Complete remission with partial hematological recovery as a palliative endpoint for treatment of acute myeloid leukemia.

ABSTRACT: Complete remission with partial hematological recovery (CRh) has been used as an efficacy endpoint in clinical trials of nonmyelosuppressive drugs for acute myeloid leukemia (AML). We conducted a pooled analysis to characterize the clinical outcomes for patients with AML who achieved CRh after treatment with ivosidenib, olutasidenib, enasidenib, or gilteritinib monotherapy in clinical trials used to support marketing applications. The study cohort included 841 adult patients treated at the recommended drug dosage; 64.6% were red blood cell or platelet transfusion dependent at study baseline. Correlations between disease response and outcomes were assessed by logistic regression modeling for categorical variables and by Cox proportional hazards modeling for time-to-event variables. Patients with CRh had a higher proportion with transfusion independence (TI) for at least 56 days (TI-56; 92.3% vs 22.3%; P < .0001) or TI for at least 112 days (TI-112; 63.5% vs 8.7%; P < .0001), a reduced risk over time for severe infection (hazard ratio [HR], 0.43; P = .0007) or severe bleeding (HR, 0.17; P = .01), and a longer overall survival (OS; HR, 0.31; P < .0001) than patients with no response. The effects were consistent across drugs. In comparison with patients with CR, the effect sizes for CRh were similar for TI-56 and for risk over time of infection or bleeding but less for TI-112 and OS. CRh is associated with clinical benefits consistent with clinically meaningful palliative effects for the treatment of AML with nonmyelosuppressive drugs, although less robustly than for CR.

FDA Approval Summary: Ruxolitinib for Treatment of Chronic Graft-Versus-Host Disease after Failure of One or Two Lines of Systemic Therapy.

On September 22, 2021, the Food and Drug Administration approved ruxolitinib for the treatment of chronic graft-versus-host disease (cGVHD) after the failure of one or two lines of systemic therapy in adult and pediatric patients 12 years and older. Approval was based on Study INCB 18424-365 (REACH-3; CINC424D2301; NCT03112603), a randomized, open-label, multicenter trial of ruxolitinib in comparison to best available therapy (BAT) for the treatment of corticosteroid-refractory cGVHD occurring after the allogeneic hematopoietic stem cell transplantation. A total of 329 patients were randomized 1:1 to receive either ruxolitinib 10 mg twice daily (n = 165) or BAT (n = 164). BAT was selected by the investigator prior to randomization. The overall response rate through Cycle 7 Day 1 was 70% (95% CI, 63-77) in the ruxolitinib arm, and 57% (95% CI, 49-65) in the BAT arm. The median duration of response, calculated from first response to progression, death, or initiation of new systemic therapies for cGVHD, was 4.2 months (95% CI, 3.2-6.7) for the ruxolitinib arm and 2.1 months (95% CI, 1.6-3.2) for the BAT arm; and the median time from first response to death or initiation of new systemic therapies for cGVHD was 25 months (95% CI, 16.8-not estimable) for the ruxolitinib arm and 5.6 months (95% CI, 4.1-7.8) for the BAT arm. Common adverse reactions included anemia, thrombocytopenia, and infections. Given the observed response rate with durability, the clinical benefit of ruxolitinib appears to outweigh the risks of treatment for cGVHD after the failure of one or two lines of systemic therapy.

FDA Approval Summary: Belumosudil for Adult and Pediatric Patients 12 Years and Older with Chronic GvHD after Two or More Prior Lines of Systemic Therapy.

On July 16, 2021, the FDA approved belumosudil, a kinase inhibitor, for adult and pediatric patients 12 years and older with chronic GvHD (cGvHD) after failure of at least two prior lines of systemic therapy. Approval was based on the results of Study KD025-213, which included 65 patients with cGvHD treated with belumosudil 200 mg daily in an open-label, single-arm cohort. Efficacy was determined by the overall response rate (ORR) through Cycle 7 Day 1, which included complete response (CR) or partial response (PR) according to the 2014 NIH consensus criteria, and durability of response. The ORR through Cycle 7 Day 1 was 75% [95% confidence interval (CI), 63-85]; 6% of patients achieved a CR, and 69% achieved a PR. The median duration of response was 1.9 months (95% CI, 1.2-2.9), and 62% (95% CI, 46-74) of responding patients remained alive without new systemic therapy for at least 12 months from response. The common adverse reactions were infections, asthenia, nausea, diarrhea, dyspnea, cough, edema, hemorrhage, abdominal pain, musculoskeletal pain, headache, phosphate decreased, gamma-glutamyl transferase increased, lymphocytes decreased, and hypertension. Additional study is warranted to confirm safety with long-term use.

Project 2025: Proposals for the Continued Success of Drug Development in Acute Myeloid Leukemia.

The Food and Drug Administration Oncology Center of Excellence initiated Project 2025 to develop 5-year goals in specific areas of oncology drug development. This meeting, in October 2020, brought together a panel of regulators and academic experts in acute myeloid leukemia (AML) to discuss opportunities to maximize the success that has recently occurred in AML drug development. The panel discussed challenges and opportunities in clinical trial design and novel endpoints, and outlined key considerations for drug development to facilitate continued growth in the field.

Framingham Risk Score Is an Ineffective Screening Strategy for Coronary Heart Disease in Long-Term Allogeneic Hematopoietic Cell Transplant Survivors.

Long-term allogeneic hematopoietic cell transplant (allo-HCT) survivors suffer an elevated risk of coronary heart disease (CHD). We conducted a prospective, nonrandomized, cross-sectional study to screen asymptomatic survivors at a single allo-HCT center using cardiac computed tomography (CT) involving coronary CT angiography (CCTA) and the coronary artery calcium (CAC) score. Seventy-nine subjects with a median age of 39 years at allo-HCT and a median follow-up interval of 8 years were evaluated for CHD by Framingham Risk Score (FRS) and cardiac CT. CHD was detected in 33 of 79 (42%) subjects; 91% of lesions were nonobstructive, 19.5% of were noncalcified and 30% had associated valvular calcification. Overall, CAC was significantly superior to FRS in detecting early CHD in allo-HCT survivors [∆C = 0.25; P < 0.0001]. While both FRS and CAC were highly, >95% specific, FRS had a sensitivity, positive and negative predictive values of only 28% (95% CI, 14%-47%), 90% (95% CI, 55%-100%) and 60% (95% CI, 47%-73%), respectively. In contrast, the sensitivity, positive and negative predictive values of CAC were 78% (95% CI, 60%-91%), 96% (95% CI, 80%-100%) and 83% (95% CI, 69%-93%), respectively. Significantly, cardiac CT detected CHD in 23 of the 68 (34%) survivors deemed to have a low Framingham risk. Radiation exposure during cardiac CT was negligible, and there were no adverse events. In conclusion, CAC score with or without CCTA is a safe, feasible and sensitive screening technique for CHD. The FRS greatly underestimates CHD in allo-HCT survivors.

FDA Approval Summary: Tocilizumab for Treatment of Chimeric Antigen Receptor T Cell-Induced Severe or Life-Threatening Cytokine Release Syndrome.

On August 30, 2017, the U.S. Food and Drug Administration approved Actemra (tocilizumab, Genentech, Inc., South San Francisco, CA) for the treatment of severe or life-threatening chimeric antigen receptor (CAR) T cell-induced cytokine release syndrome (CRS) in adults and in pediatric patients 2 years of age and older. The approval was based on a retrospective analysis of data for patients who developed CRS after treatment with CTL019 and KTE-C19 on prospective clinical trials. Evaluable patients had been treated with intravenous tocilizumab 8 mg/kg (12 mg/kg for patients <30 kg) for severe or life-threatening CRS; only the first episode of CRS was included in the analysis. The efficacy population for the CTL019 cohort included 24 male and 21 female patients (total 45 patients) of median age 12 years. The median time from the start of CRS to the first dose of tocilizumab was 4 days (range, 0-18 days). Patients were considered responders if CRS resolved within 14 days of the first dose of tocilizumab, if no more than 2 doses of tocilizumab were needed, and if no drugs other than tocilizumab and corticosteroids were used for treatment. Thirty-one patients (69%; 95% confidence interval, 53%-82%) achieved a response as defined. In an independent cohort of 15 patients with KTE-C19-induced CRS, 53% responded. Further study is needed to determine the optimal dose of tocilizumab and to confirm the safety of its use for treatment of patients with CAR T cell-induced CRS. IMPLICATIONS FOR PRACTICE: Severe or life-threatening chimeric antigen receptor (CAR) T cell-induced cytokine release syndrome (CRS) requires urgent treatment to prevent fatal outcomes. In two independent cohorts, the majority of patients with severe or life-threatening CAR T cell-induced CRS responded to treatment with one or two doses of tocilizumab in addition to advanced supportive care. More research is needed to determine the optimal dose and schedule of tocilizumab for treatment of CAR T cell-induced CRS.

National Institutes of Health Hematopoietic Cell Transplantation Late Effects Initiative: The Immune Dysregulation and Pathobiology Working Group Report.

Immune reconstitution after hematopoietic stem cell transplantation (HCT) beyond 1 year is not completely understood. Many transplant recipients who are free of graft-versus-host disease (GVHD) and not receiving any immunosuppression more than 1 year after transplantation seem to be able to mount appropriate immune responses to common pathogens and respond adequately to immunizations. However, 2 large registry studies over the last 2 decades seem to indicate that infection is a significant cause of late mortality in some patients, even in the absence of concomitant GVHD. Research on this topic is particularly challenging for several reasons. First, there are not enough long-term follow-up clinics able to measure even basic immune parameters late after HCT. Second, the correlation between laboratory measurements of immune function and infections is not well known. Third, accurate documentation of infectious episodes is notoriously difficult. Finally, it is unclear what measures can be implemented to improve the immune response in a clinically relevant way. A combination of long-term multicenter prospective studies that collect detailed infectious data and store samples as well as a national or multinational registry of clinically significant infections (eg, vaccine-preventable severe infections, opportunistic infections) could begin to address our knowledge gaps. Obtaining samples for laboratory evaluation of the immune system should be both calendar and eventdriven. Attention to detail and standardization of practices regarding prophylaxis, diagnosis, and definitions of infections would be of paramount importance to obtain clean reliable data. Laboratory studies should specifically address the neogenesis, maturation, and exhaustion of the adaptive immune system and, in particular, how these are influenced by persistent alloreactivity, inflammation, and viral infection. Ideally, some of these long-term prospective studies would collect information on long-term changes in the gut microbiome and their influence on immunity. Regarding enhancement of immune function, prospective measurement of the response to vaccines late after HCT in a variety of clinical settings should be undertaken to better understand the benefits as well as the limitations of immunizations. The role of intravenous immunoglobulin is still not well defined, and studies to address it should be encouraged.

CD34+ selection and the severity of oropharyngeal mucositis in total body irradiation-based allogeneic stem cell transplantation.

OBJECTIVE: The purpose of the present study was to evaluate the impact of ex vivo T cell depleted (TCD) by CD34+ selection on the incidence and severity of oropharyngeal mucositis (OM) after myeloablative allogeneic stem cell transplant (allo-SCT) with total body irradiation (TBI) conditioning. This approach has the advantage of avoiding methotrexate for graft versus host disease (GVHD) prophylaxis. PATIENTS AND METHODS: We analyzed the incidence and severity of OM in a cohort of 105 consecutive patients who underwent CD34+ selected (peripheral blood stem cells (PBSCs) from human leukocyte antigen (HLA)-identical siblings) allo-SCT with total body irradiation (TBI) conditioning. OM was graded by the World Health organization (WHO) and the Bearman regimen-related toxicity (RRT) scales. RESULTS: The incidence of WHO grade 3-4 OM was 34.3 %. There were no cases of grade 3-4 OM by the RRT scale. Significant correlation was found between the severity of OM and the use of intravenous (IV) narcotic medications (r (2) = 0.15, p = 0.004), total parenteral nutrition (TPN; r (2) = 0.68, p < 0.001), and hospital length of stay (LOS) (r (2) = 0.12, p = 0.01). DISCUSSION: TBI-induced OM can inflict significant morbidity in the early transplant period, and the incidence of WHO grade 3-4 OM can exceed 50 % when methotrexate is used for GVHD prophylaxis. In the CD34+ selected setting, methotrexate is avoided and the incidence of WHO grade 3-4 OM, use of TPN, and need for narcotic analgesia appear to be lower than historic evidence from standard T-replete allogeneic transplantation. CONCLUSION: We conclude that toxicity from OM is tolerable in CD34+ selected allo-SCT and should be prospectively measured in randomized trials comparing CD34+ selection versus T-replete transplantation.

Clinical and biological predictors of outcome following relapse of CML post-allo-SCT.

Although there are now fewer allo-SCTs performed for CML, leukemic relapse post transplant remains a persistent problem. To better define clinical and biological parameters determining postrelapse outcome, we studied 59 patients with CML relapsing after HLA-identical sibling allo-SCT between 1993 and 2008. Eighteen (30.5%) were transplanted in advanced phase and 41 (69.5%) in chronic phase. With a median follow-up from relapse of 7.9 years, 5-year post relapse survival (PRS) was 62%. Multivariate analysis found disease status at transplant, time to diagnosis of relapse from transplant and pretransplant tyrosine kinase inhibitor (TKI) use as significant factors associated with PRS. Analysis of BCR-ABL transcript expression in the hematopoietic progenitor compartment was performed in 36 patients (22 relapsed, 8 non-relapsed and 6 TKI alone controls). Patients with BCR-ABL expression in their early hematopoietic stem cell compartment (Lineage(-)CD34(+)CD38(-)CD90(+)) had worse survival irrespective of the disease status. We conclude that disease status remains the strongest clinical prognostic factor for PRS in CML following allo-SCT. The persistence of BCR-ABL expression in the progenitor cell compartment in some patients after SCT emphasizes the need to target CML-leukemia stem cells.

Male survivors of allogeneic hematopoietic stem cell transplantation have a long term persisting risk of cardiovascular events.

Long-term survivors of allogeneic stem cell transplantation (SCT) have increased risk of cardiovascular disease. We retrospectively studied cardiovascular risk factors (CVRFs) in 109 SCT survivors (62 males, 47 females; median age 34 years) five years or more after bone marrow (15) or T cell-depleted peripheral blood (94) SCT for CML (56), acute leukemia (29), MDS (13), and others (11). One death and two cardiovascular events were reported. At five and ten years after SCT, respectively, 44% and 52% had abnormal lipid profiles; 23% of 5-year survivors met the Adult Treatment Panel III threshold for dyslipidemia treatment, which is substantially higher than the age-matched general population. There were significant increases in prevalence of hypertension (p < 0.001), diabetes (p = 0.018), and body mass index (p = 0.044) after SCT compared with baseline. The Framingham general cardiovascular risk score (FGCRS) in males at five years after SCT projected a doubling (median 10.4% vs. 5.4%) in the 10-year risk of cardiovascular events. Females received HRT after SCT, and none had increased FGCRS. Chronic GVHD and C-reactive protein were not associated with CVRF at any time. All CVRFs stabilized between five and ten years after SCT. Thus, SCT survivors have sustained elevations in CVRFs. Males have a significantly increased risk of cardiovascular events in their second and third decade after SCT.

Repeated PR1 and WT1 peptide vaccination in Montanide-adjuvant fails to induce sustained high-avidity, epitope-specific CD8+ T cells in myeloid malignancies.

BACKGROUND: We previously showed that vaccination with one dose of PR1 and WT1 peptides induces transient anti-leukemia immunity. We hypothesized that maintenance of a sustained anti-leukemia response may require frequent boost injections. DESIGN AND METHODS: Eight patients with myeloid malignancies were enrolled in this phase II study, and 6 completed 6 injections of PR1 and WT1 peptides in Montanide-adjuvant with GM-CSF, every two weeks. RESULTS: Both high- and low-avidity PR1 or WT1-specific CD8(+) T cells were detected in all evaluable patients after the first vaccine dose. Repeated vaccination led to selective deletion of high avidity PR1- and WT1-specific CD8(+) T cells and was not associated with significant reduction in WT1-expression. Additional boosting failed to increase vaccine-induced CD8(+) T-cell frequencies further and in all patients the response was lost before the 6(th) dose. PR1- or WT1-specific CD8(+) T cells were not detected in bone marrow samples, excluding their preferential localization to this site. Following a booster injection three months after the 6(th) vaccine dose, no high-avidity PR1 or WT1-specific CD8(+) T cells could be detected, whereas low-avidity T cells were readily expanded. CONCLUSIONS: These data support the immunogenicity of PR1 and WT1 peptide vaccines. However, repeated delivery of peptides with Montanide-adjuvant and GM-CSF leads to rapid loss of high-avidity peptide-specific CD8(+) T cells. These results may offer an explanation for the lack of correlation between immune and clinical responses observed in a number of clinical trials of peptide vaccination. New approaches are needed to induce long-term high-avidity memory responses against leukemia antigens.