Prognostic Factors in Aplastic Anaemia

Aplastic anemia secondary to dual cancer immunotherapies a physician nightmare: case report and literature review

Background

Treatment with immune checkpoint inhibitors has revolutionized cancer treatment over the past several years. Despite their clinical benefits, a wide range of immune-mediated toxicities can be observed including hematological toxicities. Although, the majority can easily be managed, immune-mediated adverse events rarely can be severe and difficult to approach. Herein, we are reporting a case of very severe aplastic anemia secondary to ipilimumab (I) and nivolumab (N) treatment that failed various treatment including intensive immune suppressive therapy.

Case presentation

We described a case of a 45-year old white male, heavy smoker presented to the clinic complaining of left flank pain. He was found to have a metastatic renal cell carcinoma for which he was treated with dual immunotherapy and later complicated by severe immune related adverse events. The patient later died after failing intensive immune suppressive therapy.

Conclusion

Immunotherapy has become an established pillar of cancer treatment improving the prognosis of many patients with variant malignancies. Yet, lethal adverse events can occur in rare cases. It is our duty, as physicians, to remain alert and cautious.

Should we still use Camitta's criteria for severe aplastic anemia?

Background

The criteria by Camitta for diagnosis in severe aplastic anemia (SAA) has been used since 1976. However, there has been no attempt to verify the Camitta's criteria, that the survival in patients with SAA may differ by absolute neutrophil count (ANC), platelet count (PLT), and corrected reticulocyte count (CRC), which are components of the Camitta's criteria.

Methods

117 SAA patients diagnosed by the Camitta's criteria were analyzed, retrospectively. Univariate and multivariate analyses were used to evaluate the factors affecting overall survival (OS).

Results

Response by immunosuppressive therapy (IST) or stem cell transplantation (SCT) significantly affected OS (P=0.001). Therefore, we excluded treatment responders for analysis. Finally, 92 SAA patients including treatment non-responders by IST or SCT and conservative care group were analyzed by using univariate and multivariate analyses. The median age of analyzed patients was 54.5 years. Male to female ratio was 1:1. The median follow-up duration was 74.23 months (range, 54.71-93.74 months). The median ANC, PLT, and CRC were 394/µL, 12,000/µL, and 0.39%, respectively. In multivariate analyses, ANC <500/µL or ≥500/µL (P=0.015, HR 2.694, 95% CI: 1.20-6.01) and age (P=0.015, HR 1.022, 95% CI: 1.00-1.04) were the significant factors for OS.

Conclusion

ANC could be an essential, not an optional criterion for diagnosing SAA. This study suggests the possibility that the Camitta's criteria be modified. Studies in large cohorts are needed to transform the Camitta's criteria.

Clinical management of aplastic anemia

Acquired aplastic anemia is a potentially fatal bone marrow failure disorder that is characterized by pancytopenia and a hypocellular bone marrow. Hematopoietic stem-cell transplantation or bone marrow transplantation (BMT) is the treatment of choice for young patients who have a matched sibling donor. Immunosuppression with either anti-thymocyte globulin and cyclosporine or high-dose cyclophosphamide is an effective therapy for patients who are not suitable BMT candidates owing to age or lack of a suitable donor. Results of BMT from unrelated and mismatched donors are improving, but presently this treatment option is best reserved for those patients who do not respond, relapse or develop secondary clonal disorders following immunosuppressive therapy. Efforts are currently underway to both improve immunosuppressive regimens and to expand the application of BMT.

Acquired aplastic anemia in childhood

In comparison to past decades, children who have acquired aplastic anemia (AA) enjoy excellent overall survival that reflects improvements in supportive care, more accurate exclusion of children who have alternate diagnoses, and advances in transplantation and immunosuppressive therapy (IST). Matched sibling-donor hematopoietic stem cell transplants (HSCT) routinely provide long-term survival in the range of 90%, and 75% of patients respond to IST. In this latter group, the barriers to overall and complication-free survival include recurrence of AA, clonal evolution with transformation to myelodysplasia/acute myelogenous leukemia, and therapy-related toxicities. Improvements in predicting responses to IST, in alternative-donor HSCT, and in rationalizing therapy by understanding the pathophysiology in individual patients are likely to improve short- and long-term outcomes for these children.

Predicting response to immunosuppressive therapy and survival in severe aplastic anaemia

Horse anti-thymocyte globulin (h-ATG) and ciclosporin are the initial therapy for most patients with severe aplastic anaemia (SAA), but there is no practical and reliable method to predict response to this treatment. To determine whether pretreatment blood counts discriminate patients with SAA who have a higher likelihood of haematological response at 6 months to immunosuppressive therapy (IST), we conducted a single institution retrospective analysis on 316 SAA patients treated with h-ATG-based IST from 1989 to 2005. In multivariate analysis, younger age, higher baseline absolute reticulocyte count (ARC), and absolute lymphocyte count (ALC) were highly predictive of response at 6 months. Patients with baseline ARC > or = 25 x 10(9)/l and ALC > or = 1 x 10(9)/l had a much greater probability of response at 6 months following IST compared to those with lower ARC and ALC (83% vs. 41%, respectively; P < 0.001). This higher likelihood of response translated to greater rate of 5-year survival in patients in the high ARC/ALC group (92%) compared to those with a low ARC/ALC (53%). In the era of IST, the baseline ARC and ALC together serve as a simple predictor of response following IST, which should guide in risk stratification among patients with SAA.

An update on the management of severe idiopathic aplastic anaemia in children

The current outlook for a child with severe idiopathic aplastic anaemia (AA) is very much better than in previous decades. In part, this may reflect better differentiation of idiopathic and inherited marrow failure. For children with idiopathic AA and a human leucocyte antigen (HLA)-matched sibling donor (MSD), allogeneic haematopoietic stem-cell transplantation (AHSCT) is the primary therapy of choice, offering long-term disease-free survival of 90%, although graft-versus-host disease remains a cause of long-term morbidity. A greater treatment challenge remains for those children without a MSD. Combination immunosuppressive therapy (IST) is associated with response rates of 70% or more. However, relapse and clonal evolution with transformation to myelodysplasia or acute myeloid leukaemia remain significant problems after IST and long-term event-free survival rates are less impressive. For children who do not have a sustained response to IST, alternate donor AHSCT should be considered. New HLA typing technologies, novel stem cell sources, reduced-intensity conditioning and graft engineering have reduced toxicity and improved the outcome after alternate donor AHSCT. Emerging therapies that capitalise on recent advances in our understanding of the pathophysiology of idiopathic AA and the immunobiology of AHSCT and IST may further improve the long-term outcome of this disease.

Evaluation of angiogenesis and vascular endothelial growth factor expression in the bone marrow of patients with aplastic anemia

It is generally appreciated that bone marrow function and growth of myelopoietic cells depends on an intact microvasculature. A pivotal regulator of angiogenesis is vascular endothelial growth factor (VEGF). Here, we describe analysis of VEGF expression and microvessel density in the bone marrow of patients with aplastic anemia by immunohistochemistry. Bone marrow was examined at diagnosis and at the time of hematological remission after immunosuppressive therapy using anti-thymocyte globulin, cyclosporin A, and glucocorticoids or allogeneic stem cell transplantation. At diagnosis, both VEGF expression and microvessel density were found to be significantly lower in aplastic anemia compared to normal bone marrow (aplastic anemia, 1.1 +/- 0.7 events per field, versus controls, 5.9 +/- 3.0 events per field; P < 0.05). In response to successful therapy, VEGF and microvessel density in the bone marrow increased substantially. Serum VEGF levels were also found to be significantly lower at diagnosis in aplastic anemia compared to healthy controls (aplastic anemia, 51 +/- 35 pg/ml versus controls, 444 +/- 220 pg/ml; P < 0.05). VEGF in the serum increased substantially after successful immunosuppressive therapy or stem cell transplantation (P < 0.05). Taken together, these data show that aplastic anemia is associated with reduced angiogenesis and reduced VEGF expression.

Antithymocyte globulin and cyclosporine for severe aplastic anemia: association between hematologic response and long-term outcome

CONTEXT

In most patients, aplastic anemia results from T-cell-mediated immune destruction of bone marrow. Aplastic anemia can be effectively treated by stem cell transplantation or immunosuppression.

OBJECTIVE

To assess long-term outcomes after immunosuppressive therapy.

DESIGN, SETTING, AND PATIENTS

Cohort of 122 patients (31 were < or =18 years and 91 were >18 years) with severe aplastic anemia, as determined by bone marrow cellularity and blood cell count criteria, were enrolled in a single-arm interventional research protocol from 1991 to 1998 at a federal government research hospital.

INTERVENTIONS

A dose of 40 mg/kg per day of antithymocyte globulin administered for 4 days, 10 to 12 mg/kg per day of cyclosporine for 6 months (adjusted for blood levels), and a short course of corticosteroids (1 mg/d of methylprednisolone for about 2 weeks).

MAIN OUTCOME MEASURES

Survival, improvement of pancytopenia and transfusion-independence, relapse, and evolution to other hematologic diseases.

RESULTS

Response rates were 60% at 3 months after initiation of treatment, 61% at 6 months, and 58% at 1 year. The blood cell counts of patients who responded no longer satisfied severity criteria and they were transfusion-independent. Overall actuarial survival at 7 years was 55%. Survival was associated with early satisfaction of response criteria (86% vs 40% at 5 years; P<.001) and by blood counts at 3 months (reticulocyte count or platelet count of >50 x 10(3)/ microL predicted survival at 5 years of 90% [64/71] vs 42% [12/34] for patients with less robust recovery [P<.001 by log-rank test]). There were no deaths among responders more than 3 years after treatment. Relapse was common, but severe pancytopenia usually did not recur. Relapse did not influence survival. Thirteen patients showed evolution to other hematologic diseases, including monosomy 7.

CONCLUSIONS

Approximately half of patients with severe aplastic anemia treated with antithymocyte globulin and cyclosporine have durable recovery and excellent long-term survival. These outcomes were related to the quality of hematologic recovery.

Bone marrow histopathology of patients with severe aplastic anaemia before treatment and at follow-up

Pretreatment bone marrow biopsies of 63 patients with severe aplastic anaemia (SAA) who were not transplanted and of whom 55 received ATG, were evaluated according to the amount and character of residual haematopoiesis ('genuine' aplasia/intermediate/hypoplastic myelodysplasia (MD], inflammatory infiltrate (Te Velde & Haak, 1977, grade I/II/III), and number of mast cells (normal or slightly increased/increased). Of 61 evaluable biopsies, 47 were 'genuine' aplastic, 11 intermediate and three hypoplastic MD. Inflammatory infiltrates were graded as III in 36/60 evaluable biopsies, as II in 21 and I in three. A moderate to marked increase of mast cells was seen in 19/61. Of grade III patients, 86% had a less than 90 d interval between diagnosis and administration of ATG, versus 50% of grade I/II patients (P less than 0.01). No other correlations with pretreatment characteristics were found. No significant prognostic value for survival or response to ATG of any of these three criteria has been identified. More patients with grade III inflammation tended to show adequate recovery at 4 and 6 months after ATG. Stem cell damage, not identifiable morphologically, and/or impairment of accessory cells might play a major role in eventual outcome of SAA patients. Thirty-five patients are currently alive, median 3.8 years (up to 12.4) after ATG. Follow-up bone marrow aspirates and biopsies of 32 patients were evaluable and none showed normal haematopoiesis. One patient revealed persistent aplasia. Of the remaining 31, haematopoiesis was decreased in 14 and increased in eight. All had dyserythropoiesis, 28 dysplastic myelopoiesis and in 16/29 with evaluable megakaryocytes, dysmegakaryopoiesis was found. Sixteen patients had normo- to hypercellular bone marrows with two dysplastic cell lines (consistent with myelodysplastic syndrome (MDS) according to the FAB-group). The prognostic impact of the dysplastic abnormalities found in these patients needs longer follow-up. Close observation is indicated in view of the previously recognized, albeit uncommon, evolution of SAA to MDS/acute non-lymphocytic leukaemia.

Acute erythremic myelosis (DiGuglielmo) following atypical aplastic anemia

A patient presented with acute erythromyelosis (DiGuglielmo) which was developed after 3 yr of aplastic anemia. Aplastic anemia differed from the classical form, since erythroid cells and megakaryocytes were relatively preserved in the bone marrow. Treatment with androgens induced the increase of hematocrit and reticulocyte as well as general improvement. The sudden appearance of hemorrhagic syndrome due to thrombocytopenia was associated with aggravation of anemia and granulocytopenia. In the bone marrow, giant multinuclear proerythroblasts with bizarre nuclear morphology and PAS positivity with coarse granules was found. Serum erythropoietin (Ep) level was high. Bone marrow cells culture in vitro revealed two types of erythroid colonies: typical and giant multinuclear cells, both benzidine-positive. The number of colonies was irrespective to the Ep dose. "Autonomous" Ep independent growth of these colonies was also demonstrated. The number of colonies was more than 3 times higher per number of cells seeded when compared to normals, which indicated malignant proliferation and Ep independent growth. Treatment with 6-mercaptopurine and transfusions was without effect and the patient died after 15 days with signs of cerebral bleeding.

Subsets of patients with aplastic anemia identified by flow microfluorometry

We used flow microfluorometry to analyze peripheral-blood mononuclear cells from 50 patients with aplastic anemia, to determine whether patients who would recover after immunosuppressive therapy could be distinguished before treatment from those who would not recover. Cells were labeled with murine monoclonal antibodies that are relatively specific for B cells, T cells, T-cell subsets, and monocytes. The data suggested that the number of lymphocytes and the ratios of various subclasses of T cells were not useful in identifying patients who were likely to recover. The complete absence of monocytes was found to identify patients who would not recover, but the presence of monocytes was also sometimes associated with lack of recovery. An unexpected finding was the significant (P less than 0.0001) association between clinical recovery and the presence of a population of small cells (4 to 8 micron) that were phenotypically associated with the erythroid lineage. If this association is confirmed, flow microfluorometry may be useful in selecting the optimal treatment for individual patients with aplastic anemia.

Results of immunosuppression in 170 cases of severe aplastic anaemia. Report of the European Group of Bone Marrow Transplant (EGBMT)

This is a report of the European Group of Bone Marrow Transplant (EGBMT) on the influence of immunosuppression (IS) on survival of patients with severe aplastic anaemia (SAA). Fourteen teams participated in this survey involving 170 cases treated from 1974 to December 1980. The 1 year survival was 62.7%. Three types of treatment were used: (1) anti-thymocyte globulin (ATG) alone, (2) anti-thymocyte globulin and haplo-identical related bone marrow infusion, and (3) high dose bolus-6-methyl-prednisolone (b-6 MePr). There was no statistical difference in survival between these three groups. Androgens did not modify survival. Blood counts before treatment had a significant prognostic value. Patients with less than 0.2 X 10(9)/l granulocytes and less than 10 X 10(9)/l reticulocytes had 40% 1 year survival; the others had more than 70% 1 year survival. Patients with complete or partial reconstitution had the same good prognosis. In contrast, patients with no improvement after IS had a 27% 1 year survival. Several successive courses of IS improved the prognosis of non-responding patients. This survey confirms that IS improves the survival of patients with SAA. A prospective study will be performed to define the best and safest form of IS and to correlate clinical results with in vitro tests.

The use of antithymocyte globulin in the treatment of severe aplastic anemia in children

The benefit of antithymocyte globulin in severe aplastic anemia in the pediatric age group was assessed. Four children received ten alternate-day courses of ATG (horse antihuman thymocyte globulin) as well as antihistamines and corticosteroids to minimize allergic reactions. The outcome of 19 other children with severe aplastic anemia who received ATG was also summarized. Combined data reveal that 12 of 23 have had a complete or partial response with residual thrombocytopenia and a probability of 48% survival one year from the start of ATG therapy as projected by life table analysis. Only one death has been recorded in the responding group. Response rate did not appear to be influenced by age, sex, etiology, initial blood count, interval prior to ATG therapy, or dose of ATG employed. Complications were minimal and included minor urticarial reactions and intermittent fever. Therapy with ATG should be considered in childhood severe aplastic anemia when bone marrow transplantation is not possible.

[Bone marrow transplantation for aplastic anaemia (author's transl)]

From March 1975 until May 1980 twelve patients with severe aplastic anemia were grafted with bone marrow from HLA-identical siblings by the Munich Cooperative Group for Bone Marrow Transplantation. Six patients are alive between 10 months and more than 5 years after grafting with normal blood values and marrow. One patient is treated as an out patient for chronic localized graft-versus-host disease (GvHD), five patients are well and without treatment. Six patients have died, one patient with a cerebral hemorrhage the day before transplantation, three patients following rejection of grafts 32, 40 and 55 days after grafting, one patient with severe GvHD 85 days after grafting and one patient, probably with interstitial pneumonia, following cerebral hemorrhage. Three of 6 patients who were conditioned with Cyclophosphamide (CY) only died following rejection of the graft. Two adults who were conditioned with CY and "total lymphoid irradiation" and three children, who wer given unirradiated leukocyte concentrates from the marrow donor after grafting, did not reject their grafts. The results of the Munich-Cooperative Group for Bone Marrow Transplantation are comparable to those of large, specialized centers for bone marrow transplantation, they indicate possibilities of cure of severe aplastic anemia by marrow grafts from HLA-identical siblings. They confirm that better results are obtained with earlier transplantation in the course of the disease.

Bone-marrow transplantation. A preliminary study in aplasia and leukaemia

Six patients with aplastic anaemia, and nine patients with acute leukaemia in relapse, underwent bone-marrow transplantation between November, 1975, and November, 1979. All patients with aplastic anaemia developed a functioning marrow graft and four were alive 42, 24, 22, and 17 months respectively after the procedure. Two died within the first four months after the procedure from graft-versus-host disease (GVHD) and associated infection, while two of the survivors are still troubled by chronic GVHD. Of the nine patients with acute leukaemia, seven died within the first few months after the procedure. However, two patients remained alive, with no evidence of recurrent leukaemia, 18 and nine months respectively after the graft. These results confirm that bone-marrow transplantation is a useful therapeutic procedure in severe aplastic anaemia, but is of limited value in the treatment of acute leukaemia in relapse.

Aplastic anemia: recent advances in pathogenesis and treatment

Successful bone marrow transplantation and bone marrow culturing techniques have generated a large body of research into the pathogenesis and treatment of aplastic anemia. Most prominent has been the emphasis on autoimmune mechanisms. Several etiologic types and diagnostic criteria are discussed, the evidence supporting immune and other mechanisms of pathogenesis is examined, and results of current therapeutic trials are addressed.