Near-IR light-cleavable conjugates and conjugate precursors
Inventors
Schnermann, Martin John • Nani, Roger Rauhauser • Gorka, Alexander Patrick • Kobayashi, Hisataka
Assignees
US Department of Health and Human Services
Publication Number
US-10874739-B2
Publication Date
2020-12-29
Expiration Date
2037-08-07
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Abstract
Embodiments of near-infrared light-cleavable heptamethine cyanine-based conjugates, particularly targeting agent-drug conjugates, according to Formula I and conjugate precursors are disclosed. The disclosed targeting agent-drug conjugates are useful for targeted delivery and release of a drug. Methods of making and using the conjugates and precursors also are disclosed.
Core Innovation
This disclosure concerns near-infrared light-cleavable conjugates particularly targeting agent-drug conjugates comprising heptamethine cyanine fluorophores, conjugate precursors, and methods of making and using the conjugates. The targeting agents promote preferential or targeted delivery of a drug to a target site. The conjugates undergo photodegradation when irradiated with near-infrared light (650-900 nm), resulting in intramolecular cleavage and release of the drug. Advantageously, these conjugates are fluorophores whose fluorescence is lost upon photodegradation, enabling monitoring for location and drug release.
The problem being addressed is the lack of linker strategies for antibody-drug conjugates that provide improved cleavage selectivity with site-specific drug delivery. Existing intracellular enzymatic cleavage approaches have little inherent tumor selectivity, leading to off-target drug release and dose-limiting toxicities. Moreover, premature drug release in circulation is a significant issue. Near-IR light offers a solution due to tissue penetration, minimal toxicity, and clinical validation, but existing methods do not exploit near-IR externally applied stimuli to trigger site-specific drug release.
The invention provides conjugates where a heptamethine cyanine fluorophore scaffold cages the drug. Upon irradiation with near-IR light, a singlet oxygen-mediated cleavage mechanism causes cleavage of the cyanine scaffold, releasing the drug. The conjugate's fluorescence allows real-time monitoring of targeting and drug release. By separating drug release from cellular internalization, drug release occurs extracellularly at the target site, transferring molecules to adjacent antigen-negative cells to achieve bystander effects important for therapeutic efficacy.
Claims Coverage
The patent claims twelve independent inventive features mainly covering compositions of conjugates with specific chemical structures and methods of using these conjugates with near-infrared light for targeted drug release.
Composition of near-IR cleavable targeting agent-drug conjugates
Conjugates having a chemical structure according to Formula I, comprising heptamethine cyanine fluorophores linked to a drug moiety and a targeting agent (e.g., antibody), with specified substituents (R1-R19), linkers (L1, L2), and moieties (G1, G2, ring A) that enable near-infrared light-induced cleavage and drug release.
Tunable substituents for wavelength and biodistribution control
The presence and identities of substituents R1 and R4 (e.g., methyl, ethyl) and ring A (e.g., sulfonated phenyl) modulate the effective wavelength for photodegradation and improve biodistribution, allowing tuning of the conjugate's properties for deeper tissue penetration and in vivo use.
Conjugates with multiple heptamethine cyanine-drug moieties
Conjugates wherein multiple heptamethine cyanine-drug moieties (1-6) are conjugated to a single targeting agent, increasing fluorescence and potentially increasing drug payload released upon irradiation.
Pharmaceutical compositions comprising the conjugates
Pharmaceutical compositions comprising the conjugates and pharmaceutically acceptable carriers formulated for various administration routes suitable for in vivo delivery and subsequent drug release upon near-IR irradiation.
Methods for targeted light-induced drug release
Methods for administering the conjugates to biological samples or subjects, irradiating with near-infrared light of defined wavelength and intensity to induce cleavage and drug release, and optionally monitoring fluorescence loss to control irradiation dosing.
Theranostic methods combining diagnosis and treatment
Methods involving administering the conjugates, initially irradiating with fluorescence-inducing but cleavage-insufficient light to image and diagnose tumors, followed by therapeutic irradiation to release the drug selectively at the tumor site.
Kits for preparing and using conjugates
Kits comprising conjugates or precursors and instructions for conjugating drugs and targeting agents, optionally including solutions and reagents facilitating preparation and subsequent use of light-cleavable conjugates.
Precursor compounds for customized conjugation
Precursor compounds of defined chemical structure (Formula IV) that can be conjugated to drugs and targeting agents to form the near-IR cleavable conjugates, enabling custom synthesis of targeted conjugates.
Synthesis methods for conjugates and intermediates
Chemical synthesis pathways for precursor compounds, intermediate conjugates, and final targeting agent-drug conjugates incorporating the heptamethine cyanine fluorophore and appropriate linkers for light-induced cleavage.
Use of antibodies targeting tumor-associated antigens
Conjugates wherein the targeting agent is an antibody, such as panitumumab or trastuzumab, capable of recognizing tumor biomarkers (e.g., HER1, HER2), enabling tumor-targeted delivery of drug payloads.
Light parameters for effective cleavage
Use of near-infrared light with specified wavelengths (650-900 nm), intensities (1-1000 mW/cm2), and doses (1-250 J/cm2) to induce targeted drug release from the conjugates upon irradiation at or near the target site.
Monitoring drug release via fluorescence decay
Methods comprising monitoring conjugate fluorescence before and during irradiation, using the decrease in fluorescence as an indicator of cleavage completion and extent of drug release for precise control of therapeutic activation.
The claims collectively cover the chemical composition of near-infrared light-cleavable targeting agent-drug conjugates, pharmaceutical formulations, methods of their use for site-specific drug delivery activated by near-IR light, methods for monitoring drug release via fluorescence, synthesis protocols, and related kits. These inventive features provide a comprehensive system for targeted, externally controlled drug delivery using heptamethine cyanine fluorophore conjugates.
Stated Advantages
Site-specific delivery and selective activation of drug release using near-infrared light minimizes off-target toxicity.
Near-IR light provides significant tissue penetration and minimal toxicity, enabling clinical applicability for in vivo treatment.
Fluorescence of the conjugates allows real-time visualization and monitoring of drug localization and release in biological samples or subjects.
Extracellular release of drugs from conjugates enables bystander effects, enhancing therapeutic efficacy by affecting adjacent antigen-negative cells.
Customizable conjugate structure allows tuning of photodegradation wavelength and biodistribution to optimize treatment efficacy.
Compatibility with existing clinical near-IR optical tools facilitates adoption and integration into therapeutic regimens.
Documented Applications
Targeted delivery and site-specific release of anti-cancer drugs, particularly in tumor treatment, using antibody-conjugated heptamethine cyanine fluorophores activated by near-infrared light.
Fluorescence-guided surgery for tumor margin identification followed by targeted drug release to treat residual cancerous tissue.
In vitro and ex vivo diagnostics involving detection of target molecules in biological samples through targeted conjugate binding and near-IR fluorescence imaging.
Theranostic methods combining tumor diagnosis and treatment by sequential fluorescence imaging and drug release triggered by near-IR irradiation.
Customized preparation of conjugates for research or personalized medicine applications by conjugating selected drugs and targeting agents to precursor compounds.
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