New research suggests several factors are associated with failure to discontinue immune suppression after allogeneic hematopoietic cell transplant (HCT).
Patients older than 50 years, those with advanced stage disease, patients with a mismatched unrelated donor, and those who received peripheral blood stem cells from an unrelated donor were less likely to discontinue immune suppression successfully,, of Moffitt Cancer Center in Tampa, Fla., and colleagues reported in .
The researchers analyzed data from 827 patients in two national Blood and Marrow Transplant Clinical Trial Network studies (and ). These randomized, phase 3 trials enrolled patients with hematologic malignancies who received myeloablative conditioning before allogeneic HCT.
The patients’ median age at HCT was 44 years (range, less than 1 to 67 years), and 55.1% were male. The median follow-up was 72 months (range, 11-124 months).
At 5 years, 20% of patients (n = 168) had successfully discontinued immune suppression and were still alive. A total of 342 patients (41.4%) were able to stop immune suppression, but 127 of them had to resume it after developing graft-versus-host disease (GVHD). There were an additional 47 patients who died or relapsed after stopping immune suppression.
The researchers identified several factors that were significantly associated with lower odds of discontinuing immune suppression and being free of GVHD, including:
- Being older than 50 years versus younger than 30 years (adjusted odds ratio [aOR], 0.27; 99% confidence interval [CI], 0.14-0.50; P less than .001).
- Having a mismatched unrelated donor versus having a matched sibling (aOR, 0.37; 99% CI, 0.14-0.97; P = .008).
- Receiving peripheral blood stem cells versus bone marrow, from unrelated donors only (aOR, 0.46; 99% CI, 0.26-0.82; P less than .001).
- Having advanced stage disease versus early disease (aOR, 0.45; 99%CI, 0.23-0.86; P = .002).
The researchers also found that discontinuing immune suppression was not significantly associated with a decreased risk of relapse, with a hazard ratio (HR) of 1.95 (99% CI, 0.88-4.31; P = .03).
There was no significant association between acute GVHD–related variables and discontinuation of immune suppression. However, there were a few factors significantly associated with a lower likelihood of discontinuation after chronic GVHD, including:
- Current skin involvement (HR, 0.33; 99% CI, 0.14-0.80; P = .001).
- Unrelated well-matched donor versus matched sibling donor (HR, 0.29; 99% CI, 0.10-0.79; P = .001).
- Unrelated mismatched donor versus matched sibling donor (HR, 0.17; 99% CI, 0.03-0.95; P = .008).
In total, 127 patients had to resume immune suppression because of GVHD. Such failed attempts at discontinuing immune suppression were associated with receiving peripheral blood stem cells from an unrelated donor versus bone marrow from an unrelated donor, with an HR of 2.62 (99% CI, 1.30-5.29; P less than .001).
A history of acute or chronic GVHD was associated with failure to discontinue immune suppression, the researchers noted.
Lastly, the researchers developed dynamic prediction models for the probability of freedom from immune suppression and GVHD at 1, 3, and 5 years in the future. The team found that graft type, donor type, age, state history, and timing of immune suppression discontinuation were all associated with the likelihood of being free from immune suppression and GVHD at all three time points. Disease risk was only associated with freedom from immune suppression and GVHD at the 1-year mark.
The researchers said their findings must be validated in an independent cohort of patients and, after that, should be tested in a prospective trial.
The current study was funded by the National Heart Lung and Blood Institute. Two of the researchers reported relationships with more than 30 pharmaceutical companies.
SOURCE: Pidala J et al. JAMA Oncol. 2019 Sep 26. .