Controlled Comparison of Two Moxifloxacin Containing Treatment Shortening Regimens in Pulmonary Tuberculosis

The current recommended treatments for tuberculosis (TB) require a patient to take multiple drugs for six to eight months. Because the course of therapy is long, many patients do not adhere to treatment and as a consequence they have a poor outcome. In these cases either the sputum is not cleared of the bacteria causing tuberculosis, or the disease returns again (called relapse). Response to medication can be monitored during treatment by collecting regular sputum samples and examining these samples by culture, for the organisms that cause tuberculosis.

The commonly used drugs to treat tuberculosis are rifampicin, isoniazid, ethambutol and pyrazinamide. Previous studies in animals and in humans suggest that a new drug called moxifloxacin may also be an effective treatment in tuberculosis. Moreover, promising laboratory studies on mice suggest that moxifloxacin may enable the total duration of chemotherapy to be reduced to four months, which would be a significant improvement for patients taking medication for tuberculosis.

This study will involve comparisons that are designed to assess whether substituting moxifloxacin for individual drugs in existing treatment combinations will enable tuberculosis treatment to be shortened. Patients selected for the study will be allocated to one of three treatment groups. The first group will be given six months standard treatment. A second group will receive moxifloxacin substituted for ethambutol, as part of a four month regimen, to see whether the shorter treatment is not inferior to the standard six month treatment. The third group will receive moxifloxacin substituted for isoniazid, as part of a four month regimen, to see whether the shorter treatment is not inferior to the standard six month treatment.

Hypotheses:

• In treatment-naïve adults with active pulmonary TB treated with eight weeks of moxifloxacin (M), isoniazid (H), rifampicin (R) and pyrazinamide (Z) (i.e. a standard regimen where moxifloxacin is substituted for ethambutol (E)), followed by nine weeks of moxifloxacin, isoniazid and rifampicin, followed by nine weeks of placebo, the proportion of patients who experience treatment failure or disease relapse in the twelve months following treatment completion will not be inferior to that observed in patients who are treated with a standard regimen (eight weeks of ethambutol, isoniazid, rifampicin and pyrazinamide followed by eighteen weeks of isoniazid plus rifampicin) (Comparison 1).
• In treatment-naïve adults with active pulmonary TB treated with eight weeks of ethambutol, moxifloxacin, rifampicin and pyrazinamide (i.e. a standard regimen where moxifloxacin is substituted for isoniazid), followed by nine weeks of moxifloxacin and rifampicin followed by nine weeks of placebo, the proportion of patients who experience treatment failure or disease relapse in the twelve months following treatment completion will not be inferior to that observed in patients who are treated with a standard regimen (eight weeks of ethambutol, isoniazid, rifampicin and pyrazinamide followed by eighteen weeks of isoniazid plus rifampicin) (Comparison 2).

Inclusion criteria

• Signed written consent or witnessed oral consent in the case of illiteracy, before undertaking any trial related activity.
• Two sputum specimens positive for tubercle bacilli on smear microscopy at least one of which must be processed and positive at the study laboratory.
• Aged 18 years or over.
• No previous anti-tuberculosis chemotherapy.
• A firm home address that is readily accessible for visiting and willingness to inform the study team of any change of address during the treatment and follow-up period.
• Agreement to participate in the study and to give a sample of blood for HIV testing (see appendices 1 & 2).
• Pre-menopausal women must be using a barrier form of contraception or be surgically sterilised or have an IUCD in place.
• Laboratory parameters performed up to 14 days before enrolment.

• Serum aspartate transaminase (AST) and alanine transaminase (ALT) activity less than 3 times the upper limit of normal.
• Serum total bilirubin level less than 2.5 times upper limit of normal. Creatinine clearance (CrCl) level greater than 30 mls/min.
• Haemoglobin level of at least 7.0 g/dL.
• Platelet count of at least 50x109cells/L.
• Serum potassium greater than 3.5 mmol/L.
• Negative pregnancy test (women of childbearing potential).

Exclusion criteria

• Unable to take oral medication.
• Previously enrolled in this study.
• Received any investigational drug in the past 3 months.
• Received an antibiotic active against M. tuberculosis in the last 14 days (fluoroquinolones, macrolides, standard anti-tuberculosis drugs).
• Any condition that may prove fatal during the first two months of the study period.
• TB meningitis or other forms of severe tuberculosis with high risk of a poor outcome
• Pre-existing non-tuberculosis disease e.g. diabetes, liver or kidney disease, blood disorders,peripheral neuritis, chronic diarrhoeal disease in which the current clinical condition of the patient is likely to prejudice the response to, or assessment of treatment.
• Pregnant or breast feeding.
• Suffering from a condition likely to lead to uncooperative behaviour e.g. psychiatric illness or alcoholism.
• Contraindications to any medications in the study regimens.
• Known to have congenital or sporadic syndromes of QTc prolongation or receiving concomitant medication reported to increase the QTc interval (e.g. amiodarone, sotalol, disopyramide, quinidine, procainamide, terfenadine).
• Known allergy to any fluoroquinolone antibiotic or history of tendinopathy associated with quinolones.
• Patients already receiving anti-retroviral therapy.
• Patients whose initial isolate is shown to be multiple drug resistant (i.e. resistant to rifampicin and isoniazid) or monoresistant to rifampicin, or resistant to any fluoroquinolone)
• Weight less than 35kg
• HIV infection with CD4 count less than 250 cells/µL.
• End stage liver failure (class Child-Pugh C).