Competing risks occur commonly in medical research. For example, both treatment-related mortality and disease recurrence are
important outcomes of interest and well-known competing risks in cancer ...research. In the analysis of competing risks data,
methods of standard survival analysis such as the Kaplan-Meier method for estimation of cumulative incidence, the log-rank
test for comparison of cumulative incidence curves, and the standard Cox model for the assessment of covariates lead to incorrect
and biased results. In this article, we discuss competing risks data analysis which includes methods to calculate the cumulative
incidence of an event of interest in the presence of competing risks, to compare cumulative incidence curves in the presence
of competing risks, and to perform competing risks regression analysis. A hypothetical numeric example and real data are used
to compare those three methods in the competing risks data analysis to their respective counterparts in the standard survival
analysis. The source and magnitude of bias from the Kaplan-Meier estimate is also detailed.
Because the outcome of allogeneic hematopoietic cell transplantation (HCT) is predominantly influenced by disease type and status, it is essential to be able to stratify patients undergoing HCT by ...disease risk. The Disease Risk Index (DRI) was developed for this purpose. In this study, we analyzed 13 131 patients reported to the Center for International Blood and Marrow Transplant Research who underwent HCT between 2008 and 2010. The DRI stratified patients into 4 groups with 2-year overall survival (OS) ranging from 64% to 24% and was the strongest prognostic factor, regardless of age, conditioning intensity, graft source, or donor type. A randomly selected training subgroup of 9849 patients was used to refine the DRI, using a multivariable regression model for OS. This refined DRI had improved prediction ability for the remaining 3282 patients compared with the original DRI or other existing schemes. This validated and refined DRI can be used as a 4- or 3-group index, depending on the size of the cohort under study, for prognostication; to facilitate the interpretation of single-center, multicenter, or registry studies; to adjust center outcome data; and to stratify patients entering clinical trials that enroll patients across disease categories.
•The DRI successfully stratified patients in a very large allogeneic transplantation registry cohort.•The DRI was refined by using this cohort to build a more inclusive and conditioning intensity–independent index.
Anti–programmed cell death protein 1 (PD-1) monoclonal antibodies are being increasingly tested in patients with advanced lymphoma. Following treatment, many of those patients are likely to be ...candidates for allogeneic hematopoietic stem cell transplant (HSCT). However, the safety and efficacy of HSCT may be affected by prior PD-1 blockade. We conducted an international retrospective analysis of 39 patients with lymphoma who received prior treatment with a PD-1 inhibitor, at a median time of 62 days (7-260) before HSCT. After a median follow-up of 12 months, the 1-year cumulative incidences of grade 2-4 and grade 3-4 acute graft-versus-host disease (GVHD) were 44% and 23%, respectively, whereas the 1-year incidence of chronic GVHD was 41%. There were 4 treatment-related deaths (1 from hepatic sinusoidal obstruction syndrome, 3 from early acute GVHD). In addition, 7 patients developed a noninfectious febrile syndrome shortly after transplant requiring prolonged courses of steroids. One-year overall and progression-free survival rates were 89% (95% confidence interval CI, 74-96) and 76% (95% CI, 56-87), respectively. One-year cumulative incidences of relapse and nonrelapse mortality were 14% (95% CI, 4-29) and 11% (95% CI, 3-23), respectively. Circulating lymphocyte subsets were analyzed in 17 patients. Compared with controls, patients previously treated with PD-1 blockade had significantly decreased PD-1+ T cells and decreased ratios of T-regulatory cells to conventional CD4 and CD8 T cells. In conclusion, HSCT after PD-1 blockade appears feasible with a low rate of relapse. However, there may be an increased risk of early immune toxicity, which could reflect long-lasting immune alterations triggered by prior PD-1 blockade.
•HSCT after PD-1 blockade is feasible, although may be associated with increased early immune toxicity.•PD-1 blockade may cause persistent depletion of PD1+ T cells and alterations in T-cell differentiation impacting subsequent treatment.
Idelalisib is a small-molecule inhibitor of PI3Kδ with demonstrated efficacy for the treatment of relapsed/refractory chronic lymphocytic leukemia (CLL). To evaluate idelalisib as front-line therapy, ...we enrolled 24 subjects in a phase 2 study consisting of 2 months of idelalisib monotherapy followed by 6 months of combination therapy with idelalisib and the anti-CD20 antibody ofatumumab. After a median follow-up period of 14.7 months, hepatotoxicity was found to be a frequent and often severe adverse event. A total of 19 subjects (79%) experienced either grade ≥1 ALT or AST elevation during the study, and 13 subjects (54%) experienced grade ≥3 transaminitis. The median time to development of transaminitis was 28 days, occurring before ofatumumab introduction. Younger age and mutated immunoglobulin heavy chain status were significant risk factors for the development of hepatotoxicity. Multiple lines of evidence suggest that this hepatotoxicity was immune mediated. A lymphocytic infiltrate was seen on liver biopsy specimens taken from 2 subjects with transaminitis, and levels of the proinflammatory cytokines CCL-3 and CCL-4 were higher in subjects experiencing hepatotoxicity. All cases of transaminitis resolved either by holding the drug, initiating immunosuppressants, or both, and rates of recurrent toxicity were lower in patients taking steroids when idelalisib was reinitiated. A decrease in peripheral blood regulatory T cells was seen in patients experiencing toxicity on therapy, which is consistent with an immune-mediated mechanism. These results suggest that caution should be taken as drugs within this class are developed for CLL, particularly in younger patients who have not received prior disease-specific therapy. This study was registered at www.clinicaltrials.gov as #NCT02135133.
•Idelalisib as upfront therapy for CLL caused an early hepatotoxicity in a subset of primarily younger patients with IGHV-mutated disease.•Multiple lines of evidence suggest that this adverse effect is immune mediated, perhaps through inhibition of regulatory T cells.
Clonal hematopoiesis (CH) can be transmitted from a donor to a recipient during allogeneic hematopoietic cell transplantation. Exclusion of candidate donors with CH is controversial since its impact ...on recipient outcomes and graft alloimmune function is uncertain.
We performed targeted error-corrected sequencing on samples from 1,727 donors age 40 years or older and assessed the effect of donor CH on recipient clinical outcomes. We measured long-term engraftment of 102 donor clones and cytokine levels in 256 recipients at 3 and 12 months after transplant.
CH was present in 22.5% of donors, with
(14.6%) and
(5.2%) mutations being most common; 85% of donor clones showed long-term engraftment in recipients after transplantation, including clones with a variant allele fraction < 0.01.
CH with a variant allele fraction ≥ 0.01, but not smaller clones, was associated with improved recipient overall (hazard ratio HR, 0.79;
= .042) and progression-free survival (HR, 0.72;
= .003) after adjustment for significant clinical variables. In patients who received calcineurin-based graft-versus-host disease prophylaxis, donor
CH was associated with reduced relapse (subdistribution HR, 0.59;
= .014), increased chronic graft-versus-host disease (subdistribution HR, 1.36;
= .042), and higher interleukin-12p70 levels in recipients. No recipient of sole
or
-CH developed donor cell leukemia (DCL). In seven of eight cases, DCL evolved from donor CH with rare
or splicing factor mutations or from donors carrying germline
mutations.
Donor CH is closely associated with clinical outcomes in transplant recipients, with differential impact on graft alloimmune function and potential for leukemic transformation related to mutated gene and somatic clonal abundance. Donor
-CH is associated with improved recipient survival because of reduced relapse risk and with an augmented network of inflammatory cytokines in recipients. Risk of DCL in allogeneic hematopoietic cell transplantation is driven by somatic myelodysplastic syndrome-associated mutations or germline predisposition in donors.
Chronic graft-versus-host disease (cGVHD) is associated with inadequate reconstitution of tolerogenic CD4+CD25+FOXP3+ regulatory T cells (Tregs). Previous phase 1 studies identified a low daily dose ...of interleukin-2 (IL-2) that was well tolerated, did not exacerbate alloimmunity, augmented Treg in vivo, and was associated with improvement of active cGVHD. In the current phase 2 study, 35 adults with steroid-refractory cGVHD received daily IL-2 (1 × 106 IU/m2) for 12 weeks. Median time from transplantation and cGVHD onset was 616 days (range, 270-2145 days) and 317 days (range, 28-1880 days), respectively. Two patients withdrew and 5 required IL-2 dose reductions due to side effects. Twenty of 33 evaluable patients (61%) had clinical responses at multiple cGVHD sites (liver, skin, gastrointestinal tract, lung, joint/muscle/fascia). Three patients (9%) had progressive cGVHD. Compared with pretreatment levels, Treg and natural killer cell counts rose >fivefold (P < .001) and >fourfold (P < .001), respectively, without significant change in conventional CD4 T cells (Tcons) or CD8 T cells. The Treg:Tcon ratio rose >fivefold (P < .001). Clinical responders initiated IL-2 earlier (508 vs 917 days after transplantation, P = .005; 249 vs 461 days after cGVHD onset; P = .03). Treg:Tcon ratios ≥0.07 at baseline and ≥0.2 at week 1 also predicted clinical response (P = .003; P = .0003, respectively). After a 4-week treatment hiatus, clinical responders were eligible to continue IL-2 therapy indefinitely. During 2 years of extended IL-2 therapy, clinical and Treg immune responses persisted, while Tcon count and Treg:Tcon ratio gradually normalized. Low-dose IL-2 provides durable clinical improvement in active cGVHD and extended therapy is well-tolerated.
•Low-dose IL-2 is efficacious in steroid-refractory cGVHD, with objective responses in >50% of patients, and durable disease control.•IL-2 initiation earlier after cGVHD onset, prior to severe impairment of Treg:Tcon ratios, improves likelihood of clinical response.
The outcome of allogeneic HSCT varies considerably by the disease and remission status at the time of transplantation. Any retrospective or prospective HSCT study that enrolls patients across disease ...types must account for this heterogeneity; yet, current methods are neither standardized nor validated. We conducted a retrospective study of 1539 patients who underwent transplantation at Dana-Farber Cancer Institute/Brigham and Women's Hospital from 2000 to 2009. Using multivariable models for overall survival, we created a disease risk index. This tool uses readily available information about disease and disease status to categorize patients into 4 risk groups with significantly different overall survival and progression-free survival on the basis of primarily differences in the relapse risk. This scheme applies regardless of conditioning intensity, is independent of comorbidity index, and was validated in an independent cohort of 672 patients from the Fred Hutchinson Cancer Research Center. This simple and validated scheme could be used to risk-stratify patients in both retrospective and prospective HSCT studies, to calibrate HSCT outcomes across studies and centers, and to promote the design of HSCT clinical trials that enroll patients across diseases and disease states, increasing our ability to study nondisease-specific outcomes in HSCT.
Programmed cell death-1 (PD-1)/programmed death ligand-1 blockade may potentially augment graft-vs-tumor effects following allogeneic hematopoietic cell transplantation (alloHCT), but retrospective ...studies of anti–PD-1 therapy reported substantial toxicity from graft-versus-host-disease (GVHD). Here, we report the results of a prospective clinical trial of PD-1 blockade for relapsed hematologic malignancies (HMs) after alloHCT (NCT01822509). The primary objective in this phase 1 multicenter, investigator-initiated study was to determine maximum tolerated dose and safety. Secondary objectives were to assess efficacy and immunologic activity. Patients with relapsed HMs following alloHCT were eligible. Nivolumab was administered every 2 weeks until progression or unacceptable toxicity, starting with a 1-mg/kg cohort, with planned deescalation based on toxicity to a 0.5-mg/kg cohort. Twenty-eight patients were treated (n = 19 myeloid, n = 9 lymphoid). Median age was 57 years (range 27-76), and median time from alloHCT to enrollment was 21 months (range 5.6-108.5). Two of 6 patients treated at 1 mg/kg experienced dose-limiting toxicity (DLT) from immune-related adverse events (irAEs). Twenty-two patients were treated at 0.5 mg/kg, and 4 DLTs occurred, including 2 irAEs and 2 with fatal GVHD. The overall response rate in efficacy-evaluable patients was 32% (8/25). With a median follow-up of 11 months, the 1-year progression-free survival and overall survival were 23% and 56%, respectively. In this first prospective clinical trial of an anti–PD-1 antibody for post–alloHCT relapse, GVHD and irAEs occurred, requiring dose deescalation, with only modest antitumor activity. Further studies of anti–PD-1 therapy post–alloHCT may require specific toxicity mitigation strategies. This trial was registered at www.clinicaltrials.gov as #NCT 01822509.
•This first prospective trial of PD-1 blockade for post–alloHCT relapse showed activity primarily in lymphoid malignancies.•Minimal activity was seen in myeloid malignancies, and GVHD and immune-related adverse events occurred.
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Umbilical cord blood (UCB) is a valuable source of hematopoietic stem cells (HSCs) for use in allogeneic transplantation. Key advantages of UCB are rapid availability and less stringent requirements ...for HLA matching. However, UCB contains an inherently limited HSC count, which is associated with delayed time to engraftment, high graft failure rates, and early mortality. 16,16-Dimethyl prostaglandin E2 (dmPGE2) was previously identified to be a critical regulator of HSC homeostasis, and we hypothesized that brief ex vivo modulation with dmPGE2 could improve patient outcomes by increasing the “effective dose” of HSCs. Molecular profiling approaches were used to determine the optimal ex vivo modulation conditions (temperature, time, concentration, and media) for use in the clinical setting. A phase 1 trial was performed to evaluate the safety and therapeutic potential of ex vivo modulation of a single UCB unit using dmPGE2 before reduced-intensity, double UCB transplantation. Results from this study demonstrated clear safety with durable, multilineage engraftment of dmPGE2-treated UCB units. We observed encouraging trends in efficacy, with accelerated neutrophil recovery (17.5 vs 21 days, P = .045), coupled with preferential, long-term engraftment of the dmPGE2-treated UCB unit in 10 of 12 treated participants. This study was registered at www.clinicaltrials.gov as #NCT00890500.
Key Points
Hematologic cancers that recur after allogeneic hematopoietic stem-cell transplantation are often difficult to treat. A small pilot study suggests that ipilimumab may induce durable responses in a ...subgroup of patients with these cancers.
Allogeneic hematopoietic stem-cell transplantation (HSCT) is the only cure for many patients who have advanced hematologic cancers, principally through the induction of a graft-versus-tumor effect.
1
Unfortunately, more than one third of patients who have undergone transplantation have a relapse of disease.
2
The prognosis for these patients is poor; the majority die within 1 year after relapse despite salvage chemotherapy, donor-lymphocyte infusion, or retransplantation.
3
–
5
Immune escape (i.e., tumor evasion of the donor immune system) contributes to relapse after allogeneic HSCT, and immune checkpoint inhibitory pathways probably play an important role.
6
The engagement of cytotoxic T-lymphocyte–associated protein 4 (CTLA-4) and programmed . . .
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