World Anti-Doping Agency (WADA) v. Fédération Internationale d'Escrime (FIE), Ysaora Thibus

At a glance

Parties

World Anti-Doping Agency (WADA) v. Fédération Internationale d'Escrime (FIE) and Ysaora Thibus

Case no.

CAS 2024/A/10748

Forum and rules

Court of Arbitration for Sport, appeals arbitration under the Code of Sports-related Arbitration (Article R47)

Applicable rules

FIE Anti-Doping Rules (FIE ADR), interpreted consistently with the World Anti-Doping Code

Panel

Jacques Radoux (President), Luigi Fumagalli, Janie Soublière

Sector

Fencing; anti-doping

Outcome

WADA's appeal was dismissed (7 July 2025). The FIE Doping Disciplinary Tribunal's finding of No Fault or Negligence, with no period of ineligibility, was confirmed.

Amount

WADA sought a four-year ban. Ms Thibus claimed CHF 10.000 for moral harm and CHF 30.000 towards her legal fees. The published award redacts the costs rulings (operative ¶¶ 3–4). All other prayers for relief were dismissed. At first instance, the DDT had ordered Ms Thibus to pay CHF 16.245,00 to the FIE.

The dispute

Ysaora Thibus is a French international foil fencer. She tested positive for ostarine, a non-Specified Substance (a SARM), after an in-competition test at the Challenge International de Paris on 14 January 2024. She did not contest the violation. She explained that she had been contaminated through kissing her partner, Race Imboden, who had secretly been taking the ostarine product MK-2866 since 5 January 2024. The FIE Doping Disciplinary Tribunal (DDT) accepted this "Kissing Scenario". It found No Fault or Negligence and imposed no ineligibility, although it disqualified her results from 14 January to 8 February 2024. WADA appealed and sought a four-year ban. It argued that the scenario was pharmacokinetically implausible, that Prof. Alvarez's contamination study was uncontrolled, and that her partner's use of ostarine did not exclude her own intentional use.

Key holdings

1. CAS has jurisdiction under Article 13.2.1 of the FIE ADR because the athlete is an International-Level Fencer. WADA's appeal, filed on 17 July 2024, was admissible: under Article 13.6.1, WADA had 21 days after the French anti-doping agency's own appeal deadline of 26 June 2024 expired. ¶¶ 111–112, 115
2. To show that the violation was not intentional, the athlete must establish on a balance of probability that her scenario is a plausible explanation and is not fatally undermined by scientific (pharmacokinetic) evidence. WADA conceded that if the Kissing Scenario was accepted, the result would be No Fault or Negligence. ¶¶ 123–124
3. The CAS review is de novo. Even so, WADA's Appeal Brief attacked only the scientific plausibility of the scenario, not the facts the DDT had accepted. Procedural fairness and good faith therefore barred WADA from requiring the athlete to prove those facts again. WADA could have reserved its right to call Mr Imboden. The facts were taken as established: Mr Imboden ordered and took ostarine without her knowledge. ¶¶ 126–129
4. Prof. Alvarez's contamination study could have been stricter and better documented. It was still sufficiently controlled to carry decisive weight. It was peer-reviewed and has not been contested. The subjects were tested clean beforehand. Prof. Alvarez took the urine vials and the ostarine bottle with him, and a misleading sentence in the published article was a translation error. The allegation of systemic contamination was unsubstantiated. ¶ 133
5. The Panel excluded a second, intentional source of ostarine. The urinary concentrations in the study matched the 13 ng/mL found in the sample, and the study's curve matched the Walpurgis Study. Direct intake would likely have produced higher levels. The linear concentrations in her hair indicated external contamination. WADA's experts accepted that 13 ng/mL does not, in itself, exclude contamination. ¶¶ 132, 134–136
6. The contamination ran over nine days with a cumulative effect, because ostarine takes 6 to 9 days to be excreted. The exact timing of the first kiss on 14 January 2024 was therefore not critical. The violation was not intentional and the athlete bears No Fault or Negligence (Article 10.5 FIE ADR). No ineligibility was imposed and the DDT's disqualification ruling stands. ¶¶ 137–140

Procedural history

1. 14 January 2024In-competition urine test at the 2024 Challenge International de Paris (women's team foil). The sample later revealed ostarine.
2. 8 February 2024The ITA, for the FIE, notifies the adverse analytical finding and imposes a mandatory provisional suspension.
3. 20 February 2024The athlete attributes the finding to contamination by her partner, waives B-sample analysis and requests a hearing.
4. 13 May 2024Virtual hearing before the FIE Doping Disciplinary Tribunal.
5. 4 June 2024The DDT notifies its decision (operative part rendered 21 May 2024): violation found, No Fault or Negligence, no ineligibility, results from 14 January to 8 February 2024 disqualified.
6. 17 July 2024WADA files its Statement of Appeal with CAS.
7. 12 September 2024Order on Language: the proceedings are to be in English; French exhibits need no translation.
8. 25 November 2024Panel constituted.
9. 6 March 2025Hearing at CAS headquarters in Lausanne, including expert hot-tubbing.
10. 7 July 2025Award: appeal dismissed and DDT decision confirmed.

Tribunal, counsel and experts

Decided by

• Jacques Radoux President, Court of Arbitration for Sport
• Luigi Fumagalli Co-arbitrator, Court of Arbitration for Sport — appointed by the claimant
• Janie Soublière Co-arbitrator, Court of Arbitration for Sport — appointed by the respondent

For the claimant

WADA (in-house) · Nicolas Zbinden · Michael Kottmann · Robert Kerslake

For the respondent

Yvan Henzer · Joëlle Monlouis · Thierry Chiron

Experts

Christiane Ayotte (claimant) · Martial Saugy (claimant) · Jean-Claude Alvarez (respondent) · Pascal Kintz (respondent)

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Keywords

• ostarine
• SARMs
• contamination
• kissing scenario
• no fault or negligence
• intentional anti-doping rule violation
• source of prohibited substance
• balance of probability
• pharmacokinetics
• hair analysis
• Walpurgis Study
• de novo review
• procedural fairness
• FIE Anti-Doping Rules
• World Anti-Doping Code
• fencing
• 2024 Olympic Games
• MK-2866

Summary generated with AI from the published documents — refer to the award for the authoritative text.