Outcome of 93 patients with relapse or progression following allogeneic hematopoietic cell transplantation

Improved outcome in AML relapse after allogeneic transplant with high-intensity chemotherapy followed by 2nd allogeneic stem cell transplant or donor lymphocyte infusion

Acute myeloid leukemia (AML) relapse after allogeneic stem cell transplant (alloSCT) remains a major therapeutic challenge. While patients with longer remission after initial alloSCT are recommended to receive cell therapy (CT) such as 2^ndalloSCT or donor lymphocyte infusion (DLI), survival for patients who relapse within 6 months of alloSCT has been dismal. We evaluated the outcomes of AML relapse after alloSCT to assess the impact of different treatments on long-term survival. One hundred and seventy-two patients with AML underwent alloSCT at the Penn State Cancer Institute from January 2014 to August 2019. Sixty-nine patients relapsed (median age, 60 years; range, 10-75). Of these, 4 patients underwent 2^ndalloSCT, and 26 received DLI. One-year overall survival (OS) in all cases was 20.3% (95% CI: 11.8-30.4%). Patients with ECOG performance status (PS) 0-2 at relapse showed a better 1-year OS than those with PS 3-4. Median OS for patients who received chemotherapy only or chemotherapy with CT was 74 or 173.5 days, respectively (p < 0.001). Relapsed patients receiving conventional re-induction chemotherapy were categorized as the high-intensity chemotherapy (H) group, while those receiving treatments such as hypomethylating agents or targeted agents were categorized as the low-intensity chemotherapy (L) group. The H group showed a better 1-year OS compared with the L group. Patients who received H + CT showed a better 1-year OS of 52.9% than the other 3 groups (p < 0.001). Even for patients with post-alloSCT remission duration of less than 6 months, the statistical significance was preserved. Factors including age, donor source at 1^stalloSCT, time to relapse, blast counts, PS at relapse, and treatment type after post-alloSCT relapse were used for a multivariate analysis, and matched or mismatched related donor and H + CT after alloSCT were identified as independent factors associated with OS. These findings support the use of H + CT as the treatment option of choice for AML patients who relapse after alloSCT when feasible.

Novel agents targeting leukemia cells and immune microenvironment for prevention and treatment of relapse of acute myeloid leukemia after allogeneic hematopoietic stem cell transplantation

Relapse remains the worst life-threatening complications after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with acute myeloid leukemia (AML), whose prognosis has been historically dismal. Given the rapid development of genomics and immunotherapies, the interference strategies for AML recurrence have been changing these years. More and more novel targeting agents that have received the U.S. Food and Drug Administration (FDA) approval for de novo AML treatment have been administrated in the salvage or maintenance therapy of post-HSCT relapse. Targeted strategies that regulate the immune microenvironment of and optimize the graft versus leukemia (GVL) effect of immune cells are gradually improved. Such agents not only have been proven to achieve clinical benefits from a single drug, but if combined with classic therapies, can significantly improve the poor prognosis of AML patients who relapse after allo-HSCT. This review will focus on currently available and promising upcoming agents and also discuss the challenges and limitations of targeted therapies in the allogeneic hematopoietic stem cell transplantation community.

Risk Factors Influencing Outcome of Acute Leukemia Patients Who Experience Relapse After Allogeneic Hematopoietic Stem-Cell Transplantation

BACKGROUND

Prognosis of acute leukemia patients who experience relapse after hematopoietic stem-cell transplantation (HSCT) remains poor. Identifying risk factors influencing outcome of these patients is essential.

PATIENTS AND METHODS

Follow-up of 234 acute leukemia patients who underwent allogeneic HSCT from matched related donor was performed for occurrence of posttransplantation relapse. Statuses of remission and survival were assessed at 6 months after treatment of relapse. Analysis of risk factors influencing postrelapse overall survival (prOS), complete remission (CR), and nonrelapse mortality (NRM) was carried out.

RESULTS

Posttransplantation relapse occurred in 43 patients (17.9%). After treatment, 11 patients (25.6%) experienced postrelapse remission, the prOS rate was 20.9% (9 patients), and the NRM rate was 25.6% (11 patients). Older age (P = .007) and failure to experience remission after relapse treatment (P = .027) were associated with lower prOS in multivariate analysis. Female sex (P = .027), posttransplantation extramedullary relapse (P = .001), and absence of postrelapse graft-versus-host disease P = .025) were associated with lower CR rate. Also, presence of extramedullary relapse (P = .011) was associated with lower risk of NRM whereas treatment of posttransplantation relapse with donor lymphocyte infusion with or without chemotherapy (P = .002) and occurrence of postrelapse graft-versus-host disease (P = .025) were associated with higher risk of NRM.

CONCLUSION

Survival of acute leukemia patients who experience relapse after allogeneic HSCT is poor, especially in elderly patients and those who do not experience remission after relapse treatment.

Comparable post-relapse outcomes between haploidentical and matched related donor allogeneic stem cell transplantation

We investigated the impact of donor type on post-relapse survival (PRS) in 85 patients with hematological relapse after their first allogeneic hematological stem cell transplantation (allo-HSCT) for hematological malignancy. The median follow-up was 64 months among survivors. Both 3-year overall survival and 3-year PRS were similar in haploidentical donor (HID) and matched sibling donor (MRD) transplantation (13.0%±4.7% vs 19.4%±7.1%, P=0.913 and 7.7±3.9% vs 9.7±5.3%, P= 0.667). Higher rates of post-relapse grade II-IV and III-IV acute GvHD (aGvHD) were observed in HID transplantation patients. A higher cumulative incidence of post-relapse extensive chronic GvHD was also observed for HID transplantation patients. Multivariate analyses confirmed that treatment including donor lymphocyte infusion (DLI), late relapse >1 year, and in first CR at transplantation were associated with superior PRS (P=0.012, hazard ratio (HR)=0.527 (0.320-0.866)); P=0.033, HR=0.534 (0.300-0.952) and P=0.046, HR=0.630 (0.400-0.992). The data suggest that post-relapse outcomes are comparable in HID and MRD transplantation, and that DLI is safe for relapsed patients after haploidentical transplantation.

Treatment of relapse after allogeneic stem cell transplantation in children and adolescents with ALL: the Frankfurt experience

Therapy for post-transplant relapse of paediatric ALL is limited. Standardised curative approaches are not available. We hereby describe our local procedure in this life-threatening situation. A total of 101 ALL patients received their first allogeneic stem cell transplantation (SCT) in our institution. After relapse, our primary therapeutic goal was to cure the patient with high-dose chemotherapy or specific immunotherapy (HDCHT/SIT) followed by a second SCT from a haploidentical donor (transplant approach). If this was not feasible, low-dose chemotherapy and donor lymphocyte infusions (LDCHT+DLI) were offered (non-transplant approach). A total of 23 patients suffered a post-transplant relapse. Eight patients received HDCHT/SIT, followed by haploidentical SCT in 7/8. Ten received LDCHT+DLI. The eight patients treated with a second transplant and the ten treated with the non-transplant approach had a 4-year overall survival of 56% and 40%, respectively (P=0.232). Prerequisites for successful treatment of post-transplant relapse by either a second transplant or experimental non-transplant approaches are good clinical condition and the capacity to achieve haematological remission by the induction treatment element.

Prognostic index for relapsed acute leukemia after allogeneic stem cell transplant

We retrospectively studied patients who relapsed after allogeneic stem cell transplantation (SCT) to identify factors influencing outcomes. Of the 296 patients (196 with AML and 100 with ALL), 102 (34%) experienced relapse at a median of 222 days (range: 30-2,748) after SCT. Multivariable analysis showed that high disease risk (hazard risk [HR]: 1.95; 95% confidence interval [CI]: 1.17-3.24; p = 0.010), unrelated donor (HR: 1.76; 95% CI: 1.10-2.80; p = 0.018), and interval of < 180 days from SCT to relapse (HR: 2.10; 95% CI: 1.26-3.51; p = 0.004) were independent factors of 2-year post-relapse survival (PRS). These factors were used as a prognostic index for PRS. The 2-year PRS in patients of score 0, score 1, score 2, and score 3 was 38%, 19%, 3%, and 0%, respectively (p < 0.001). Our new prognostic index may be helpful for selecting the treatment for relapsed patients after SCT.

The second therapeutic trial for children with hematological malignancies who relapsed after their first allogeneic SCT: long-term outcomes

The impact of a second all-SCT on the long-term outcomes of children who relapse after allo-SCT has been unclear. We retrospectively analyzed the long-term outcomes of different salvage treatments for such children. Sixty-six children with hematological malignancies (40 ALL, 22 AML, three MDS, and one CML) who relapsed after a first allo-SCT received either a second allo-SCT (n = 16) or CTx and/or DLI (n = 50). The median follow-up for all children was 9.1 yr. The five-yr OS after relapse was significantly better in patients who underwent a second allo-SCT (42.9%) than in patients treated with CTx and/or DLI (11.8%) (p < 0.05). However, this advantage diminished with increasing time. The eight-yr OS for these groups of patients were 21.4% and 11.8%, respectively (p = n.s.). Among the 16 patients who received a second allo-SCT, two died more than five yr after the second allo-SCT. A second allo-SCT can therefore lead to a prolonged OS in patients who relapse after allo-SCT. However, a second allo-SCT should be selected carefully. This is because the mortality rate is still high, even when there is an extensive duration of time following the second allo-SCT.

Donor CD3(+) lymphocyte infusion after reduced intensity conditioning allogeneic stem cell transplantation: single-center experience

Donor lymphocyte infusions (DLI) can induce remission in patients with hematologic malignancies who relapse after allogeneic stem cell transplantation. However, graft-vs-host disease (GVHD) remains a major complication of this strategy. We have used escalating doses of DLI for many years, and wanted to assess the risk factors for GVHD and transplant-related mortality as well as disease outcomes according to the reason for DLI. We analyzed 65 patients who received a total of 111 DLI for different reasons and at different intervals after transplantation. Median number of DLI was 2 (range, 1-4), median interval between transplantation and DLI was 9 months (range, 1-41 months) and median number of infused CD3(+) cells/kg recipient body weight was 2.5 × 10(7) (range, 1 × 10(6)-11.8 × 10(7)). Reasons for DLI were relapse or progression in 37 patients (57%), residual disease in 15 patients (23%), and persistence of mixed chimerism in 13 patients (20%). Seven patients (11%) developed acute GVHD grade II to IV and 5 patients (8%) developed extensive chronic GVHD. In univariate analysis, we could identify a transplantation-DLI interval ≤6 months, the dose of DLI (≥1 × 10(7)), and DLI number as predictive factors of GVHD. In multivariate analysis, these results were confirmed only for the transplantation-DLI interval (hazard ratio = 19.48; 2.23-170.34; p = 0.007). Our findings indicate that this form of adoptive immunotherapy is well tolerated and induces a low incidence of GVHD and transplant-related mortality, supporting further investigation as an upfront modality to enhance the graft-vs-tumor response in high-risk patients.

Optimizing management of myelodysplastic syndromes post-allogeneic transplantation

Allogeneic hematopoietic stem cell transplantation is still the only potentially curative treatment for patients with myelodysplastic syndromes. Improvements in donor selection, supportive care and the introduction of reduced-intensity conditioning have led to a decrease in early transplant mortality. However, relapse rates have not changed significantly in recent years. Furthermore, treatment options for patients relapsing after hematopoietic stem cell transplantation are limited and often short-lived. Thus, optimizing the post-transplant outcome by maintenance approaches or minimal residual disease-directed preemptive therapy is an important goal of current clinical research. Further strategies aiming at an improved prevention of graft-versus-host disease are currently under investigation.

Relapse after allogeneic stem cell transplantation

Since allogeneic stem cell transplantation (SCT) represents an intensive curative treatment for high-risk malignancies, its failure to prevent relapse leaves few options for successful salvage treatment. While many patients have a high early mortality from relapse, some respond and have sustained remissions, and a minority has a second chance of cure with appropriate therapy. The prognosis for relapsed hematological malignancies after SCT depends on four factors: the time elapsed from SCT to relapse (with relapses occurring within 6 months having the worst prognosis), the disease type (with chronic leukemias and some lymphomas having a second possibility of cure with further treatment), the disease burden and site of relapse (with better treatment success if disease is treated early), and the conditions of the first transplant (with superior outcome for patients where there is an opportunity to increase either the alloimmune effect, the specificity of the antileukemia effect with targeted agents or the intensity of the conditioning in a second transplant). These features direct treatments toward either modified second transplants, chemotherapy, targeted antileukemia therapy, immunotherapy or palliative care.