In March 1961 Dr. Francis Kelsey (in charge of the Thalidomide approval process for the US) read Dr. Leslie Florence’s letter in the British Medical Journal from December 1960. Florence was wondering if Thalidomide was responsible for nerve damage in some of his patients. Kelsey became even more sceptical about the safety of Thalidomide.
Source: Michael Magazanik: Silent Shock. The men behind the Thalidomide scandal and an Australian family’s long road to justice. Melbourne 2015, p. 89.