New TB drugs on the horizon

Addressing journalists on the eve of the 41st Union World Conference on Lung Health Dr Ann Ginsberg, Chief Medical Officer of the TB Alliance said they were confident that in the shorter to medium term there would be combination drugs able to reduce the current six month treatment regimen for TB to four months.

The long term vision of the TB Alliance is to develop a regimen that would cure a person of TB within 10 days.

The TB Alliance is a non-profit organisation dedicated to finding faster-acting and affordable drug regimens to fight TB by partnering with pharmaceutical companies and donors.

The first TB drug Streptomycin was developed in 1946 – a major breakthrough at the time as TB was a fatal disease with no cure. However, despite the addition of a couple of drugs, there has been no improvement in the TB drug regimen since the 1970s.

The aim is to develop a shorter and simpler drug regimen for drug sensitive TB. Currently, the six month regimen involves lots of drugs that taste horrible and have side-effects. However, these drugs are effective and do cure patients.

For patients with drug-resistant TB the challenge is to develop treatment that is shorter than the current two year regimen, safer and at a lower cost – currently the treatment takes two years and is very expensive with patients having to undergo a course of painful injections. Many patients with extensively drug resistant TB are not cured.

The challenge for patients co-infected with HIV and TB is to develop drugs that can be co-administered with most antiretrovirals. For those with latent TB (TB in their system, but their immune systems are able to suppress it), the challenge is to develop drugs that offer a shorter regimen (currently between six and nine months) and is safer.Moxifloxacin - an approved drug, but never scheduled for TB – is currently in Phase III trials and it is hoped that it will reduce the current treatment regimen from six to four months. The tests are primarily happening in Africa.

PA-824 is in Phase II trials and is being tested both for drug sensitive TB as well as drug-resistant TB. It is a new mechanism of action (drug).

TMC 207 is specifically looking at drug-resistant TB and according to Ginsberg showing great promise. It is being developed by Johnson & Johnson and Tibotec. The TB Alliance is also trialing the drug for drug-sensitive TB.

NC-001 is a combination of Moxifloxacin, PA-824 and Pyrazinamide and is showing in studies in mice that it has the potential to reduce the treatment time for drug sensitive TB to four months. It is also showing promise for drug-resistant TB. This drug combination is currently being tested only in South Africa.

Ginsberg said they were engaging with drug regulators across the world to ensure the drugs become available within a short time once successfully navigating the research pipeline.

She said the key steps that had to be taken to ensure these new drugs were “protected” against abuse leading to resistance included a critical need to provide the drugs as fixed drug combinations. This would make it impossible to prescribe single drugs – a fatal step when treating TB.

A tougher element was ensuring that there were drug sensitivity tests at the point of care. This would ensure that patients who may be resistant to some of the drugs in the new fixed drug combinations were not exposed to further resistance.

* Health-e is reporting from The Union conference in Berlin thanks to support from the National Press Foundation and The Union.

Source: Health-e News , By Anso Thom