Shares in Johnson & Johnson were given a nudge upwards after its experimental tuberculosis drug bedaquiline moved a big step closer to approval in the all-important US market.

An advisory panel to the US Food and Drug Administration has recommended a accelerated approval of J&J's bedaquiline as a treatment for mutli-drug resistant TB (MDR-TB).

The panel unanimously agreed that there was "substantial evidence" that the drug is effective, and voted 11-to-7 that safety findings support the proposed indication.

Taken together, these votes represent a recommendation for approval, but also highlight uncertainty over the strength of bedaquiline's safety profile at this time, particularly as some patients died while taking part in clinical trials of the drug (though a link has not been established).

In one of mid-stage trials, 10 patient deaths were recorded out of 79 people taking bedaquiline and standard therapies, versus just two among 81 patients in the control arm, sparking concern.

A Phase III trial - which is to being patient recruitment shortly - should, however, help to shed further light on any safety issues associated with the drug. 

If approved, bedaquiline will not only become the first drug with a new mechanism of action for TB in more than 40 years, but also the first medicine specifically for treating MDR-TB, which is posing a significant threat in the battle against the spread of this highly infectious disease.