Immunotherapy for Cancer! Kara L. Davis, D.O.! Anne T. and Robert M. Bass Endowed Faculty Scholar in Pediatric Cancer and Blood Diseases! Assistant Professor of Pediatrics! Bass Center for Childhood Cancer and Blood Disorders! Stanford University! ! Objectives! • Childhood leukemia leads the way for targeted T- cell therapies! • What are chimeric antigen T cells! • Use in heme malignancies and solid tumors! • Limitations in Efficacy! • Toxicity concerns! • Immune Checkpoint Inhibition for anti-cancer effect! • Successes and Challenges! Childhood Leukemia was universally fatal 100 years ago! Gittins, Arch. Dis Child, 1933! Now childhood leukemia is a poster child for success in cancer treatment! Pui et al, NEJM 2006! Survival after relapse from childhood ALL K Nguyen et al 2147 Table 4 Univariate analyses of risk factors associated with survival after relapse Univariate analyses of survival post 5-year survival rates P-value relapse risk factors (N 1961) post relapse±s.e. (%) ¼ Time to relapse Early 21.0±1.8 o0.0001 Intermediate 37.9±2.7 Late 53.1±3.9 Relapse site Isolated marrow 24.1±2.1 o0.0001 Concurrent marrow 39.4±5.0 Isolated CNS 58.7±3.2 Isolated testicular 58.0±8.2 Other extramed±CNS 55.9±9.9 Figure 2 Kaplan–Meier estimates of survival after relapse for patients Age group stratified by NCI risk group at diagnosis and timing of relapse. There o1 year 19.8±4.4 o0.0001 were significant differences in outcome for those SR vs HR patients 1–9 years 45.0±2.1 experiencing either an early (33.1±3.6 vs 14.9±2.1%, Po0.0001), 10+ years 18.2±2.8 intermediate (52.2±3.7 vs 22.0±3.9%, Po0.0001) or late relapse (59.6±4.6 vs 39.5±7.2%, Po0.0001). Trial era But relapsed leukemia is still a bigEarly problem! 36.2±1.9 0.66 Late 36.6±3.1 Sex Male 35.4±2.2 0.51 • OverFemale time, from 38.0±2.5 Lineage 1988-2002B studies 37.2±2.1 o0.0001 addressingT relapsed23.0 ±ALL4.0 CNS status at diagnosis haveCNS-3 not improved 14.5±4.5 o0.0001 CNS-2 and CNS-1 37.7±1.7 outcomes ! WBC o50 k 41.6±2.0 o0.0001 X50 k 24.3±2.6 Race White 38.5±2.0 0.02 Hispanic 30.5±3.8 Figure 3 Kaplan–Meier estimates of survival after relapse for patients Black 30.1±5.9 stratified by treatment era and timing of relapse. There was no Other Nguyen et al, Leukemia,38.1±6.9 2008! difference in survival between early and late trials among patients who ± ± experienced an early relapse (19.3 2.1 vs 23.4 3.4%, P 0.10), or NCI risk intermediate relapse (39.3±3.3 vs 36.0±4.8%, P 0.49)¼ or late Standard 50.4±2.4 o0.0001 relapses (53.3±4.3 vs 54.4±9.2%, P 0.66). ¼ ¼ High 22.6±2.1 CCG-1952, CCG-1953, CCG-1961 and CCG-1962. A total of Abbreviations: CNS, central nervous system; NCI, National Cancer 1961 children were included in this analysis (Figure 3). The Institute; WBC, white blood cells. results demonstrated that patients who relapsed early had dismal survival regardless of treatment era (5-year post-relapse survival: 19.3±2.1 vs 23.4±3.4%, P 0.10). Similarly, there were no diagnosis were excluded from the multivariate analyses, as they ¼ statistically significant differences in survival between those cannot be classified by NCI risk group. Age at diagnosis, CNS treated on early and late trials, for patients experiencing either disease, sex, lineage and NCI risk group were significant an intermediate (39.3±3.3 vs 36.0±4.8%, P 0.49) or late predictors of survival post relapse. Trial era, WBC at diagnosis ¼ relapse (53.3±4.3 vs 54.4±9.2%, P 0.66). and race were not significant in predicting survival in the ¼ Univariate analyses (n 1961) were conducted to study the multivariate analysis. Multivariate analyses stratified for time ¼ association of presenting clinical and laboratory features at to relapse, the site of relapse and age at diagnosis resulted in initial diagnosis, time to relapse and the site of relapse with the same significant predictors as before. Trial era, WBC at survival post relapse (Table 4). Significant associations were diagnosis and race were not significant factors. found with site and timing of relapse, age at diagnosis, WBC at diagnosis, lineage (B vs T), CNS status at diagnosis, race and NCI risk; exceptions were trial era and sex. Multivariate analyses Discussion stratified by timing of relapse and the site of relapse were conducted on the subset of patients (n 1391) with complete Despite improved treatments and increasing dose intensity in ¼ data for all the variables (Table 5). Infants o1 year of age at primary therapy for newly diagnosed patients with ALL, patients Leukemia The search for surface targets in B cell cancers! Piccaluga et al., Leuk & Lymphoma 2010! What is a CAR-T cell?! ! VH! V V VL scFv! L! H! α β ε δ ϒ ε + TM! . CD28/41BB! ζ ζ costim CD3#! Monoclonal antibody! T-cell Receptor! Chimeric Antigen Receptor! How CAR-T cells work…! T cell! Tumor cell! CAR enables T cell to Expression of recognize tumor cell CAR! antigen! Viral DNA! Insertion! Antigen! Tumor cell CAR T cells! apoptosis! multiply and release cytokines! Courtesy of David Miklos! Timeline of Development! CAR T cells: CAR design impacts function! Therapeutic Advances in Hematology 6(5) First generation CAR Second generation CAR Third generation CAR ScFv antigen-binding domain VH VH VH V V V L L L hinge linker Costim C Costim C CD3 ‘first signal’ ‘first signal’ ‘first signal’ CD28 CD137 (4-1BB) 1 1 Costim C CD3 CD27 CD28 ‘second signal’ ‘second signal’ CD134 (OX40) 2 CD137 (4-1BB) CD3 ‘third signal’ Tasian et al., Ther Adv Hema, 2015! Figure 1. Generations of chimeric antigen receptors (CARs) utilized in clinical testing. Constructs encoding synthetic CARs targeting tumor-associated antigens (such as CD19) can be stably transduced into human T cells for infusion into patients with relapsed/refractory cancer. CARs are comprised of (1) an extracellular MHC- independent antigen-binding domain usually derived from a monoclonal antibody single chain variable fragment (ScFv), (2) an extracellular spacer domain or ‘hinge’ (in some CARs), (3) a transmembrane linking domain and (4) an intracellular co-stimulatory T cell signaling domain or multiple domains. With increased understanding of the critical Given the potential for clinically significant CAR importance of the intracellular ‘second signal’ T-cell induced toxicities (discussed below), opti - activation for CAR T-cell efficacy, subsequent mal CAR design thus must carefully balance generations of CARs have optimized ScFv and desired antitumor potency with minimization of linker component design and, more importantly, hazardous side effects [Gardner and Jensen, 2014]. have incorporated additional intracellular costim- ulatory signaling domains [e.g. CD27, CD28, Various groups have focused intensively in the past CD134 (OX40), CD137 (4-1BB)] in efforts to decade on targeting the B-lymphocyte antigen, increase the expansion, persistence and potency CD19, a phosphoglycoprotein ubiquitously of CAR T cells, as well as to prevent cellular expressed on malignant and nonmalignant B-cells. exhaustion in vivo (Figure 2). Based upon the clinical efficacy and apparent toler- ability of targeting CD20 (another commonly Most CARs used in current clinical trials of engi- expressed B cell antigen) with the anti-CD20 mon- neered T cells for patients with B-ALL are derived oclonal antibody rituximab in patients with B-cell from second generation constructs with CD3ζ hematologic malignancies [Cramer and Hallek, and another signaling endodomain. Delivery of a 2012], it was hypothesized that the CD19 receptor second costimulatory signal has indeed appeared could be similarly targeted with engineered T cells to induce significantly greater T-cell expansion expressing a CD19-redirected CAR and that treat- and longer-term persistence in vivo to date in ment with these CD19 CAR T cells would also be treated patients. ultimately tolerable in patients [Cooper et al. 2004; Kochenderfer and Rosenberg, 2013]. Third generation CAR constructs comprised of CD3ζ and two additional co-stimulatory endodo- In preclinical studies, several research teams mains transduced into T cells are also under clini- observed that co-incubation of CD19 CAR T cells cal evaluation, but have not thus far resulted in with B-cell leukemia or lymphoma cell lines greater efficacy than second generation CARs induced potent T-cell degranulation, cytokine [Davila et al. 2012; Sadelain et al. 2013; Kenderian production and tumor cytotoxicity in vitro. et al. 2014; Mackall et al. 2014]. Furthermore, treatment of human ALL cell 230 http://tah.sagepub.com Design affects Function! CD19-CD28-Zeta CD19-41BB-Zeta V V H Anti-CD19 H Anti-CD19 VL VL NCI! TM vs. TM UPENN! KITE! NOVARTIS! MSKCC! CD28 4-1BB! SEATTLE! JUNO (JCAR015)! JUNO (JCAR017)! CD3ζ CD3ζ Persist less than 3 months Persist 6 months or more in most patients in most patients Increased Persistence of CD19.BB.z vs CD19.28.z CAR in Clinical TrialsCD19-CAR! 100000 CD19.28.z-Bethesda CD19.BB.z-Penn 10000 1000 100 10 1 0 3 6 9 12 Days Since Infusion 0.1 transgene copies/100 ng of DNA 0 7 14 21 28 35 42 49 56 100 200 300 Lee, Lancet, 2014! Days Since Infusion Months Since Infusion Maude, NEJM, 2014! Efficacy of CAR-T cells ! Current strategies for treatment after relapse are suboptimal! Clo/CTX/VP-16 for Advanced Childhood ALL Clofarabine, Etoposide, CyclophosphamideBlinatumomab! ! Locatelli et al, Br J Haematol, 2009! Fig 3.