Oral Regimens for Whipple’s Disease: A Non-Inferiority Trial of Doxycycline-Hydroxychloroquine Versus Standard Intravenous Therapy

Highlights

• Oral doxycycline plus hydroxychloroquine for 12 months demonstrated non-inferior efficacy to the established intravenous ceftriaxone followed by oral trimethoprim-sulfamethoxazole regimen in Whipple’s disease.
• The oral-only regimen showed a trend toward fewer serious adverse events and two deaths occurred only in the intravenous group due to nosocomial infections.
• Oral therapy offers substantial advantages in patient convenience, reduced hospitalization, and lower risk of hospital-acquired complications.

Study Background and Disease Burden

Whipple’s disease is a rare, chronic, systemic infection caused by the bacterium Tropheryma whipplei, affecting predominantly middle-aged men. Its classical presentation is malabsorption with weight loss, diarrhea, arthralgia, and multi-organ involvement. Untreated, the disease is fatal, but prompt antibiotic therapy is curative. The current standard of care—intravenous ceftriaxone or meropenem for 2 weeks followed by oral trimethoprim-sulfamethoxazole for a year—achieves a 98% cure rate. However, the need for hospital-based intravenous therapy introduces risks of catheter-related and nosocomial infections, patient inconvenience, and significant healthcare costs. An effective oral-only regimen could substantially improve care, especially for patients with limited access to inpatient services or those at high risk for hospital-acquired complications.

Study Design

This phase 2/3, prospective, open-label, randomized, controlled, non-inferiority trial was conducted across Germany, enrolling adults (≥18 years) with confirmed Whipple’s disease, all diagnosed and enrolled at Charité-Universitätsmedizin Berlin within one month of starting any treatment. Participants were randomized (1:1) to:

• Intravenous ceftriaxone (2 g daily for 14 days) followed by oral trimethoprim-sulfamethoxazole (960 mg twice daily) for 12 months (n=31).
• Oral doxycycline (100 mg twice daily) plus hydroxychloroquine (200 mg twice daily) for 12 months (n=29).

Ten additional participants who had already received intravenous ceftriaxone were assigned non-randomly to the intravenous group. For those in the oral group with central nervous system (CNS) involvement (PCR-positive T. whipplei in CSF), high-dose trimethoprim-sulfamethoxazole (960 mg five times daily) was added until CSF clearance. The primary endpoint was complete clinical remission without recurrence over 24 months (intention-to-treat analysis), with a non-inferiority margin of -18%. Safety was a key secondary endpoint.

Key Findings

Of 310 individuals screened, 64 were enrolled and 60 included in the analysis (31 IV group, 29 oral group). In the intention-to-treat population:

• Clinical remission without recurrence occurred in 25/31 (81%) in the intravenous group and 28/29 (97%) in the oral-only group. The risk difference was 15.9 percentage points (95% CI -1.2 to 33.1), with the lower CI above the -18% non-inferiority threshold.
• Post-hoc per-protocol analysis confirmed non-inferiority of the oral-only regimen.
• No relapses occurred in either group during the 24-month observation period.
• Two deaths occurred in the intravenous group, both due to nosocomial infections; none occurred in the oral group.
• Serious adverse events were reported in 13/31 (42%) intravenous group participants and 8/29 (28%) oral group participants (p=0.244), a non-significant difference but favoring the oral regimen.

The most common adverse events included gastrointestinal disturbances and hypersensitivity reactions, consistent with known profiles of the antibiotics used. Notably, the oral regimen obviated the risks associated with venous access and hospitalization.

Expert Commentary

The results of this well-designed non-inferiority trial have meaningful implications for clinical practice. Oral doxycycline plus hydroxychloroquine provides a practical, safe, and effective alternative to the traditional intravenous-oral regimen. This is particularly relevant given the rare but serious risks of hospital-acquired complications and the logistical challenges of prolonged intravenous therapy. The definition of clinical remission was robust and the 24-month follow-up adds confidence regarding relapse rates.

Limitations include the small sample size inherent to the rarity of Whipple’s disease, and the open-label design, which may introduce performance or detection bias. CNS involvement required temporary intensification of therapy in the oral group, which may limit the generalizability of the oral-only strategy for all patients, particularly those with complicated disease. Nonetheless, the lack of relapses and the favorable safety profile strengthen the case for oral therapy as a new standard, particularly for non-CNS disease.

Current guidelines have not yet incorporated these findings, but this study is likely to prompt revisions and broaden the range of evidence-based options available to clinicians. Mechanistically, both regimens provide effective anti-T. whipplei coverage, and the addition of hydroxychloroquine may enhance bactericidal activity through pH modulation in intracellular compartments.

Conclusion

This German multicenter randomized controlled trial demonstrates that oral doxycycline and hydroxychloroquine is non-inferior to standard intravenous ceftriaxone followed by oral trimethoprim-sulfamethoxazole for the treatment of Whipple’s disease, with a similar or improved safety profile. Oral therapy can reduce hospitalization, healthcare costs, and patient inconvenience, while maintaining excellent efficacy. Further real-world surveillance and studies in patients with CNS involvement will help refine optimal management strategies.

References

1. Moos V, Krüger J, Allers K, et al. Oral treatment of Whipple’s disease with doxycycline and hydroxychloroquine versus intravenous therapy with ceftriaxone followed by oral trimethoprim-sulfamethoxazole in Germany: a phase 2/3, prospective, open-label, randomised, controlled, non-inferiority trial. Lancet Infect Dis. 2025 Jul;25(7):788-800. doi: 10.1016/S1473-3099(24)00797-7 IF: 31.0 Q1 B1

Download PDF

2. Fenollar F, Puechal X, Raoult D. Whipple’s disease. N Engl J Med. 2007;356:55-66.
3. Marth T. Whipple’s disease: clinical review and recent developments. Curr Opin Gastroenterol. 2016;32(2):101-7.