Technology

Introduction

Lumiphore’s chelation technology meets the unmet need of rapid, stable chelation at or below physiological temperature with exceptional in-vivo stability for a wide range of radionuclides. Our mBFC technology is the next generation of chelation technology with fundamental features surpassing DOTA, DTPA, and DFO for radiotheranostic applications.

Our proprietary chelation platform, paired with an appropriate targeting vector (such as an antibody, antibody fragment, protein or peptide), facilitates reliable localization of radionuclides to biological sites of interest.

The company’s proprietary ‘Raymond Chelation Technology’ reworks Nature’s siderophore components into macrocyclic Bi-Functional Chelators (mBFCs), suitable for:

attachment to targeting vectors, quick and stable binding radiometals of interest, simple chelation protocol at physiological temperature, one mBFC, many metal compatibility, and high TRF intensity fluorescent reporting capabilities in vitro for cell based discovery.

These macrocyclic BFCs are best-in-class materials for reliable incorporation and delivery of metal ion payloads in medicine.

Science Of Raymond’s Macrocyclic Bi-Functional Chelators (MBFC)

The academic research of Prof. Kenneth Raymond (University of California – Berkeley) has focused on aromatic bidentate chelating units commonly used by bacteria in nature as iron scavengers, known as siderophores. These chelators bind metal ions using only oxygen atoms, which results in chelators that have unmatched aqueous stability with hard metal ions such as lanthanides, actinides, and group III and group IV transition metals.

Examples of these bidentate chelators include hydroxyisophthalamides (IAMs), hydroxypyridinones (HOPOs), and dihydroxyterephthalamides (TAMs), shown below.

Lumiphore, we have linked multiple copies of these bidentate chelators together into larger macrocyclic molecular frameworks, collectively described as macrocyclic BiFunctional Chelators. The bifunctional characteristic being both metal binding and disease targeting elements achieved through covalent chemistry options of the mBFC.

Decades of experience designing these molecular frameworks, has resulted in the preorganization of bidentate chelators for metal ion binding. Preorganization greatly enhances the stability of the chelator-metal ion complexes. The macrocyclic BFCs can be conceptualized as molecular ‘cages’ that inhibit the release of the metal ion, once bound. With unsurpassed ease of use, high stability, and rapid chelation, these macrocyclic BFCs form the basis of the company’s chelation technology, and set the new standard for use of radionuclides in diagnostic and therapeutic applications.

Single Molecule Targeted Radio-Theranostics (TRT)

Radiotheranostics is a combination of the terms radioactive therapeutics and diagnostics. Targeted RadioTheranostics (TRTs) are a growing segment of the multi-billion-dollar radio-pharmaceutical market. Major pharmaceutical companies such as Bayer AG and Novartis AG have made major investments leading to revenue-generating therapies with more to come from them and others.

Broadly speaking, this class of radio-pharmaceuticals are also known under a myriad of coined terms and initialisms such as:

  • AWE antibody warhead enabling technology
  • MRT molecularly-targeted radiation
  • PRRT peptide receptor radionuclide therapy
  • RIT radio-immunotherapy
  • RLT radio-ligand therapy
  • TTC thorium targeted conjugates
  • TRT targeted radio-therapeutics
  • TRT targeted radionuclide therapy
  • TRT targeted radiotheranostics

Lumiphore’s primary focus is making use of its macrocyclic BFC technology in the development of Targeted RadioTheranostics (TRT). Lumiphore, with its partner Bayer AG, entered the new era of personalized medicine with TRTs, a class of molecular constructs for diagnosis, monitoring, and treatment of cancer.

The power of this approach lies in the ability to use one radionuclide for diagnosis and monitoring (e.g. Zr-89 PET), while swapping in a different radionuclide (e.g. Lu-177 or Th-227) for targeted therapy of primary tumors and metastases, using the same prodrug material.

Lumiphore’s macrocyclic BFC technology solves the unmet need of enabling single molecule TRT with material benefits of ease of use, fast incorporation of the radio-isotope at or below physiological temperature, and holding the isotope tightly in vivo. Unlike chemotherapy, TRTs bind and kill tumor cells while minimizing damage to healthy cells and tissues limiting collateral damage to healthy cells. TRTs have the advantage of a wider therapeutic window over nontargeted chemotherapeutic agents. These TRTs are molecular conjugates comprising a targeting vector covalently linked to a chelator that holds the radionuclide payload.

The radioactive payload delivers localized radiation to the cancer cells, promoting cell death primarily through DNA damage. Alpha radiation is a very potent with a limited range kill range of 75-200 micrometers (only a few cell diameters), and it is the most effective form of radiation for causing irreparable double strand DNA breakage. Beta radiation is generally less potent that alpha, but it also has an extended kill range of up to half a centimeter. Using the same mBFC for the alpha and beta radiation, and PET imaging of cancer sites provides ability to track therapeutic progress.

The benefits of the company’s mBFCs for TRTs are:

Ease-of-Use

•     radiolabeling performed under physiologic conditions & mild temperatures

•     preserve sensitive targeting agents

•     ease-of-use for the radio-pharmacy

Radio-metal Tightly Held

•     delivery & dosage maximized by chelators holding the radio-metal during delivery effectively minimizing side effects of released radiometal

Delivering radio-active therapeutic potency

•     Potential to kill tumor cells with low-number target receptor expression.

Enables fluorescent tracking

•     chelators can be used to develop assays for bio-distribution, PK, metabolism, etc.

Multiple covalent chemistries

•     mBFCs can be provided with many different linker chemistry for targeting agent labeling

•     includes NHS ester, maleimide, isothiocyanate, amine, carboxylate, carbonyl, and others

Compatible with all targeting agent classes

•     ideal for targeting agents with secondary structures or thermal sensitivities such as antibodies, Fabs, scFvs, minibodies, diabodies, etc.

•     easily coupled with peptides, peptoids, nucleic acids, oligos, small molecules, hormones and other targetingagents

Introducing Lumi804 – Next Generation Radiometal Chelation

Lumiphore has introduced its new 1,2-HOPO macrocyclic BFC for TRT use dubbed Lumi804TM. This single molecule chelate can handle a variety of radio-metals and is available for licensing and collaboration opportunities.

One mBFC – Multiple Radiometals

Retaining a small but important degree of flexibility is a feature of all of our macrocyclic BFCs. Shown above are the crystal structures of Eu-, Lu- and Zr-Lumi804 parent mBFCs, demonstrating how a wide range of metal ion sizes can all be accommodated by a single partially flexible chelator.

Additionally, Europium is highly sensitized by Lumi804 with a quantum yield approaching 30% - highest available for aqueous environment. This an other core features are enabling in vitro assay and analysis utilizing Time Resolved Fluorescence (TRF) or TR-FRET.

Stable In-Vivo Chelation

Complex stability was probed with 1:1 metal:Lumi804 complexes, HPLC purified, incubated in 250 mM DTPA at pH = 7.4 for up to 18 days. As Lumi804 has a characteristic absorption spectra differentiating the Prescence or absence of chelated metal, this was monitored for up to 18 days at 24C.

Sensitive Mix-and-Read Diagnostics for Drug Discovery and Diagnostics

Demand in diagnostic assays is greatest for reagents with sensitivity better than can be achieved with organic fluorescent molecules. It is generally recognized that luminescent lanthanide reporters have shown great promise for increased sensitivity via time-gated measurement, but development of bright and stable metal reporters has lagged.

Lumiphore’s mix-and-read assay technology leverages similar macrocyclic bifunctional chelators as employed in TRTs. These fluorescent mBFC reporters are attached to antibodies used in time-resolved Förster resonance energy transfer (TR-FRET) tests and assays. This technology produces very high sensitivity, eliminates background noise, eliminates labor-intensive steps (just mix-and read), and has been adapted to large laboratory operations all the way down to the doctor’s office point-of-care testing.

The company’s benefits of MBFCs to metal fluorescence diagnostics and assays over current fluorescent systems are:

High sensitivity

Long lifetimes and high quantum yields yield time-resolved measurement with high signal-to-noise (improved sensitivity) that is competitive with traditional fluorophores.

Multiplexing: more data density per assay unit

Compounds are compatible with TR-FRE assay formats with demonstrated pentaplex capabilities.

Elimination of quenching

A large Stokes Shift (gap between excitation and emission energies) means mBFCs are not as susceptible to  self-quenching and easily tunes optics with wide transmissions.

Recovery of information from archives

Resistance to photo bleaching allows archiving of samples for improved quality control and for comparisons between old and new data.

Lumiphore’s macrocyclic chelation technology facilitates bright luminescent and stable metal ion complexes suitable for ultrasensitive detection. The company has developed a hydroxyisophthalamide macrocyclic BFC to bind and sensitize the luminescent metal terbium (Lumi4®-Tb). Facilitating time-gated reporting that outlasts the fluorescence of other molecules, resulting in vastly improved signal-to-noise.

Lumi804-Eu binds and sensitizes the luminescent metal europium, which emits at different wavelength than terbium, permitting simultaneous multi-channel fluorescent testing. Both Lumi4®-Tb and Lumi804™-Eu are used in high value homogenous assays.

 

Publications

  • Foster, A. et al.: Novel theranostic agent for PET imaging and targeted radio-pharmaceutical therapy of tumour-infiltrating immune cells in glioma. EBioMedicine (by THE LANCET) 71: 1-10, 2021. [https://doi.org/10.1016/j.ebiom.2021.103571]
  • Nigam, S. et al.: Zr-89 and Lu-177 labeled Lumi804-anti-CD11b antibody for PET imaging and targeted radiopharmaceutical therapy in an orthotopic mouse model of glioma. Society of Nuclear Medicine and Molecular Imaging (abstract/poster), 2020.
  • Bhatt, N.B., Pandya, D.N., Xu, J., Tatum, D., Magda, D, Wadas, T.J. “Evaluation of macrocyclic hydroxyisophthalamide ligands as chelators for zirconium-89.” PLoS One 2017 Jun 2;12(6):e0178767.
  • Tinianow, J.N.; Pandya, D.N.; Pailloux, S.L.; Ogasawara, A.; Vanderbilt, A.N.; Gill, H.S.; Williams, S.P.; Wadas, T.J.; Magda, D.; Marik, J. “Evaluation of a 3-hydroxypyridin-2-one (2,3-HOPO) Based Macrocyclic Chelator for 89Zr4+ and Its Use for ImmunoPET Imaging of HER2 Positive Model of Ovarian Carcinoma in Mice.” Theranostics, 2016; 6(4): 511-521.
  • Pandya, D.N.; Pailloux, P.; Tatum, D.; Magda, D.; Wadas, T.J. “Di-macrocyclic terephthalamide ligands as chelators for the PET radionuclide zirconium-89.” Chem. Commun., 2015, 51, 2301.
  • Chen, T. et al.: Time Gated Luminescence Imaging of Immunolabeled Human Tissues. Anal. Chem. 89: 12713−12719, 2017. [https://doi.org/10.1021/acs.analchem.7b02734]
  • Tinianow, J.N. et al.: Evaluation of a 3-hydroxypyridin-2-one (2,3-HOPO) Based Macrocyclic Chelator for 89Zr4+ and Its Use for ImmunoPET Imaging of HER2 Positive Model of Ovarian Carcinoma in Mice. Theranostics 6 (4): 511-521, 2016. [https://doi.org/10.7150/thno.14261]
  • Mohandessi, S. et.al.: Cell-Penetrating Peptides as Delivery Vehicles for a Protein-Targeted Terbium Complex. Chem. Eur. J. 18 (35): 10825-10829, 2012.[https://doi.org/10.1002/chem.201201805]
  • Xu, J. et al.: Octadentate Cages of Tb(III) 2-Hydroxyisophthalamides: A New Standard for Luminescent Lanthanide Labels. J. Am. Chem. Soc. 133 (49), 19900–19910, 2011.[https://doi.org/10.1021/ja2079898]
  • Morgner, F. et al.: A Quantum Dot-Based Molecular Ruler for Multiplexed Optical Analysis. Angew. Chem. Int. Ed. 49 (41): 7570-7574, 2010 [https://doi.org/10.1002/anie.201002943]
  • Geißler, D. et al.: Quantum Dot Biosensors for Ultrasensitive Multiplexed Diagnostics. Angew. Chem. Int. Ed. 49 (8): 1396-1401, 2010. [https://doi.org/10.1002/anie.200906399]

Subscribe for Company and Technology Updates