Refining Conditioning Intensity and Graft Choice to Boost Adult Stem Cell Transplant Success
Key takeaways
- A moderate conditioning intensity (TCI 3.5‑4.0) appears safest for patients ≥ 65 years receiving cord‑blood grafts, while a higher intensity (TCI 4.5‑5.0) reduces relapse in those aged 50‑64 without worsening overall survival [1].
- One‑year survival after adult UCB transplantation improves markedly for patients who survive the first 12 months [2].
- In patients ≥ 65 years, a large proportion experience at least one documented infection within the first year, and infection‑related mortality has a substantial impact on overall survival, particularly among those with severe graft‑versus‑host disease [3].
Conditioning intensity: age‑specific sweet spots
For patients 65‑74 years old, a higher TCI (4.5‑5.0) was linked to a 61 % increase in overall mortality compared with a moderate score (3.5‑4.0) (hazard ratio 1.61, p = 0.032) [1].
Conversely, the middle‑aged group (50‑64 years) showed a 36 % reduction in relapse when the higher TCI was used (hazard ratio 0.64, p = 0.014), yet overall mortality remained unchanged [1].
Younger adults (< 50 years) displayed no significant differences in mortality, relapse, or non‑relapse mortality across the two intensity levels [1].
Early mortality after adult cord‑blood transplantation
Early mortality after adult UCB transplantation is substantial, and among patients who survive the first year, late mortality is primarily driven by disease relapse [2].
Infection burden in older allo‑HCT recipients
In older allo‑HCT recipients, a large proportion experienced at least one microbiologically documented infection within the first post‑transplant year [3].
Risk factors for higher infection rates included poor functional status and graft‑versus‑host disease [3].
Infection‑related mortality had a substantial impact on overall survival, particularly among patients with severe GVHD [3].
Balancing efficacy and safety: emerging strategies
- Age‑adjusted conditioning – In patients ≥ 65 years, a lower TCI score (3.5‑4.0) was associated with lower overall mortality compared with a higher score (4.5‑5.0), while in younger cohorts the higher score did not affect overall mortality [1].
- Landmark survival insight – Survival after the 1‑year landmark is durable, and late mortality is primarily driven by relapse [2].
- Infection vigilance – In older allo‑HCT recipients, infection incidence is high and infection‑related mortality is substantial, particularly among those with severe GVHD [3].
