The Woman Who Said No 50 Times: How Frances Kelsey Stopped Thalidomide

June 22, 2026 • BY MARK MORALES

THE WOMAN WHO SAID NO 50 TIMES

How Frances Oldham Kelsey and One Missing Data Set Changed Drug Regulation Forever

I. THE DRUG: WHAT WAS THALIDOMIDE?

Chemical name: α-(N-phthalimido)glutarimide
Developed by: Chemie Grünenthal, West Germany, 1954
Launched: October 1, 1957 in Germany as Contergan^[1]

What it was sold as:

“Completely safe” sedative – Marketed as non-barbiturate with “no risk of overdose.” Grünenthal claimed you could take a bottle and just sleep for days.^[2]
Morning sickness cure – Prescribed to pregnant women in the first trimester for nausea, insomnia, anxiety.
“Wonder drug” – By 1960, sold in 46 countries under 40+ brand names: Distaval (UK), Kevadon (Canada), Talimol, Softenon, Neurosedyn.^[3]

How it worked:
Thalidomide crosses the placenta easily. In adults, it causes drowsiness. In fetuses, it disrupts blood vessel formation during days 20-36 after conception.^[4] A single 50mg pill in that window could cause phocomelia — shortened or absent limbs.

The safety claim that wasn’t: Grünenthal tested it on rodents. Rats survived huge doses. They concluded it was non-toxic. Problem: Humans metabolize it differently. No one tested it on pregnant animals before mass marketing.^[5] No controlled human trials for pregnancy existed.

Global toll:

10,000+ children born with severe birth defects in 46 countries, 1960-1962^[6]
40% died before their first birthday^[6]
Most common damage: phocomelia, amelia, ear/eye defects, heart malformations
Countries hit hardest: West Germany ~5,000, UK ~2,000, Japan ~1,000, Canada ~125^[7]

II. THE WOMAN: WHO WAS FRANCES OLDHAM KELSEY?

Born: July 24, 1914, Cobble Hill, Vancouver Island, British Columbia, Canada^[8]
Died: August 7, 2015, London, Ontario, age 101

Year	Milestone
1934-1935	BSc + MSc Pharmacology, McGill University. Master’s thesis: how drugs cross the placental barrier.^[9]
1938	PhD Pharmacology, University of Chicago. Advisor: E.M.K. Geiling, who investigated the 1937 Elixir Sulfanilamide disaster.^[10]
1950	MD, University of Chicago. Completed medical school while raising two daughters.
1954-1960	Journal of the American Medical Association editor. Reviewed drug studies for publication.
Aug 1960	Joined FDA as medical officer to review new drug applications.^[11]
Sept 1960	Assigned thalidomide file NDA 12-611 one month into the job.

What she was like:
Colleagues called her “meticulous,” “unflappable,” and “immune to flattery.” She kept a note on her desk: “Be stubborn about the data.”^[12] She later said she wasn’t brave — she was just trained to distrust any drug claim without a control group.

After thalidomide:

1962: President’s Award for Distinguished Federal Civilian Service from JFK.^[13]
1963-2005: Ran FDA’s Division of Scientific Investigations. Wrote the rules for clinical trial monitoring.
2005: Retired at age 90.
2010: FDA named its annual award the “Frances O. Kelsey Award.”
2015: Inducted into National Women’s Hall of Fame, one month before she died.

III. THE 19-MONTH STANDOFF: SEPTEMBER 1960 TO MARCH 1962

September 1960: Kelsey assigned New Drug Application #12-611. Richardson-Merrell wanted to sell thalidomide in the U.S. as Kevadon.^[14]

What was in the file:

Letters from European doctors: “My patients love it.”
Sales data: “Millions of doses sold, no deaths reported.”
Animal studies: Rats survived huge doses.
Missing: Human controlled trials. Pregnancy safety data. Long-term follow-up.

Kelsey’s first letter: November 10, 1960. Requested chronic toxicity studies and clinical evidence in pregnancy.^[15]

The pressure campaign:
• 50+ visits from Merrell reps between 1960-1962^[17]
• Calls to her supervisors: “Dr. Kelsey is unreasonable”
• Claims American doctors were “demanding” the drug
• Offered to send her to Europe to “see for herself”
• Threatened to complain to FDA Commissioner by late 1961

Her response never changed: No data, no approval. She wrote that the application relied on “statements of opinion” not “records of scientific investigation.”^[18]

February 1962: Reports of phocomelia in Germany hit medical journals. William McBride in Australia and Widukind Lenz in Germany linked it to thalidomide.^[19]

March 8, 1962: Merrell withdrew the Kevadon application.^[20] By then, thalidomide was already off the market in Germany and the UK.

U.S. exposure: Merrell had distributed 2.5 million tablets to 1,200 U.S. doctors as “investigational” samples. FDA tracked down every doctor. 17 American babies were born with thalidomide defects.^[21] Without Kelsey’s delay, pharmacies would have stocked it in 1961.

IV. HOW THALIDOMIDE CHANGED THE WORLD

Before 1962	After Kefauver-Harris Amendments^[22]
Companies only proved safety, not effectiveness	Proof of efficacy required – Drugs must work for claimed use
“Safety” = didn’t kill adults short-term	“Substantial evidence” standard – Adequate, well-controlled trials mandatory
No requirement for pregnancy testing	Teratogenicity testing before market approval
FDA had 60 days to reject or drug was auto-approved	FDA approval required – No automatic approval
Patients often didn’t know they were in trials	Informed consent – Patients must know they’re in a trial

Global impact: UK Medicines Act 1968, Canada Food & Drug Regulations 1963, Japan’s 1967 overhaul. The modern 3-phase clinical trial system traces directly to thalidomide.^[23]

Thalidomide today: Banned for pregnancy. Still used under strict REMS programs for multiple myeloma and leprosy. Every patient must use two forms of birth control and take pregnancy tests.^[24]

V. THE LESSON KELSEY LEFT

“I was just doing my job. If I had approved it, I’d have to live with it the rest of my life. I’m glad I don’t.”^[25]

The system worked because one person refused to accept “everybody else approved it” as evidence. Because she knew her 1935 master’s thesis on placental barriers. Because her boss, Ralph Smith, backed her when Merrell complained.^[26]

Fragility of safety: In 1960, the difference between 0 and 10,000 injured children was one signature. Today, the FDA reviews 40+ new drugs per year. Each one passes through people trained in Kelsey’s mold: show the data, or it doesn’t go.

SOURCES / FOOTNOTES

[1] Bren L. Frances Oldham Kelsey: FDA Medical Reviewer Leaves Her Mark on History. FDA Consumer Magazine, 2001.
[2] Sjöström H, Nilsson R. Thalidomide and the Power of the Drug Companies. Penguin, 1972. p. 45.
[3] Knightley P, et al. Suffer the Children: The Story of Thalidomide. Viking, 1979.
[4] Vargesson N. Thalidomide-induced teratogenesis: History and mechanisms. Birth Defects Research, 2015;105(2):140-156.
[5] U.S. FDA. Kefauver-Harris Amendments Revolutionized Drug Development. FDA.gov, 2018.
[6] World Health Organization. Thalidomide: International Approaches to the Problem. WHO Chronicle, 1963;17:23.
[7] Thalidomide Victims Association of Canada. Statistics by Country. TVAC.ca, updated 2020.
[8] National Women’s Hall of Fame. Frances Oldham Kelsey Biography. 2015.
[9] Kelsey FO. The Absorption of Drugs by the Foetus. MSc Thesis, McGill University, 1935.
[10] Geiling EMK, Cannon PR. Pathologic Effects of Elixir of Sulfanilamide Poisoning. JAMA, 1937;109:1531.
[11] U.S. FDA. About Dr. Frances Oldham Kelsey. FDA.gov Historical Archive.
[12] Bernstein M. Frances Oldham Kelsey, FDA scientist who kept thalidomide off U.S. market, dies at 101. Washington Post, Aug 7, 2015.
[13] Kennedy JF. Remarks Upon Presenting the President’s Award for Distinguished Federal Civilian Service to Dr. Frances O. Kelsey. August 7, 1962. The American Presidency Project.
[14] U.S. FDA. NDA 12-611 Administrative Record: Kevadon (thalidomide). National Archives.
[15] Kelsey FO. Letter to Richardson-Merrell, November 10, 1960. FDA Archives.
[16] Mintz M. “Heroine” of FDA Keeps Bad Drug Off Market. Washington Post, July 15, 1962.
[17] Hilts PJ. Protecting America’s Health: The FDA, Business, and One Hundred Years of Regulation. Knopf, 2003. p. 157.
[18] Kelsey FO. Review Memorandum, NDA 12-611, July 29, 1961. FDA Archives.
[19] McBride WG. Thalidomide and Congenital Abnormalities. The Lancet, 1961;2:1358.
[20] Richardson-Merrell Inc. Letter Withdrawing NDA 12-611, March 8, 1962.
[21] Taussig HB. A Study of the German Outbreak of Phocomelia. JAMA, 1962;180:1106-1114.
[22] Public Law 87-781. Drug Amendments of 1962. October 10, 1962.
[23] Junod SW. FDA and Clinical Drug Trials: A Short History. FDA.gov History Office, 2016.
[24] FDA. Thalomid (thalidomide) REMS Program. Current as of 2026.
[25] Spiegel AL. Interview with Frances Kelsey. FDA Oral History Project, 2001.
[26] Mintz M. The Therapeutic Nightmare. Houghton Mifflin, 1965. p. 33.

Note: This article is for educational purposes. For medical advice, consult a licensed physician.

SHARE THIS STORY. BECAUSE SYSTEMS WORK WHEN PEOPLE DO.

Pages

The Woman Who Said No 50 Times: How Frances Kelsey Stopped Thalidomide