For people with mycosis fungoides or Sézary syndrome, the numbers have always been hard to come by. Both are rare cutaneous T-cell lymphomas. Both progress, often through round after round of treatment. And the one big trial of the antibody mogamulizumab had a flaw that made survival hard to judge: so many patients switched treatment arms that nobody could say cleanly whether the drug helped them live longer.
On June 30, 2026, at a major cutaneous lymphoma congress, researchers presented two attempts to fill that gap. Kyowa Kirin, the drug’s maker, funded the work.
How they did it
Neither study was a new head-to-head trial. Each reused individual records from 186 patients who received the drug in the phase 3 MAVORIC trial and set them against real-world registry records from two countries. Statistical adjustments were used to account for differences between the groups. In MAVORIC, mogamulizumab had beaten vorinostat on progression-free survival, but the crossover left overall survival unanswered.
Australia and Denmark
The Australian study, led by a Melbourne team at Peter MacCallum, drew on 67 patients given vorinostat over the period from January 2005 to November 2024. Among those on mogamulizumab, median overall survival was never reached. The vorinostat patients had a median of 31.0 months. The hazard ratio for death came out at 0.48, with a p-value of 0.002. Time to the next treatment was longer too, 9.13 months against 5.82, but that gap was not statistically significant.
Denmark offered a different comparison, since vorinostat is not available there. Researchers used national registries covering 209 patients on standard care from January 1996 through April 2024. Again the mogamulizumab group did not reach a median. Patients on standard care had 17.0 months. The hazard ratio was 0.38, with p below 0.001.
“Indirect treatment comparisons help to bridge critical evidence gaps in MF and SS, giving clinicians a clearer picture of long-term outcomes in real-world practice,” said Professor H. Miles Prince, the Melbourne principal investigator.
What the numbers cannot say
The caveats are real. Both studies look backward, and the Danish records stretch across nearly three decades, during which care for these patients changed. The Biotech Times noted that clinicians and payers will probably want sensitivity analyses and longer follow-up before they act on the results.
Kyowa Kirin’s own statement says the work is meant to close evidence gaps that hold back access in some countries. Mogamulizumab, sold as Poteligeo, won FDA approval in 2018 for adults whose MF or SS had relapsed or resisted treatment, after at least one earlier systemic therapy.
Sources
- New Analyses Advance Understanding of Long-Term Survival Outcomes with Mogamulizumab in Mycosis Fungoides and Sezary Syndrome (Kyowa Kirin North America)
- Kyowa Kirin mogamulizumab data show survival gains in rare CTCL (The Biotech Times)
