Preconditioning Frailty Phenotype Influences Survival and Relapse for Older Allogeneic Transplantation Recipients

Hematologic malignancies disproportionately affect older adults. Hematopoietic cell transplantation (HCT) is potentially curative, but poor overall survival (OS) has limited its use in older adults. Fried's frailty phenotype (FFP) is a geriatric assessment tool that combines objective and subjective performance measures: gait speed, grip strength, activity level, exhaustion, and weight loss. People meeting ≥3 criteria are classified as frail; 1 or 2 criteria, as pre-frail; and 0 criteria, as fit. To evaluate the association of pre-HCT FFP with post-HCT outcomes, we assessed FFP prior to conditioning for 280 HCT recipients age ≥60 years with acute leukemia or a myeloid neoplasm at 3 institutions. When analyzing survival by age group, patients age ≥70 years had inferior OS compared to patients age 60 to 69 years (P = .002), with corresponding OS estimates of 38.9% (95% confidence interval [CI], 27.8% to 49.9%) and 59.3% (95% CI, 51.9% to 65.9%). Nonrelapse mortality (NRM) also was significantly higher in the older patients (P = .0005); the 2-year cumulative incidences of NRM were 38.5% (95% CI, 27.5% to 49.2%) and 17.2% (95% CI, 12.3% to 22.8%), for older and younger recipients, respectively. The cumulative incidences of relapse did not differ by age group (P = .3435). Roughly one-third (35.5%) of the patients were fit, 57.5% were pre-frail, and 7.5% were frail, with corresponding 2-year OS estimates of 68.4% (95% CI, 57.9% to 76.8%), 45.5% (95% CI, 37.4% to 53.2%), and 45.8% (95% CI, 23.4% to 65.8%) (P = .013). FFP was not significantly associated with NRM, but being frail or pre-frail was associated with a higher rate of disease-related deaths (33.3% and 27.3%, respectively, compared with 17.4% for fit patients; P = .043). In univariate modeling of restricted mean survival time with a 3-year horizon (RMST_3y), the factors that were significantly associated were FFP, age, Karnofsky Performance Status (KPS), Disease Risk Index (DRI), and HCT-specific Comorbidity Index (HCT-CI). Of those factors, only FFP (P = .006), age (P = .006), KPS (P = .004), and DRI (P = .005) were significantly associated in multivariate modeling of RMST_3y. Estimates of RMST_3y were computed and 5 risk-groups were created with survival ranging from 31.4 months for those who were age 60 to 69 years, fit, had KPS 90 to 100, and low/intermediate-risk DRI compared to 10.5 months for those who had high-risk features for all the evaluated factors. In univariate and multivariate analyses for restricted mean time to relapse with a 3-year horizon (RMRT_3y), FFP (pre-frail versus fit, P = .007; frail versus fit, P = .061) and DRI (P = .001) were the only significant factors. Predicted RMRT_3y was longest (30.6 months) for those who were fit and had low/intermediate-risk DRI scores and shortest (19.1 months) for those who were frail and had high-risk or very high-risk DRI scores. Both age and FFP impact survival after HCT. Incorporation of FFP into pre-HCT evaluations may improve decision-making and counseling regarding HCT risk for older adults. Our findings support future trials designed to reverse frailty, such as pre-HCT supervised exercise programs, and correlative analyses to unravel the connection of frailty and relapse to generate future targets for intervention. Finally, exploration of novel HCT platforms to reduce relapse in pre-frail and frail patients, as well as reduce NRM in adults age >70 years, are warranted.

Geriatric Assessment Reveals Actionable Impairments in Hematopoietic Stem Cell Transplantation Candidates Age 18 to 80 Years

Allogeneic hematopoietic stem cell transplantation (HCT) is a potentially curative treatment for both malignant and nonmalignant hematologic diseases; however, reported rates of treatment-related mortality approach 30%. Outcomes are worse in patients who begin HCT with functional impairments. To detect such impairments, a geriatric assessment (GA) is recommended in adults age ≥65 years. Younger HCT candidates also may be impaired because of chemotherapy regimens pre-HCT. Therefore, we hypothesized that GA can be beneficial for adult patients of all ages and subsequently created a clinical pretransplantation optimization program to assess all HCT candidates using a modified GA. One-hundred fifty-seven patients were evaluated in 4 functional domains- physical, cognitive, nutritional, and psychological-at 2 time points prior to HCT-new patient evaluation (NPE) and sign-off (SO)-between October 2017 and January 2020. At NPE, 80.9% of the patients had at least 1 domain with a functional impairment, and physical (P = .006), cognitive (P = .04), and psychological (P = .04) impairments were associated with an increased likelihood of not proceeding to HCT. In addition, patients age 18 to 39 years were more likely than older patients to have a physical function impairment (P = .001). Between NPE and SO, 51.9% of the patients had resolution of 1 or more impairments, and nutritional impairment at SO was predictive of worse overall survival (P = .01). Our study shows that GA can identify functional impairments in patients of all ages. Early identification of impairments could facilitate referrals to supportive care and resolution of impairments prior to HCT, suggesting that GA could be recommended for HCT candidates of all ages.

Female Sex Is Associated with Improved Long-Term Survival Following Allogeneic Hematopoietic Stem Cell Transplantation

Life expectancy for long-term survivors of allogeneic hematopoietic stem cell transplantation (alloHSCT), defined as those living ≥5 years post-transplantation, is significantly lower compared with that of the age-matched general population despite a relatively low primary disease relapse rate at >2 years post-transplantation. Among several factors, patient sex is increasingly recognized as a prognostic indicator of long-term survival. We examined the influence of patient sex and donor-recipient sex matching on overall survival (OS) in a landmark analysis of long-term survivors. Using our institutional database supplemented with individual patient record review, we retrospectively investigated the relative influence of recipient sex and donor-recipient sex matching on outcomes of long-term survivors of alloHSCT between 1994 and 2014. Over this 20-year period, 247 met inclusion criteria for analysis; males and females had similar demographic and treatment characteristics. However, significantly more deaths after the 5-year landmark occurred in male recipients. Interestingly, donor sex did not have a significant impact on OS in multivariate analysis, and differences in OS of donor-recipient sex pairs was driven by recipient sex. In addition to recipient sex, only chronic graft-versus-host disease (cGVHD) retained significance as a covariate with an impact on OS in multivariate analysis. Men experienced slightly higher, but statistically nonsignificant, rates and increased severity of cGVHD, and had higher cGVHD-related mortality compared with females. In this long-term survival analysis of adult alloHSCT recipients, one of the only to include follow-up to 15 years, our results show that women survive significantly longer than men irrespective of their age at transplantation. This outcome is independent of other common pretransplantation prognostic indicators, such as donor sex or performance status at transplantation. The inferior survival in males is consistent with survival outcomes described in the transplantation literature. Increasing evidence suggests a biological basis for long-term sex-determined outcomes, possibly owing to differing rates or severity of cGVHD or sustained alloimmune tolerance in females. Larger studies are warranted to validate these retrospective clinical results.

Multi-omics analyses of radiation survivors identify radioprotective microbes and metabolites

Ionizing-radiation causes acute radiation syndrome leading to hematopoietic, gastrointestinal and cerebrovascular injuries. Substantial federal efforts have been made to develop therapeutic radioprotectants for routine clinical use, however it remains a long-standing and unresolved problem.

We investigated a population of mice that recovered from high-dose radiation to live normal lifespans. These elite-survivors harbored distinct gut microbiota that developed post-radiation and protected against radiation-induced damage and death in germ-free and conventionally housed recipients. Elevated abundances of members of the bacterial taxa Lachnospiraceae and Enterococcaceae were associated with post-radiation restoration of hematopoiesis and gastrointestinal repair. These bacteria were also found to be more abundant in leukemia patients undergoing radiotherapy who also displayed milder gastrointestinal dysfunction. Metabolomics revealed increased fecal concentrations of microbially derived propionate and tryptophan metabolites in elite-survivors. The concentrations of these metabolites correlated with long-term radioprotection, mitigation of hematopoietic and gastrointestinal syndromes, and a reduction in pro-inflammatory responses.

The novelty of our work lies in the first identification of gut microbiota and downstream metabolites in providing protection against lethal radiation. Furthermore, our work provides a comprehensive omics dataset at the bacteria and metabolite levels that is of broad interest and serves as a powerful resource and example for the identification of actionable therapeutic targets derived from microbiome studies.

Multi-omics analyses of radiation survivors identify radioprotective microbes and metabolites

Ionizing radiation causes acute radiation syndrome, which leads to hematopoietic, gastrointestinal, and cerebrovascular injuries. We investigated a population of mice that recovered from high-dose radiation to live normal life spans. These "elite-survivors" harbored distinct gut microbiota that developed after radiation and protected against radiation-induced damage and death in both germ-free and conventionally housed recipients. Elevated abundances of members of the bacterial taxa Lachnospiraceae and Enterococcaceae were associated with postradiation restoration of hematopoiesis and gastrointestinal repair. These bacteria were also found to be more abundant in leukemia patients undergoing radiotherapy, who also displayed milder gastrointestinal dysfunction. In our study in mice, metabolomics revealed increased fecal concentrations of microbially derived propionate and tryptophan metabolites in elite-survivors. The administration of these metabolites caused long-term radioprotection, mitigation of hematopoietic and gastrointestinal syndromes, and a reduction in proinflammatory responses.