Preliminary testing of two long-acting injectable drugs indicates it might be possible to keep HIV at bay indefinitely with injections every month or two.

Johnson & Johnson and partner ViiV Healthcare, which specializes in HIV drugs, announced results from the first 32 weeks of the planned 96-week study, which combines one drug from each company.

Significant additional testing is needed, but the treatment could eventually be a huge advance over a disease once almost universally fatal.

The 309 patients tested all had prior treatment with standard daily pills that reduced the HIV virus to undetectable levels in their blood. About 95 percent of those who then got the experimental injections had the bloodbourne virus kept in check, versus 91 percent in a comparison group getting three standard drugs each day.