Helen McCarthy

Ibrutinib as Initial Therapy for Patients with Chronic Lymphocytic Leukemia

BACKGROUND Chronic lymphocytic leukemia (CLL) primarily affects older persons who often have coexisting conditions in addition to disease-related immunosuppression and myelosuppression. We conducted an international, open-label, randomized phase 3 trial to compare two oral agents, ibrutinib and chlorambucil, in previously untreated older patients with CLL or small lymphocytic lymphoma. METHODS We randomly assigned 269 previously untreated patients who were 65 years of age or older and had CLL or small lymphocytic lymphoma to receive ibrutinib or chlorambucil. The primary end point was progression-free survival as assessed by an independent review committee. RESULTS The median age of the patients was 73 years. During a median follow-up period of 18.4 months, ibrutinib resulted in significantly longer progression-free survival than did chlorambucil (median, not reached vs. 18.9 months), with a risk of progression or death that was 84% lower with ibrutinib than that with chlorambucil (hazard ratio, 0.16; P<0.001). Ibrutinib significantly prolonged overall survival; the estimated survival rate at 24 months was 98% with ibrutinib versus 85% with chlorambucil, with a relative risk of death that was 84% lower in the ibrutinib group than in the chlorambucil group (hazard ratio, 0.16; P=0.001). The overall response rate was higher with ibrutinib than with chlorambucil (86% vs. 35%, P<0.001). The rates of sustained increases from baseline values in the hemoglobin and platelet levels were higher with ibrutinib. Adverse events of any grade that occurred in at least 20% of the patients receiving ibrutinib included diarrhea, fatigue, cough, and nausea; adverse events occurring in at least 20% of those receiving chlorambucil included nausea, fatigue, neutropenia, anemia, and vomiting. In the ibrutinib group, four patients had a grade 3 hemorrhage and one had a grade 4 hemorrhage. A total of 87% of the patients in the ibrutinib group are continuing to take ibrutinib. CONCLUSIONS Ibrutinib was superior to chlorambucil in previously untreated patients with CLL or small lymphocytic lymphoma, as assessed by progression-free survival, overall survival, response rate, and improvement in hematologic variables. (Funded by Pharmacyclics and others; RESONATE-2 ClinicalTrials.gov number, NCT01722487.).

Incidence of potential glycosylation sites in immunoglobulin variable regions distinguishes between subsets of Burkitt's lymphoma and mucosa-associated lymphoid tissue lymphoma

Summary. Recently, a high incidence of novel N‐glycosylation sites introduced by somatic mutation was observed in the immunoglobulin variable region genes of follicular lymphoma. As these are positively selected and are uncommon in normal B cells, they may have a role in tumour growth and behaviour. Sites are not characteristic of chronic lymphocytic leukaemia or myeloma, but are detectable in ∼50% of diffuse large cell lymphomas. Another feature of the variable region genes of certain lymphomas is ongoing somatic mutation. To determine whether glycosylation is associated with this phenomenon, we analysed variable region gene sequences of Burkitts lymphoma (BL) and mucosa‐associated lymphoid tissue (MALT) lymphoma. Novel sites were common in endemic BL (82%) and in 4/5 patients with Iranian BL. However, sporadic BL had a lower incidence (43%). Patients with MALT lymphoma had a low frequency (9%) of novel sites, comparable to normal B cells. These findings distinguish glycosylation sites from ongoing mutation and may reflect different environmental influences on these tumours.

Anti‐idiotype vaccines

The potential for vaccination to suppress tumour growth on a continuing basis is clear. The clinical setting is critical, requiring adequate immune capacity and minimal residual disease. Idiotypic (Id) determinants of B-cell tumours provide clone-specific antigens, and testing of Id vaccine designs has relevance for the myriad of new tumour antigens being identified. Id immunoglobulin protein vaccination has moved from preclinical models to clinical trials with evidence for efficacy in lymphoma. To streamline individual vaccine manufacture, and to engage multiple immune effector pathways, DNA vaccines provide an exciting alternative. Variable regions genes encoding Id determinants can be assembled in a DNA vaccine format. However, activation of significant immunity against Id determinants, or similar weak tumour antigens, requires the fusion of genes encoding proteins aimed to stimulate Tcell help. Translation to patients has begun and early monitoring data are encouraging. A platform now exists for testing additional strategies to maximize efficacy of these flexible vaccines, with relevance for both cancer and infectious diseases. It is perhaps surprising that haematological malignancies have been a popular focus for the development of vaccination strategies. The reason for surprise is that these malignancies occupy the immune system and if any tumours were to induce immunological tolerance, it should be this group. However, there is evidence for immune control of tumour growth, seen most clearly for Epstein– Barr virus (EBV)-associated B-cell malignancies (Macsween & Crawford, 2003). The potential for cellular attack on tumours is also clear from the successful eradication of tumour following allogeneic transplantation, which is largely dependent on immune-mediated graft versus leukaemia effects (Goulmy, 1997). These observations, together with the failure of chemotherapy to cure many haematological malignancies, despite improved remission rates with new targeted drug therapies, have fuelled the development of immunotherapeutic approaches. Passive antibody has long been attractive for attacking tumour cells, and anti-CD20 has now found a place in treatment protocols for several B-cell tumours (Maloney et al, 1994). However, the ability of passive antibody to suppress tumour may be transient and appears most effective in combination with chemotherapy (Cheson, 2002). In contrast, active vaccination should induce a continuing attack on tumour cells without the need for further treatment. The challenge for vaccination is to induce an effective immune response in patients who may have a tolerized or damaged immune system. The critical ingredients for success include selection of a target antigen, and engagement of an appropriate immune effector response that is able to suppress tumour growth. Differentiation molecules such as CD20 are unattractive for active vaccination as successful induction of immunity may lead to persistent autoreactivity, with consequences for normal B cells. Ideal target molecules are tumour-specific and are expressed by all members of the neoplastic clone. Candidates include the idiotypic immunoglobulin (Id Ig) of Bcell tumours, the clonotypic T-cell receptor of T-cell tumours, expressed translocation peptides such as bcr-abl of chronic myeloid leukaemia and mutated proto-oncogenes. Tumourassociated potential targets with limited expression on normal cells include cancer-testis antigens, identified first in melanoma but now known to be expressed in myeloma (van Baren et al, 1999). Aberrantly expressed proteins, such as glycosylated mucins, also present possible targets and normal proteins that are overexpressed by tumour cells are being investigated. The list is growing, partly because of micro-gene array and serological analysis of antigens by recombinant expression cloning (SEREX) technologies (Preuss et al, 2002). Potential targets include transcription factors, anti-apoptotic proteins and essential molecules-like telomerase (reviewed by Stevenson et al, 2004). For these autologous proteins, breaking tolerance and the autoimmune consequences of successful vaccination are again important considerations. For this reason, and because Id Ig is clearly defined, we began our studies of vaccination using this as a model. The Ig Id is defined as the sum of individual antigenic determinants or idiotopes of the variable region. In some cases an idiotope may lie in the actual antigen-binding site, and in some cases may derive from variable region sequences outside the antigen-binding site. Antigenic determinants shared between different Igs are called public idiotopes; they are the molecular basis for serological crossreactivity between Ig molecules and are often located in framework regions (Capra et al, 1977). By definition, these are expressed on normal serum Ig (sIg) and therefore are very unlikely to function as immunogenic determinants. Antigenic determinants unique to a particular antibody are called private idiotopes. These represent unique tumourspecific antigens, and can also act as clonal markers for each tumour. Correspondence: Professor Freda K Stevenson, Molecular Immunology Group, Tenovus Laboratory, Cancer Sciences Division, Southampton University Hospitals Trust, Southampton SO16 6YD, UK. E-mail: fs@soton.ac.uk

Longitudinal copy number, whole exome and targeted deep sequencing of 'good risk' IGHV-mutated CLL patients with progressive disease.

The biological features of IGHV-M chronic lymphocytic leukemia responsible for disease progression are still poorly understood. We undertook a longitudinal study close to diagnosis, pre-treatment and post relapse in 13 patients presenting with cMBL or Stage A disease and good-risk biomarkers (IGHV-M genes, no del(17p) or del(11q) and low CD38 expression) who nevertheless developed progressive disease, of whom 10 have required therapy. Using cytogenetics, fluorescence in situ hybridisation, genome-wide DNA methylation and copy number analysis together with whole exome, targeted deep- and Sanger sequencing at diagnosis, we identified mutations in established chronic lymphocytic leukemia driver genes in nine patients (69%), non-coding mutations (PAX5 enhancer region) in three patients and genomic complexity in two patients. Branching evolutionary trajectories predominated (n=9/13), revealing intra-tumoural epi- and genetic heterogeneity and sub-clonal competition before therapy. Of the patients subsequently requiring treatment, two had sub-clonal TP53 mutations that would not be detected by standard methodologies, three qualified for the very-low-risk category defined by integrated mutational and cytogenetic analysis and yet had established or putative driver mutations and one patient developed progressive, therapy-refractory disease associated with the emergence of an IGHV-U clone. These data suggest that extended genomic and immunogenetic screening may have clinical utility in patients with apparent good-risk disease.

Eradication of minimal residual disease improves overall and progression-free survival in patients with chronic lymphocytic leukaemia, evidence from NCRN CLL207: a phase II trial assessing alemtuzumab consolidation.

With immunochemotherapy, remission duration and survival in patients with chronic lymphocytic leukaemia is dependent on the level of minimal residual disease (MRD) after treatment. This phase II trial assessed alemtuzumab consolidation post‐chemotherapy in patients who responded with persistent low levels of detectable disease. Blood was screened for MRD using multi‐parameter flow cytometry, 6–24 months post‐chemotherapy. MRD‐positive participants received alemtuzumab 30 mg subcutaneously 3 times weekly for 6 weeks. Following a marrow assessment, MRD‐negative participants or non‐responders stopped therapy and MRD‐positive participants with 1 + log reduction had 6 more weeks of alemtuzumab. Alemtuzumab consolidation was received by 47 participants. One death and 19 of 22 serious adverse events reported from 17 (36%) participants were alemtuzumab‐related. MRD eradication from blood and bone marrow was achieved in 39 (83%) participants at the end of consolidation, with 18 (38%) remaining MRD‐negative in the blood 6 months later. Of the 18 participants who were MRD‐negative at 6 months, the median time to MRD relapse was 46 months, which was similar to patients who were MRD‐negative at baseline and were followed up. The 5‐year progression‐free survival (PFS) and overall survival (OS) of participants who were MRD‐negative at 6 months was significantly better than MRD‐positive participants [PFS: 78% vs. 39% (P = 0·010), OS: 89% vs. 64% (P = 0·029)].

Additional trisomies amongst patients with chronic lymphocytic leukemia carrying trisomy 12: the accompanying chromosome makes a difference

Recurrent cytogenetic abnormalities in chronic lym- phocytic leukemia (CLL), namely deletions of chromo- somes 11q, 13q, 17p and trisomy 12 (+12), define sub- groups of patients with different clinical behavior and response to treatment. 1 We and others previously report- ed a minor proportion of CLL cases with co-existing tri- somies of chromosomes 12 and 19 who share specific clinico-biological characteristics. 2-4 However, since the cohort was small, no definitive conclusions could be drawn. Here, we analyzed a large, multi-institutional series. We confirm and significantly extend previous observations through the identification of subgroups of +12 CLL cases harboring particular concurrent trisomies demonstrating distinctive clinico-biological profiles. We analyzed an unselected cohort of 4486 CLL patients with available classic cytogenetic (n=4285) or high-density 250K single nucleotide polymorphism (SNP)-array (n=201) data. We identified 712 cases (16% of the cohort) carrying +12. 5 Median time from diagnosis to cytogenet- ic/SNP analysis was 1.5 months (range 0-194); the major- ity of cases included in survival analysis were untreated prior to testing (94%). The study was approved by the local Ethics Review Committees. Details of the study cohort and the methodologies used are provided in the Online Supplementary Appendix.

NCRI phase II study of CHOP in combination with ofatumumab in induction and maintenance in newly diagnosed Richter syndrome.

Richter syndrome (RS) is associated with chemotherapy resistance and a poor historical median overall survival (OS) of 8–10 months. We conducted a phase II trial of standard CHOP‐21 (cyclophosphamide, doxorubicin, vincristine, prednisolone every 21 d) with ofatumumab induction (Cycle 1: 300 mg day 1, 1000 mg day 8, 1000 mg day 15; Cycles 2–6: 1000 mg day 1) (CHOP‐O) followed by 12 months ofatumumab maintenance (1000 mg given 8‐weekly for up to six cycles). Forty‐three patients were recruited of whom 37 were evaluable. Seventy‐three per cent were aged >60 years. Over half of the patients received a fludarabine and cyclophosphamide‐based regimen as prior CLL treatment. The overall response rate was 46% (complete response 27%, partial response 19%) at six cycles. The median progression‐free survival was 6·2 months (95% confidence interval [CI] 4·9–14·0 months) and median OS was 11·4 months (95% CI 6·4–25·6 months). Treatment‐naïve and TP53‐intact patients had improved outcomes. Fifteen episodes of neutropenic fever and 46 non‐neutropenic infections were observed. There were no treatment‐related deaths. Seven patients received platinum‐containing salvage at progression, with only one patient obtaining an adequate response to proceed to allogeneic transplantation. CHOP‐O with ofatumumab maintenance provides minimal benefit beyond CHOP plus rutuximab. Standard immunochemotherapy for RS remains wholly inadequate for unselected RS. Multinational trials incorporating novel agents are urgently needed.

Sustained efficacy and detailed clinical follow-up of first-line ibrutinib treatment in older patients with chronic lymphocytic leukemia: extended phase 3 results from RESONATE-2.

Results of RESONATE-2 (PCYC-1115/1116) supported approval of ibrutinib for first-line treatment of chronic lymphocytic leukemia. Extended analysis of RESONATE-2 was conducted to determine long-term efficacy and safety of ibrutinib in older patients with chronic lymphocytic leukemia. A total of 269 patients aged ≥65 years with previously untreated chronic lymphocytic leukemia without del(17p) were randomized 1:1 to ibrutinib (n=136) or chlorambucil (n=133) on days 1 and 15 of a 28-day cycle for 12 cycles. Median ibrutinib treatment duration was 28.5 months. Ibrutinib significantly prolonged progression-free survival versus chlorambucil (median, not reached vs. 15 months; hazard ratio, 0.12; 95% confidence interval, 0.07-0.20; P<0.0001). The 24-month progression-free survival was 89% with ibrutinib (97% and 89% in patients with del[11q] and unmutated immunoglobulin heavy chain variable region gene, respectively). Progression-free survival rates at 24 months were also similar regardless of age (<75 years [88%], ≥75 years [89%]). Overall response rate was 92% (125/136). Rate of complete response increased substantially from 7% at 12 months to 18% with extended follow up. Greater quality of life improvements occurred with ibrutinib versus chlorambucil in Functional Assessment of Chronic Illness Therapy-Fatigue (P=0.0013). The most frequent grade ≥3 adverse events were neutropenia (12%), anemia (7%), and hypertension (5%). Rate of discontinuations due to adverse events was 12%. Results demonstrated that first-line ibrutinib for elderly patients with chronic lymphocytic leukemia provides sustained response and progression-free survival benefits over chemotherapy, with depth of response improving over time without new toxicity concerns. This trial was registered at clinicaltrials.gov identifier 01722487 and 01724346.

Guideline for the treatment of chronic lymphocytic leukaemia: A British Society for Haematology Guideline

Anna H. Schuh, Nilima Parry-Jones, Niamh Appleby, Adrian Bloor, Claire E. Dearden, Christopher Fegan, George Follows, Christopher P. Fox, Sunil Iyengar, Ben Kennedy, Helen McCarthy, Helen M. Parry, Piers Patten, Andrew R. Pettitt, Ingo Ringshausen, Renata Walewska and Peter Hillmen NIHR BRC Oxford Molecular Diagnostic Centre, Oxford University Hospitals NHS Trust and Department of Oncology, University of Oxford, John Radcliffe Hospital, Oxford, Department of Haematology, Aneurin Bevan University Health Board, Abergavenny, Haematology, Christie Hospital, Manchester, Haematology, Royal Marsden Hospital NHS Trust, London, Cardiff & Vale University Health Board, Cardiff, Haematology, Addenbrooke’s Hospital, Cambridge, Clinical Haematology, Nottingham University Hospitals NHS Trust, Nottingham, Haematology, Royal Marsden NHS Trust, Sutton, Department of Haematology, University Hospital Leicester, Leicester, Haematology, Bournemouth and Christchurch Hospitals, Bournemouth, NIHR-ACL Haematology, University of Birmingham, Birmingham, Kings College Hospital, London, UK, Clatterbridge Cancer Centre NHS Foundation Trust, Liverpool, University of Cambridge, Cambridge, and Haematology, Leeds Teaching Hospital NHS Trust, Leeds, UK

Single-agent ibrutinib versus chemoimmunotherapy regimens for treatment-naïve patients with chronic lymphocytic leukemia: A cross-trial comparison of phase 3 studies

Chemoimmunotherapy (CIT) and targeted therapy with single‐agent ibrutinib are both recommended first‐line treatments for chronic lymphocytic leukemia (CLL), although their outcomes have not been directly compared. Using ibrutinib data from the RESONATE‐2 (PCYC‐1115/1116) study conducted in patients ≥65 years without del(17p), we performed a cross‐trial comparison with CIT data from published phase 3 studies in first‐line treatment of CLL. Progression‐free survival (PFS), overall survival (OS), and safety data for ibrutinib (median follow‐up 35.7 months) were evaluated alongside available CIT data. CIT regimens included: fludarabine + cyclophosphamide + rituximab (CLL8, CLL10), bendamustine + rituximab (CLL10), obinutuzumab + chlorambucil and rituximab + chlorambucil (CLL11), and ofatumumab + chlorambucil (COMPLEMENT‐1). Median age across studies was 61‐74 years, with older populations receiving ibrutinib, obinutuzumab + chlorambucil, or rituximab + chlorambucil. Median follow‐up varied across studies/regimens (range 14.5‐37.4 months). Among all patients, PFS appeared longer with ibrutinib relative to CIT and OS appeared comparable. Relative to CIT studies that similarly excluded patients with del(17p) (CLL10) or enrolled older/less‐fit patients (CLL11), PFS appeared favorable for ibrutinib in high‐risk subgroups, including advanced disease, bulky lymph nodes, unmutated IGHV status, and presence of del(11q). Grade ≥ 3 infections ranged from 9% (ofatumumab + chlorambucil) to 40% (fludarabine + cyclophosphamide + rituximab), and was 25% with ibrutinib. Grade ≥ 3 neutropenia was 12% for ibrutinib and 26%‐84% for CIT. Although definitive conclusions cannot be made due to inherent limitations of cross‐trial comparisons, this report suggests that ibrutinib has a favorable benefit/risk profile and may potentially eliminate the need for chemotherapy in some patients. Randomized, comparative studies are needed to support these findings.