Aadi Bioscience’s lead drug ABI-009 (nab-sirolimus) has had its Phase Transition Success Rate (PTSR) drop by 22 points to 10% after a Phase II study evaluating it in neuroendocrine tumours was terminated, as of 11 June.

The Phase II investigator-sponsored study was evaluating ABI-009, an mTOR inhibitor bound to human albumin, in patients with neuroendocrine tumours and neuroendocrine gastroenteropancreatic tumours. In the latter indication, the drug’s PTSR score dropped by 26 points, taking it to 17%. PTSR is the probability, given as a percentage, of a drug progressing successfully from one development stage to the next. The study was terminated due to slow enrolment, as per a 10 June update on ClinicalTrials.gov.

ABI-009 is Los Angeles, California-based Aadi’s lead candidate. The company completed a rolling NDA in May for its use as a treatment for advanced malignant PEComa, which is associated with the highest known alteration rate of TSC1 or TSC2 genes. Based on recent clinical data, Aadi also plans to initiate a registrational trial in solid tumours with TSC1 or TSC2 inactivating alterations by YE21, as per a 4 June press release.

In addition to the PTSR changes, ABI-009’s Likelihood of Approval (LoA) in neuroendocrine tumours and neuroendocrine gastroenteropancreatic tumours also dropped to 4% and 10%, respectively. The LoA is calculated by compounding the PTSR at each stage the drug is yet to progress through and uses and uses a combination of machine learning and a proprietary algorithm.

Manasi Vaidya is a Associate Editor for Pharmaceutical Technology parent company GlobalData’s investigative journalism team. A version of this article originally appeared on the Insights module of GlobalData’s Pharmaceutical Intelligence Center. To access more articles like this, visit GlobalData.