Study participants will be randomly chosen to receive either lefamulin alone or doxycycline followed by lefamulin in a 1:1 ratio. Each participant will receive 14 lefamulin pills or 14 doxycycline pills and 14 lefamulin pills in the mail and take them as directed for one week (each). Participants will collect one culture sample and one sample to confirm M. genitalium infection on the same day they take their first pill then mail the two samples to the laboratory. They will also answer questions about their symptoms, any side effects, and their behavior with their sex partners. Participants will collect samples two more times and answer questions three more times if they are randomly chosen to receive lefamulin alone or four more times if they are randomly chosen to receive doxycycline followed by lefamulin during the study. The study team will culture M. genitalium then determine minimum inhibitory concentrations (MICs) to three antibiotics (azithromycin, moxifloxacin, and lefamulin) to see whether it is resistant to any of these antibiotics. The study team will also test for M. genitalium to confirm whether the participants have an infection at baseline and see if lefamulin cured the infection upon completion of the lefamulin.~After 20 patients have been enrolled, the study team will conduct an interim analysis to assess futility. Futility will be defined as less than five percent probability that true efficacy is greater than or equal to 60 percent (i.e., less than or equal to three of the first 10 participants experience microbiologic cure). If neither lefamulin alone nor doxycycline followed by lefamulin meets criteria for futility, the study team will continue the study. If one regimen meets criteria for futility, the study team will drop the regimen that met the criteria for futility and continue to administer the other regimen to the remaining 20 participants. If both regimens meet criteria for futility, the study team will halt the study.~Study participants will be informed of their M. genitalium test of cure results. If the lefamulin does not cure the infection, the study physician will consult with the referring physician who will continue to treat the infection per clinic standard of care.
The purpose of this drug study is to find out whether the antibiotic lefamulin (trade name Xenleta) will cure Mycoplasma genitalium infections that have not been cured by prior antibiotics while finding out whether it is more effective if the antibiotic doxycycline is taken first.