MAGE-A3 or NY-ESO1 Expression and Spontaneous Antibody Responses to NY-ESO1 in Newly Diagnosed Multiple Myeloma Patients Are Associated with Worse Overall Survival

Abstract The cancer-testis antigens (CTA) are highly immunogenic antigens expressed in various tumors but not in normal tissues (except during gametogenesis), making them an attractive target for cancer immunotherapy. Expression of CTAs such as MAGE-A3, MAGE-C1 (CT7), MAGE-C2 (CT10), NY-ESO1 and the SSX antigens has been previously reported in multiple myeloma (MM). To date, however, these reports have included a heterogeneous group of newly diagnosed and relapsed/refractory patients, all in different stages of treatment. Therefore, the extent and prognostic significance of CTA expression, and of de novo immune responses against CTA in newly-diagnosed MM patients are not known. We now report on both CTA expression and antibody responses in MM patients at diagnosis and on their prognostic significance. From 8/00-11/04, we treated 67 newly-diagnosed, symptomatic patients with a thalidomide, doxorubicin, and dexamethasone-based induction regimen. (Brit J Haematol 2006; 132:155). Median age was 58; 54% were ISS stage I, 28% ISS II, and 18% ISS III. Nine of 63 tested (14%) had deletion 13q by FISH, while 24% had soft tissue involvement by MM. Responses to induction therapy included 10 (15%) CR, 16 (24%) VGPR, 26 (39%) PR, 6 (8%) stable or progressive disease, and 9 (13%) inevaluable. Post-induction 54 underwent autoSCT and 9 also underwent alloSCT.. Median overall survival (OS) has not been reached with 61% alive at median follow up of 65 months. Cryopreserved pre-treatment bone marrow plasma cells were used to assess CTA expression by RT-PCR. Pre- and post-treatment sera were used to assess antibody (Ab) responses against CTA proteins by ELISA. Fifty-two patients had sufficient RNA for PCR, and 46 had baseline serum for ELISA. OS of these groups did not differ significantly from the entire cohort. At least 1 CTA was expressed in 77% of cases, including MAGE-A3 (52%), SSX1 (40%), CT7 (29%), CT10 (25%), NY-ESO1 (21%), and SSX5 (17%). Three or more CTA were expressed in 29% of cases. Individually MAGE-A3 or NY-ESO1 expression at diagnosis conferred a poorer prognosis (MAGE-A3: median OS 66 mos. vs. not reached, p=0.02 by log-rank; NY-ESO1: median OS 65 mos. vs. not reached, p=0.09). These poorer outcomes were independent of ISS stage, presence of del 13q, or response to induction therapy. No other CTA was associated with an OS difference, nor was the total number of CTA expressed prognostically significant. Baseline Ab responses, all at titers > 1:1600, were noted to NY-ESO1 in 6/46 (13%) patients, 5 of whom also had Ab to the NY-ESO1 homologue LAGE-1. Ab responses were also noted to CT7 (n=2), CT10 (n=1) and SSX4 (n=1). No Ab responses were noted to MAGE-A3. The effect of induction therapy on antibody titers was inconsistent, with increases, decreases, and no changes seen. Interestingly, 2 of the 6 NY-ESO1 Ab+ patients had no NY-ESO1 expression in bone marrow plasma cells. Both, however, had extensive soft tissue (ST) plasmacytomas, suggesting another source of NY-ESO1 antigen. Presence of NY-ESO1 Ab correlated significantly with baseline ST involvement, with 67% of Ab+ patients having ST disease compared with 20% of Ab− patients (p=0.05). NY-ESO1 Ab+ patients also had significantly poorer OS (med 21 mos. vs. not reached, p=0.009), independent of other prognostic factors. In sum, CTA expression is frequent in newly diagnosed MM patients, and expression of MAGE-A3 or NY-ESO1 is associated with worse long-term survival. Spontaneous antibody responses against NY-ESO1 are seen in untreated patients, and are associated with ST involvement and poorer survival. Further exploration of biologic differences between CTA+ and CTA-MM, as well as immunotherapeutic strategies which target these antigens, are warranted.