Myeloma Patients with Deletion of 17p: Impact of Tandem Transplant and Clone Size

Introduction The presence of deletion 17p or monosomy 17 (del(17p)/-17) detected by fluorescence in situ hybridization (FISH) is well-established as a high-risk (HR) factor in multiple myeloma (MM). The del(17p)/-17 clone size and the clinical impact in patients that have ≥60% involved nuclei is controversial. Optimal treatment is also controversial, with tandem autologous stem cell transplantation (ASCT) explored but not uniformly adopted in the real world (ENM02, StaMMina). At our center, we have routinely offer tandem transplantation for del(17p)/-17 and now review our experience over a 10-year period, including the significance of del(17p)/-17 genetic variations on outcomes. Methods We performed a retrospective chart review of all patients identified with del(17p)/-17 patients who were offered tandem transplant and underwent at least one ASCT at Princess Margaret Cancer Centre from 2009-2019. Patient and disease characteristics, responses, and survival outcomes were collected from the Myeloma and Transplant databases and electronic patient records under REB approval. Results Patient, disease, and treatment characteristics. We identified 100 patients with del(17p)/-17 who underwent ASCT at our center. These patients were separated into three groups: those with a deletion of the TP53 locus (57%), those that had monosomy 14 (17%), and those with a relative loss the TP53 locus (eg. aneusomy or polyploidy,13%). The median % of nuclei with del(17p) was 39% (range 5-93%), with 27 (25%) over 60%. 28% of patients carried at least one other cytogenetic abnormality besides del(17p), most commonly t(4;14). All patients were intended for tandem transplant, but only 69 (69%) completed both transplants. Reasons for not proceeding to a second transplant were: patient declined (29%), toxicity (26%), clinical trial (19%), progression prior to the second transplant (13%), with one early death (3%). Median age at transplant was 61 years (range 40-72); most were male (61%) with advanced R-ISS II and III (97%). The most common induction regimen used was cyclophosphamide, bortezomib and dexamethasone (CYBORD)(87%), with 10% requiring a 2 nd induction regimen for inadequate response/progression. Standard conditioning was melphalan 200mg/m 2 for both first and second transplants. Median time from diagnosis to first ASCT was 5.9 months (range 3-24) and time from first to second transplant was 3.3 months (range 1-7). Most patients (90; 84%) received maintenance therapy post-transplant: 47% lenalidomide, 29% multiple agents (commonly lenalidomide and a proteasome inhibitor) Response and survival outcomes After induction, the rate of VGPR (very good partial response) or greater was 53%, increasing to 73% after 1 st ASCT, 85% after 2 nd ASCT. At a median follow-up of 32 months (range 3-130), the median PFS for all patients was 39.2 months 95% CI (24.1-46) and median OS was not yet reached (NYR) (95% CI 57.9-NYR). When analyzed by whether single or tandem transplant was performed, median PFS was 21.8 months (95% CI 10.3-43.3) for single ASCT, and 42.1 months (95% CI 32.8-NYR) for tandem ASCT (P=0.0096). The median OS was 57.6 months for single ASCT (95% CI 22.2-86.5), but NYR for tandem ASCT (95% CI 105.6-NYR) (p=0.0022). On subgroup analysis, patients with ≥60% del(17p) achieved a median PFS 45 months (95% CI 14.4-NYR) and median OS 68.5 months (95% CI 20.9-68.5), median was only PFS 24.9 months (95% CI0.4-NYR) and median OS 29.3 months (95% CI 0.4-68.5) for those who received single ASCT. (table1) TP53 signal pattern analysis (table 2) showed the median OS for patients with monosomy 17 was NYR, while it was 105.7 months for patients with deletion, and 86.5 months for those with relative loss. Median PFS was 43.3 months for the monosomy group, 32.8 months for deletion group, and NYR for relative loss. Conclusions Our experience shows that MM patients with del(17p)/-17 appear to have deeper responses and improved outcomes with more aggressive tandem transplantation. However, approximately 1/3 of our patients intended for tandem transplant did not undergo a second transplant, identifying a focus of future investigation and optimization. Our analysis also suggests that clone size of del(17p) >60% does impact OS negatively, but improved with tandem transplantation. The type of deletion also appears to affect outcomes with deletion having worse PFS but not worse OS. Figure 1 Figure 1. Disclosures Prica: Astra-Zeneca: Honoraria; Kite Gilead: Honoraria. Reece: Takeda: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria; Millennium: Research Funding; Sanofi: Honoraria; BMS: Honoraria, Research Funding; Karyopharm: Consultancy, Research Funding; GSK: Honoraria. Trudel: Amgen: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Research Funding; BMS/Celgene: Consultancy, Honoraria, Research Funding; Genentech: Research Funding; Roche: Consultancy; Sanofi: Honoraria; Pfizer: Honoraria, Research Funding. Chen: Beigene: Membership on an entity's Board of Directors or advisory committees; Astrazeneca: Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy.

Interrelation of 5q-Deletions and Mutations of TP53 in Patients with Myelodysplastic Syndromes and Complex Aberrations

Introduction: Cytogenetic changes occur in 50% of patients (pts) with Myelodysplastic Syndromes (MDS). Complex aberrations (cA, = 3 or more) are associated with a very poor outcome. In about 50% of the cases with cA aberrations of the TP53 locus are detectable. Those pts show an even worse outcome with a significantly shortened median overall survival (OS) compared to pts with wildtype TP53 (wtTP53). One of the most common cytogenetic aberrations in MDS is an interstitial deletion of the long arm of chromosome 5 (5q). As an isolated aberration, it is associated with a rather favorable prognosis. As part of a cA, 5q deletions however are assumed to even worsen the prognosis further. We wanted to find out in which prevalence 5q deletions and TP53 changes appear together and how those two factors in combination or not influence the OS of pts with MDS and cA. Methods: 218 pts with MDS or sAML and cA were identified and extensively characterized. 126 of them were diagnosed with MDS, 89 with sAML and 3 with CMML. Cytogenetic analysis by chromosome banding (CBA) and fluorescence in situ hybridization (FISH) of the TP53 locus on 17p as well as sequencing of TP53 either by Sanger or by Next Generation Sequencing was available for all pts. Multicolour FISH (mFISH) was available for 146 pts, SNP array analysis for 42 pts. The median number of cytogenetic aberrations was 8 (range 3-50). At the time of first diagnosis with cA the median age was 72 (range: 29-95). Median OS of the entire cohort was 10.7 months (95% CI: 8.0-16.4). Results: In 146 of 218 pts we found alterations of TP53: a single hit mutation in 32 pts, a single deletion in 22 pts, a combined mutation and deletion in 67 pts and more than 1 mutation in 25 pts. The OS of those 146 pts was 6.6 months compared to 22 months of the pts with wtTP53 (p-value <0.0001). In 161 of 218 pts we found deletions of 5q (del(5q)). The median OS of those pts was significantly shorter than those of pts without del(5q) (8.4 vs. 20 months, p-value 0.001). 130 of 218 pts both had a del(5q) and an alteration of TP53, 31 pts only had a del(5q) and wtTP53 and 16 pts showed different types of TP53 alterations without del(5q). The median OS of pts with TP53 multi hit status as defined by Bernard (Bernard et al., Nature Medicine 2020) was 6.6 months, 5.3 months in pts with single hit TP53 mutations and a del(5q) and 21.6 months in pts, with wtTP53 and del(5q) (p-value = 0.0025, figure 1). Conclusion: Mutations and/or deletions of TP53 show a strong association with del(5q). Both were frequent in our cohort of 218 pts with MDS and cA. There also was a large intersection of 130 pts with both del(5q) and TP53 alteration. The combination of both changes seems to further worsen the already poor prognosis of pts with MDS and cA. Our observation that those two factors appear together frequently supports the hypothesis that the presence of del(5q) may promote the acquisition of cA. This is in accordance with Hsu´s hypothesis that in small clones with a mono-allelic TP53 mutation a del(5q) may favor the loss of heterozygosity of TP53 which could in a next step lead to a higher complexity of cytogenetic aberrations (Hsu et al, 2019). It is remarkable that the presence of del(5q) in combination with a single hit status of TP53 confers the same bad prognosis compared to multi hit TP53 status (figure 1).We will continue analyzing pts with MDS and cA to examine the influence of different TP53 and 5q alterations on the prognosis, the disease progression and median OS of those pts with cA. Figure 1 Disclosures Platzbecker: Novartis: Consultancy, Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Geron: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria; BMS: Consultancy, Honoraria.

TP53 Mutation in Waldenstrom Macroglobulinemia

Background. Waldenstrom macroglobulinemia (WM) is a B-cell malignancy characterized by bone marrow (BM) infiltration of clonal lymphoplasmacytic cells, which produce a monoclonal immunoglobulin M. MYD88L265P mutation may be considered as a founder event because of it high frequency in WM. WM cells may acquire additional genetic hits that may potentially promote disease progression: CXCR4 or CD79B mutations, copy number variation,…TP53 is a tumor suppressor gene that functions as regulator influencing cellular responses to DNA damage. Little is known regarding TP53 alteration in WM. Our aim was to screen TP53 mutation in a large cohort of WM at diagnosis to analyze the genomic landscape of WM using targeted next generation sequencing (NGS) and genome wide single nucleotide polymorphism array (SNPa) and to identify clinical and biological characteristics. Method. BM samples of 125 WM (mean age: 67 years) were analyzed at diagnosis. Tumoral DNA was extracted following CD19 B cell selection. TP53 mutations were analyzed by targeted NGS to scan the coding exons of TP53. MYD88L265P, CD79A, CD79B, and CXCR4mutations were analyzed by sanger sequencing and/or NGS. Genome-Wide Human SNP Array 6.0 (Affymetrix chips) was performed in 62 cases. CN-LOH (copy neutral- loss of heterozygosity) and CNA (copy number aberration) were mapped using console 3.02 software (Affymetrix). Flow cytometry was performed to assess P53 and p21 expression after nutlin3a exposition to characterize functional mutant of TP53. Viability and cell growth of treated cells were determined using the MTS assay. Results. We have identified TP53 mutations using NGS in 7.3 % of WM (6 non-sense, 3 frameshift mutations located in the DNA binding domain) (TP53mut WM). The mutation load of TP53 varied from 13% to 98.9% (mean: 62.0%) using the variant allele frequency in NGS. We next examined the effects of nutlin-3a which is an mdm2 inhibitor on WM patients CD19+ cells genotyped for TP53 mutation. Nutlin-3a increased the expression of p53 and p21 in TP53Wild WM patients using flow cytometry (n=6). In contrast, in TP53MutWM cells, no significant variation of p53, p 21 and viability using MTS assay was observed suggesting the presence of functional mutation of TP53. The minimal deleted region of 17p in 17p deleted (TP53Del) samples was mapped using SNP array and contained 79 genes, among which was systematically comprised the loss of TP53. A high correlation between TP53 mutation and deletion 17p (p<106) was observed. One case of CN-LOH was observed at TP53 locus (1,6% of cases). Overall, we have identified alteration of TP53 locus including mutation, deletion and copy neutral loss of heterozigosity in 11, 2% of WM. Using SNP array, we found a relationship between deletion 17p, alteration of TP53 locus including mutation, UPD or del17p (TP53Alt) and TP53Mutand a greater frequency of genomic aberrations in WM compared toTP53wild (p=0.01, p=0.024 and p=0.06 respectively). A higher frequency of WM patients with more than 3 CNA identified by SNPa was observed in TP35Mut group (p=0.03) and del17p group (p<0.00001). No association was observed between TP53Mut and CXCR4 and MYD88mutations. We thoughtto identify clinical and biological characteristics of WM according to TP53Mutand/or Del17pfeatures. With a median follow-up of 5 years, 33 (26%) patients had died. 69% of cases were treated. Front line therapy included rituximab-based regimens in 76%, alkylating agent in 78%, fludarabine in 6%. The WM with TP53alteration, irrespective of TP53Mut or del17p, displayed features of adverse prognosis in regards to higher serum levels of b2m (89% versus 40%, p=0.012), and also greater IPSSWM score 2 and 3 (50% versus 30%, and 43% versus 30%, p=0.041, respectively). Importantly, the presence of TP53alteration, irrespective of TP5Mut or del17p, was associated to poor outcome in overall survival in our series, TP53alteration (p=0.003), del17p (p=0.002), and TP53Mut(p=0.015). TP53 alteration prognostic value was independent of CXCR4 or MYD88L265Pmutations. Conclusion: A low frequency of TP53 mutation was observed in WM at diagnosis. We identified a genomic signature associated to their presence. In addition, a pejorative prognostic value of TP53 mutation was observed in WM highlighted the need of new therapeutic in this sub group of WM. Disclosures Leleu: TEVA: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria; LeoPharma: Honoraria; Pierre Fabre: Honoraria; Amgen: Honoraria; Bristol-Myers Squibb: Honoraria; Takeda: Honoraria; Celgene: Honoraria; Janssen: Honoraria.

Allogeneic Stem Cell Transplantation in Adult Patients with Acute Myeloid Leukemia and 17p Abnormalities in First Complete Remission: A Study from the Acute Leukemia Working Party (ALWP) of the European Society of Blood and Marrow Transplantation (EBMT)

Introduction: Acute myeloid leukemia (AML) with 17p abnormalities (abn(17p)), usually affecting TP53 locus, carries a very poor prognosis due to high refractoriness to conventional chemotherapy, with long-term survival of less than 5%. Allogeneic stem cell transplantation (SCT) appears as the only potential curative option in high-risk AML. To specifically address outcomes after SCT in patients with abn(17), we retrospectively analysed data from the EBMT registry. Methods: De novo or secondary AML with abnormal karyotype transplanted between 2000 and 2013 have been allocated. From a dataset of 5495 patients with AML undergoing SCT, we included only those patients for whom data were sufficient to confirm the presence of abn(17p) resulting in a loss or a disruption of the TP53 locus. Results: One hundred thirty-nine patients have been selected including 125 patients (90%) in first remission (CR1) and 14 (10%) in second remission. For further analysis, we focused on the 125 patients in CR1. Median age was 54 (range, 18-69) year-old and the median follow-up was 21 (range, 3-146) months. Eighty-five percent of the patients had a de novo AML, while 15% had a secondary AML. Abn(17p) was associated to a monosomal karyotype in 83% of patients, complex karyotype in 91%, monosomy 5 or 5q deletion (-5/5q-) in 55%, monosmy 7 (-7) in 39% and both -5/5q and -7 in 27%, respectively. Median time from diagnosis to CR1 was 57 (range, 18-170) days. Fifty-one (41%) of the patients received a myeloablative conditioning regimen and 73 (59%) had a reduced-intensity conditioning regimen. The vast majority of patients (70%) had a karnofsky performance status of more than 90% at the time of SCT. The 2-year overall survival (OS) and leukemia-free survival (LFS) were 28% and 24%, respectively. The 2-year non-relapse mortality (NRM) was 15%, and 2-yr relapse incidence (RI) was 61%. The cumulative incidence of grade II to IV acute graft-versus-host disease (GvHD) was 24% and that of chronic GvHD was 21%. In multivariate analysis, the presence of a -5/5q- in addition to abn(17p) was significantly and independently associated with worse OS, LFS and higher RI. Age and donor type did not correlate with outcome. Conditioning intensity was not statistically associated with OS, LFS and NRM when adjusted for patients'age. Conclusion: In contrast to the dismal prognosis reported for AML patients harboring abn(17p) undergoing conventional chemotherapy, allogeneic SCT provides long-term responses in about 25% of a selected group of patients harboring this cytogenetic abnormality at diagnosis and transplanted in CR1. Post and pre transplant targeted therapy may further improve results. Disclosures Milpied: Celgene: Honoraria, Research Funding.

Lenalidomide Overcomes Poor Prognosis Conferred by del13q and t(4;14) but Not del17p13 in Multiple Myeloma: Results of the Canadian MM016 Trial.

The outcome of conventional therapy in MM is highly heterogeneous and appears to be largely dictated by the presence of recurrent genomic aberrations. Among these t(4;14), deletion 17p13 (TP53 locus), maf gene translocations and to a lesser extent del13q define a subgroup of patients with high risk disease. We here report on the efficacy (RR, PFS and OS) of lenalidomide and dexamethasone (len-dex) in relapsed MM patients according to their del13q, t(4;14) and del17p13 status. The MM016 is a multicenter single arm open label expanded access program for len in relapsed and refractory MM. Pts received dex orally (40mg, days 1–4; 9–12 and 17–20 for 4 cycles, then days 1–4 beginning with cycle 5) and len 25mg orally on days 1–21 of a 28 days cycle. FISH studies with commercially available probes detected the presence or absence of del13q, t(4;14)(p16;q32) and del17p13 on the interphase bone marrow aspirates. Blade criteria were used to define RR. PFS and OS were defined according to the international uniform response criteria. 159 patients with FISH results available for a least one of the genomic aberrations were included in this analysis: median age was 61 yrs (32–85), 50.3% had ISS stage II or III, median beta2-microglobulin was 3.055 mg/L (0.69–17.5), median number of prior treatments was 3 (1–6) with 50.3% previously treated with thalidomide, 43.7% with bortezomib and 73% with SCT. Del13q, t(4;14) and del17p13 were detected in 57 (37.3%), 21(19.1%) and 11 (11.6%) of patients, respectively. The overall response RR (CR+PR) to len-dex was 77.3% (14.4% CR and nCR) and 64.9% for the del13q, 76.2% for t(4;14) and 63.6% for del17p patients. The median PFS was 10.56 months (95%C.I.[6.65–14.48]). The median OS was not reached at the time of this analysis with 55.4% alive at a median follow-up of 16 months. PFS and OS were also similar when results were analyzed according to the presence or absence of del13q, t(4;14), ISS stage and prior SCT. In univariate analysis, prior thalidomide or bortezomib exposure, number of prior lines of therapy, depth of response (CR vs PR) and the presence of del17p13 by FISH did result in lower PFS and OS. However in multivariate analysis only the presence of 17p13 deletion and the depth of response correlated with PFS and OS (Table). Treatment with len-dex overcomes the poor prognosis conferred by t(4;14), high beta2-microglobulin and del13q in relapsed and refractory MM. Patients with deletion of the TP53 locus still fare very poorly despite a rapid initial response to len-dex. Confirmation of these results in patients with del17p13 with a larger prospective study is clearly warranted. Variable PFS OS HR, 95% CI p value HR, 95% CI p value t(4;14) 0.92(0.29–2.13) 0.920 1.26(0.46–3.42 0.641 Del 13 0.90 (0.44–1.83) 0.783 0.56 (0.25–1.29) 0.179 Del17p13 6.26 (2.48–15.77) 0.000 3.83(1.34–10.93) 0.012 ISS III 2.03 (0.42–9.82) 0.376 1.72 (0.39–11.33) 0.378 Prior Thal 1.12 (0.51–2.44) 0.768 1.22 (0.53–2.82) 0.633 Prior Bortez 1.29 (0.61–2.74) 0.501 1.66 (0.74–3.71) 0.215 Response ≤ PR vs CR 3.031 (2.14–4.27) 0.000 2.17 (1.50–3.12) 0.000