ALBERT

Description: Background: Cytopenia post allograft can be multi-factorial. Known causes include viral infection, septicaemia, graft versus host disease (GVHD), nutritional deficiency, myelotoxic drugs, relapsed malignancy but immune mediated cases are increasingly observed. There remains a group of cases where no obvious cause is identified. The incidence of this complication is small but may be underestimated and treatment options and results are not defined. Aim: This single centre analysis retrospectively evaluated cases of post-transplant cytopenia presumed to be immune mediated or with no obvious cause and response to antiCD20 antibody (Rituximab) therapy. Study period was 2012 to 2019. Data was collected from electronic patient records, case notes and haematology data base. Results: From 2012 to 2019, 988 patients received allograft (n=390) or autograft (n=598) for haematological malignancy or bone marrow failure syndrome. Twenty-four cases received Rituximab for cytopenia post allograft (24/390, 6.2%). Median age was £9yr. (range: 19-68), 19 were males (79.2%) and allograft were done for severe aplastic anaemia (n=4), Ac. Leukaemia (n=6), Hodgkins disease (n=4), non-Hodgkins lymphoma (n=4), MPD/MDS (n=5) and myeloma (n=1). Conditioning was reduced intensity in n22 case, myeloablative in 2 cases and included campath (n=18) or ATG (n=2) in 20 cases (83.3%). Donor was sibling (n=6) or unrelated (n=22) and 23 (96%) patients received PBSC. All allografts were donor/patient CMV matched (NN: 15, PP: 9). Rituximab was used at a median of 171 days post transplant (range: 55-6174). Cytopenia was trilineage in 8, bilineage in 10 and single lineage in 6 cases. Median haematological parameters were as follows: Hb 78gm/L (68-152), WBC: 2x109/L (0-12), Platelets 28x109/L (4-638). DCT was positive in 7 of the 15 cases where results were available. Seventeen of the 22 cases who had bone marrow evaluation showed hypocellular marrow with no malignancy (3 had normocellular marrow) . Seven of the 10 cases where reticulocyte count pre-rituximab was available, showed response above 2% . Cytopenia was not related to infection, viruses, it B12 or folate deficiency. Response to rituximab therapy was defined as CR (normal counts, transfusion independence, no treatment with steroids or G-CSF), Stable (improvement in counts with platelets〉50, Hb〉100 and ANC〉1.0 without support) or no response. Rituximab was delivered weekly in the dose of 375mg/m2 for 4 weeks. Twelve patients achieved complete response (50%), 3 achieved stabilization (12.5%) and 9 did not show any response (37%) for overall response rate of 63%. All patients with positive DCT responded to Rituximab (7/7, 100%) but even in negative DCT group 4 responded (4/8, 50%). Response was 100% in single lineage cytopenia (6/6), 40% in bilineage cytopenia (4/10) and 63% in trilineage cytopenia (5/8) [p=0.052]. Three patients received second course of Rituximab for recurrence of cytopenia and all achieved second complete response (all three had autoimmune haemolysis). Numbers are too small to identify the predictors but there was trend towards better outcome in patients younger than 40 yrs. age (10/12 vs. 5/12, p=0.035) and patients with Hodgkins disease (4/4 vs. 11/20, p=0.09) but there was no effect of gender, intensity of conditioning, use of campath/ATG or CMV status. Treatment was well tolerated and infusion reactions were uncommon. We identify that the main drawback of this analysis is substantial amount of missing data, especially haematological investigations that precludes identification of predictors or trends. Conclusion: Rituximab should be considered as an option for management of post allograft cytopenia with immune aetiology or with no identified cause. Response rate is substantial and the benefit is sustained. It will be useful to have larger cohort of cases to identify the predictors of response. Disclosures Kulkarni: Therakos, Clegene: Honoraria. Murray:Therakos: Honoraria. Castleton:Novartis, Pfizer, Amgen: Consultancy, Honoraria. Cavet:AMGEN, Autolus, Celgene, EUSA, Jansen/J&J, Novartis,: Consultancy, Honoraria, Research Funding, Speakers Bureau. Wiseman:Novartis, Celgene: Consultancy, Honoraria. Somervaille:Novartis: Consultancy. Sommerfeld:Gilead: Other: Educational grant. Bloor:Abvie, Gilead, Novartis, Autolus, Celgene, etc: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Educational grant.

Description: Introduction Therapy-related myeloid neoplasms (tMN) are an increasing healthcare problem resulting from rising long-term survival from primary cancers. Approximately 80% of cases are associated with an adverse karyotype and have a dismal prognosis; pre-existing clonal haematopoiesis (CH) appears to be a predisposing factor and mutations in genes including TP53, PPM1D and DNMT3A have been detected prior to chemo- or radiotherapy exposure. In contrast ~20% of tMN are characterised by balanced chromosome rearrangements and have a relatively favourable outcome; chemotherapy agents targeting topoisomerase II have been implicated in generating these rearrangements however the involvement of CH has not previously been described. Methods and results We performed whole exome sequencing (WES) of samples taken at diagnosis (D) and molecular complete remission (mCR) followed by targeted capture and error-corrected deep sequencing (ECS) on ≥2 mCR samples for 11 patients with therapy-related acute promyelocytic leukemia (tAPL) and 20 patients with de novo APL (dnAPL). All patients had t(15;17) / PML-RARA at diagnosis with no additional cytogenetic abnormality. The median age of patients with tAPL was 46.7y (range 30-78); primary cancer types were breast (4), colorectal (2), lymphoma (3), CNS (1) and testicular (1). Ten patients had received chemotherapy and 4 radiotherapy. The median latency between primary cancer treatment and tAPL diagnosis was 3.9y (range 2.2-6.1). Patients received a mixture of chemotherapy- and arsenic-based treatments. The median age of patients with dnAPL was 40.3y (range 18-69); all patients were treated with the AIDA regimen and none developed tMN subsequently. There were no significant differences between the number or type of mutations between dnAPL and tAPL however disease associated somatic mutations were detectable in mCR samples by ECS in 4/11 tAPL samples compared to 0/20 dnAPL samples (p=0.04). Mutations detected in mCR were UPN1: PPM1D exon (e) 6 1bp deletion (del, variant allele fraction, VAF, D 32% mCR 11.3%); UPN2: DNMT3A e8 1bp del (VAF D 40.2% mCR 0.48%); UPN3: DNMT3A e10 1bp del (VAF D 35.4% mCR 2.9%); UPN4: MYCN e3 6bp insertion (ins, VAF D 38% mCR 0.37%). We screened samples from these patients and a further 39 dnAPL patients for a panel of genes with known CH associated mutations (CH-M) using ECS and detected additional mutations in 2 tAPL patients (UPN4, DNMT3A G104R, VAF D 0% mCR 3% and UPN5 DNMT3A R693H VAF D 2% mCR 25%, who subsequently developed tMN with complex karyotype). We did not detect CH-M in diagnostic samples from any patient with dnAPL and publicly available NGS datasets encompassing 220 patients only showed 1 APL case with a CH-M (DNMT3A e8 ins, prior cytotoxic exposure unknown). We detected treatment-emergent CH clones in mCR by ECS in 6/59 dnAPL patients treated with AIDA (DNMT3A n=3, PPM1D n=2, TP53 n=1, SF3B1 n=1). Applying the same techniques to six patients with therapy-related core-binding factor AML, we identified a persistent CH-M in mCR in one (DNMT3A e15 del, VAF D 38%, mCR 11.8%). DNA samples taken at the time of primary cancer diagnosis were available from UPN 1-3. In UPN1 we detected the PPM1D mutation in a lymph node (LN) involved with T-cell lymphoma (LN) (VAF 2.1%) and an uninvolved staging bone marrow (VAF 3.3%). In UPN3 the DNMT3A mutation was detected in a breast biopsy (VAF 0.7%) and LN involved with carcinoma (VAF 0.9%). In UPN2 the DNMT3A mutation was not detected in the LN biopsy diagnostic for Hodgkin lymphoma. We used FACS to isolate T, B, monocyte, granulocyte and CD34+ cells from complete remission samples from UPN1-4 with 〉99% purity and detected the persistent mutations in each cell compartment e.g. UPN3 VAF: T cell 1.3%, B cell 8.6%, monocyte 4%, granulocyte 3.7%, CD34+ 3.9%. Diagnostic material from UPN1 and 4 was injected into irradiated NSG mice. After 12 weeks we detected multilineage human engraftment in both samples by FACS in 1/3 mice from UPN1 and 2/3 mice from UPN4. We detected the PPM1D and MYCN mutations respectively in bone marrow samples from each engrafting mouse. Conclusions Together these findings indicate that tMN with balanced chromosome rearrangements can occur on a background of non-malignant CH. Using ECS we observed this phenomenon in 5/17 (29%) patients with therapy-related APL or CBF AML. This has important implications for planning curative therapy, notably for tAPL where effective cytotoxic-free regimens are available. Disclosures Russell: Pfizer: Consultancy, Honoraria, Speakers Bureau; Jazz Pharma: Speakers Bureau; Daiichi Sankyo: Consultancy. Hills:Daiichi Sankyo: Consultancy, Honoraria.

Description: Introduction: As the number of long-term survivors following HSCT is increasing, the long-term risks and associated morbidity has become important component of survivorship program. The known risk factors for developing cancer include use of chemotherapy agents, radiation exposure, immune dysfunction, previous malignancy in addition to other factors and as HSCT process involves all these factors, this single centre retrospective analysis was undertaken to evaluate the risk of developing SSC in the patients receiving transplant. Methods: From February 1982 to February 2016, 2231 patients received 2495 transplants (median age: 46yr., range: 14-76 yr.; M: 1586, F: 909) for haematological malignancies (Leuk: 744, lymphoma:767, myeloma:848, solid tumours/other:136). Donor was allogeneic (n=744) or autologous (n=1751) and conditioning was with (n=614) or without TBI (n=1881). Donor was sibling (n=375), matched unrelated (n=355), haploidentical relative (n=3) or umbilical cord blood (n=11). Source of stem cell was marrow (n=367), PBSC (n=2086), both (n=31) or cord blood (n=11). GVH prophylaxis included Campath or ATG in 369 cases. Of all the patients 1985 received single transplant, 231 had two, 13 had 3 and 2 had 4 HSCT procedures. Data was analysed as of 15/04/2016 using competing risk model with death as the competing event. Comparison of incidence to general population was performed by computing standardized incidence rates (SIR). Patients with second haematological malignancy were not included in this analysis. Results: Median follow-up was 5.3 years (range: 0-32 years). Patient follow-up was more than 10 years in 467 cases (19%), between 5 to 10 years in 430 (17%), 2 to 5 years in 607 (24%) and less than 1 year in 997 cases (40%). 36% patients were followed-up for more than 5 years. Second solid cancers developed in 116 patients with the incidence of 1% at 5yr (95% CI: 0.5-2.6), 3% at 10 yr (95% CI: 1.6-5.3), 6% at 15yr (95%CI: 3.6-8.8) and 10% (95% CI: 5.9-15.5) at 20 years. Median time to develop SSC from date of HSCT was 11 yr (range: 0.4-28.1 yr). Primary site for SSC included skin (n=37), breast (n=22), GI (n=15), GU (n=16), H&N (n=10), lung (n=6), CNS (n=4), Endocrine (n=4) & HPB (n=2). There was no difference with type of transplant i.e. auto or allograft. Autograft and allograft groups were analysed separately. In univariate analysis, allograft group showed higher cumulative incidence of SSC with use of PBSC (p

Description: Introduction: Chronic graft-versus-host disease (cGVHD) is a major cause of morbidity and non-relapse mortality in allogeneic haematopoietic stem cell transplant patients (Allo-HSCT). Extracorporeal Photopheresis (ECP) is now an established second-line treatment for steroid-refractory cGVHD. Here we report a large, multi-centre case series of 115 patients treated with ECP for cGVHD. To the best of our knowledge, this is the largest reported series of patients receiving fortnightly ECP for cGVHD. Method:A retrospective case note audit identified 115 consecutive Allo-HSCT patients who commenced fortnightly ECP for cGVHD between 2007 and 2016 at The Christie and Central Manchester NHS Foundation Trusts. cGVHD was classified and graded using the National Institutes of Health (NIH) consensus response criteria. Results: Median age when starting ECP was 49 years (range 18-75). 61% patients were male (n=70) and 39% Female (n=45). Underlying disease groups undergoing Allo-HSCT included Acute Leukaemia/Myelodysplastic Syndrome (n=69; 60%), Lymphoma (10%; n=12), Chronic leukaemia (13%; n=15) Myeloma (14%; n=16) and Aplastic Anaemia (3%; n=3). 24% of patients had myeloablative conditioning (n=27) and 76% had reduced-intensity conditioning (n=88). 61% (n=70) received stem cells from Voluntary Unrelated Donors (VUD) and 39% (n=45) Siblings (Sib). Patients received post Allo-HSCT GvHD prophylaxis with Calcineurin inhibitors, either alone, or in combination with Methotrexate and/or Mycophenolate Mofetil. Median time to stopping Calcineurin inhibitor post Allo-HSCT was 12 months (range 0-88). 14 patients received Donor Lymphocyte Infusions (DLI). Median time to development of GvHD post Allo-HSCT was 5 months (range 0-33). 94% developed cutaneous cGVHD (n=108), 32% oral cGVHD (n=37), 23% gut cGVHD(n=27), 24% liver cGVHD (n=28), 11% lung cGVHD (n=13) and 26% ocular cGVHD (n=30). 49% (n=57) patients had sclerodermoid disease. 37% (n=43) had one, 31% (n=36) two, 21% (n=24) three, 9% (n=10) four and 2% (n=2) five organ involvement. All 115 patients had been previously treated with immunosuppressive drugs - 109 Prednisolone; 73 Calcineurin Inhibitors; 60 Mycophenolate mofetil and other (ATG, n=1; Basiliximab, n=1; Methotrexate, n=6; Rituximab, n=10; and Thalidomide, n=18). Median duration of ECP treatment was 12 months (range 1-27 months). Response to ECP was assessed using NIH Criteria - 29% (n=33) Complete Response (CR), 19% (n=22) Partial Response (PR), 16% (n=18) Stable Disease (SD), 11% (n=13) Progressive Disease (PD), 17% (n=19) Death and 9% (n=10) Other. As a result of ECP treatment 26% (n=30) were able to stop steroid treatment while the remaining 74% were able to reduce their steroid dose. There was no overall difference in response between the two centres. Patients with cutaneous and oral cGVHD were more likely to achieve a PR or better (cutaneous p=0.03; oral p=0.05) but there was no difference with other organ involvement. The chance of response was not influenced by the number of organs involved. Median Overall Survival (OS) from the date of Allo-HSCT was 110 months (range 8-221). OS was not influenced by age, donor type, diagnostic group (Acute Leukaemia/Myelodysplastic Syndrome, Lymphoma, Chronic Leukaemia, Myeloma and Aplastic Anaemia), gender or the number and type of organs involved. The only exception was oral cGVHD which was associated with a lower OS (p=0.03). Patients with cGVHD achieving a CR/PR with ECP treatment, had a significantly better OS (40 months vs. median not reached, p

Description: Introduction: Azacitidine (AZA) represents a significant advance in the treatment of adults with acute myeloid leukaemia (AML) (Dombret et al Blood 2016 126:291-9) and myelodysplasia (MDS) (Fenaux et al Lancet Oncol 2009) 10:223-32) ineligible for intensive chemotherapy. However complete response (CR) rates remain modest and disease progression is almost inevitable. Consequently, additional agents which improve the clinical activity of AZA and other hypomethylating agents are urgently required. Pre-clinical and Phase II studies have identified the potential of co-administration of histone deacteylase inhibitors, notably vorinostat (VOR), with AZA as a strategy to improve its clinical activity. We have therefore compared outcomes after AZA monotherapy or combined AZA and VOR in a prospective randomized trial in adults with high risk AML and MDS. Patients and Methods: 259adults with AML or high risk MDS deemed ineligible for intensive chemotherapy were randomized to receive either AZA (75 mg/m2) x 7 days every 28 days or AZA in combination with VOR 300 mg bd days 3-9 po for a minimum of 6 cycles. Patients were assessed for response, using modified Cheson criteria, after 3 and 6 cycles of therapy. Patients who achieved a major clinical response (CR, CRi or PR) were eligible to receive continued treatment until loss of response, toxicity or death. Major response after 6 cycles and overall survival (OS) were co-primary endpoints. 219 patients had AML (newly diagnosed n= 108) and 44 had MDS (newly diagnosed n= 30). Results: Co-administration of VOR did not increase either the major response rate at 6 months compared with AZA monotherapy (33% AZA v 37% AZA+VOR, OR (95% CI)=1.2 (0.7,2.0), p=0.55) or improve OS (1 year OS AZA 43% versus AZA/VOR 44%, HR (95% CI)=1.06 (0.8, 1.4), p=0.68). No benefit of addition of VOR was observed in any patient subgroup. In multivariate analysis of the study population, a low presentation white blood count (p=0.029) and a diagnosis of MDS vs AML (p=0.0048) was associated with significantly improved survival, whilst disease status (CR v advanced disease) (p=0.023) and low presentation white blood count (p=0.034) significantly improved major response rates. Presentation karyotype was not predictive of either survival or response. Both adverse events (AE) and serious adverse events (SAE) were balanced between treatment arms with 64 and 89 patients in the AZA arm experiencing AE and SAEs respectively versus 75 and 97 in the combination arm respectively. Discussion: To our knowledge this is the largest randomized study of epigenetic therapy in AML and MDS. We conclude that the addition ofVOR to AZA therapy does not increase either major response rates or overall survival in patients with AML and high risk MDS. Alternative therapeutic strategies with the potential to increase response to AZA are required in this patient population. Disclosures Ferguson: Celgene: Consultancy. Raghavan:Celgene: Consultancy. Quek:Celgene: Research Funding. Cavenagh:Celgene: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau. McMullin:Novartis: Honoraria, Speakers Bureau. Pillai:Celgene: Honoraria. Vyas:Celgene: Honoraria, Research Funding.

Description: Introduction: With a median age of diagnosis in the late 60s, many patients with Acute Myeloid Leukemia (AML) are deemed unsuitable for conventional curative therapy (typically anthracycline and ara-C). The decision may be based upon a patient's age, cytogenetic profile, fitness, comorbidities, or indeed a preference for less-intensive therapy. Survival in these patients has traditionally been poor with

Description: Introduction: Since the seminal paper of LeBlanc in 2008, despite several negative studies, the scientific community has retained optimism with respect to the usefulness of mesenchymal stroma cells (MSCs) in refractory acute graft-versus-host disease (GvHD). A prevailing theme of past studies was that, while pediatric GvHD responded to MSCs, adult GvHD did not. As reported, we developed proprietary protocols GMP-quality MSC production from bone marrow (BM) mononuclear cells expanded in platelet lysate-enriched media. Patients and Methods: We present treatment data with MSC-FFM for 61 children/adolescents and 31 adults with either "only" steroid-refractory (SR) GvHD (27%) or GvHD which had additionally proven refractory to up to five additional lines of therapy (MR-GvHD) (73%). Pediatric patients tended to have more MR-GvHD than adults. Patients from 23 centers in 6 countries were included. Most patients had severe GvHD (37% °III, 59% °IV, Glucksberg scale). 31 patients (34%) were female,61 male (66%). 69 have a malignant disease (75%), and 23 a non-malignant (25%) disease as indication for transplantation. Donors were MSD (n=21, 23%), MUD (n=56, 61%), haploidentical (n=14, 15%), and 1 MMUD (1%). Patients received myeloablative conditioning with TBI-, Treosulfan-, Busulfan- and Fludarabine-based regimen, with serotherapy, mostly ATG. 89% of patients had had immunosuppression for GvHD prophylaxis, 13% CSA alone, 49% CSA+MTX or MMF; or others (n=15, 16%). Median onset of aGvHD was at 40 days (range: 6-280 d), another 28 days (range: 5-380) until the first infusion of MSC-FFM. Recommended dose and interval is 4 weekly doses of 1-2M MSC/kg body weight; the average patient received only 3 doses, the interval approximately staggered as recommended, with a median dose of 1.4M MSC/kg. Any reduction in GvHD activity by at least one full grade was classified as a partial (PR), absence of any degree of GvHD as a complete response (CR). Results: Day-28 response rates were 84%/25%/59% overall (OR)/CR/PR for children and 80%/35%/45% for adults resulting in a day-28 response rate for the entire cohort: 82%/28%/54%). At last follow-up (LFU) many of the pediatric responders had continued to improve from partial to complete response to response rates of 84%/59%/25% OR/CR/PR, in adults responses were largely unchanged (77%/35%/42%; LFU for the entire cohort: 81%/51%/30%). GvHD °III and °IV were equally likely to respond or resolve. Looking at response rates of SR- vs. MR-GvHD, of the SR-GvHD 96% responded (MR-GvHD: 81%), as well as early and LFU responses in SR-GvHD were more likely to be complete responses (60% and 72% for SR-GvHD, 16% and 43% for MR-GvHD, day-28 and LFU, respectively). Day-28-response was highly predictive of long-term responsiveness, in that only one non-responder on day 28 achieved a response long term, and only two initial partial responders' GvHD relapsed to the same degree of severity as before MSC treatment. The historical expected survival probability for patients with steroid-refractory severe GvHD being in the order of 20% at 6 months. The patients reported here with °III or °IV aGVHD achieved 6-month overall survival probabilities of 65% and 61%, respectively. In total 6 patients relapsed and died (of note: only 69 patients were at risk), 28 deaths were treatment-related. 6-month overall survival rates for children and adults were 68% and 54%, respectively (n.s.). In terms of adverse reactions to MSC-FFM, one case each of spontaneously remitting headache and nausea/vomiting were reported shortly after infusion of the thawed cells. Both events occurred in children and were possibly related to the rapid infusion of DMSO-containing ice-cold fluid and not the active substance. Conclusion: MSC-FFM emanates as a highly efficacious treatment for severe pediatric and adult advanced GvHD, with OR in excess of 80% and survival rates approximating those of patients without GvHD. The very low relapse mortality may suggest that severe GvHD effectively suppresses leukemic recurrence. Better and faster responses of SR- vs. MR-GvHD make a case for early treatment with MSC-FFM. Disclosures Bader: Medac: Patents & Royalties, Research Funding; Cellgene: Consultancy; Neovii: Research Funding; Riemser: Research Funding; Novartis: Consultancy, Speakers Bureau. Kuci:Medac: Patents & Royalties. Kuci:Medac: Patents & Royalties. Bug:Amgen: Honoraria; Jazz Pharmaceuticals: Other: Travel Grant; Neovii: Other: Travel Grant; Astellas Pharma: Other: Travel Grant; Janssen: Other: Travel Grant; Celgene: Honoraria; Novartis Pharma: Honoraria, Research Funding. Lang:Miltenyi Biotec: Patents & Royalties, Research Funding. Sykora:Aventis-Behring: Research Funding; medac: Research Funding. Seifried:Medac: Other: BSD owns IP and is contract manufacturer; Uniqure BV: Research Funding. Bonig:Kiadis Pharma: Consultancy.

Description: Activating mutations of the receptor tyrosine kinase FLT3 are seen at diagnosis in one-third of younger adults with acute myeloid leukemia (AML) and are associated with an increased risk of relapse. FLT3 remains the subject of intense clinical interest as a therapeutic target. To date FLT3-targeted monotherapy has produced only transient clinical responses with no prospective trial producing an overall survival benefit. Here we report the results of the first randomised trial of a FLT3 inhibitor (Lestaurtinib, CEP701) given sequentially to chemotherapy as first line treatment for newly-diagnosed AML. FLT3-mutated patients entering the UK MRC AML15 and UK NCRI AML17 trials between January 2007 and October 2012 were randomised to receive either oral Lestaurtinib 80mg bid, or placebo, for up to 28 days after each of 4 courses of chemotherapy. Based on early pharmacokinetic data provision was made for dose reduction to 40mg bid for patients on concomitant azole anti-fungal drugs. 500 patients were randomised (175 AML15, 325 AML17). Median age was 49yrs (5-68, only 5 were

Description: Established adverse prognostic factors in chronic lymphocytic leukemia (CLL) include CD38 expression, relative lack ofIgVH mutation, and defects of theTP53 gene. However, disruption of the p53 pathway can occur through mechanisms other than TP53 mutation, and we have recently developed a simple screening test that detects p53 dysfunction due to mutation of the genes encoding either p53 or ATM, a kinase that regulates p53. The present study was conducted to examine the predictive value of this test and to establish the relationship between p53 dysfunction, CD38 expression, and IgVHmutation. CLL cells from 71 patients were examined forIgVH mutation, CD38 expression, and p53 dysfunction (detected as an impaired p53/p21 response to ionizing radiation). Survival data obtained from 69 patients were analyzed according to each of these parameters. Relative lack ofIgVH mutation (less than 5%; n = 45), CD38 positivity (antigen expressed on more than 20% of malignant cells; n = 19), and p53 dysfunction (n = 19) were independently confirmed as adverse prognostic factors. Intriguingly, all p53-dysfunctional patients and all but one of the CD38+ patients had greater than 5% IgVH mutation. Moreover, patients with p53 dysfunction and/or CD38 positivity (n = 31) accounted for the short survival of the less mutated group. These findings indicate that the poor outcome associated with having less than 5%IgVH mutation may be due to the overrepresentation of high-risk patients with p53 dysfunction and/or CD38 positivity within this group, and that CD38− patients with functionally intact p53 may have a prolonged survival regardless of the extent of IgVH mutation.