New targeted imaging agents and the diagnosis, prognosis of progressive disease

According to a media release issued today by Progenics Pharmaceuticals, early clinical studies of two of their investigational products — the imaging agents [123I]-MIP-1072 and [123I]-MIP-1095 — suggest potential of these two agents in enhancement of imaging techniques to identify the exact location of cancer in bone, tissue, and the prostate itself.

The data from these early studies has just been published by Barrett et al. in the Journal of Nuclear Medicine.

[123I]-MIP-1072 and [123I]-MIP-1095 are small, novel, radiolabeled molecules that can target prostate-specific membrane antigen (PSMA). Barrett et al. adminustered both products to seven men with a documented history of prostate cancer by histopathology or radiologic evidence of metastatic disease. They also administered [123I]-MIP-1072 to six healthy volunteers. All the colunteers then underwent whole-body planar and single photon emission computed tomography/computed tomography (SPECT/CT) imaging.

The basic findings of the study are as follows:

  • [123I]-MIP-1072 and [123I]-MIP-1095 were able to facilitate visualization of prostate cancer lesions in soft tissue, bone, and the prostate gland within 0.5 to 1 h after injection, with retention beyond 48 h.
  • [123I]-MIP-1072 was excreted in the urine, with 54 percent and 74 percent present by 24 and 72 h, respectively.
  • By contrast, only 7 percent and 20 percent of [123I]-MIP-1095 had been excreted renally by 24 and 72 h, respectively.

The authors conclude that [123I]-MIP-1072 and [123I]-MIP-1095 can detect lesions in soft tissue, bone, and the prostate gland at as early as 1–4 h. They also state that these two novel molecules have good pharmacokinetic and pharmacodynamic profiles and can potentially be further developed as diagnostic and (perhaps) therapeutic radiopharmaceuticals.

Apparently Progenics has recently acquired all rights to these two molecules, as well as to another small, radiolabeled molecule known as [99mTc]MIP-1404. An international, multi-center Phase II trial is already investigating the clinical activity of [99mTc]MIP-1404 and is currently enrolling patients.

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