This study is for children with HIV-1, a virus that attacks the immune system. Researchers are testing a medicine called **Doravirine (DOR)** to see how it works in kids aged 4 weeks to less than 12 years old, weighing under 45 kg. It includes kids who are either new to treatment or have stable HIV levels. Pharmacokinetics (PK) means understanding how the drug moves in the body. The study looks at how DOR works with other medicines, like **NRTIs** (nucleoside reverse transcriptase inhibitors). Safety through Week 24 is also checked. After 96 weeks, kids can join an extension study for more treatment.

• The study lasts up to 96 weeks with a possible extension.
• Participants must have confirmed HIV-1 and weigh between 3 and 45 kg.
• Excludes those with liver, kidney, or other significant health issues.

Children must not have a history of treatment failure or show resistance to DOR. If you're a girl who can have children, you must take a pregnancy test before joining. This study is important to help find safe treatments for kids with HIV. If you're interested, talk to your doctor to see if you qualify!