Merck’s chikungunya vaccine V-184 saw its Phase Transition Success Rate (PTSR) leap 11 points to 74% after its Phase II trial completed. The PTSR score change occurred on 15 June after updated the trial from suspended to completed on 9 June. PTSR is the probability, given as a percentage, of a drug progressing successfully from one development stage to the next.

Vienna, Austria-based Themis Biosciences, a Merck subsidiary, ran the 41-patient Phase II in collaboration with the Walter Reed Army Institute of Research, according to The placebo-controlled study tested the safety and chikungunya antibody titer of two doses of a live recombinant measles-vectored chikungunya vaccine (MV-CHIK) delivered four weeks apart. Chikungunya fever is a viral, mosquito-borne disease most commonly found in Asia and Africa. Themis is also developing vaccines for Zika and Lassa fever, according to the company website.

The Phase II update resulted in a modest one-point bump to the drug’s Likelihood of Approval (LoA), which rose to 7%. LoA is identified via GlobalData’s analysis using a combination of machine learning and its proprietary algorithm and is calculated by compounding the PTSR at each stage the drug is yet to progress through. Both LoA and PTSR can be calculated for a drug by considering characteristics like therapy area, indication and molecule type.

Merck has a market cap of $193.98bn.

William Newton is a Healthcare Reporter 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.