They knew that this was a cure a long time ago.
That's why they bombed the factory?
"The Al-Shifa factory was not making chemical weapons" - Interview with technical manager of bombed pharmaceutical factory in Sudan
The US missile attack that destroyed the Al-Shifa Pharmaceutical Factory in Khartoum was a brutal act of war. The claims by Clinton and the US administration that the factory was making a chemical component of nerve gas have largely been discredited.
The factory was Sudan's largest commercial manufacturer of prescription drugs for both medical and veterinary purposes, producing 50 percent of the country's supply. The consequences of its destruction, on the lives and health of the Sudanese people, will be immense. One man who has an intimate knowledge of the factory and of the Baaboud family who built it is Tom Carnaffin. A 57-year-old engineer who has worked all over the world building and commissioning industrial plants, Carnaffin has worked as technical manager for the Baaboud family since 1991.
https://www.wsws.org/en/articles/1998/09/sud-s12.html