Lamble, Adam J.

We present a subset analysis on the adolescent cohort of the S1826 randomized phase three trial, comparing nivolumab, doxorubicin, vinblastine, dacarbazine (N-AVD) to brentuximab vedotin-AVD (BV-AVD) in newly diagnosed advanced-stage (AS, stages III and IV) classic Hodgkin lymphoma (cHL). Among 994 patients enrolled, 24% (n = 240) were age 12-17 years. The 3-year progression-free survival (PFS) was significantly higher in the N-AVD group (93% [95% CI, 87 to 96]) compared with the BV-AVD group (82% [95% CI, 73 to 88]; hazard ratio, 0.37 [95% CI, 0.17 to 0.80]). One N-AVD and two BV-AVD patients received protocol-specified residual site radiotherapy (RT). Rates of febrile neutropenia and sepsis were low in both groups. Severe immune-related adverse events were infrequent, although thyroid dysfunction was seen in 7% with N-AVD. Sensory neuropathy (grade ≥2) was more frequent with BV-AVD (14% v 7%) by clinician report. Although premature discontinuation of therapy was reported in 12 N-AVD patients and four BV-AVD patients, no PFS events were noted in the N-AVD group. Patient-reported outcomes indicated less toxicity with N-AVD. N-AVD demonstrated high 3-year PFS in adolescents with AS cHL, with minimal RT use. S1826 exemplifies the benefits of harmonized clinical trial protocols, resulting in timely access to novel agents for adolescents.

Abstract Lineage switch (LS), defined as the immunophenotypic transformation of acute leukemia, has emerged as a mechanism of relapse after antigen-targeted immunotherapy, which is associated with dismal outcomes. Through an international collaborative effort, we identified cases of LS after a host of antigen-targeted therapies (eg, CD19, CD22, CD38, and CD7), described how LS was diagnosed, reviewed treatment approaches, and analyzed overall outcomes for this form of postimmunotherapy relapse. Collectively, 75 cases of LS were evaluated, including 53 (70.7%) cases of B-cell acute lymphoblastic leukemia (B-ALL) transforming to acute myeloid leukemia (AML), 17 (22.7%) cases of B-ALL transforming to mixed phenotypic acute leukemia (MPAL)/acute leukemias of ambiguous lineage (ALAL), and 5 (6.7%) cases of rare LS presentation (ie, T-cell ALL to AML). An additional 10 cases with incomplete changes in immunophenotype, referred to as “lineage drift” were also described. With a primary focus on the 70 cases of LS from B-ALL to AML or MPAL/ALAL, LS emerged at a median of 1.5 months (range, 0-36.5) after immunotherapy, with 81.4% presenting with LS within the first 6 months from the most proximal immunotherapy. Although most involved KMT2A rearrangements (n = 45, 64.3%), other rare cytogenetic and/or molecular alterations were uniquely observed. Treatment outcomes were generally poor, with remission rates of <40%. The median overall survival after LS diagnosis was 4.8 months. Outcomes were similarly poor for those with rare immunophenotypes of LS or lineage drift. This global initiative robustly categorizes lineage changes after immunotherapy and, through enhanced understanding, establishes a foundation for improving outcomes of LS.

Background: Cure rates for children, adolescents, and young adults with cHL are high, but patients with a slow early response (SER) to front-line chemotherapy are at an increased risk of relapse compared with patients who have a rapid early response (RER). To avoid long-term toxicity while optimizing outcomes, treatment for pediatric cHL is now shifting to a response-adapted approach. KEYNOTE-667 (NCT03407144) is an open-label phase 2 study designed to evaluate the efficacy and safety of pembrolizumab plus chemotherapy consolidation with or without radiotherapy (RT) followed by pembrolizumab maintenance in patients with cHL and SER to front-line chemotherapy. The study includes 2 groups of patients: those with low-risk cHL (stage IA, IB, and IIA without bulky disease) and those with high-risk cHL (stage IIEB-IVB cHL). Prior analysis of the low-risk group showed that consolidation with pembrolizumab plus doxorubicin, vinblastine, and dacarbazine (AVD) and RT followed by maintenance pembrolizumab had manageable safety and promising antitumor activity in patients with low-risk cHL and SER to front-line doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD). We present updated results for patients with low-risk cHL and SER to ABVD. Methods: Patients eligible for the low-risk group were aged 3-25 years and had newly diagnosed stage IA, IB, or IIA cHL without bulky disease, measurable disease, and a Lansky Play-Performance Scale score of ≥50 (aged <16 years) or a Karnofsky Performance Status score of ≥50 (aged ≥16 years). All patients in the low-risk group received 2 cycles of ABVD followed by early response assessment (PET and CT/MRI). Patients with a RER (ie, Deauville score [DS] 1-3) received nonstudy therapy. Patients with SER (ie, DS 4 or 5) received consolidation with pembrolizumab 2 mg/kg up to 200 mg (aged 3-17 years) or 200 mg (aged 18-25 years) IV Q3W plus 2 cycles of AVD. Patients then underwent late response assessment (LRA; PET and MRI/CT). All patients with SER received involved-site RT: 21.6 Gy for complete PET response (ie, DS 1-3) or 30.6-36 Gy for partial PET response (ie, DS 4 or 5). All patients received maintenance pembrolizumab for up to 17 cycles. The primary end point was objective response rate (ORR) by blinded independent central review (BICR) per Cheson 2007 IWG criteria. Secondary end points included PET negativity after consolidation and safety. Results: 78 patients with low-risk cHL received front-line ABVD. As of the data cutoff date (February 29, 2024), 10 of 78 patients had SER to ABVD and received consolidation with pembrolizumab plus AVD; 4 had completed consolidation and maintenance, 1 was continuing to receive treatment, and 5 had discontinued because of complete response (CR). Median time from allocation to data cutoff was 19.9 months (range, 5.6-44.8). Patients had received a median of 11.5 doses of pembrolizumab (range, 5-17) and the median time on pembro was 7.4 months (range, 3.5-11.3). The median age of patients was 16 years (range, 7-20), 6 (60%) were male, and 8 (80%) had Ann Arbor stage II disease. Of 10 patients who received consolidation, all (100%) had an LRA. The ORR was 100% (95% CI, 69-100; 9 CR and 1 partial response). Six patients (60%) were PET negative by BICR. Seven patients (70%) were PET negative by investigator review, all of whom received a reduced dose of RT. During consolidation, treatment-related adverse events (AEs) were reported in 8 patients (80%); grade 3 or 4 treatment-related AEs occurred in 4 patients (40%). No patients discontinued or died due to treatment-related AEs. Seven patients (67%) had pembrolizumab-related AEs, 3 of whom (30%) had a grade 3 event (vomiting, lymphocyte count decreased, white blood cell count decreased). Immune-mediated AEs occurred in 3 patients (30%; all grade 1 or 2 hypothyroidism). Conclusion: After additional follow-up, consolidation withpembrolizumab plus AVD and RT followed by pembrolizumab maintenance continued to demonstrate promising activity and manageable safety in patients with low-risk cHL and SER to ABVD. Of patients with a LRA, 60% were PET negative by BICR; 70% of patients were PET negative by investigator review and received a reduced dose of RT. These results support further evaluation of pembrolizumab plus AVD consolidation as a treatment option for patients with low-risk CHL and SER to front-line ABVD.

Introduction: Lineage switch (LS) refers to the transformation of acute leukemia from one cell lineage to another (e.g., lymphoid (ALL) to myeloid (AML)). This rare phenomenon, distinct from treatment induced malignancy (i.e., t-AML) and mixed phenotype acute leukemia (MPAL), is increasingly being observed following cell surface antigen targeting. Given challenges in the diagnosis and treatment of LS, Project EVOLVE was developed to globally identify cases of LS following immunotherapy. Methods: A protocol and data collection form for this IRB exempt study was widely disseminated to capture deidentified LS case information across multiple centers and cancer consortia. This included collection of data from published reports of LS, with authors contacted to obtain additional information. For this analysis, LS was defined by the emergence of cell-surface markers warranting reclassification of the original leukemia as a different lineage derivation based on the immunophenotype, including cases of AML emerging alongside the original ALL. “Confirmed” LS cases included those where retention of original cytogenetic or molecular aberrations and/or the clonal immunoglobulin rearrangement patterns were verified to confirm the clonal relationship. “Suspected” LS cases included those where samples to confirm clonality marker retention could not be obtained, but the clinical presentation was consistent with LS. The term “transition” was applied when immunophenotypic shifts were transient. Cases with new cytogenetic abnormalities unrelated to the original diagnosis and compatible with t-AML were excluded. Statistical analysis was primarily descriptive. Data cut-off was July 26, 2023. Results: A total of 58 cases were identified, including 19 cases referenced in prior publications. Of the 58, 11 cases were excluded from this initial analysis, including: 4 cases of t-AML, 2 cases of T-ALL to AML, and 5 “transition” cases. Collectively, 47 cases of LS (43 “confirmed”; 4 “suspected”), spanning across 3 continents and 8 countries, were analyzed. (Fig. 1A) Cases included transition from B-ALL to AML in 36 (76.6%) and to MPAL/biphenotypic/ambiguous lineage in 11 (23.4%). Two likely had MPAL at diagnosis and a third with chronic myeloid leukemia. The median age at initial diagnosis was 8.4 years (range, 1 day-76.5 years); median age at LS presentation was 11.0 years (range 0.4-77.3 years). Twenty-three (48.9%) were male and 19 (40.4%) had prior stem cell transplant (SCT). Baseline cytogenetics showed KMT2A rearrangement in 27 (57.4%). Baseline myeloid antigen co-expression was seen in 22 of 23 patients with submitted data, but variation in degree of expression across patients and antigens was substantial. The most proximal immunotherapy prior to development of LS was CAR T-cells in 23 (48.9%) and blinatumomab in 24 (51.1%). The median time from the most proximal immunotherapy to development of LS was 1.6 months (range, 7 days-36.5 months). In 7 (29.2%) patients receiving blinatumomab, LS developed during the infusion. LS presented as isolated marrow relapse in 27 (57.4%), isolated CNS in 2 (4.3%), isolated non-CNS extramedullary disease in 3 (6.4%), combined relapse in 14 (29.8%) and unreported in 1. First line treatment for LS was chemotherapy induction in 31 (66.0%), palliative care/no therapy in 8 (17.0%), and alternative therapies in the remaining 8 (17.0%). In 35 (74.5%) patients, remission induction was the goal of first line therapy. Fifteen (31.9%) achieved a complete remission (CR) of whom 2 were treated with palliative intent. Across all patients, 8 (17.0%) are alive in remission, the longest being 4.7 years from LS diagnosis; 2 (4.3%) are alive with active LS and 37 (78.7%) died from LS, their original disease, or complications of treatment of LS (Fig 1B). For those alive in CR (n=8), 7 (87.5%) proceeded to a consolidative SCT for treatment of LS and 1 patient, an octogenarian remains in remission after AML directed therapy. Conclusions: LS is emerging as an important mechanism of immune escape following immunotherapy. Project EVOLVE provides the largest dataset of patients with LS to date. This systematic, international effort reveals substantial complexity and variability in diagnosing and managing LS. Unfortunately, outcomes following LS are grim, underscoring the critical need to identify risk factors of and optimal therapies for this leukemia transformation.

Background: Pediatric patients (pts) with low-risk cHL achieve high cure rates with standard chemo. However, those with a SER to front-line chemo are at higher risk of relapse than pts with a rapid early response (RER). Current treatment options are also associated with long-term toxicities such as secondary malignancies, cardiovascular disease, and pulmonary and gonadal toxicity. Novel treatment approaches are needed to optimize outcomes while minimizing long-term toxicity. KEYNOTE-667 (NCT03407144) is an open-label, phase 2 study that included an analysis of safety and efficacy of doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) induction in pediatric pts with low-risk cHL followed by consolidation with pembro plus AVD and involved-site radiotherapy (ISRT) and pembro maintenance in those with SER to front-line ABVD. We present an interim analysis of pts with low-risk cHL enrolled in this trial. Methods: Eligible pts were 3-25 y old and had newly diagnosed stage IA, IB, or IIA cHL without bulky disease, measurable disease per investigator assessment, and a Lansky Play-Performance Scale ≥50 (aged <16 y) or a Karnofsky score of ≥50 (aged ≥16 y). Pts initially received 2 cycles of induction with ABVD. Response was then assessed by PET/MRI/CT (early response assessment). Pts with RER received nonstudy therapy per treating physician. Pts with SER (Deauville score [DS], 4 or 5) received consolidation with pembro 2 mg/kg up to 200 mg IV Q3W (3-17 y) or 200 mg IV Q3W (18-25 y) in combination with 2 cycles of AVD followed by a late response assessment (LRA) with PET/MRI/CT. All pts with a SER then received ISRT (21.6 Gy for pts with a complete PET response [DS, 1-3]; 30.6-36 Gy for pts with a partial PET response [DS, 4 or 5]) plus maintenance pembro Q3W for up to 17 cycles. Primary end point was ORR by blinded independent central review (BICR) per Cheson 2007 IWG criteria in pts with SER determined at any time after starting pembro and before start of new anticancer therapy. Secondary end points included rate of PET negativity after consolidation, EFS, OS, and safety. Results: 73 pts with low-risk cHL were enrolled, 9 of whom had SER to ABVD induction. 64 pts had a RER and received nonstudy treatment. At data cutoff (March 1, 2023), 2 of 9 pts (22%) with SER had completed consolidation and maintenance therapy, 5 (56%) were ongoing, and 2 (22%) had discontinued, both because of complete response. Median time from enrollment to data cutoff was 8.7 mo (range, 2.2-32.9). Median age was 16 y (range, 7-20), 5 pts (56%) were male, 2 (22%) had Ann Arbor stage I disease, and 7 (78%) had Ann Arbor stage II disease. Pts with SER had received a median of 8 doses of pembro (range, 1-17); median time on pembro was 4.8 mo (range, <0.1-11.3). Of 9 pts who received consolidation therapy with pembro plus AVD, 6 (67%) had a LRA (3 are still in consolidation and have not reached the LRA timepoint), of whom 3 (50%) were PET negative by BICR (2 [33%] were PET negative by investigator review). Of 73 pts who received ABVD induction, 66 (90%) had an AE regardless of causality. 33 pts (45%) experienced grade 3/4 AEs, most commonly (≥10%) neutrophil count decreased (n = 19; 26%) and neutropenia (n = 9; 12.3%). One pt experienced grade 4 febrile neutropenia. Twelve pts (16%) had serious AEs. No pts discontinued treatment or died because of AEs. Treatment-related AEs due to ABVD induction occurred in 59 pts (81%), with grade 3/4 events in 31 (42%). Of the 9 pts with SER to ABVD induction who received consolidation and maintenance therapy, 7 (78%) experienced an AE regardless of causality. Two pts (22%) had grade 3/4 AEs. No serious AEs were reported during consolidation and maintenance therapy, and no pts discontinued treatment or died because of AEs. Treatment-related AEs occurred in 6 pts (67%) who received consolidation and maintenance therapy; with grade 3/4 events in 2 pts (22%). Six pts (67%) experienced AEs related to pembro; most commonly (≥3 pts) anemia, nausea, vomiting (n = 3 each [33%]). Two pts experienced grade 3/4 AEs related to pembro (vomiting, white blood cell count decreased). One pt (11%) experienced an immune-mediated AE (grade 2 hyperthyroidism). Conclusion: Early results from the low-risk cHL cohort of KEYNOTE-667 suggest that induction therapy with ABVD and consolidation with pembro plus AVD had a manageable safety profile. Among the relatively small number of pts with a SER to ABVD, 50% with a LRA had a PET-negative response by BICR and received a reduced dose of RT.

Hodgkin lymphoma (HL) is a highly curable form of cancer, and current treatment regimens are focused on improving treatment efficacy while decreasing the risk of late effects of treatment. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for pediatric HL provide recommendations on the workup, diagnostic evaluation, and treatment of classic HL, including principles of pathology, imaging, staging, systemic therapy, and radiation therapy. This portion of the NCCN Guidelines focuses on the management of pediatric classic HL in the upfront and relapsed/refractory settings.