Introduction
Radiolabeling of a monoclonal antibody (mAb) with a metallic radionuclide requires the conjugation of a bifunctional chelator to the mAb. The conjugation, however, can alter the physical and immunological properties of the mAb, consequently affecting its tumor targeting pharmacokinetics. In this study, we investigated the effect of the amount of 2-(p-isothiocyanatobenzyl)-cyclohexyl-diethylenetriamine-pentaacetic acid (CHX-A″) conjugated to MORAb-009, a mAb directed against mesothelin and the effect of MORAb dose on the biodistribution of 111In labeled MORAb-009.
Methods
We used nude mice bearing A431/K5 tumor as a mesothelin-positive tumor model and A431 tumor as a mesothelin-negative control. To find the optimal level of CHX-A″ conjugation, CHX-A″-MORAb-009 conjugates with 2.4, 3.5, and 5.5 CHX-A″ molecules were investigated. To investigate the effect of injected MORAb-009 dose on neutralizing the shed-mesothelin in the circulation, the biodistribution studies were performed after the i.v. co-injection of the 111In labeled MORAb-009 (2.4 CHX-A″/MORAb-009) with three different doses, 0.2, 2, and 30 μg of MORAb-009.
Results
The tumor uptake in A431/K5 tumor was 4 times higher than that in A431 tumor, indicating that the tumor uptake in A431/K5 was mesothelin-mediated. The conjugate with 5.5 CHX-A″ showed a lower isoelectric point (pI) and lower immunoreactivity (IR) than the 2.4 CHX-A″ conjugate. These differences were reflected in biodistribution of the 111In label. The 111In labeled MORAb-009 conjugated with 2.4 CHX-A″ produced higher tumor uptake, and lower liver and spleen uptakes than the 5.5 CHX-A″ conjugate. The biodistribution studies also revealed that the tumor uptake was significantly affected by the injected MORAb-009 dose and tumor size. The 30 μg dose produced higher tumor uptake than the 0.2 and 2 μg doses whereas the 30 μg dose produced lower liver and spleen uptakes than the 0.2 μg dose.
Conclusion
This study demonstrates that the number of chelate conjugation and the injected dose are two important parameters to achieve high tumor and low non-target organ uptake of 111In labeled MORAb-009. This study also suggests that the injected dose of mAb could be individualized based on the tumor size or the blood level of shed-antigen in a patient to achieve the ideal tumor-to-organ radioactivity ratios.
Background: Clinical pharmacy continues to rapidly evolve as does the need to incorporate unique learning opportunities in pharmacy residency training (eg, transitions of care). Objective: To describe the impact of incorporating pharmacy residents into a pharmacist-managed emergency department culture review service (CRS). Methods: This retrospective study included 500 cultures with positive results evaluated by a pharmacy resident during weekend staffing shifts for patients discharged from the emergency department or urgent care center (UCC). The primary outcome of this study was the number of interventions performed by pharmacy residents. Results: Of the 500 cultures evaluated, 275 (55%) required action by the pharmacy residents, resulting in 233 interventions. Modification of antimicrobial therapy occurred 70 times. When surveyed, a majority of residents strongly agreed that the CRS had a positive impact. Based on evaluations, residents achieved mastery of pertinent residency performance objectives. Conclusion: Incorporation of pharmacy residents into a pharmacist-managed emergency department CRS promotes safe and effective medication use to patients discharged from an emergency department or UCC while providing residents additional experience in designing a therapeutic regimen, providing education to patients, and communicating with health-care teams to manage medication therapy.
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