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. Author manuscript; available in PMC: 2020 Aug 8.
Published in final edited form as: Bioconjug Chem. 2019 Sep 13;31(1):28–36. doi: 10.1021/acs.bioconjchem.9b00546

Table 1.

Comparison of NIR-PIT with the PDT method.

Near Infrared Photoimmunotherapy (NIR-PIT) Photodynamic Therapy (PDT)
Structurally defined high molecular weight antibody conjugate Mixture of low molecular weight porphyrins
Specifically targets cells via a cell-surface-binding antibody Relies on non-specific accumulation of dye in tissues after hydrophobic binding to plasma proteins.
Resistant to quenching effects due to 3D structure Oxygen concentration dependent and quenched readily on non-specific albumin binding
Acts on the targeted cell surface only after binding Relies on absorption of dyes internally into cells throughout the body
No normal, untargeted, cell activity Remains inside cancer cells longer than normal cells. Normal cells allowed to partially clear dye prior to laser application. https://www.cancer.gov/about-cancer/treatment/types/surgery/photodynamic-fact-sheet
Acts on only cells specifically bound by antibody-dye conjugate. Limited to no off-target tissue effects. Acts on all surrounding tissues containing dye. Substantial effects on surrounding tissues.
Damages and compromises conjugate-bound outer cell membranes Damages cells by intracellular radical formation and damage to intracellular membranes and mitochondria
Cetuximab-IR700DX dose = 640 mg/m2 Porfimer dose 2 mg/kg. Laser light at 40–50 hours followed by recommended debridement and second light dose at 96–120 hours.
Wavelength of light 690–700 nm Wavelength of light 630 nm
Extinction coefficient, ε =165,000 M−1cm−1 ε > 200 times lower than IR700DX
Clinical light dose 50 J/cm2; 100 J/cm Light dose of 200 or 300 J/cm2
Light exposure around 5 minutes Light exposure 8 minutes 20 seconds
Systemic treatment Local treatment
Curative intent on widely disseminated cancers Palliative. Porfimer sodium only approved agent for endobronchial and esophageal cancers for relief of blockages due to tumor growth.
Insertion of laser into tumor recommended, if possible, to reduce normal tissue exposure and damage
Inflammation a sign of a strong immune response Inflammation may be fatal
High risk of possible ocular damage
Patients susceptible to severe side-effects due to normal daylight, light bulbs etc. acting on dye located in/near all skin. Effects last for six weeks.