Didanosine therapy is indicated for which of the following conditions?

Didanosine, also known as ddI, is an antiviral medication that is specifically indicated for the treatment of HIV (Human Immunodeficiency Virus) infection. It belongs to a class of drugs called nucleoside reverse transcriptase inhibitors (NRTIs), which work by inhibiting the reverse transcriptase enzyme that HIV requires to replicate its genetic material and multiply in the body. By effectively lowering the viral load and improving immune function, didanosine helps manage HIV infection and delays the progression to AIDS.

In contrast, other conditions like diabetes, hypertension, and cancer are managed with entirely different classes of medications, which target those specific diseases and their underlying mechanisms. Diabetes is typically treated with insulin or oral hypoglycemic agents, hypertension is managed with antihypertensives, and cancer treatment often involves chemotherapy, radiation, or targeted therapies. Therefore, didanosine's specific role in HIV management makes it the correct answer in this context.