(showing a propensity to bind with certain bacteria), but was more
chemically unstable and easier to manipulate in the lab. Ehrlich knew of a
chemical compound named atoxyl that had been shown to kill
trypanosomes, single-cell parasites that cause diseases like African
sleeping sickness. He was intrigued by atoxyl, particularly once he
realized that it was a chemically unstable arsenic-based molecule and not
a true aniline dye.
And so the testing began. Ehrlich and his colleagues Alfred Bertheim
and Sahachiro Hata began to chemically modify atoxyl in 1907, feverishly
altering the composition of the molecule bit by bit. Different versions
were further modified, and a numbering system was generated based upon
these modifications. The eighteenth version of the fourth compound
(number 418) was effective in curing sleeping sickness, but was causing
blindness in some of Hata’s lab animals and was therefore abandoned. By
the summer of 1910, in what can only be described as crude experimental
processes, Compound 606 had been created and tested. The sixth version
of the sixth compound (606, arsphenamine) showed tremendous success in
lab animals with various diseases, including syphilis.^3
Syphilis likely was not present in Europe before explorers brought it
back from the New World in 1495, and it raged for four hundred years
across the continent with its slow-motion terror of blisters, aching
testicles, sore throat, raised skin rash, and in its final stages, facial
deformities and brain infections. With no effective treatment, mankind
was defenseless against the corkscrew-shaped bacterium. Until Compound
606.
The German chemical company Hoechst AG, also located in the
Frankfurt area, began marketing Compound 606 in 1910 as “Salvarsan.”
Through trial and error, Paul Ehrlich had created a molecule that was part
stain, part poison. The dye portion of arsphenamine would bind to the
surface of the syphilis bacterium, whereas the arsenate portion killed it. In
so doing, he had developed the world’s first synthetic chemotherapeutic
agent. For good measure, Ehrlich coined the term “chemotherapy.”
Salvarsan rapidly became the most prescribed medicine in the world,
leading to hopes that it would have broad application among many
different types of bacteria. Unfortunately, Salvarsan, and its improved
version, Neosalvarsan, had extremely narrow efficacy across the microbial
world. This, paired with its significant side effects, made it a qualified