1
|
Perazzolo S. SAAM II: A general mathematical modeling rapid prototyping environment. CPT Pharmacometrics Syst Pharmacol 2024; 13:1088-1102. [PMID: 38863172 PMCID: PMC11247119 DOI: 10.1002/psp4.13181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 05/16/2024] [Accepted: 05/17/2024] [Indexed: 06/13/2024] Open
Abstract
Simulation Analysis and Modeling II (SAAM II) is a graphical modeling software used in life sciences for compartmental model analysis, particularly, but not exclusively, appreciated in pharmacokinetics (PK) and pharmacodynamics (PD), metabolism, and tracer modeling. Its intuitive "circles and arrows" visuals allow users to easily build, solve, and fit compartmental models without the need for coding. It is suitable for rapid prototyping of models for complex kinetic analysis or PK/PD problems, and in educating students and non-modelers. Although it is straightforward in design, SAAM II incorporates sophisticated algorithms programmed in C to address ordinary differential equations, deal with complex systems via forcing functions, conduct multivariable regression featuring the Bayesian maximum a posteriori, perform identifiability and sensitivity analyses, and offer reporting functionalities, all within a single package. After 26 years from the last SAAM II tutorial paper, we demonstrate here SAAM II's updated applicability to current life sciences challenges. We review its features and present four contemporary case studies, including examples in target-mediated PK/PD, CAR-T-cell therapy, viral dynamics, and transmission models in epidemiology. Through such examples, we demonstrate that SAAM II provides a suitable interface for rapid model selection and prototyping. By enabling the fast creation of detailed mathematical models, SAAM II addresses a unique requirement within the mathematical modeling community.
Collapse
Affiliation(s)
- Simone Perazzolo
- Nanomath LLC, Spokane, Washington, USA
- University of Washington, Seattle, Washington, USA
| |
Collapse
|
2
|
Orcutt KD, Henry KE, Habjan C, Palmer K, Heimann J, Cupido JM, Gottumukkala V, Cissell DD, Lyon MC, Hussein AI, Liu D, Li M, Johnson FL, Schultz MK. Dosimetry of [ 212Pb]VMT01, a MC1R-Targeted Alpha Therapeutic Compound, and Effect of Free 208Tl on Tissue Absorbed Doses. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27185831. [PMID: 36144563 PMCID: PMC9504749 DOI: 10.3390/molecules27185831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 08/26/2022] [Accepted: 08/27/2022] [Indexed: 01/28/2023]
Abstract
[212Pb]VMT01 is a melanocortin 1 receptor (MC1R) targeted theranostic ligand in clinical development for alpha particle therapy for melanoma. 212Pb has an elementally matched gamma-emitting isotope 203Pb; thus, [203Pb]VMT01 can be used as an imaging surrogate for [212Pb]VMT01. [212Pb]VMT01 human serum stability studies have demonstrated retention of the 212Bi daughter within the chelator following beta emission of parent 212Pb. However, the subsequent alpha emission from the decay of 212Bi into 208Tl results in the generation of free 208Tl. Due to the 10.64-hour half-life of 212Pb, accumulation of free 208Tl in the injectate will occur. The goal of this work is to estimate the human dosimetry for [212Pb]VMT01 and the impact of free 208Tl in the injectate on human tissue absorbed doses. Human [212Pb]VMT01 tissue absorbed doses were estimated from murine [203Pb]VMT01 biodistribution data, and human biodistribution values for 201Tl chloride (a cardiac imaging agent) from published data were used to estimate the dosimetry of free 208Tl. Results indicate that the dose-limiting tissues for [212Pb]VMT01 are the red marrow and the kidneys, with estimated absorbed doses of 1.06 and 8.27 mGyRBE = 5/MBq. The estimated percent increase in absorbed doses from free 208Tl in the injectate is 0.03% and 0.09% to the red marrow and the kidneys, respectively. Absorbed doses from free 208Tl result in a percent increase of no more than 1.2% over [212Pb]VMT01 in any organ or tissue. This latter finding indicates that free 208Tl in the [212Pb]VMT01 injectate will not substantially impact estimated tissue absorbed doses in humans.
Collapse
Affiliation(s)
- Kelly D. Orcutt
- Viewpoint Molecular Targeting, Inc., Coralville, IA 52241, USA
| | | | | | | | | | | | | | | | | | | | - Dijie Liu
- Viewpoint Molecular Targeting, Inc., Coralville, IA 52241, USA
| | - Mengshi Li
- Viewpoint Molecular Targeting, Inc., Coralville, IA 52241, USA
| | | | - Michael K. Schultz
- Viewpoint Molecular Targeting, Inc., Coralville, IA 52241, USA
- Department of Radiology, The University of Iowa, Iowa City, IA 52242, USA
- Department of Radiation Oncology, The University of Iowa, Iowa City, IA 52242, USA
- Departments of Radiology and Radiation Oncology, The University of Iowa, Iowa City, IA 52242, USA
- Correspondence: ; Tel.: +1-(319)-335-8017
| |
Collapse
|
3
|
Zaid NRR, Kletting P, Winter G, Prasad V, Beer AJ, Glatting G. A Physiologically Based Pharmacokinetic Model for In Vivo Alpha Particle Generators Targeting Neuroendocrine Tumors in Mice. Pharmaceutics 2021; 13:2132. [PMID: 34959413 PMCID: PMC8703774 DOI: 10.3390/pharmaceutics13122132] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 12/04/2021] [Accepted: 12/07/2021] [Indexed: 12/13/2022] Open
Abstract
In vivo alpha particle generators have great potential for the treatment of neuroendocrine tumors in alpha-emitter-based peptide receptor radionuclide therapy (α-PRRT). Quantitative pharmacokinetic analyses of the in vivo alpha particle generator and its radioactive decay products are required to address concerns about the efficacy and safety of α-PRRT. A murine whole-body physiologically based pharmacokinetic (PBPK) model was developed for 212Pb-labeled somatostatin analogs (212Pb-SSTA). The model describes pharmacokinetics of 212Pb-SSTA and its decay products, including specific and non-specific glomerular and tubular uptake. Absorbed dose coefficients (ADC) were calculated for bound and unbound radiolabeled SSTA and its decay products. Kidneys received the highest ADC (134 Gy/MBq) among non-target tissues. The alpha-emitting 212Po contributes more than 50% to absorbed doses in most tissues. Using this model, it is demonstrated that α-PRRT based on 212Pb-SSTA results in lower absorbed doses in non-target tissue than α-PRRT based on 212Bi-SSTA for a given kidneys absorbed dose. In both approaches, the energies released in the glomeruli and proximal tubules account for 54% and 46%, respectively, of the total energy absorbed in kidneys. The 212Pb-SSTA-PBPK model accelerates the translation from bench to bedside by enabling better experimental design and by improving the understanding of the underlying mechanisms.
Collapse
Affiliation(s)
- Nouran R. R. Zaid
- Medical Radiation Physics, Department of Nuclear Medicine, Ulm University, 89081 Ulm, Germany; (P.K.); (G.G.)
- Biophysics and Medical Imaging Program, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus 44839, Palestine
| | - Peter Kletting
- Medical Radiation Physics, Department of Nuclear Medicine, Ulm University, 89081 Ulm, Germany; (P.K.); (G.G.)
- Department of Nuclear Medicine, Ulm University, 89081 Ulm, Germany; (G.W.); (V.P.); (A.J.B.)
| | - Gordon Winter
- Department of Nuclear Medicine, Ulm University, 89081 Ulm, Germany; (G.W.); (V.P.); (A.J.B.)
| | - Vikas Prasad
- Department of Nuclear Medicine, Ulm University, 89081 Ulm, Germany; (G.W.); (V.P.); (A.J.B.)
| | - Ambros J. Beer
- Department of Nuclear Medicine, Ulm University, 89081 Ulm, Germany; (G.W.); (V.P.); (A.J.B.)
| | - Gerhard Glatting
- Medical Radiation Physics, Department of Nuclear Medicine, Ulm University, 89081 Ulm, Germany; (P.K.); (G.G.)
- Department of Nuclear Medicine, Ulm University, 89081 Ulm, Germany; (G.W.); (V.P.); (A.J.B.)
| |
Collapse
|