- Ultra-thinly traded nano cap Aptose Biosciences (NASDAQ:APTO) is down 27% premarket, albeit on only 100 shares, in response to its announcement that its Phase 1b clinical trial assessing lead product candidate APTO-253 in patients with blood cancers has been placed on clinical hold by the FDA.
- The agency's action was prompted by operating problems with an IV infusion pump at a clinical trial site, specifically the occurrence of back pressure at the filter while a patient was being dosed. The move is intended to ensure patient safety and also to ensure that manufacturing and dosing procedures are consistent with documented quality standards.
- Aptose completed a safety review of all patient files prior to its discovery of manufacturing documentation irregularities. No drug-related serious adverse events have been reported and the observed pharmacokinetic levels in treated patients have been in the expected range.
- The specific length of the delay is unknown, but the trial should restart as soon as the issues are fully investigated.
- APTO-253 is a small molecule that has shown potent anti-tumor activity in cancer cells via its induction of a gene that expresses proteins called Kruppel-like factors, specifically KLF4. When the KLF4 gene is induced, it up-regulates expression of a protein called p21 which leads to cell cycle arrest and apoptosis (cell death).
- Update: On September 12, the company announced that it submitted its formal responses to the FDA regarding the clinical hold.