Paul Janssen

BMJ 2003; 327 doi: (Published 27 November 2003) Cite this as: BMJ 2003;327:1290

Belgian doctor who founded a drug company, now part of Johnson & Johnson

Exactly half a century ago, Paul Janssen set himself the challenge of creating a totally independent and self supporting medical research laboratory in his native Flanders, close to the Dutch border. By the time of his death earlier this month in Rome while attending a conference, he had more than 100 patents to his name, had gained widespread international recognition for his work, and had overseen the highly successful expansion of the company that he founded in 1956, Janssen Pharmaceutica. Now part of Johnson & Johnson, Janssen Pharmaceutica has more than 40 foreign affiliates with a worldwide workforce of more than 23 000 employees.

It is all a far cry from the simple laboratory on the third floor of his parents' pharmaceutical import business in the Flemish town of Turnhout where Dr Paul, as he was always known to his colleagues, embarked on his professional career as a medical researcher in 1953.

Dr Paul's father, Constant Janssen, came from a farming background and established himself as a successful general practitioner in Turnhout. In 1933, seven years after his son's birth, the GP diversified and acquired the sole rights to import and distribute in Belgium, the Netherlands, and the Belgian Congo pharmaceutical products produced by the Richter company in Budapest.

During the second world war, Paul Janssen studied physics, biology, and chemistry at the Faculté Notre Dame de la Paix in Namur, in Belgium's French speaking region of Wallonia. Those courses convinced him of the importance of chemistry to medicine and of the need to use the former to make scientific advances in the latter.

In 1945 Paul Janssen began his medical studies in the Catholic University of Leuven. He interrupted this with an extended visit to the United States three years later to gain a better understanding of worldwide research in chemistry and pharmacology. Already he was looking to develop original drugs and to focus on synthesising molecules in order to find the relationship between their pharmacological structure and activity.

After completing his studies in Leuven, the young medical student moved to Ghent, where he qualified. A spell of military service followed in Germany, where he continued his studies in pharmacology and chemistry at Cologne University.

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Paul Janssen then divided his time for several years between study trips abroad and part time teaching at the Institute of Pharmacology and Therapeutics at Ghent University. There he came into close contact with the institute's director, Professor Corneel Heymans, who had won the Nobel prize for medicine in 1938, and, in 1956, Paul Janssen received his teaching certificate for higher education in pharmacology with a thesis on “Compounds of the R 79 type.”

Turning his back on an academic career, he devoted himself full time to the independent research he had begun three years earlier. His immediate aim was to discover active chemical compounds on which to secure a patent that he could then license to large foreign companies, using the proceeds to finance new research and recruit more associates.

The challenge facing the Flemish doctor's small team was to understand how a chemical compound produces its effect on a living organism. Once they had achieved that, they would be able to manipulate the chemical structure of a compound and predict, control, and improve its biological effects.

The first compound Dr Paul's team successfully discovered was ambucetamide, an antispasmodic found to be particularly effective for the relief of menstrual pain. It was given the number R 5. Launched in April 1955 under the brand name Neomeritine, it is still on the market today.

In the mid to late 1950s, other compounds were discovered and commercialised. Among the achievements of this period were the synthesis of Haldol (haloperidol), the first antipsychotic that allows patients to be treated at home instead of in institutions, and fentanyl, still the most widely used anaesthetic in the world.

These breakthroughs soon brought the N V Research Laboratorium Dr C Janssen, as it had become in 1958, to the attention of the American healthcare company Johnson & Johnson, which was looking for pharmaceutical research companies with a promising future.

After several months of negotiations, a merger was agreed in 1961. A key element was the formal guarantee that the Belgian company would retain its own identity and independence within the international group.

More than 30 years later, Dr Paul would say: “During the negotiations that led to this co-operation, the future and the protection of our company were uppermost in my mind. For me and my employees, the merger was a sort of life insurance.”

In 1964 the company was renamed Janssen Pharmaceutica N V. With the backing of its American parent, research expanded and almost 100 new drugs have since been discovered. The majority have been for human medicine and are used to treat infestations by fungi and worms, mental illnesses, cardiovascular diseases, allergies, and gastrointestinal disorders.

Dr Paul received more than 80 medical prizes and 22 honorary doctorates.

He leaves a wife, Dora Arts Janssen; two sons; three daughters; and 13 grandchildren.

Paul Jannsen, founder of Janssen Pharmaceutica (b Turnhout, Flanders, Belgium, 1926; q Ghent 1951), d 11 November 2003.

[ Rory Watson ]