PFS of 60% in the literature. Overall survival was 100%.

CONCLUSION

[68Ga]-DOTATATE PET can improve the specificity of imaging-based assessment of the extent of resection of WHO-2 meningiomas, thereby improving clinical outcomes. In this cohort of patients with completely resected WHO-2 meningiomas (as assessed by postoperative gadolinium-enhanced MRI and DOTATATE PET) who are conservatively managed, recurrences have been rare and amenable to radiosurgical salvage.

Cost-Effectiveness Analysis of 68Ga-DOTATATE PET/MRI in Radiotherapy Planning in Patients with Intermediate-Risk Meningioma

BACKGROUND AND PURPOSE

While contrast-enhanced MR imaging is the criterion standard in meningioma diagnosis and treatment response assessment, gallium 68Ga-DOTATATE PET/MR imaging has increasingly demonstrated utility in meningioma diagnosis and management. Integrating 68Ga-DOTATATE PET/MR imaging in postsurgical radiation planning reduces the planning target volume and organ-at-risk dose. However, 68Ga-DOTATATE PET/MR imaging is not widely implemented in clinical practice due to higher perceived costs. Our study analyzes the cost-effectiveness of 68Ga-DOTATATE PET/MR imaging for postresection radiation therapy planning in patients with intermediate-risk meningioma.

MATERIALS AND METHODS

We developed a decision-analytical model based on both recommended guidelines on meningioma management and our institutional experience. Markov models were implemented to estimate quality-adjusted life-years (QALY). Cost-effectiveness analyses with willingness-to-pay thresholds of $50,000/QALY and $100,000/QALY were performed from a societal perspective. Sensitivity analyses were conducted to validate the results. Model input values were based on published literature.

RESULTS

The cost-effectiveness results demonstrated that 68Ga-DOTATATE PET/MR imaging yields higher QALY (5.47 versus 5.05) at a higher cost ($404,260 versus $395,535) compared with MR imaging alone. The incremental cost-effectiveness ratio analysis determined that 68Ga-DOTATATE PET/MR imaging is cost-effective at a willingness to pay of $50,000/QALY and $100,000/QALY. Furthermore, sensitivity analyses showed that 68Ga-DOTATATE PET/MR imaging is cost-effective at $50,000/QALY ($100,000/QALY) for specificity and sensitivity values above 76% (58%) and 53% (44%), respectively.

CONCLUSIONS

68Ga-DOTATATE PET/MR imaging as an adjunct imaging technique is cost-effective in postoperative treatment planning in patients with meningiomas. Most important, the model results show that the sensitivity and specificity cost-effective thresholds of 68Ga-DOTATATE PET/MR imaging could be attained in clinical practice.

AFIR: A Dimensionless Potency Metric for Characterizing the Activity of Monoclonal Antibodies

For monoclonal antibody (mAb) drugs, soluble targets may accumulate several thousand fold after binding to the drug. Time course data of mAb and total target is often collected and, although free target is more closely related to clinical effect, it is difficult to measure. Therefore, mathematical models of this data are used to predict target engagement. In this article, a “potency factor” is introduced as an approximation for the model‐predicted target inhibition. This potency factor is defined to be the time‐Averaged Free target concentration to Initial target concentration Ratio (AFIR), and it depends on three key quantities: the average drug concentration at steady state; the binding affinity; and the degree of target accumulation. AFIR provides the intuition for how changes in dosing regimen and binding affinity affect target capture and AFIR can be used to predict the druggability of new targets and the expected benefits of more potent, second‐generation mAbs.

Synthesis of Some New Isoxazoline Derivatives of Chalconised Indoline 2-one as a Potential Analgesic, Antibacterial and Anthelmimtic Agents

A series of novel 1[5”-(2”’-substituted phenyl)-4”,5”’-dihydro isoxazole-3”-yl]-3-[(4 substituted phenyl)imino]1-3-dihydro-2H-indole-2-one were synthesized from different substituted chalconised indole-2,3-dione was prepared from the different chalconised Isatin. The structures of the compounds were elucidated by elemental and spectral (IR, ¹H NMR, and MS) analysis. The synthesized compounds were screened for their analgesic activity by the acetic acid induced Writhing method and in vitro antimicrobial activity against the Gram-positive bacteria—Staphylococcus aureus and the Gram-negative bacteria—Pseudomonas auroginosa, Pseudomonas mirabilis, and E. coli by the cup plate agar diffusion method. Compounds 6a₁, 6a₃, 6b₃, and 6b₂ were found to be active against bacteria. The compounds 6a₁, 6b₃, and 6a₃ show a significant analgesic activity. Synthesized compounds also screened for anthelmintic activity against Pheretima posthuma. Compounds 6a₁, 6b₁, and 6b₃ show significant anthelmintic activity.

Flux-balance analysis of mitochondrial energy metabolism: consequences of systemic stoichiometric constraints

Mitochondrial metabolism is a critical component in the functioning and maintenance of cellular organs. The stoichiometry of biochemical reaction networks imposes constraints on mitochondrial function. A modeling framework, flux-balance analysis (FBA), was used to characterize the optimal flux distributions for maximal ATP production in the mitochondrion. The model predicted the expected ATP yields for glucose, lactate, and palmitate. Genetic defects that affect mitochondrial functions have been implicated in several human diseases. FBA can characterize the metabolic behavior due to genetic deletions at the metabolic level, and the effect of mutations in the tricarboxylic acid (TCA) cycle on mitochondrial ATP production was simulated. The mitochondrial ATP production is severely affected by TCA-cycle mutations. In addition, the model predicts the secretion of TCA-cycle intermediates, which is observed in clinical studies of mitochondriopathies such as those associated with fumarase deficiency. The model provides a systemic perspective to characterize the effect of stoichiometric constraints and specific metabolic fluxes on mitochondrial function.

Key adhesion molecules are present on long podia extended by hematopoietic cells

BACKGROUND

We recently reported that CD34(+) hematopoietic cells and the KG1a cell line extend long, thin podia. These podia can dynamically extend and retract, often adhere to the substrate, and appear to connect cells up to 300 microm apart. The surface receptors found on these podia have not been described.

METHODS

By using time-lapse fluorescent microscoscopy and immunostaining techniques, we describe a method for detecting surface receptors on these podia. This includes an in situ antibody staining procedure without fixing cells.

RESULTS

We demonstrate, using CD34 selected mobilized peripheral blood cells and KG1a cells, that adhesion molecules known to play important roles in blood-cell migration and adhesion are present on these podia. These include: CD11a, CD18, CD29, CD34, CD45, CD49d, CD49e, and CD62L. Additionally, CD54 and CD44 were present on the podia extended by KG1a cells, but were not detectable on the primary CD34(+) cells. The integrin CD49d localized at the base of these podia in a time-dependent manner in KG1a cells. The frequency and morphology of these long podia on three myeloid leukemia-cell lines (KG1a, MV4-11, and AML-193) and a CD34-negative T-cell line (CEM) are also compared. KG1a and CEM cell lines extend long, dynamic podia that are similar to the podia on primary CD34(+) cells in morphology and adhesion molecule expression. The AML-193 and MV4-11 cell lines, however, did not extend these long podia.

CONCLUSIONS

We describe a technique that provides a method of detecting surface receptors on thin cell membrane projections. These results support the likely role of these podia in cell migration and cell-cell communication.

Gene identification in bacterial and organellar genomes using GeneScan

The performance of the GeneScan algorithm for gene identification has been improved by incorporation of a directed iterative scanning procedure. Application is made here to the cases of bacterial and organnellar genomes. The sensitivity of gene identification was 100% in Plasmodium falciparum plastid-like genome (35 kb) and in 98% in the Mycoplasma genitalium genome (approximately 580 kb) and the Haemophilus influenzae Rd genome (approximately 1.8 Mb). Sensitivity was found to improve in both the Open Reading Frames (ORFs) which have been identified as genes (by homology or by other methods) and those that are classified as hypothetical. False positive assignments (at the nucleotide level) were 0.25% in H. influenzae genome and 0.3% in M. genitalium. There were no false positive assignments in the plastid-like genome. The agreement between the GeneScan predictions and GeneMark predictions of putative ORFs was 97% in M. genitalium genome and 86% in H. influenzae genome. In terms of an exact match between predicted genes/ORFs and the annotation in the databank, GeneScan performance was evaluated to be between 72% and 90% in different genomes. We predict five putative ORFs that were not annotated earlier in the GenBank files for both M. genitalium and H. influenzae genomes. Our preliminary analysis of the newly sequenced G + C rich genome of Mycobacterium tuberculosis H37Rv also shows comparable sensitivity (99%).

Two new pseudopod morphologies displayed by the human hematopoietic KG1a progenitor cell line and by primary human CD34(+) cells

A primitive human hematopoietic myeloid progenitor cell line, KG1a, characterized by high expression of the CD34 surface antigen has been observed to extend long, thin pseudopodia. Once extended, these pseudopods may take on one of two newly described morphologies, tenupodia or magnupodia. Tenupodia are very thin and form in linear segments. They adhere to the substrate, can bifurcate multiple times, and often appear to connect the membranes of cells more than 300 micrometer apart. Magnupodia are much thicker and have been observed to extend more than 330 micrometer away from the cell. Magnupods are flexible and can exhibit rapid dynamic motion, extending or retracting in a few seconds. During retraction, the extended material often pools into a bulb located on the pod. Both morphologies can adhere to substrates coated with fibronectin, collagen IV, and laminin as well as plastic. The CD34 and CD44 antigens are also present on the surface of these podia. Primary human CD34(+) cells from fetal liver, umbilical cord blood, adult bone marrow, and mobilized peripheral blood extend these podia as well. The morphology that these pseudopods exhibit suggest that they may play both sensory and mechanical roles during cell migration and homing after bone marrow transplantation.

Heparin-induced thrombocytopenia: cross-reactivity between standard heparin, low molecular weight heparin, dalteparin (Fragmin) and heparinoid, danaparoid (Orgaran)

The incidence of cross-reactivity between unfractionated heparin and LMWH, fragmin, in patients with HIT is significantly lower (6/15, 40%) than hitherto reported in the literature. 7/9 patients with a negative cross-reactivity test were treated with dalteparin sodium (Fragmin) without any untoward events.

Evans' syndrome, myelofibrosis and systemic lupus erythematosus: role of procollagens in myelofibrosis

We describe an 18 yr old female with systemic lupus erythematosus presenting with Evans' syndrome (autoimmune hemolytic anemia and immune thrombocytopenia) and dense myelofibrosis. Her clinical course and response to treatment were monitored with regular blood counts, serial measurements of serum procollagen I and III and periodic bone marrow examinations. This report brings to 9 the number of well-documented cases of systemic lupus erythematosis and myelofibrosis in the literature; we discuss the pathogenesis and management of patients with this apparently rare disorder, with particular reference to the role of serum procollagen measurements as markers of myelofibrosis.

Auto-immune haemolytic anaemia in ulcerative colitis

We report 2 patients with auto-immune haemolytic anaemia (AIHA) complicating ulcerative colitis (UC), each with a hitherto undescribed feature. In the 1st case, direct antiglobulin test showed red cells coated with complement only, and the 2nd case was successfully treated with danazol. These 2 patients bring to 40 the number of cases of AIHA associated with UC. A review of the clinical details suggests that the patients may be divided into two distinct groups. In the first (4/40), AIHA seems to occur as an auto-immune event independent of the activity of UC; in the second group (36/40), AIHA is apparently dependent on active colitis, i.e. control of colitis is crucial to control haemolysis.

Haematological manifestations of primary Sjögren's syndrome: a clinicopathological study

Clinically significant cytopenias are thought to be uncommon in primary Sjögren's syndrome: only a few cases have been reported in the literature. Over a 3-year period we identified haematological abnormalities in 11 of 27 patients with Sjögren's syndrome. Six patients had a positive direct antiglobulin test, including one patient with all the features of autoimmune haemolytic anaemia and two others with some features of this condition. Four patients had immune thrombocytopenia and two patients had myelodysplastic syndrome. Neutropenia was noted in two patients, one patient had aplastic anaemia and one had pure red cell aplasia. Haematological disorders were found to be common in patients with Sjögren's syndrome (40 per cent). Accordingly, we suggest that patients with immune cytopenia(s) should be screened for Sjögren's syndrome using sensitive assays for anti-SS.A and anti-SS.B antibodies, and that patients with Sjögren's syndrome should be periodically monitored, with a full blood count to rule out any haematological abnormality.

Designing of a brain stimulator suitable for intracranial self-stimulation experiments for studying the brain-stimulation reward system

A circuit design has been developed and described for fabricating and using in the intracranial self-stimulation experiments on rat to study the brain-stimulation reward behaviour, and to explore into the underlying mechanisms of drives and motivated behaviours. The stimulator can be fabricated with parts available in India. It has been continuously used and tested during the last four years in different research studies.