A phase 0 microdosing trial to identify chemoresistance in bladder cancer.
C. Pan, S. Wang, M. He, Ralph W. de Vere White, Primo N. Lara, David R. Gandara, Philip C. Mack, Kenneth W. Turteltaub, Paul T. Henderson
Journal of Clinical Oncology March 1, 2011 DOI: 10.1200/jco.2011.29.7_suppl.264 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Preclinical study with cell lines and mouse xenografts; also describes planned phase 0 clinical trials Peer reviewed |
|---|---|
| Population | Cancer cell lines and mice bearing tumor xenografts; also mentions bladder cancer patients and dogs in planned trials |
| Dose | one microdose (1/100th of the therapeutic dose) |
| Topics | Microdosing |
| Key findings | Low levels of DNA damage induced by a subtoxic microdose of [14C]carboplatin predict chemoresistance in cancer cell lines. Microdose-induced DNA damage was linearly proportional to therapeutic-dose damage (R²=0.92, p<0.001). |
Abstract
264
Background: DNA damage is the critical step in cancer cell response to platinum (Pt) chemotherapy. We hypothesize that low levels of Pt-induced DNA damage are predictive of chemoresistance. Accelerator mass spectrometry (AMS) is an ultrasensitive method for measuring radiocarbon. By measuring 14C bound to DNA, AMS can detect carboplatin-induced DNA damage after patients receive one subtoxic microdose of 14C-labeled carboplatin.
Methods: Cancer cells and mice bearing tumor xenografts were treated with one microdose (1/100th of the therapeutic dose) or one therapeutic dose of [14C]carboplatin. Carboplatin-DNA adducts and other relevant parameters such as drug influx/efflux, intracellular drug inactivation, and repair of DNA damage, were measured and correlated with response to chemotherapy.
Results: AMS detected Pt-DNA damage when cancer cells and mice with tumor xenografts were exposed to one microdose of [14C]carboplatin. The levels of microdose-induced DNA damage were linearly proportional to the DNA damage caused by the therapeutic drug dose (R2=0.92, p<0.001); and these levels of DNA damage correlated with chemoresistance. Low DNA damage predicts chemoresistance. Measuring drug uptake/efflux, intracellular inactivation and DNA repair allowed insight into some resistance mechanisms. We have opened a phase 0 microdosing trial to study patients with bladder cancer who are scheduled to receive Pt-based chemotherapy. One subtoxic microdose of 14C-carboplatin will be administered to these patients before biopsy. Pt-induced DNA damage and repair in left-over tumor biopsy specimens and other relevant parameters will be measured and correlated with the response and toxicity of chemotherapy. Molecular analysis of genes such as ERCC1 and RRM1 will be analyzed and compared with this phase 0 results. We have opened a similar phase 0 trial in dog patients with bladder cancer.
Conclusions: The levels of DNA damage induced by nontoxic microdosing carboplatin can potentially predict chemoresistance in cancer cell lines. The clinical data of the phase 0 trial will be presented. No significant financial relationships to disclose.
Comparable studies
Other preclinical and animal studies on microdosing, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Psilocin and ketamine microdosing: effects of subchronic intermittent microdoses in the elevated plus-maze in male Wistar rats Wistar rats | 2018 | Experimental study | n = 40 |
| Repeated low doses of psilocybin increase resilience to stress, lower compulsive actions, and strengthen cortical connections to the paraventricular thalamic nucleus in rats. Rats | 2023 | Experimental study | |
| Repeated microdoses of LSD do not alter anxiety or boldness in zebrafish. Zebrafish (Danio rerio) | 2024 | Experimental study | |
| Application of microarray patches for the transdermal administration of psychedelic drugs in micro-doses. Excised neonatal porcine skin and rats | 2025 | Experimental study | |
| Toward Predicting Acute Myeloid Leukemia Patient Response to 7 + 3 Induction Chemotherapy via Diagnostic Microdosing Paired sensitive and resistant cancer cell lines, AML cell lines, and 10 viably... | 2018 | Preclinical cell line study with a pilot retrospective analysis of primary patient samples | n = 10 |