Seven-year-old Josh Hardy, a first-grader from Fredericksburg, Virginia, is set to receive an experimental antiviral drug after his family’s public campaign prompted national attention. Chimerix, the drug’s manufacturer, reached an agreement with the Food and Drug Administration to start a clinical trial of brincidofovir, with Josh as its first patient.

Josh has battled several cancers since he was diagnosed with a rare kidney cancer at nine months old. A recent bone marrow transplant left him with a severely weakened immune system, and he developed a widespread adenovirus infection. At St. Jude Children’s Research Hospital in Memphis, he remained in critical condition, suffering from heart and kidney failure.

Chimerix initially declined the family’s request for access to the drug. The company said providing it individually to Josh and other patients could slow its efforts to bring the medicine to market. The FDA’s compassionate-use policy allows patients with serious or life-threatening illnesses to request experimental drugs, but companies do not always agree to supply them.

Josh’s relatives and supporters pressed their case through social media, petitions, phone calls, emails and national television appearances. The “Save Josh” Facebook page attracted more than 15,000 supporters, while local businesses and charities joined the effort. Chimerix CEO Kenneth Moch said the campaign also brought death threats against him and other employees.

The new open-label pilot study will provide brincidofovir to 20 patients, beginning with Josh. The FDA also committed to work with Chimerix on a subsequent Phase 3 study. Moch said the arrangement could help other patients in need; the company had received more than 80 requests for compassionate use of the drug over the previous two years.

Josh’s parents welcomed the decision and thanked supporters and Chimerix. St. Jude said the drug’s safety and effectiveness in children had not yet been established and emphasized that Josh’s condition remained critical and complex.