Janssen Pharmaceutical’s approval likelihood for Sirturo (bedaquiline fumarate) to treat mycobacterium avium complex-associated lung disease (MAC-LD) dropped by 27 points to 33%, as of 5 July. This was after a Phase III trial (jRCT2031200268) in that indication was suspended. Prior to the trial’s suspension, Sirturo’s Likelihood of Approval (LoA) was at 60%.

Janssen Pharmaceutical Companies of Johnson & Johnson was conducting this Phase III trial at 30 sites in Japan, as per a ClinicalTrials.gov entry for the same study. The trial’s status, as per its record on the Japanese Registry of Clinical Trials, which was last updated on 1 July, has been changed to ‘Suspended. But its ClinicalTrials.gov entry (NCT04630145) has not yet been modified.

Sirturo is commonly known by its generic name bedaquiline and is used to treat pulmonary multidrug resistant tuberculosis (MDR-TB) as part of a combination regimen.

The Phase III trial was comparing the antimycobacterial Sirturo to rifamycin when used in combination with clarithromycin and ethambutol in patients that are refractory to treatments for MAC-LD. The study’s primary endpoint was the percentage of patients that had a sputum culture conversion in Mycobacteria Growth Indicator Tube (MGIT) at 24 weeks.

The LoA score is calculated by GlobalData’s analysis using a combination of machine learning and a proprietary algorithm. The score also takes into considering a drug’s Phase Transition Success Rate (PTSR) which is the probability of a drug moving to the next development stage. After the trial suspension, Sirturo’s PTSR dropped by 30 points to 38%. LoA and PTSR can be calculated for a drug by considering characteristics like Therapy Area, Indication and Molecule Type.

Manasi Vaidya is a Associate Editor for Clinical Trials Arena 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.