Beyond Prontosil

By 1935, enough clinical experience was available to show Prontosil effective against severe streptococcal sore throat, erysipelas, scarlet fever, puerperal sepsis, and other streptococcal infections. Striking as these successes were, they also put in relief the conditions in which Prontosil was useless or of uncertain activity, including infections caused by staphylococcal, pneumococcal, gonococcal, and anaerobic bacteria.2

Research continued at Elberfeld on the uses of Prontosil and related azo compounds, but by early 1936 Gerhard Domagk, Joseph Klarer, and Fritz Miet-zsch were also turning to sulfanilamide and the other colorless compounds that could be derived from it. Sulfanilamide, described in chapter 4, is a relatively simple compound, with structural formula:

Researchers began with the premise that therapeutic action depended not only on the presence of the sulfonamide group, SO2NH2, but also on its location in the para-position relative to the amino group, NH2, or, in azo compounds such as Prontosil, to the azo bond, —N=N—. Starting with sulfanilamide, then, variation of the compound could proceed in three directions. Substitutions could be made in the sulfonamide group, in the amino group, or in both groups at once. Prontosil and Prontosil Soluble could be viewed as products of substitution in the amino group. It was in the other direction, however, through substitution in the sulfonamide group, that effective new compounds began to be identified. By some time in 1936, Klarer and Mietzsch had synthesized a compound, at first called DB90, that Domagk found in animal trials to be as effective as Prontosil or Prontosil Soluble against streptococcal infections and more effective against infections caused by staphylococcal, gonococcal, and some anaerobic bacteria.3

The apparent effectiveness of the new compound against staphylococcal, gonococcal, and some anaerobic infections made it an obvious candidate for patenting and clinical trials. In the ideological and legal circumstances of the Third Reich, however, the process could not be straightforward. Already in 1933, the regime had made betrayal of military secrets a crime punishable by death, and Heinrich Hörlein, as a representative of I.G. Farben, had heard the company castigated by party officials for its manufacture of medicines for tropical diseases, products that purportedly benefited only the former enemies of Germany. I.G. Farben had been attacked in the National Socialist press for its international interests and connections. By April 1934, legal changes introduced by the National Socialist government required I.G. Farben to submit to the Reich War Ministry any patent applications for a product that might fall under the definition of state secret. Until October 1935, the I.G. Farben patent office in Leverkusen dealt directly with the various parts of the military. Beginning in that month, the Reich War Ministry created a central office for patent secrecy questions, and I.G. Farben funneled these matters through its Army Liaison Office (Vermittlungstelle W) in Berlin. An exception was anything having to do with weapons, about which Elberfeld and Leverkusen dealt directly with the Army General Headquarters (Oberkommando des Heeres).4

Hörlein, who regarded the secrecy requirements as a mortgage (Hypothek) that had to be borne in order to continue scientific work at Elberfeld, felt himself forced into dependence on military authorities for protection. He found such a contact for pharmaceuticals in the Army Health Inspector (Heeressanitätsinspektor), a Prof. Dr. Waldmann, and for toxic substances, which might be viewed by the Army as potential weapons, in Army Ordnance (Heereswaffenamt).5

The new compound, which soon took the trade name Uliron, was the occasion of Hörlein's first encounter with the Army Health Inspector. What made Uliron a potential secrecy problem was its action against anaerobic bacteria. Hörlein was aware that among these organisms were those responsible for gas gangrene, to which he attributed the deaths of 100,000 soldiers on the German side alone during the 1914-1918 war. Uliron was submitted for review and was not released for marketing and medical use until receipt of Waldmann's approval on May 21, 1937.6

Success with Uliron reinforced a sense of urgency at Elberfeld that was already fueled by a keen awareness of international competition in chemothera-peutic research and a conviction that further breakthroughs in the field of the sulfonamides were imminent. Two months after the approval of Uliron, in July

1937, Hörlein wrote a letter politely declining an offer by Richard Kuhn to make Domagk director of the Pathology Division of the Kaiser Wilhelm Institute for Medical Research in Heidelberg. While conceding Domagk's qualifications for the position, Hörlein was loath to see him removed from a collaborative effort that had already produced such substantial results in the field of bacterial infections, and from which still more was to be expected. Referring to Uliron, though not yet by name, he wrote that a medicine was soon to be introduced that shared the antistreptococcal action of Prontosil and Prontosil Album (sulfanilamide) but that was also a specific treatment for staphylococcal infections and was effective against gonococci and the causative agents of gas gangrene. Hörlein saw indications that the same or similar substances would be effective against all possible bacterial infections. "The whole world has been awakened by the success with Prontosil," he noted, "and in America, England, and France, they are working feverishly in this field. I believe that we can remain in the forefront if we let the apparatus we erected work as quietly as possible."7

Domagk stayed at Elberfeld, and the apparatus worked on. On March 29,

1938, Klarer sent to Domagk a compound for chemotherapeutic testing that differed from the Prontosil and Uliron groups of substances in breaking with the prior assumption that the amino group had to be directly bound to the benzene ring. In the new compound, in contrast, the amino group was joined to the ring with the aid of an aliphatic residue, CH2. On August 19, 1938, Domagk reported that the compound showed activity against blackleg or symptomatic anthrax (Pararauschbrand), an anaerobic bacterial infection. Since further chemotherapeutic tests went well, the company applied on January 27, 1939, for a patent on the procedure for making the compound (application number J 63 929; later patent number DRP 726 386). Since the new compound did not appear to show advantages over other sulfonamides in bacterial infections other than those caused by anaerobes, the patent application singled out the latter, which included gas gangrene.8

Mention of anaerobic infections set off the same alarm bells that had rung for Uliron, with the result that Army General Headquarters required the patent application for the new compound to be kept secret. Hörlein, who opposed secrecy for

Figure 5.1. Gerhard Domagk (1895-1964) at his desk (reprinted courtesy of the Bayer Archive).

Figure 5.2. Fritz Mietzsch (1896-1958), one of Gerhard Domagk's principal chemist collaborators in research on sulfon-amides (reprinted courtesy of the Bayer Archive).

Figure 5.3. Joseph Klarer (1898-1953), one of Gerhard Domagk's principal chemist collaborators in research on sulfonamides (reprinted courtesy of the Bayer Archive).

Figure 5.3. Joseph Klarer (1898-1953), one of Gerhard Domagk's principal chemist collaborators in research on sulfonamides (reprinted courtesy of the Bayer Archive).

new pharmaceutical products on principle, urged the Elberfeld researchers to find applications for the new compound that would be important in peacetime and that would thereby improve the company's chances for approval of the application. Animal studies in Domagk's laboratory showed that the substance had activity against gonococcal infections. Mesudin, as the compound was called for testing purposes, was sent to H.T. Schreus in Düsseldorf and H. Löhe in Berlin for clinical trials. Löhe's results were published in the Klinische Wochenschrift in 1940 but, because of the secrecy order, did not include the chemical formula of the compound. On February 9, 1940, Mietzsch and Werner Knauff, from I.G. Far-ben's patent office in Leverkusen, met with officials of the Reich Patent Office in Berlin. I.G. Farben was asked to "enrich" the patent application with statements about animal trials in gonococcal infections in place of earlier statements on anaerobic infections, now declared secret. Domagk accordingly conducted new animal trials, and on the basis of these the company submitted a revised application for Mesudin on June 6, 1940. Even this was not enough, and over the succeeding months Hörlein appeared personally on several occasions before the Pharmacological Administrative Department (Pharmakologischen Dienststellen) at Army General Headquarters to petition for release of the application. Approval of the revised application, which now included the chemical formula, finally came on October 7, 1941, and Klarer published the formula for the compound, now given the trade name Marfanil, in the Klinische Wochenschrift on December 13, 1941.9

Although Elberfeld researchers had recognized the special properties of the compound that became Marfanil long before the beginning of the war in September 1939, the war lent new urgency to the compound's testing, to the patent and secrecy issues, and to specification of the conditions of its use by doctors.

The war also had an increasing and largely detrimental effect on the wider research enterprise at Elberfeld. Before the war, and even in its early phases, Domagk's laboratory benefited from an expansion linked to the present success and bright future prospects of the sulfonamides. A medical doctor joined the staff in 1934, and between 1937 and 1942 another medical doctor and two bacteriologists were added. In 1939, Domagk's laboratory was expanding with the addition of more rooms. Domagk, his staff, and his chemist-collaborators pushed ahead with research on the chemotherapy of bacterial infections. Prompted by success with Mesudin, they placed special emphasis on anaerobic infections, but other targets were not neglected. Elected an honorary member of the German Society to Combat Sexually Transmitted Diseases (Deutschen Gesellschaft zur Bekämpfung der Geschlechtskrankheiten), Domagk used the occasion to call attention to experimental and clinical successes in the treatment of gonorrhea with Uliron and other compounds. By early 1940, the first favorable clinical reports on use of Mesudin against gonorrhea had come in. Research was also proceeding in Domagk's laboratory on chemotherapy of pneumococcal infections, and Domagk was optimistic that compounds would be found to surpass sulfapyridine, which had been introduced with great fanfare in 1938 by the British firm of May & Baker. Domagk published two papers in 1939 on the chemotherapy of bacterial infections.10

Despite these positive notes, it is clear that already in 1939 the Elberfeld research establishment was beginning to feel the pressure of the war. In Domagk's laboratory, turnover of personnel accelerated, leading to a noticeable slowing of the pace of work. The war accomplished in part what animal protection groups could not. There were now shortages of laboratory mice, and the deficiency could not be made up by the few mice produced in the plant's own breeding facilities. "If the war should last longer," Domagk wrote in early 1940, "we must try for a substantial increase [in production of mice] by next winter."11

By 1942 the effect of the war, and of war-related activity, played a preponderant role in Domagk's laboratory. The rapid turnover of personnel continued. Of twenty-three outgoing staff, eight, or more than a third, went to the military. The main effort of the laboratory was devoted to war-related tasks, above all the further development of the chemotherapy of wound infections. Intensive research on the treatment of gas gangrene centered on animal tests to determine the most appropriate use of Marfanil powder. So as to better approximate real conditions of use, Do-magk and his staff induced experimental infections using bacteria-bearing soil samples received from the various theaters of war. In vitro and animal tests led Do-magk to conclude that Marfanil was far superior to all other sulfonamides in the treatment of gas gangrene. On the basis of animal studies, he formulated guidelines for treatment of wound infections that were tested and confirmed in clinical trials on patients wounded by bomb or flak fragments or in serious traffic accidents. He prepared a report on these results for the Army Health Inspector and for distribution to military doctors and demonstrated some of his findings for military officials when summoned to Brussels in June 1942. Domagk's report did not take for granted the acceptance of his recommendations by military surgeons. Pointing out that the treatment of serious wound infections constituted a major part of war surgery, he noted that although very few surgeons questioned the value of serum therapy for tetanus, the value of serum therapy in gas gangrene and of sulfonamide therapy of wound infections was still controversial. This was so, he thought, because practicing surgeons were not yet familiar enough with the experimental foundations of these therapies, and he very strongly urged conformity to the experimental experience embodied in the guidelines as a guarantee of therapeutic success.12

Research also continued during 1942 on chemotherapy of other kinds of bacterial infections, but under increasingly difficult conditions. Few new compounds were delivered for testing against streptococcal infections because Domagk's chemist-collaborators were heavily occupied with production and patent questions and by ongoing work on compounds already in hand. Both new and old compounds were tested against staphylococcal infections, some of them wound infections. Domagk had little to report about research on typhus or paratyphus infections, except that sulfapyridine and sulfathiazole, both products of British research, had so far proved the most effective against paratyphus infections in mice. Animal trials of several compounds in typhus, paratyphus, and other infections had to be suspended in November 1942 because of a shortage of mice.13

Four months after submission of the annual report for 1942, in May 1943, Domagk's frustration with the deteriorating conditions of research at Elberfeld boiled over in a letter he addressed to the directors of I.G. Farben via his superiors, Hörlein in Elberfeld and Max Brüggemann in Leverkusen. Evidently responding to questions raised about the value of research in wartime, Domagk emphatically rejected the idea that "further decisive work" be deferred until after the end of the war. Such work must continue, he wrote, even under difficult conditions, when no immediate financial advantage is to be gained from it, and when there are obstacles to the building of new institutes. He complained in very strong terms of the minute regulations placed by the company on the time of researchers under conditions of total war. Such regulations damaged not only morale but also productivity, Domagk asserted, since to be productive researchers needed to dispose freely of their time. Dangerous conditions had been created by the regulations in laboratories in which human pathogens were handled, Domagk wrote, because of the fatigue suffered by staff. Conditions were especially dangerous where tuberculosis was under study, he noted, pointing out that there had already been several accidental infections among the staff. He reminded the management acidly that "research laboratories are not factories." Domagk was eager to push forward with research on the chemotherapy of tuberculosis, a project he had begun in 1941 and had proposed expanding in reports submitted to the company in January 1942, January 1943, and April 1943. His efforts had been hindered, he said, not only by the regulations on time use but also by the inability of the chemists to hold up their end of the work, that is, the synthesis of new compounds, because of their absorption in efforts to improve production.14

One month later, the war intruded in a more direct and devastating way. On June 24 and 25, 1943, Allied bombers attacked Wuppertal-Elberfeld. The building housing Domagk's laboratories was undamaged except for broken glass, but the division's working strength was seriously affected. Sixteen staff members lost all of their homes and belongings. One of the staff was killed, and others wounded. Many weeks of staff time were lost. For six to eight weeks after the bombing, only the most pressing work could be done, since animal breeding facilities and incubators were unusable and there was no gas. The plant was not fully operational again until September.15

Despite the losses and delays, research continued during 1943. Domagk's laboratory conducted animal trials of new compounds against streptococcal infections before and after the June bombing attacks. Studies proceeded on various disinfectants, and although apparently little new work was done on them in 1943, pneumococcal and staphylococcal infections were on the laboratory's agenda. Chemotherapy of gas gangrene infections remained a high priority, with medicines composed of combinations of different compounds proving most effective. On October 6, 1943, Domagk presented results on the latest methods of treatment to an audience of 900 surgeons in Dresden, and a Marfanil-Prontalbin (Prontosil Album, Sulfanilamide) combination went into use in the German army.16

Domagk assigned increasing significance to tuberculosis, probably because of its threat to public health, and work on chemotherapy of the disease intensified during 1943. Through painstaking histological studies, Domagk was able to establish that a few sulfonamide compounds, including sulfathiazole, had a limited effect on tuberculosis. His major finding, however, one already included in a previous year's report, was that the sulfonamide group was not necessary for the antitubercular effect, at least not by itself. In particular, Domagk established that the compound thiosemicarbazide had an antitubercular action without presence of a sulfonamide group in the molecule. Domagk had received the first thiosemicar-bazide compound, prepared by the Elberfeld chemist Robert Behnisch, on November 28, 1941. At first slow to respond to Domagk's finding, the chemists were now pursuing the lead more intensively. Unfortunately, Domagk noted in January 1944, research on the chemotherapy of tuberculosis was hindered by difficulties, several of which he had mentioned in his letter of May 1943. Animal trials were slowed by the lack of mice and consequent need to use guinea pigs and rabbits in their place. Space, including the room for dissections necessary in a full set of trials of antitubercular agents, was inadequate. Domagk pointed out that, in part because of the danger of the work, a room set aside for dissection of tuberculosis cadavers or animals should be set up like a large, well-lighted operating theater and should be capable of being completely disinfected. Staff should be well nourished and well rested. Under present circumstances, he reported, overwork and fatigue were common. He had proposed that food be set aside for staff working on tuberculosis, but the matter had not yet been decided. In spite of these problems, Domagk's report indicates that more than seventy compounds had been tested for antitubercular action in his laboratory during 1943.17

Domagk's associate Christian Hackmann also managed to push ahead with his research on the chemotherapy of cancer. During 1943, Hackmann's laboratory tested 247 compounds against tumors. Most were without effect, but a few had slight effect. Hackmann also continued earlier studies of tumor immunity.18

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