Sanofi terminated an experimental Clostridium difficile vaccine after an Independent Data Monitoring Committee concluded the Phase III trial was unlikely to hit its endpoints. The announcement was the second negative announcement by Sanofi regarding a vaccine program within 24 hours.

The IDMC pored over an interim analysis of the trial and determined the probability that the study will meet its primary objective is low, Sanofi announced on Friday. The trial was designed to test the efficacy and safety of a candidate toxoid vaccine in a subpopulation at risk of Clostridium difficile infection, the company said. Based on that analysis, Sanofi said it discontinued clinical development of the C. diff vaccine and will shift resources to focus on six key vaccine projects currently in development. The company did not highlight those other vaccines. Sanofi Pasteur’s website points to research in the areas of AIDs, tuberculosis and Pseudomonas aeruginosa, a respiratory infection that often occurs in chronically ill patients.

C. diff is a bacterial infection that can cause multiple symptoms from diarrhea to life-threatening inflammation of the colon. According to the Mayo Clinic, about 500,000 people in the United States become sick from C. diff. About 30,000 people in the U.S. die annually from C. diff. The infection often affects patients in hospitals or in long-term care facilities. It often occurs after use of antibiotic medications, the Mayo Clinic added.

Sanofi said investigators are notifying study volunteers of the decision to stop the program.  Data from all vaccinated volunteers in this trial will continue to be analyzed for more information and shared with the scientific community, the company added.

The announcement was a second blow to Sanofi’s vaccine program in the same week. On Nov. 30, the company announced use of its dengue vaccine Dengvaxia could worsen the effectsof the mosquito-borne illness in people who had previously not been exposed to the virus. Sanofi will propose an update in prescribing information and request that healthcare professionals determine whether or not patients may have had a prior dengue infection before using Dengvaxia, the first approved dengue vaccine.

When it announced the changes to the Dengue drug, Sanofi said it anticipates a nearly $120 million financial hit in the fourth quarter of this year. Dengvaxia only generated about $65 million in sales last year.

Share prices fell following the announcement of the Dengue drug label change and fell again on Friday after Sanofi announced the termination of the C. diff drug.  Shares have fallen to $44.39 in premarket trading.