Smith, Sonali M.

Abstract Background:The role of radiation therapy (XRT) for advanced stage Hodgkin lymphoma (HL) is controversial. In the HD15 trial, the German Hodgkin Study Group (GHSG) administered XRT for PET-positive residual disease ≥2.5 cm at least 2 weeks after completion of chemotherapy and showed 91.5 % in-field control rate with a median follow-up of 102 months (Engert, A; personal communication). However, there is no comparison arm where patients with PET-positive residual disease ≥2.5 cm did not receive XRT. SWOG S0816 was a US intergroup trial utilizing ABVD-based therapy with response adaptation based on interim PET imaging; XRT was not allowed per protocol, and counted as an event. In this analysis, we identified patients in S0816 who would have met HD15 criteria for XRT, but did not receive XRT per design. We then modeled the potential impact of XRT on disease control. Patients and Methods:Of 336 eligible and evaluable HIV-negative patients enrolled in S0816, 49 had an end-of-treatment PET (termed "PET3," to be done 6-8 weeks after completion of chemotherapy) that was positive (i.e. Deauville 4-5) upon central review. We simulated the progression free survival (PFS) if XRT had been delivered per HD15 criteria (PET positive disease and ≥2.5 cm), evaluating by assumptions of 50, 80 and 90% control of the disease within the XRT fields. Receiver operating characteristics (ROC) analyses were performed with additional size cut-off points of 2.0 and 1.5 cm. Results:The median follow-up for the 49 PET3 positive patients was 71 months (range 9.7-92.6). For these 49 patients, the observed landmark PFS at 2 years after the date of PET3 was 30.6%. Twenty-four (49%), 33(67%), and 40 (82%) of the 49 patients had at least one site of disease that met the HD15 criteria for XRT with ≥2.5 cm, ≥2.0 cm, and ≥1.5 cm size cut-offs respectively. Sixteen, 19, and 25 patients had disease progression respectively from each group at median of 1.4-1.5 months. Twelve, 12, and 15 patients had relapses limited to the sites that would have been radiated following HD15 criteria with ≥2.5 cm, ≥2.0 cm, and ≥1.5 cm respectively. Estimated landmark PFS at 2 years for the 49 PET3 positive patients assuming 50, 80, and 90 % control of the disease within the radiated sites following HD15 guideline with ≥2.5 cm, ≥2.0 cm, and ≥1.5 cm cut-off are summarized in columns A, B, and C of the table respectively. For the entire group of 336 patients, the observed PFS at 2 years was 79%. Estimated 2-year PFS for the entire group of 336 patients assuming 50, 80, and 90 % control of the disease within the radiated sites following HD15 guideline with ≥2.5 cm, ≥2.0 cm, and ≥1.5 cm cut-off are in columns D, E, and F of the table respectively. Conclusion: Among the PET3 positive patients, consolidation XRT per HD15 criteria with cut-off points of 2.5, 2.0, and 1.5 cm could have raised the 2-year PFS by 12-28 % assuming 50-90% local control within radiated sites. However, the improvement in PFS is more moderate at 1.6-3.9 % if we consider the entire cohort of 336 patients. Although there may be some gain in PFS as the cut-off point is lowered by our ROC analysis, one needs to consider the trade-off against potentially increasing normal tissue toxicity as more sites are irradiated. Table. Table. Disclosures Brem: Pharamcyclics: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Genetech: Membership on an entity's Board of Directors or advisory committees; Celgene: Speakers Bureau; Bayer: Membership on an entity's Board of Directors or advisory committees. Bartlett:Merck & Co: Research Funding; Forty Seven: Research Funding; Celgene: Research Funding; Immune Design: Research Funding; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; ImaginAB: Research Funding; Janssen: Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Acerta: Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Millennium: Research Funding; Genentech: Research Funding; Astra Zeneca: Research Funding; Pharmacyclics: Research Funding; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Meyers Squibb: Research Funding; Affimed: Research Funding; Novartis: Research Funding; Pharmacyclics: Research Funding. Evens:Seattle Genetics, Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Affimed: Consultancy; Janssen: Consultancy; Tesaro: Research Funding; Bayer: Consultancy; Acerta: Consultancy; Pharmacyclics International DMC: Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy. Rimsza:NanoString: Other: Inventor on the patent for the Lymph2Cx assay. Leonard:Novartis: Consultancy; Celgene: Consultancy; MEI Pharma: Consultancy; AstraZeneca: Consultancy; ADC Therapeutics: Consultancy; United Therapeutics: Consultancy; BMS: Consultancy; Biotest: Consultancy; Sutro: Consultancy; Karyopharm: Consultancy; Juno: Consultancy; Gilead: Consultancy; Genentech/Roche: Consultancy; Pfizer: Consultancy; Bayer: Consultancy. Kahl:Seattle Genetics: Consultancy; Genentech: Consultancy; Acerta: Consultancy; AstraZeneca: Consultancy; Abbvie: Consultancy; ADC Therapeutics: Consultancy; CTI: Consultancy; Gilead: Consultancy; Juno: Consultancy; Celgene: Consultancy. Smith:BMS: Consultancy; Portola: Honoraria. Friedberg:Bayer: Honoraria.

Abstract Abstract 879 Background: Several solid organ transplant (SOT) PTLD series have reported that PCNS disease is a poor prognostic factor (e.g., Leblond et al, JCO 2001; Maeker et al, JCO 2007; Knight et al JCO 2009; Evens et al, JCO 2010). However, these reports contained small PCNS PTLD numbers and most series studied patients (pts) in the pre-rituximab era. Methods: We performed an International retrospective analysis of PCNS SOT-related PTLD diagnosed from 1998 through 2010. Cases with secondary CNS localization were excluded. Detailed pt and disease characteristics, including frontline therapy, were evaluated. Fisher's exact test was used to compare PCNS PTLD vs non-PCNS PTLD cases. Further, univariate associations with survival were determined, while a multivariate Cox regression proportional hazards model was performed. Results: 71 PCNS PTLD cases were identified, of which 65 had complete data. There were 35 men and 30 women; the median age was 53 years (range, 20–77 years). The most common type of SOT was kidney in 72%, followed by lung 18% and 5% each pancreas and heart. The median time from SOT to PCNS PTLD was 46 months (range, 2 to 504 months). Further, only 18% occurred within 12 months of SOT, and 32% of PTLD diagnoses occurred > 10 years after SOT. 85% of pts had received prior mycophenolate, while 30% received tacrolimus prior to PCNS PTLD. According to WHO histology, 83% of PCNS PTLD cases were monomorphic subtype (all B-cell), while tumor was EBV+ in 93% despite EBV being detectable in the peripheral blood (by PCR) in only 38% of these cases. In addition, 49% of pts had poor performance status (i.e., 2–4), 48% had elevated LDH, and 48% were hypoalbuminemic at diagnosis. Interestingly, several of these characteristics were notably different when compared with a non-PCNS PTLD cohort (Table 1A). All pts here presented with CNS-related symptoms and 98% had abnormal findings on MRI showing a parenchymal brain lesion(s); 50% of pts had >1 CNS lesion and 40% had involvement of deep regions of the brain. Further, 12% had concomitant CSF involvement, while no pts had ocular involvement. In terms of therapy, 89% of pts had reduction in immunosuppression (RI). Additional frontline therapy consisted of high dose methotrexate (HD-MTX)-based therapy in 43% (46% of whom also received concurrent rituximab), whole-brain radiation in 20% (61% with rituxmab), high-dose cytarabine (HDAC)-based in 15% (30% with rituximab), while 11% received rituximab alone and 11% had no other therapy (i.e., RI alone). Altogether, 48% of pts received rituximab as part of initial therapy. The overall response rate (ORR) was 55% with 30% complete remission (CR) rate. With a median follow-up of 39 months (1–135), the 3-year progression-free survival (PFS) and overall survival (OS) for all pts were 31% and 32%, respectively (Figure 1). Pts who received rituximab vs not as a component of first line therapy had superior PFS (40% vs 22%, respectively, p=0.02) and borderline improved OS (43% vs 22%, respectively, p=0.06), while pts who did not receive rituximab nor HD-MTX-based therapy as frontline therapy did particularly poor (PFS and OS both 10%). Several pre-treatment and treatment-related factors predicted survival on univariate analysis (Table 1B). When analyzing only pre-treatment related factors in the Cox multivariate regression model, only increasing age remained significant (PFS: HR 1.04 [95%CI 1.00–1.07], p=0.031; and OS: HR 1.04 [95%CI 1.01–1.08], p=0.020). With treatment-related factors included in the model, response to frontline therapy (CR or partial remission) was the dominant predictive factor of survival on multivariate analysis (PFS: HR 0.136 [95%CI 0.047–0.390], p=0.0002; and OS: HR 0.130 [95%CI 0.045–0.381], p=0.0002). Conclusion: These data represent the largest report of PCNS PTLD to date. PCNS PTLD appears to represent a distinct biologic and clinical entity within the PTLD spectrum that retains EBV positivity, occurs late, and presents with additional high-risk features. Furthermore, outcome of PCNS PTLD remains overall modest. However, these data suggest that rituximab and HD-MTX appear to favorably impact survival. Continued study of this subset of pts is critically needed. Disclosures: No relevant conflicts of interest to declare.

Abstract Background Despite improvements in outcome following the addition of rituximab (R) to CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) (R-CHOP), patients with newly diagnosed diffuse large B-cell lymphoma (DLBCL) and International Prognostic Index (IPI) scores of 3-5 at diagnosis have a poor outcome. Enzastaurin is a potent inhibitor of PKCβ, a component of the B-cell receptor signaling complex, with preclinical activity and clinical activity in a phase II trial in patients with relapsed DLBCL, providing the rationale for this study in the primary therapy setting. Methods PRELUDE was a multi-national, randomized, double-blinded, placebo-controlled study. Patients were required to have a histologic diagnosis of DLBCL, pre-treatment IPI score ≥3, and a complete response (CR) or CRu by International Working Group Criteria, or a negative FDG-PET scan after 6–8 cycles of R-CHOP. Patients were randomly assigned in a 2:1 ratio to receive either enzastaurin 500 mg daily or an identical placebo as maintenance therapy, for a planned treatment duration of 3 years. The primary endpoint was DFS, defined as lack of disease progression or death. Assuming a 2-year DFS rate in the control group of 70%, the primary analysis had 80% power to detect a HR of 0.67, eg, a 2-year DFS rate of 79% in the enzastaurin group. Secondary endpoints included overall survival (OS) and event-free survival (EFS). Data were analyzed 3 years after the last enrolled patient initiated treatment. Results From May 2006–April 2010, 758 patients were enrolled (enzastaurin, n=504; placebo, n=254). Median age at enrollment was 64 years (range 21-89); at diagnosis, 65% of patients had stage IV disease, 48% had B symptoms, and 25% had a mass >10 cm; baseline disease and patient characteristics were well balanced between treatment arms. Fifty-seven percent had a negative PET scan following completion of R-CHOP. Median follow-up time for all patients was 48 months (range 0.03–80). At the time of analysis, 209 events had occurred. The DFS HR for enzastaurin vs. placebo was 0.92 (95% CI: 0.69, 1.22; 2-sided log-rank p=0.54). DFS at 24 and 48 months were 79% and 70% for the enzastaurin arm, and 75% and 71% for placebo, respectively. OS at 24 and 48 months was 87% and 81% for enzastaurin, and 89% and 82% for placebo; HR for enzastaurin vs. placebo was 1.04 (95% CI: 0.74, 1.47; 2-sided log-rank p=0.81). Percent of ITT population patients on therapy at 12, 24, and 36 months was 70.6%, 60.6%, and 20.1% for enzastaurin; 72.3%, 60.6%, and 22.1% for placebo. Biomarker subgroup analysis was performed and will be available at time of presentation. Treatment emergent AEs (all grades) that were possibly study drug-related and significantly different between enzastaurin and placebo included chromaturia (18.5% vs. 0.4%), QTc prolongation (10.8% vs. 3.6%), and diarrhea (10.3% vs. 2.8%). There were no significant differences in number of patients with at least 1 grade 3 or higher AE between treatment arms. No significant differences were observed in the frequency of deaths while on therapy. Conclusion Enzastaurin did not improve DFS, EFS, or OS in patients with high-risk DLBCL and CR following R-CHOP treatment. Disclosures: Crump: Roche: Honoraria; Jansen-Ortho: Honoraria; Celgene: Honoraria; Lundbeck: Honoraria; Novartis: Research Funding; Seattle Genetics: Honoraria. Off Label Use: rituximab for maintenance therapy post autolgous transplant for lymphoma. Leppä:Eli Lilly: Research Funding. Ogura:Eli Lilly: Research Funding. Rifkin:Millenium, Celgene, ONYX: Membership on an entity’s Board of Directors or advisory committees. Mackensen:Eli Lilly: Consultancy. Offner:Eli Lilly: Membership on an entity’s Board of Directors or advisory committees. Smith:Genentech, Celgene, Spectrum, Seattle Genetics, Gilead, Amgen/Micronet: Consultancy. Tobinai:Eli Lilly: Research Funding. Hahka-Kemppinen:Eli Lilly: Employment. Thornton:Eli Lilly: Employment. Shi:Eli Lilly: Employment. Lin:Eli Lilly: Employment. Kahl:Genentech: Consultancy. Savage:Eli Lilly: Consultancy.

Abstract Abstract 2877 Background: Racial disparity has been well documented in a number of cancers but the impact of race on CLL in the contemporary era is unclear. While preliminary evidence suggests that Black (B) patients (pts) have worse survival than their White (W) counterparts (Shenoy et al, Clin Lymph Myleoma Leuk, 12/2011), the importance of sex, age, socioeconomic status (SES), and whether the wide use of single use or combined therapy with R in CLL over the last decade plus has affected overall survival (OS) have not been fully explored. Further, outcome of Hispanic (H) and Asian/Pacific Islanders (A/PI) CLL pts has not been fully studied. Methods: We examined population based survival data from SEER 13 (1993–2008) for CLL within and across various races. We also investigated the impact of sex, age, and socioeconomic status (SES) on their clinical outcome. Outcomes were examined over two consecutive 8-year (yr) periods: Era-1 (1993–2000) and Era-2 (2001–2008) with the assumption of R therapy in CLL patients being more frequent after 2001 (market research data not shown). Results: We identified 24,964 pts [W =21,363 (85.5%), H =1,197 (4.7%), B =1,709 (6.8%), and A/PI =695 (2.7%)]. Differences were notable for a greater male predominance among A/PI [62% vs. 57% (B), 56% (H), 58% (W); P=0.03]; a higher proportion of pts >80 among W [22% vs. 17% (H), 15% (B), 16% (A/PI); P<0.001], and higher SES among A/PI and W pts compared to B and H (P<0.001). OS for all patients was significantly better in Era-2 vs. Era-1 at 5-yrs (65% vs. 60.4%, P<0.0001). This improvement was statistically significant in all races except A/PI pts (P=0.71) (Table). Improved survival across eras was also noted in all age groups (<50 (P<0.00001), 50–59 (P=0.007), 60–69 (P<0.0001), 70–79 (P<0.0001), >80 yrs (P<0.0001)). Further, improved OS was noted in the two SES classes evaluated (0–15% and 15.1–30% below poverty line respectively). While there were no statistical differences between males and females within either era, improvement in OS was noted in both sexes in Era-2 versus Era-1 (P<0.0001). We subsequently compared OS within and across races (Table). Despite the fact that OS improved in all races, W pts continued to have better OS in Era-2. In Era-1, while W pts had better OS than B and H pts, the OS is similar between W and A/PI. Although OS improved in all SES classes, patients with higher SES continued to have better OS in Era-2 (P<0.0001 for both). Conclusions: The OS of CLL pts has improved in the contemporary era for both sexes, all age groups, and all races except A/PI individuals. The improvement in outcome in Era-2 might be partially explained by increased use of R and other novel agents that became available after 2001. Despite the broad nature of these improvements, racial and SES differences in the survival persist and deserve further validation and pursuit of the causes. Disclosures: Shanafelt: Genentech: Research Funding; GlaxoSmith Klein: Research Funding; Teva/Cephalon: Research Funding; Celgene: Research Funding. Kay:Genentech: Research Funding; Glaxosmith Klein: Research Funding.

Abstract Background: We recently clarified the use of consolidative autologous stem cell transplantation (ASCT) as first remission consolidation therapy for high grade diffuse aggressive T and B non-Hodgkin's lymphoma (NHL)in patients with high-intermediate (HI) or High (H) age adjusted IPI disease (Stiff et al, NEJM 369:1681). After receiving CHOP or R-CHOP for 5 cycles responding patients were randomized to either 3 more induction cycles or 1 cycle followed by an ASCT using either a BCNU or TBI based preparative regimen. We found a PFS but not OS advantage for those randomized to transplant and no differential treatment effect for those with T-NHL patients as compared to B-NHL in the initial analysis of this study. In light of Phase II data suggesting a value of early ASCT for T-NHL, a lack of randomized ASCT trials for T-NHL and the inferior prognosis for T-NHL as compared to B cell disease, we further evaluated this sub group, since a post hoc analysis of the entire trial did find a survival advantage for those with H IPI disease. This then provided a unique opportunity to evaluate the role of ASCT consolidation for T-cell NHL in the setting of a prospective randomized trial. Method: Among the 370 eligible B-NHL and T-NHL patients with HI/H IPI disease treated on this trial, 40 had a T-NHL phenotype and were the subject of this analysis. Individual patient files were re-reviewed and those randomized after the first 5 cycles of CHOP were further analyzed for stage, IPI group, histology (centrally reviewed), and response to induction and consolidation and updated survival outcome. Results: Of the 40 T-NHL patients enrolled on study, 28 (70%) were randomized after induction therapy, a similar ratio to the entire trial (68%). Twelve were not randomized; 1 was ineligible for study, and of the eligible 11, 9 were HI IPI and 8 had peripheral T cell (PTCL-NOS). These 11 were not randomized due to patient choice in 2, and all of the remaining 9 pts progressed early: 2 after C1; 3 after C3, 1 after C4, and 3 after C5. For the 28 randomized, their median age was 50 and 19 were males. Of the group, 21/28 had B symptoms at diagnosis, 14 had stage IV disease, and 18 and 10 were in the HI and H IPI groups respectively. Histologies included 11 with PTCL-NOS, 7 angioimmunoblastic and 10 anaplastic large cell NHL. At randomization 13 were to continue CHOP and 15, ASCT. Of the 15 assigned to ASCT, 3 did not undergo transplant (2-refusals, 1- unable to mobilize); 7 received the BCNU-etoposide-cyclophosphamide and 5 the TBI-etoposide-cyclophosphamide preparative regimen. The 5 year estimates of PFS and OS for the randomized ASCT vs CHOP only groups (intent to treat) were 40% vs 38% (p=0.56) and 40% vs 45% (p=0.98) respectively. We found no difference in outcome based on IPI group, histology or stage of disease. Interestingly, only 1/7 patients who received BCV as the ASCT preparative regimen are long term survivors vs 4/5 receiving the TBI-based regimen. Conclusions: We did not observe a PFS/OS advantage for those with high-risk T-NHL in first remission randomized to ASCT following CHOP induction vs CHOP alone in this retrospective analysis. In addition, the 30% early drop out rate before randomization due primarily to early progression strongly suggests that more optimal induction regimens need to be developed for this disease. While the numbers are small the finding that TBI based preparative regimens might be associated with a higher PFS is of interest and deserves further study. Support: NIH/NCI grants CA180888 and CA180819; Bristol-Myers Squibb. Contributions of Dr. Raymond R Tubbs, deceased, are gratefully acknowledged. Figure 1 Figure 1. Disclosures Porcu: miRagen: Other: Investigator in a clinical trial; celgene: Other: Investigator in a clinical trial; Millenium: Other: investigator in a clinical trial; Innate Pharma: Other: Investigator in a clinical trial. Winter:Pharmacyclics: Research Funding; Medivation: Other: Provision of investigational agent for clinical trial; Seattle Genetics: Research Funding; GSK: Research Funding. Kahl:This study was coordinated by the ECOG-ACRIN Cancer Research Group (Robert L. Comis, MD and Mitchell D. Schnall, MD, PhD, Group Co-Chairs) and supported by the National Cancer Institute of the National Institutes of Health under the following award number: Research Funding. Smith:Juno: Consultancy; TGTX: Consultancy; AbbVie: Consultancy; Celgene: Consultancy; Genentech: Consultancy, Other: on a DSMB for two trials ; Gilead: Consultancy; Portola: Consultancy; Amgen: Other: Educational lecture to sales force; Pharmacyclics: Consultancy. Rimsza:NCI/NIH: Patents & Royalties: L.M. Rimsza is a co-inventor on a provisional patent, owned by the NCI of the NIH, using Nanostring technology for determining cell of origin in DLBCL.. Fisher:Gilead: Consultancy; Seattle Genetics: Consultancy; Johnson and Johnson: Consultancy. Friedberg:Bayer: Honoraria, Other: Data Safety Monitoring Board.

AbstractThe investigators present results on the long-term value and limitations of early interim positron emission tomography (PET) scanning in advanced Hodgkin lymphoma.

Background:With an expanding array of novel treatment options in follicular lymphoma (FL), we largely lack effective biomarkers to predict response in this molecularly heterogeneous disease. Activating mutations focused on components of the nutrient‐sensing arm of the mTORC1 pathway (RRAGC, ATP6V1B2, ATP6AP1), are particularly enriched in FL, occurring in ∼30% of cases. Meanwhile, clinical mTOR inhibitors (mTORi) have shown some promise, with response rates of 50–60% in relapsed/refractory FL.Aims:We therefore sought to determine whether gene mutation status ‐ particularly in genes regulating the mTOR pathway – may represent biomarkers of mTORi‐response in FL.Methods:We retrospectively analyzed pre‐treatment tumor samples from relapsed/refractory FL patients treated on two phase II clinical trials with single agent mTOR inhibitors, everolimus (NCT00436618) or temsirolimus (NCT00290472), with well characterized clinical outcomes. In total, 21 patients had available biopsies, consisting of 15 everolimus‐ and 6 temsirolimus‐treated cases.Tumor DNA extracted from formalin fixed paraffin embedded (FFPE) tissue was subjected to targeted sequencing using a 22 gene panel comprising genes recurrently mutated in FL, and PI3K/AKT/mTOR pathway genes mutated in germinal center lymphomas. Libraries were prepared using capture‐based target enrichment (Nonacus), and sequenced on the NextSeq550 (Illumina) with a mean coverage depth of x700. A stringent bioinformatic pipeline was adopted with variants called with VarScan2, and a 10% variant allele frequency (VAF) threshold was employed to filter out sequencing artefacts due to the FFPE material. 100% (15/15) of a selection of variants were validated by Sanger sequencing. Staining for pS6 was undertaken on tissue slides to examine downstream mTOR activation by immunohistochemistry.Results:Overall response rate (CR and PR) was 48% (10/21). Mutational analysis showed no significant association between clinical response and mTORC1‐pathway mutations (mut) taken individually or collectively; although, absolute numbers of mutations in these genes were low, including RRAGC (responder: 0/10 mut vs non‐responder: 1/11 mut), ATP6AP1 (responder: 1/10 vs non‐responder: 1/11), and ATP6V1B2 (responder: 1/10 vs non‐responder 3/11). Notably, no difference in pS6 staining was seen between responders and non‐responders.However, we found mutations in the epigenetic regulator CREBBP to be enriched in the responder group (100% (10/10) responders vs 54.5% (6/11) non‐responders, p = 0.04). This effect was more pronounced when considering only mutations within the catalytic histone acetyltransferase (HAT) domain of CREBBP, with HAT mutations seen in 100% (10/10) responders, and 27.3% (3/11) non‐responders (p = 0.001).Summary/Conclusion:Mutations in the mTOR pathway did not predict for response to mTOR inhibition in our study. The enrichment of CREBBP mutations in responders, and particularly those affecting the catalytic HAT domain, points to CREBBP as a potential biomarker of response which warrants validation in trials of drugs modulating the PI3K/AKT/mTOR axis. More broadly our data may lend support to a distinct clinical and biological behavior of CREBBP HAT domain‐mutant disease that also warrants further evaluation. Taken together, our findings highlight the potential opportunities afforded by undertaking correlative studies, and underlines the need to incorporate prospective biomarker discovery into clinical trials in order to help focus future therapeutic strategies more rationally.

Abstract Serum soluble chemokines/cytokines produced by Hodgkin cells and the tumor microenvironment might be of value as biomarkers in classic Hodgkin lymphoma (cHL). We assessed serum thymus and activation-related chemokine (TARC), macrophage-derived chemokine (MDC), interleukin-10 (IL-10), and soluble CD163 (sCD163) levels at baseline, time of interim fluorodeoxyglucose positron emission tomography (PET), and after therapy in cHL patients treated on S0816, an intergroup phase 2 response-adapted study evaluating escalated therapy for interim PET (PET2)–positive patients (www.clinicaltrials.gov #NCT00822120). Epstein-Barr virus (EBV) status was assessed, and 559 serum samples were evaluated for TARC, MDC, IL-10, and sCD163 by immunoassay. EBV positivity correlated with higher sCD163 and IL-10 levels but lower TARC levels. While baseline biomarker levels were not associated with outcome, sCD163 levels at the time of PET2 were associated with favorable progression-free survival (PFS), adjusting for PET2 status. After therapy TARC, MDC, and IL-10 correlated with PFS and overall survival (OS) on univariable analysis, which remained significant adjusting for international prognostic score. When also adjusting for end-of-therapy PET results, TARC and IL-10 remained significantly associated with shorter PFS and OS. Exploratory analysis in PET2-negative patients showed that elevated posttherapy TARC and IL-10 levels were associated with PFS. Serum cytokine levels correlate with outcome in cHL and should be investigated further in risk-adapted cHL trials.