ALBERT

Description: Introduction Chromosome instability (CIN) is a driver of copy number aberrations (CNAs) in cancer, and is a major factor leading to tumor heterogeneity and resistance to therapy. By definition, CIN is an increased rate or ongoing acquisition and accumulation of CNAs and not simply the existence of structurally and numerically abnormal aneuploid clones. In multiple myeloma (MM), the most common whole-chromosome CNAs involve either hyperdiploid or non-hyperdiploid clones. Secondary segmental CNAs are associated with high-risk (HR) in MM and involve gains of 1q21 and deletions of 17p (del17p). These types of intra-chromosomal segmental CNAs are also found in the CIN phenotypes of the autosomal recessive (AR) chromosome instability syndromes. These syndromes include Fanconi anemia, Bloom's syndrome, and ICF syndrome (Immunodeficiency, Centromeric instability and Facial anomalies). These chromosome instability syndromes display a spectrum of aberrations characterized by higher rates of chromosomal breaks, chromatid exchanges, quadriradials, and pericentromeric aberrations. In particular, patients with ICF syndrome show a marked increase of 1q12 pericentromeric instability including 1q12 decondensation, triradials, multibranched chromosomes 1q, and 1q micronuclei. ICF patients also show transient 1q aberrations including isochromosome 1q (iso1q) and unbalanced translocations of 1q to 9q and 16q. In MM, we have previously reported increasing pericentromeric instability during tumor progression resulting in increasing CNAs of 1q21 by unbalanced jumping translocations of 1q12 (JT1q12). Strikingly, in a subset of MM patients with 1q21 CNAs of ≥ 5 a distinct cytogenetic phenotype emerges which demonstrates transient 1q12 aberrations including 1q12 decondensation, triradials, and multibranched chromosomes 1q morphologically identical to those seen in ICF patients. In MM this chromosome instability leads to a cascade of increasing clonal 1q21 duplications, iso 1qs, and unbalanced 1q translocations with 16q and 17p, resulting in losses in these receptor chromosomes (RC) and massive intra-clonal CNA heterogeneity. Methods To investigate the cytogenetic impact and progression of high CNAs of 1q21, we performed a comprehensive metaphase analysis of 50 patients showing segmental aneuploidies with 4 or more copies of 1q by G-banding. Locus specific FISH and spectral karyotyping were used to identify the key transient unstable and clonal structural aberrations of 1q12 resulting in segmental aneuploidies in the derivative RCs. Probe for 1q12 (Vysis) was used according to the manufacturer's protocol. Locus specific BAC clones for 1q21 (CKS1B) and 17p (TP53) were prepared and analyzed as previously described (Sawyer et al., Blood 123: 2014). IGH translocations were investigated with IGH break apart probes (Vysis). Results Data for 50 patients including CNAs of 1q21 of ≥ 4, IGH translocations, del(17p), derivative RCs, are presented. The t(4;14) was found in 15 patients, del(17p) in 23, and both aberrations were found in 8 patients. All patients showed unbalanced gains of 1q and deletions of RCs, the most frequent being 7 patients with der(1;16) and 6 with iso1q. In four of the 23 patients with del(17p), the deletion was due to a JT1q12 to 17p. Seven patients with 1q21 CNAs of ≥ 5 showed profound instability involving the 1q12 satellite DNA, demonstrating both transient and clonal aberrations driving the 1q21 CNAs. These aberrations included unstable 1q21 triplications, JT1q12s, iso1q formation with intra-arm 1q12 CNAs, and region specific breakage-fusion-bridge cycle amplifications. Conclusions Among patients with ≥ 5 CNAs of 1q21, a subset develop an acquired HR chromosome instability phenotype with an elevated rate of 1q12 pericentromeric instability characterized by concomitant deletions in 16q, iso1q, del(17p), and intra-arm segmental instability. These patients show pronounced instability in the 1q12 satellite DNA, morphologically identical to ICF syndrome, suggesting hypomethylation of this region as a driver of both 1q21 CNAs and deletions in RCs. We hypothesize that region specific hypomethylation of 1q12 provides the genomic background for the onset of an acquired 1q12 chromosome instability phenotype in MM similar to that found in ICF syndrome. For myeloma patients demonstrating this 1q12 chromosome instability phenotype we propose the term "jumping 1q syndrome." Disclosures Epstein: University of Arkansas for Medical Sciences: Employment. Davies:Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; ASH: Honoraria; Abbvie: Consultancy; TRM Oncology: Honoraria; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; MMRF: Honoraria; Janssen: Consultancy, Honoraria. Morgan:Takeda: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria.

Description: Introduction Hyperhaploid multiple myeloma is a rare numerical aberration group defined by a range of 24-34 chromosomes. We have previously shown that hyperhaploid myeloma is associated with a poor prognosis with a 5-year survival rate of 23.1%, compared to 64% for hyperdiploid myeloma, and 80.4% for those with a normal karyotype. It is known that hyperhaploid myeloma frequently has monosomy of chromosome 17, making it a high risk group, but no data are currently available on the mutational status of this interesting sub-group, or how the copy number difference arises. Methods We analyzed data from whole genome, whole exome, and targeted panel sequencing from 1141 newly diagnosed myeloma patients. Internal samples were selected for whole exome or targeted sequencing based on previous karyotype information, or were identified in the process of other sequencing studies. The CoMMpass dataset was screened for the presence of hyperhaploidy. Hyperhaploid samples without prior karyotype information were identified by conflicting copy number profile and B allele frequency information, where the samples had incorrectly been normalized to a diploid copy number. These samples were re-normalized to a haploid copy number. Copy number, B allele frequency, and mutations of key genes were examined. Results In the entire dataset 9 hyperhaploid samples were identified, of which 2 came from the CoMMpass dataset. From those with gene expression array data, 5/7 were GEP70 high risk and all belonged to the D1 hyperdiploid gene expression subgroup. Samples had a median of 13 monosomies (range 9-14), which in general were those not associated with trisomies in hyperdiploid samples. The chromosomes traditionally trisomic in hyperdiploid myeloma were disomic in hyperhaploid myeloma. We examined the B allele frequency of these disomic chromosomes and saw that they all retained heterodisomy. Retention of heterodisomy indicates that the method of generating hyperhaploidy is through deletion of the monosomic chromosomes, rather than reverting to a haploid genome followed by duplication of some chromosomes. Retention of heterodisomy was also seen on chromosome 18, which is not normally trisomic in hyperdiploid samples, indicating that heterodisomy of chromosome 18 may be essential for a viable plasma cell clone. We examined the hyperhaploid samples for frequently mutated genes and found that 8/9 (88.8%) of hyperhaploid samples had a mutation in TP53. This rate of mutation far exceeds the overall rate of mutation in newly diagnosed patients (5.5%), indicating an oncogenic dependency in this group. The sample without mutation of TP53 had only 9 monosomies, fewer than the other samples (12-14 monosomies), indicating there may be a prognostic difference that is dependent on the total chromosome count. All samples with TP53 mutation also had monosomy of chromosome 17, indicating bi-allelic inactivation of TP53. The variant allele frequency of the TP53 mutations was high (median=0.94), indicating that bi-allelic inactivation was a clonal event. No other significant mutations were found, including those that encode chromosome segregation or kinetochore proteins. Conclusions We have previously described bi-allelic inactivation of TP53 as Double Hit myeloma, and here we identify that hyperhaploid myeloma belongs to this poor prognosis group. The method of generating the hyperhaploid clone is through deletion of chromosomes, which may happen in a way that is similar to gain of chromosomes in hyperdiploid myeloma. These Double Hit patients may be good candidates for new therapies, but using next generation sequencing techniques researchers must be careful when normalizing data to correctly identify them as hyperhaploid rather than hyperdiploid, using copy number and B allele frequency data. Disclosures Davies: MMRF: Honoraria; TRM Oncology: Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy; ASH: Honoraria. Morgan:Takeda: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Janssen: Research Funding; Celgene: Consultancy, Honoraria, Research Funding.

Description: Background. The TT approach has significantly improved the outcome of multiple myeloma (MM) by combining new drugs with a regimen that comprises induction, tandem autologous stem cell transplantation (ASCT), consolidation and maintenance. However, a group of 15% of patients with high risk multiple myeloma (HRMM) have derived little benefit despite similar response rates to induction chemotherapy and ASCT when compared to low risk MM. The poor outcome of HRMM is explained by early relapse post ASCT resulting in a short progression free survival (PFS) with only 15-20% of patients surviving long-term. Daratumumab (Dara) is a human IgG1k anti-CD38 monoclonal antibody that has shown favorable results in early single-arm studies and more recently in phase III studies for relapsed/refractory and newly diagnosed MM. In TT7, we introduced Dara during all phases of therapy, including immune consolidation early post ASCT, to improve responses rate and PFS in HRMM. Methods. Patients had newly diagnosed HRMM as defined by high risk cytogenetic abnormalities, presence of extramedullary disease, 〉3 focal lesions on CT-PET, elevated LDH due to MM, or ISS II/III with cytogenetic abnormality. Dara (16mg/kgx1) was added to induction with KTD-PACE (carfilzomib, thalidomide, dexamethasone; and four-day continuous infusions of cisplatin, doxorubicin, cyclophosphamide, etoposide). Conditioning for tandem autologous stem cell transplantation (ASCT) was with fractionated melphalan (50mg/m2x4) (fMEL) based on prior observations that patients with adverse cytogenetics fare better with fMEL rather than single high dose MEL200mg/m2.In the inter tandem ASCT period immunological consolidation with Dara (16mg/kg) alone for 2 doses was followed by Dara (16mg/kg) on day 1 combined with K (36mg/m2) and D (20mg) weekly for 2 cycles. DaraKD was administered to avoid treatment free periods allowing for myeloma regrowth. The 2nd ASCT was followed by further immunological consolidation with Dara (16mg/k) for 2 doses, and maintenance therapy for 3 yrs with 3-months block of alternating Dara-KD (dara 16mg/kg day 1; K 36mg/m2 and dex 20mg weekly) and Dara-lenalidomide (R)D (dara 16mg/kg day 1; R 15mg day 1-21 q28 and D 20mg weekly). Results. TT7 enrolled 43 patients thus far. The median follow-up was 11 months (range: 1-22). The median age was 61 yrs (range 44-73). Sixteen patients were ≥65 yrs (37.2%). A mean of 29.4x106 CD34+ cells/kg (range: 4.6-86.4) were collected. 36 patients completed ASCT #1 (83.7%) and 18 (41.9%) ASCT #2, whilst 14 patients have proceeded to the maintenance phase. R-ISS II/III or metaphase cytogenetic abnormalities were present in 85.1 and 58.1% of patients, respectively. Elevated LDH or 〉3FL on CT-PET were noted in 30 and 41.8%. The 1-yr cumulative incidence estimates for reaching VGPR and PR were 87 and 83%, respectively. A CR or sCR was achieved in 68 and 46%. The 1-yr estimates of PFS and OS were 91.6 and 87.2%. 40 subjects are alive, whilst 5 progressed on study therapy and 3 subsequently died. 38 patients are progression free at the time of reporting. Dara was well-tolerated and no subjects discontinued therapy due to dara-related side effects. The CR and sCR rates compared favorably to the predecessor HRMM TT5 protocol where CR and sCR rates were 59 and 27%. Conclusion. The early results of TT7 point to increased response rates of HRMM to a dara-based TT regimen with especially higher rates of CR and sCR. Longer follow-up is required to determine if these early results translate into superior PFS and OS. Figure Disclosures van Rhee: Karyopharm Therapeutics: Consultancy; Kite Pharma: Consultancy; Adicet Bio: Consultancy; Takeda: Consultancy; Sanofi Genzyme: Consultancy; Castleman Disease Collaborative Network: Consultancy; EUSA: Consultancy. Walker:Celgene: Research Funding. Morgan:Amgen, Roche, Abbvie, Takeda, Celgene, Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Other: research grant, Research Funding. Davies:Amgen, Celgene, Janssen, Oncopeptides, Roche, Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Consultant/Advisor; Janssen, Celgene: Other: Research Grant, Research Funding.

Description: Introduction. Our TT regimens for newly diagnosed multiple myeloma (MM) incorporate novel agents into a sequential treatment program comprising induction, tandem autologous stem cell transplantation and consolidation followed by 3 years of maintenance. Herein, we report the very long-term results in a large cohort of 1986 patients treated on successive TT protocols, the most mature of which (TT1, 2, and 3a) have a median follow-up ranging from 12.8 to 23.1 yrs. Methods. TT1 (1990) was followed by TT2 (1998), which introduced Thalidomide (T) in a randomized fashion. TT3 used bortezomib (V) throughout, with TT3a (2003) and 3b (2006) having different maintenance. TT3a used in year 1 of maintenance V, T and dexamethasone (D) and in years 2 and 3 TD. TT3b introduced lenalidomide (R) during maintenance for 3 years together with V and D. TT4 (2009) only enrolled patients with GEP-defined low risk disease and randomized patients to a standard arm or light arm using a similar regimen as TT3b. TT5 (2009) was specifically designed for patients who have a high 70-gene score and employed a dose dense treatment approach. Finally, TT6 (2009) accrued previously treated, patients irrespective of GEP-defined risk using a treatment schema similar to that used in TT5. Gene expression profiling was used to assign molecular classifications. These include HY (hyperdiploidy), LB (gene expression patterns frequently seen in patients with fewer focal bone lesions), MF (spikes in MAF and MAFB expression), MS (hyperactivation of MMSET +/- FGFR3), PR (over-expression of proliferation-related genes), and CD-1 or CD-2 (different forms of aberrant CCND1 and CCND3 expression). A mixed parametric cure model was used to estimate the proportion of patients with long-term, event-free survival, or the "cure fraction." When using progression free survival (PFS) in the model, the cure fraction is the percent of patients who are likely to never experience relapse based on trends in the survival times that have been observed. When using complete remission duration (CRD) in the model, the model estimates the cure fraction among patients who achieved complete response. Results. The median follow-up on the entire cohort patients was 11.6 years (range: 0.0-27.6) The median overall survival was 9.2 years, with 79.3% and 48.0% having an event-free survival greater than 3 and 10 years, respectively. Overall, patients with GEP70 low risk MM had estimated PFS and CRD cure fractions of 20.1% and 32.7%, respectively. GEP70 high risk MM patients fared much worse with estimated cure fractions of only 8.2 and 11.0%. The estimated PFS- and-CRD based cure fractions increased over time with successive protocols (PFS-cure: 6.0% in TT1 to 27.7% in TT4; CRD-cure: 9.3 to 49.8%). These cure fractions were consistent with the early plateau in the PFS and CRD curves seen at 9 years in TT4 patients. The highest cure fractions were seen in the CD-1 molecular group (34.9 and 40.3%) with intermediate outcomes in the HY (20.1 and 30.0%) and MS (22.8 and 33.5%) groups (Table 1). Surprisingly, low cure fractions were observed in the LB (1.1 and 13.5%) and CD-2 groups (13.5 and 26.4%). CD-1, LB and CD-2 groups had similar 5-yr PFS rates of 60, 60 and 63% respectively, but a steady low rate of relapse was observed in the CD-2 and especially the LB group. These findings were confirmed in a 5-yr landmark analysis showing high PFS and CRD cure fractions in the CD-1 group of 62.7 and 72.3% respectively contrasting to much lower cure fractions in the CD-2 (47.2 and 49.2%) and LB (30.8 and 45.0%) groups. Conclusions. We report excellent long-term outcomes in patients with GEP70 low risk MM and cure fractions in the range of 20-30%. Patients with LB and CD-2 subgroups have lower overall cure rates, despites similar initial 5-yr PFS rates compared to the superior performing CD-1 group, which can be explained by the occurrence of late relapses. Table 1 Disclosures van Rhee: EUSA: Consultancy; Adicet Bio: Consultancy; Takeda: Consultancy; Sanofi Genzyme: Consultancy; Kite Pharma: Consultancy; Karyopharm Therapeutics: Consultancy; Castleman Disease Collaborative Network: Consultancy. Walker:Celgene: Research Funding. Davies:Janssen, Celgene: Other: Research Grant, Research Funding; Amgen, Celgene, Janssen, Oncopeptides, Roche, Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Consultant/Advisor. Morgan:Amgen, Roche, Abbvie, Takeda, Celgene, Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Other: research grant, Research Funding. OffLabel Disclosure: anti-CD38 monoclonal antibody targeting myeloma

Description: Our systematic investigation on MYC (C-Myc) - a crucial pro-regeneration transcription factor - has determined that genetic aberrations (chromosomal rearrangements) and overexpression of the gene are highly prevalent in multiple myeloma (MM). At diagnosis, the rearrangements of MYC locus (8q24) were detected in 51% of MM patients using karyotyping and interphase FISH with DNA probe sets to MYC and the flank genomic sequences. The abnormalities of 8q24 in MM include monosomy (5%), amplification (≥3 copies; 13%), break-apart (14%), jumping (11%), and others (8%). Such aberrations were present in 49% of low-risk MM (183/376) and in 62% of high-risk MM (51/82) defined by the gene expression profiling cancer-risk model (GEP-70). The GEP also indicated that 74% of MM patients had excessively high levels of MYC overexpression. Nonetheless, there was no significant correlation between the MYC cytogenetic abnormalities and the levels of MYC expression in myeloma tumor cells - unlike the primary IGH translocations that drive transcriptional spikes of its partner genes. MYC expression by GEP was unable to precisely predict the presence of MYC chromosomal rearrangements in MM. In fact, the clinical outcomes of MM patients with MYC aberrations vs. the patients without detectable 8q24 events showed that neither the numerical variations nor the structural rearrangements of 8q24 had significant impact on the overall survival of patients who were treated on Total Therapy protocols. Further, we have shown that chromosomal rearrangements and the levels of MYC overexpression were not intrinsically relevant to the translation of MYC protein in myeloma. Importantly, the fate of myeloma cells was associated with the presence of two endogenous polypeptide-isoforms of MYC - the canonical MYC protein alias (P01106; 48.8kD) and an alternative MYC protein alias (alt-MYC; 〉 50kD). In newly diagnosed MM, P01106 was absent in most of the patients; whereas, it was a constitutive alias well maintained across the myeloma tumor cells from the patients with relapsed and progressive diseases and in all of the self-renewable myeloma cell lines. In contrast, alt-MYC alias was present as a stand-alone alias or co-existing with P01106 alias in newly diagnosed myeloma. Most importantly, both MYC aliases were absent in some cell lines and primary tumor cells suggesting cancer cell growth may not be dependent on any of MYC aliases despite of high levels of MYC transcription. Since the MYC gene originated from a viral integration, MYC mRNA has dual-translation features due to an internal ribosome entry segment (IRES) at 5'UTR. Previous studies have determined that the translations can be alternatively initiated from an in-frame CUG (Leucine) codon to generate NP_002458 alias or at a downstream canonical cap-dependent AUG (Methionine) codon to generate P01106 alias. Although these two aliases share identical C-termini, the translational switch can extend the N-terminal in NP_002458 alias. In vitro, the switch of P01106 to alt-MYC has resulted in cell growth arrest. Such alternation was induced by a transient gene transfection of P53 tumor suppressor (TP53); seemingly, the alternative MYC alias acts as an antagonist to P01106 in cell proliferation. Overall, it was generally unpredictable which of the MYC aliases were the dominant driver; therefore, MYC cytogenetic rearrangements and overexpression may have unknown indirect impacts on the outcomes. We are currently examining the precise amino acid sequences on both N-terminal and C-terminal ends of MYC aliases to study the regulatory mechanisms of the translational switching. This may indicate a novel anti-cancer strategy to cease cancer proliferation by deliberately inducing alternative translation of the antagonistic alias of an oncogene, and eventually overcome cooperation of the chromosomal rearrangements and dysregulated oncogene transcriptions in progressive cancer cells. Disclosures van Rhee: Adicet Bio: Consultancy; Karyopharm Therapeutics: Consultancy; EUSA: Consultancy; Castleman Disease Collaborative Network: Consultancy; Takeda: Consultancy; Sanofi Genzyme: Consultancy; Kite Pharma: Consultancy.