Purpose:

Patients with relapsed pediatric solid malignancies have few therapeutic options, and many of these patients die of their disease. B7-H3 is an immune checkpoint protein encoded by the CD276 gene that is overexpressed in many pediatric cancers. Here, we investigate the activity of the B7-H3–targeting antibody–drug conjugate (ADC) m276-SL-PBD in pediatric solid malignancy patient-derived (PDX) and cell line–derived xenograft (CDX) models.

Experimental Design:

B7-H3 expression was quantified by RNA sequencing and by IHC on pediatric PDX microarrays. We tested the safety and efficacy of m276-SL-PBD in two stages. Randomized trials of m276-SL-PBD of 0.5 mg/kg on days 1, 8, and 15 compared with vehicle were performed in PDX or CDX models of Ewing sarcoma (N = 3), rhabdomyosarcoma (N = 4), Wilms tumors (N = 2), osteosarcoma (N = 5), and neuroblastoma (N = 12). We then performed a single mouse trial in 47 PDX or CDX models using a single 0.5 m/kg dose of m276-SL-PBD.

Results:

The vast majority of PDX and CDX samples studied showed intense membranous B7-H3 expression (median H-score 177, SD 52). In the randomized trials, m276-SL-PBD showed a 92.3% response rate, with 61.5% of models showing a maintained complete response (MCR). These data were confirmed in the single mouse trial with an overall response rate of 91.5% and MCR rate of 64.4%. Treatment-related mortality rate was 5.5% with late weight loss observed in a subset of models dosed once a week for 3 weeks.

Conclusions:

m276-SL-PBD has significant antitumor activity across a broad panel of pediatric solid tumor PDX models.

Translational Relevance

B7-H3 (CD276) has emerged as a promising immunotherapy target in many human malignancies. Here, we evaluated the efficacy of the B7-H3–targeted antibody–drug conjugate m276-SL-PBD in a large panel of pediatric solid tumor patient- and cell-derived xenograft models. Potent antitumor activity was observed in the majority of models studied, supporting the clinical development of m276-SL-PBD in high-risk childhood solid malignancies.

Pediatric cancer mortality has declined by 65% since 1970 (1). A large proportion of this progress can be attributed to marked reduction in deaths from leukemia, which has been achieved through optimization of chemotherapy regimens (2). In contrast, there has been only modest improvement in survival probabilities for children, adolescents, and young adults with many high-risk solid malignancies despite dramatic intensification of cytotoxic therapy (3), such that survivors face lifelong complications due to intensive, multimodal therapy, underscoring a critical need for development of new therapies for pediatric cancer (4–6). Novel therapeutic approaches are thus required to improve outcomes for high-risk childhood solid malignancies.

While immune checkpoint inhibitors have shown remarkable efficacy in many adult solid malignancies, there has not been a significant activity signal in clinical trials for patients with pediatric solid tumors (7, 8), at least in part due to the fact that pediatric tumors generally have low mutation burdens and thus few neoantigens, and generally low expression of PD-L1 (9–11). CD19-directed chimeric antigen receptor (CAR) engineered T-cell therapy has shown remarkable efficacy in B-cell leukemias (12–14), but as yet few convincing durable responses in solid malignancies have been observed for CAR T cells targeting surface antigens relevant for pediatric solid tumors. Antibody–drug conjugates (ADC) couple the specificity of antibodies with highly potent cytotoxic agents, conferring increased potency and potential for bystander killing not seen with mAbs alone (15–18). There are currently 10 FDA-approved ADCs for a variety of human cancers, dozens in clinical development, but in children only ADCs against leukemias and lymphomas have been actively developed.

The B7-H3 protein (encoded from the CD276 gene) is a checkpoint molecule that is highly expressed in pediatric solid tumors, with reportedly limited expression in normal tissues (19–25). Overexpression of B7-H3 is correlated with tumor progression, metastasis, and poor clinical outcome across a variety of malignancies (26, 27). mAbs targeting B7-H3 cause limited toxicity and have demonstrated some antitumor activity in clinical trials (28, 29). Furthermore, intrathecal delivery of 131I-8H9 (omburtamab) is in late-phase clinical development for neuroblastomas with brain and/or leptomeningeal metastasis, to date showing a manageable toxicity profile with tumoricidal doses (30). Recent work has concerned development of B7-H3 CAR-T cells (23, 24), with one study demonstrating efficacy in Ewing sarcoma, osteosarcoma, and medulloblastoma xenografts (22). Finally, a pyrrolobenzodiazepine (PBD)-armed ADC against CD276 (m276-PBD, a precursor to m276-SL-PBD) showed antitumor activity in a variety of adult cancer preclinical models, including superiority over a monomethyl auristatin E (MMAE)-armed anti-CD276 ADC (31). While both PBD and MMAE are DNA-binding agents, the superiority of PBD is likely due to PBD functioning irrespective of the stage of the cell cycle, thereby eradicating both the tumor and the tumor vasculature. Together, these data suggest CD276 is a rational target for further ADC development. Here, we present results from the Pediatric Preclinical Testing Consortium (PPTC) investigation of m276-SL-PBD across a large and diverse panel of pediatric cancer patient-derived (PDX) and cell line–derived xenograft (CDX) models.

RNA sequencing analysis

PDX RNA sequencing (RNA-seq) data were gathered from the PPTC dataset available on cBioPortal (32). Normal tissue RNA-seq data were gathered from the Genome-Tissue Expression (GTEx) resource (https://gtexportal.org/home/). Patient tumor RNA-seq data were collected from the Treehouse Childhood Cancer Initiative (https://treehousegenomics.soe.ucsc.edu/), which included data from the Therapeutically Applicable Research to Generate Effective Treatments initiative (https://ocg.cancer.gov/programs/target). The associated data and code used to generate the figures are available in an open-access GitHub Repository at https://github.com/nathankendsersky/pptc_cd276.

IHC

Tissue microarrays (TMA) including human normal childhood tissues, human neuroblastoma primary tumors, and PDX arrays for the histologies studied here were constructed as described previously, with normal tissues obtained from surgical or autopsy specimens at the Children's Hospital of Philadelphia (Philadelphia, PA), as described previously (33–35). Staining was performed with a polyclonal B7-H3 antibody (R&D, AF1027) at a 1:1,000 dilution. Aperio GENIE Classifier (Leica Biosystems) was used to annotate tumor regions and exclude stroma and necrosis. Tumor classification was reviewed and any discordant classifications were manually annotated by a pathologist (J. Pogoriler). For each tumor core, Aperio Membrane V9 algorithm (Leica Biosystems) was used to quantify staining intensity and percentage of tumor cells stained. H-scores were calculated by the following formula [(1 × %cells intensity = 1) + (2 × %cells intensity = 2) + (3 × %cells intensity = 3)]. Cores in which fewer than 100 cells were available for evaluation were excluded.

ADC generation

The antibody used to create the m276-SL-PBD ADC, called m276-SL, is a modified version of the fully human m276 IgG1 antibody (31) engineered to contain four mutations (S239C, L234A/L235A/P329G) in the Fc domain (36). The S239C mutation was used for site-specific maleimide-based PBD conjugation via a dipeptide (valine-alanine) linker (36) while the LALA-PG mutations were used to prevent undesirable interactions of the ADC with Fc receptors that could potentially result in off-target killing (37). Further details about the synthesis of the modified ADC will be published separately.

Preclinical trials

CB17SC scid−/− female (5–8 weeks) mice (Taconic Farms or ENVIGO) were used to propagate subcutaneous xenografts. All mice were maintained under barrier conditions and experiments were conducted using protocols and conditions in accordance with the Institutional Animal Care and Use Committee at The University of Texas Health San Antonio (UTHSA; San Antonio, TX), M.D. Anderson Cancer Center (Houston, TX), and the Children's Hospital of Philadelphia (Philadelphia, PA). The number of mice per group (control and treatment) was varied as indicated, with 10, 2, or 1 animal(s). For randomized controlled trials with either 10 or 2 mice per arm, 0.5 mg/kg of m276-SL-PBD or (0.5 mg/kg) of 100 μL/20 g PBS was administered intraperitoneally once a week for 3 weeks (days 1, 8, and 15). A dose of 0.5 mg/kg was chosen because it was the lowest effective dose discovered in Seaman and colleagues (31). For the single mouse trial (SMT; N = 1) study (38), a single dose of 0.5 mg/kg m276-SL-PBD was administered intraperitoneally. Treatment was initiated when tumor volumes reached 200 mm3, and tumor volume and event-free survival (EFS) were monitored as reported previously (29).

Statistical methods

A tumor event was defined as a quadrupling of tumor volume from the day of treatment initiation, where tumor volume was estimated from caliper measurements as (4/3) × π × ((length + width)/4)3. The exact time to event was estimated by interpolating between the measurements directly preceding and following the event, assuming log-linear growth. Differences in EFS between experimental groups of N > 2 were evaluated using the Gehan–Wilcoxon test, and differences in minimum relative tumor volume (RTV; ratio of current tumor volume to volume at treatment initiation) were evaluated using the Wilcoxon rank-sum test.

Area over the curve (AOC) is the area above the RTV growth curve but below the event threshold of RTV = 4. It was calculated for each mouse using the trapezoid rule and was then divided by 4; a day of complete tumor remission, therefore, adds exactly 1 to the AOC. The AOC is correlated with time to event, but also captures the maximum extent and durability of tumor remission. It is a continuous, composite measure of tumor response over the course of the experiment and is therefore well suited for genomic analyses of association between tumor response and specific mutations.

The objective response categories are progressive disease (PD, which is subdivided among treated mice into PD without and with growth delay, PD1 and PD2, respectively), stable disease (SD), partial response (PR), complete response (CR; no measurable tumor mass for one recording), and maintained CR (MCR; no measurable tumor mass for at least three consecutive weekly recordings) as described previously (39). Response rate is defined as the percentage of mice with PR or better. Mice experiencing a possibly treatment-related death (i.e., drug toxicity), mice with failed engraftment, and mice that unexpectedly die for reasons unrelated to treatment are excluded from statistical analyses of time to event, minimum tumor volume, and objective response.

For experiments of groups of N = 2 mice per group, we did not perform any statistical tests of group differences but have reported all other summary statistics. For the SMT, we report time to event, AOC, minimum RTV, and the objective response measure for each PDX or CDX model tested.

B7-H3 is highly expressed in high-risk pediatric solid malignancies with limited normal childhood tissue expression

CD276 mRNA was generally highly expressed in pediatric solid tumors, compared to generally low expression in a panel of 1,641 normal tissues samples from 25 organs (Fig. 1A). Likewise, CD276 mRNA was highly expressed in each PDX model studied here (32). Ewing sarcoma models had the lowest median mRNA expression of CD276 (median = 37.42 transcripts per million, TPM, normalized by trimmed mean of M-values) whereas osteosarcomas (median = 165.92 TPM) and Wilms tumors (median = 142.29 TPM) showed the highest levels of mRNA expression (Fig. 1B). IHC of three tumor TMAs showed strong staining across the tested PDXs (Fig. 2A–C). Osteosarcoma models showed the highest expression of CD276 (median H-score = 243.0). Overall, we observed a moderate correlation (R = 0.527, P = 7.13e-05) between mRNA (TPM) and protein expression (median H-Score; Supplementary Fig. S1). For the normal tissue array, the membrane algorithm was applied to assist in reproducible evaluation of the intensity of membranous staining, with pathologist review to determine which cell types were staining in any given tissue (Supplementary Fig. S2). Strong staining (3+) was seen in the basal layer of the epidermis of the skin. Weak (2+) staining was present in the adrenal cortex, bladder urothelium, basal layer of the esophageal epithelium, prostatic epithelium, pancreatic islet tissue, ovarian stroma, splenic stroma, and a subset of pituitary cells. Staining of the bone marrow hematopoietic cells as well as the epithelium in the ileocecum, colon, and stomach varied from negative (0) to weak (2+). Equivocal (1+) staining was present in a subset of cardiac myocytes, a subset of aortic stromal cells, a subset of gastrointestinal tract stromal cells (appendix, colon, small intestine, stomach), gallbladder epithelium, basal urothelium of the ureter, fallopian tube epithelium and subsets of cortical neurons, renal podocytes and subset of renal tubular cells, pancreatic exocrine tissue, hepatocytes, pulmonary epithelium, a subset of germinal center cells (lymph node, tonsils, spleen), salivary gland acinar cells, and a subset of developing spermatozoa. Staining was negative in other tissues including cerebellum, mature bone, skeletal muscle, and thyroid.

m276-SL-PBD shows strong antitumor activity in pediatric PDX models

The efficacy and toxicity of m276-SL-PBD was initially evaluated in 26 pediatric PDX and CDX models in randomized controlled trial with either 10 or 2 mice per arm (Table 1; Supplementary Table S1). This was followed by a SMT using a single dose of m276-SL-PBD in 47 distinct models (33 PDX, 14 CDX; Table 2; ref. 40). m276-SL-PBD was generally well tolerated with a treatment-related mortality rate of 5.5% when administered in three weekly doses and 0% when administered as a single dose. In the randomized trials with three doses given weekly, late weight loss was observed in the Ewing sarcoma, rhabdomyosarcoma, and Wilms tumor models, but not in the osteosarcoma and neuroblastoma models (Supplementary Figs. S3–S6). No significant weight loss was observed in the SMT with a single administered dose of m276-SL-PBD (data not shown).

In the randomized trials, m276-SL-PBD induced significantly prolonged EFS in all tested mice across all models. The minimum RTV in treated mice was significantly less than the starting mean tumor volume for all models studied with the exception of one of five osteosarcoma models (OS-9) and one of 12 neuroblastoma models (NB-1691; Fig. 3A; Supplementary Figs. S3–S7). m276-SL-PBD showed objective responses in all models except the NB-1691 neuroblastoma model (PD1 response) and the OS-9 osteosarcoma model (SD response; Table 1). All Ewing, rhabdoid tumors, and Wilms models, and four of five osteosarcomas and 10 or 12 neuroblastomas showed a MCR (N = 16) or CR (N = 5). The overall response rate (PR or better) was 92.3% in the randomized trial (Supplementary Table S2). In the SMT, a single dose of m276-SL-PBD significantly prolonged EFS and decreased minimum RTV in models across all histologies tested (Figs. 3B and C; Supplementary Figs. S8 and S9). The overall response rate was 91.5% with 31 of 47 (66%) models showing a MCR (Table 2; Supplementary Table S2). The 10 models studied in both trial designs showed concordant responses (KT-10, KT-11, Rh-18, Rh-30, Rh-36, SK-NEP-1, ES-1, NB-1643, OS-1). Across both the randomized trial and SMT, we observed no correlation between CD276 expression (mRNA or protein) and objective response category (Supplementary Fig. S10).

B7-H3 is an immunomodulatory cell surface protein in the B7 superfamily, which includes other well-characterized members such as PD-L1 (41). Here we confirm and extend the previous reports of high expression on the majority of high-risk pediatric solid tumors, with significant normal childhood tissue expression by IHC limited mainly to the basal layer of skin (not previously reported), and weak expression noted in a variety of different childhood tissues (Supplementary Fig. S2; refs. 20–25). Whether or not this normal tissue expression will be a liability for an ADC that requires internalization remains unknown. In addition, B7-H3 has been shown to play a role in metastasis, and high B7-H3 expression is associated with poor outcomes across a variety of malignancies (23). However, the precise mechanisms that lead to B7-H3 overexpression and how the protein exerts its protumor function are not defined. Early studies suggested B7-H3 played a role in T-cell costimulation (42, 43). Other data point to a potential immunosuppressive, checkpoint mechanism (44, 45). Future studies are required to more precisely define the role of B7-H3 in normal human development as well as pediatric cancer tumor cell-intrinsic and extrinsic mechanisms of immune evasion.

B7-H3 has emerged as a promising immunotherapeutic target for a variety of cancers, with several immunotherapeutic platforms targeting this protein in development, including antibodies, bispecific antibodies, ADCs, and CAR T cells (22–24, 28–31). Because solid pediatric malignancies tend to have low mutational burden and immunologically cold microenvironments, which hinder adaptive immunotherapeutic approaches (9–11), ADCs may be ideal platforms for differentially expressed proteins in the plasma membrane.

We used the m276 antibody platform and covalently linked PBD with a cleavable valine-alanine linker and a drug–antibody ratio (DAR) of 2. The m276-SL-PBD ADC showed potent antitumor activity against pediatric solid xenografts at 0.5 mg/kg regardless of whether this was administered once or weekly for 3 weeks. Overall response rates above 90% in both the randomized and SMTs, with limited observed toxicity, is an encouraging signal for clinical development. Importantly, m276 binds human and mouse B7-H3 with equal affinity (31), which further supports a potential therapeutic index in pediatric patients. The weight loss in the multidose experiments in some of the sarcoma and Wilms models may be due to a cumulative effect of PBD, as has been previously observed in clinical trials of PBD-family agents (46), as well as the sensitivity of CB17SC scid−/−/−animals to DNA-damaging agents. No skin toxicity was observed in the mice treated in this study.

Our results with m276-SL-PBD confirm the utility of the SMT design as an efficient and accurate design for screening large panels of xenograft models. A retrospective analysis of 67 agents tested by the Pediatric Preclinical Testing Program using N = 8 or 10 mice per group evaluated whether a single mouse chosen at random predicted the group median objective response. Out of 2,134 total comparisons, the single mouse matched the group median response 78% of the time and fell within one response category away 95% of the time (40). More recent work analyzed 30 agents tested by the PPTC from 2015 to 2018 and observed exact and near match rates of 82% and 94%, respectively (47).

It is very likely that ADC payloads may need to be tailored to potentially unique cytotoxic vulnerabilities and mechanisms or drug resistance in childhood cancer. Especially in the relapse setting after dose intensive chemotherapy, many of the favored payloads in licensed ADCs like DM1 may not be ideal as they are substrates for P-glycoprotein and other drug efflux pumps. In addition, it was recently demonstrated that m276-SL-PBD confers advantages over m276-MMAE due to PBD-mediated eradication of tumor-associated vasculature in adult tumor xenograft models (31). However, ADCs with PBD-family cytotoxic agents have shown toxicity in the clinic (48), and the antitumor activity seen at 0.5 mg/kg must be viewed in the context of a dose and schedule that can be achieved in the clinic. It is reassuring in our study that deescalation from 0.5 mg/kg once a week for 3 weeks to a single 0.5 mg/kg dose had no impact on antitumor activity, suggesting that with an ideal target, stable linker, and brisk internalization kinetics, PBD containing ADCs directed at B7-H3 can be developed clinically. Our data support further development of B7-H3 ADCs for childhood cancers.

S. Seaman reports a patent for 62/947.135 pending and a patent 10604582 issued. Y. Feng reports a patent for 62/947135 pending. B. St. Croix reports a patent for 62/947,135 pending and a patent 10604582 issued. No disclosures were reported by the other authors.

N.M. Kendsersky: Data curation, visualization, writing–original draft, writing–review and editing. J.Lindsay: Data curation, visualization, writing–original draft, writing–review and editing. E.A. Kolb: Conceptualization, funding acquisition, writing–review and editing. M.A. Smith: Conceptualization, resources, formal analysis, supervision, writing–original draft, project administration, writing–review and editing. B.A. Teicher: Conceptualization, writing–review and editing. S.W. Erickson: Data curation, formal analysis, visualization. E.J. Earley: Data curation, formal analysis, visualization. Y.P. Mosse: Conceptualization, supervision, investigation, writing–review and editing. D. Martinez: Data curation, formal analysis, investigation, visualization. J. Pogoriler: Data curation, formal analysis, investigation, visualization. K. Krytska: Data curation, formal analysis, investigation. K. Patel: Data curation, formal analysis, visualization, methodology. D. Groff: Data curation, investigation. M. Tsang: Data curation, investigation. S. Ghilu: Data curation, investigation. Y. Wang: Data curation, investigation, methodology. S. Seaman: Conceptualization, resources. Y. Feng: Resources. B. St. Croix: Conceptualization, resources, writing–original draft, writing–review and editing. R. Gorlick: Conceptualization, resources, data curation, formal analysis, supervision, funding acquisition, writing–review and editing. R. Kurmasheva: Conceptualization, supervision, writing–original draft, writing–review and editing. P.J. Houghton: Conceptualization, resources, supervision, funding acquisition, investigation, writing–original draft, project administration, writing–review and editing. J.M. Maris: Conceptualization, resources, supervision, funding acquisition, investigation, writing–original draft, project administration, writing–review and editing.

This work was supported by NCI U01 CA199287 (to J.M. Maris), NCI R35 CA220500 (to J.M. Maris), NCI U01 CA199221 (to Richard G. Gorlick), NCI U01 CA199297 (to P.J. Houghton), CPRIT RP160716 (to P.J. Houghton), NCI F31 CA239424 (to N.M. Kendsersky), NCI F31 CA254244 (to J. Lindsay), NCI U01 CA199222 (to Gregory J. Gatto), and the Giulio D'Angio Endowed Chair (to J.M. Maris).

The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

1.
Siegel
RL
,
Miller
KD
,
Jemal
A
. 
Cancer statistics, 2019
.
CA Cancer J Clin
2019
;
69
:
7
34
.
2.
Hunger
SP
,
Mullighan
CG
. 
Acute lymphoblastic leukemia in children
.
N Engl J Med
2015
;
373
:
1541
52
.
3.
Perkins
SM
,
Shinohara
ET
,
DeWees
T
,
Frangoul
H
. 
Outcome for children with metastatic solid tumors over the last four decades
.
PLoS One
2014
;
9
:
e100396
.
4.
Diller
L
,
Chow
EJ
,
Gurney
JG
,
Hudson
MM
,
Kadin-Lottick
NS
,
Kawashima
TI
, et al
Chronic disease in the childhood cancer survivor study cohort: a review of published findings
.
J Clin Oncol
2009
;
27
:
2339
55
.
5.
Oeffinger
KC
,
Hudson
MM
. 
Long-term complications following childhood and adolescent cancer: foundations for providing risk-based health care for survivors
.
CA Cancer J Clin
2004
;
54
:
208
36
.
6.
Hudson
MM
. 
Survivors of childhood cancer: coming of age
.
Hematol Oncol Clin North Am
2008
;
22
:
211
31
.
7.
Geoerger
B
,
Zwaan
CM
,
Marshall
LV
,
Michon
J
,
Bourdeaut
F
,
Casanova
M
, et al
Atezolizumab for children and young adults with previously treated solid tumours, non-Hodgkin lymphoma, and Hodgkin lymphoma (iMATRIX): a multicentre phase 1–2 study
.
Lancet Oncol
2020
;
21
:
134
44
.
8.
Davis
KL
,
Fox
E
,
Merchant
MS
,
Reid
JM
,
Kudgus
RA
,
Liu
X
, et al
Nivolumab in children and young adults with relapsed or refractory solid tumours or lymphoma (ADVL1412): a multicentre, open-label, single-arm, phase 1–2 trial
.
Lancet Oncol
2020
;
21
:
541
50
.
9.
Majzner
RG
,
Heitzeneder
S
,
Mackall
CL
. 
Harnessing the immunotherapy revolution for the treatment of childhood cancers
.
Cancer Cell
2017
;
31
:
476
85
.
10.
Majzner
RG
,
Simon
JS
,
Grosso
JF
,
Martinez
D
,
Pawel
BR
,
Santi
M
, et al
Assessment of programmed death-ligand 1 expression and tumor-associated immune cells in pediatric cancer tissues
.
Cancer
2017
;
123
:
3807
15
.
11.
Davis
KL
,
Fox
E
,
Reid
JM
,
Liu
X
,
Minard
CG
,
Weigel
B
, et al
ADVL1412: Initial results of a phase I/II study of nivolumab and ipilimumab in pediatric patients with relapsed/refractory solid tumors—A COG study
.
J Clin Oncol
35: 15s
, 
2017
(
suppl; abstr 10526
).
12.
Lee
DW
,
Kochenderfer
JN
,
Stetler-Stevenson
M
,
Cui
YK
,
Delbrook
C
,
Feldman
SA
, et al
T cells expressing CD19 chimeric antigen receptors for acute lymphoblastic leukaemia in children and young adults: a phase 1 dose-escalation trial
.
Lancet
2015
;
385
:
517
28
.
13.
Maude
SL
,
Frey
N
,
Shaw
PA
,
Aplenc
R
,
Barrett
DM
,
Bunin
NJ
, et al
Chimeric antigen receptor T cells for sustained remissions in leukemia
.
N Engl J Med
2014
;
371
:
1507
17
.
14.
Gardner
R
,
Wu
D
,
Cherian
S
,
Fang
M
,
Hanafi
LA
,
Finney
O
, et al
Acquisition of a CD19-negative myeloid phenotype allows immune escape of MLL-rearranged B-ALL from CD19 CAR-T-cell therapy
.
Blood
2016
;
127
:
2406
10
.
15.
de Goeij
BECG
,
Lambert
JM
. 
New developments for antibody-drug conjugate-based therapeutic approaches
.
Curr Opin Immunol
2016
;
40
:
14
23
.
16.
Diamantis
N
,
Banerji
U
. 
Antibody-drug conjugates–an emerging class of cancer treatment
.
Br J Cancer.
2016
;
114
:
362
7
.
17.
Beck
A
,
Goetsch
L
,
Dumontet
C
,
Corvaïa
N
. 
Strategies and challenges for the next generation of antibody-drug conjugates
.
Nat Rev Drug Discov
2017
;
16
:
315
37
.
18.
Kovtun
YV
,
Goldmacher
VS
. 
Cell killing by antibody-drug conjugates
.
Cancer Lett
2007
;
255
:
232
40
.
19.
Lee
YH
,
Martin-Orozco
N
,
Zheng
P
,
Li
J
,
Zhang
P
,
Tan
H
, et al
Inhibition of the B7-H3 immune checkpoint limits tumor growth by enhancing cytotoxic lymphocyte function
.
Cell Res
2017
;
27
:
1034
45
.
20.
Wang
L
,
Zhang
Q
,
Chen
W
,
Shan
B
,
Ding
Y
,
Zhang
G
, et al
B7-H3 is overexpressed in patients suffering osteosarcoma and associated with tumor aggressiveness and metastasis
.
PLoS One
2013
;
8
:
e70689
.
21.
Zhou
Z
,
Luther
N
,
Ibrahim
GM
,
Hawkins
C
,
Vibhakar
R
,
Handler
MH
, et al
B7-H3, a potential therapeutic target, is expressed in diffuse intrinsic pontine glioma
.
J Neurooncol
2013
;
111
:
257
64
.
22.
Majzner
RG
,
Theruvath
JL
,
Nellan
A
,
Heitzeneder
S
,
Cui
Y
,
Mount
CW
, et al
CAR T cells targeting B7-H3, a pan-cancer antigen, demonstrate potent preclinical activity against pediatric solid tumors and brain tumors
.
Clin Cancer Res
2019
;
25
:
2560
74
.
23.
Du
H
,
Hirabayashi
K
,
Ahn
S
,
Kren
NP
,
Montgomery
SA
,
Wang
X
, et al
Antitumor responses in the absence of toxicity in solid tumors by targeting B7-H3 via chimeric antigen receptor T cells
.
Cancer Cell
2019
;
35
:
221
37
.
24.
Nguyen
P
,
Okeke
E
,
Clay
M
,
Haydar
D
,
Justice
J
,
O'Reilly
C
, et al
Route of 41BB/41BBL costimulation determines effector function of B7-H3-CAR.CD28ζ T cells
.
Mol Ther Oncolytics
2020
;
18
:
202
14
.
25.
Modak
S
,
Kramer
K
,
Gultekin
SH
,
Guo
HF
,
Cheung
NKV
. 
Monoclonal antibody 8H9 targets a novel cell surface antigen expressed by a wide spectrum of human solid tumors
.
Cancer Res
2001
;
61
:
4048
54
.
26.
Tekle
C
,
Nygren
MK
,
Chen
YW
,
Dybsjord
I
,
Nesland
JM
,
Mælandsmo
GM
, et al
B7-H3 contributes to the metastatic capacity of melanoma cells by modulation of known metastasis-associated genes
.
Int J Cancer
2012
;
130
:
2282
90
.
27.
Ye
Z
,
Zheng
Z
,
Li
X
,
Zhu
Y
,
Zhong
Z
,
Peng
L
, et al
B7-H3 overexpression predicts poor survival of cancer patients: a meta-analysis
.
Cell Physiol Biochem
2016
;
39
:
1568
80
.
28.
Loo
D
,
Alderson
RF
,
Chen
FZ
,
Huang
L
,
Zhang
W
,
Gorlatov
S
, et al
Development of an Fc-enhanced anti-B7-H3 monoclonal antibody with potent antitumor activity
.
Clin Cancer Res
2012
;
18
:
3834
45
.
29.
Powderly
J
,
Cote
G
,
Flaherty
K
,
Szmulewitz
RZ
,
Ribas
A
,
Weber
J
, et al
Interim results of an ongoing phase I, dose escalation study of MGA271 (Fc-optimized humanized anti-B7-H3 monoclonal antibody) in patients with refractory B7-H3-expressing neoplasms or neoplasms whose vasculature expresses B7-H3
.
J Immunother Cancer
2015
;
3
:
O8
.
30.
Kramer
K
,
Kushner
BH
,
Modak
S
,
Pandit-Taskar
N
,
Smith-Jones
P
,
Zanzonico
P
, et al
Compartmental intrathecal radioimmunotherapy: results for treatment for metastatic CNS neuroblastoma
.
J Neurooncol
2010
;
97
:
409
18
.
31.
Seaman
S
,
Zhu
Z
,
Saha
S
,
Zhang
XM
,
Yang
MY
,
Hilton
MB
, et al
Eradication of tumors through simultaneous ablation of CD276/B7-H3-positive tumor cells and tumor vasculature
.
Cancer Cell
2017
;
31
:
501
15
.
32.
Rokita
JL
,
Rathi
KS
,
Cardenas
MF
,
Upton
KA
,
Jayaseelan
J
,
Cross
KL
, et al
Genomic profiling of childhood tumor patient-derived xenograft models to enable rational clinical trial design
.
Cell Rep
2019
;
29
:
1675
89
.
33.
Kononen
J
,
Bubendorf
L
,
Kallioniemi
A
,
Bärlund
M
,
Schraml
P
,
Leighton
S
, et al
Tissue microarrays for high-throughput molecular profiling of tumor specimens
.
Nat Med
1998
;
4
:
844
7
.
34.
Pilla
D
,
Bosisio
FM
,
Marotta
R
,
Faggi
S
,
Forlani
P
,
Falavigna
M
, et al
Tissue microarray design and construction for scientific, industrial and diagnostic use
.
J Pathol Inform
2012
;
3
:
42
.
35.
Bosse
KR
,
Raman
P
,
Zhu
Z
,
Lane
M
,
Martinez
D
,
Heitzeneder
S
, et al
Identification of GPC2 as an oncoprotein and candidate immunotherapeutic target in high-risk neuroblastoma
.
Cancer Cell
2017
;
32
:
295
309
.
36.
Jeffrey
SC
,
Burke
PJ
,
Lyon
RP
,
Meyer
DW
,
Sussman
D
,
Anderson
M
, et al
A potent anti-CD70 antibody-drug conjugate combining a dimeric pyrrolobenzodiazepine drug with site-specific conjugation technology
.
Bioconjug Chem
2013
;
24
:
1256
63
.
37.
Lo
M
,
Kim
HS
,
Tong
RK
,
Bainbridge
TW
,
Vernes
JM
,
Zhang
Y
, et al
Effector-attenuating substitutions that maintain antibody stability and reduce toxicity in mice
.
J Biol Chem
2017
;
292
:
3900
8
.
38.
Ghilu
S
,
Li
Q
,
Fontaine
SD
,
Santi
D V.
,
Kurmasheva
RT
,
Zheng
S
, et al
Prospective use of the single-mouse experimental design for the evaluation of PLX038A
.
Cancer Chemother Pharmacol
2020
;
85
:
251
63
.
39.
Robles
AJ
,
Kurmasheva
RT
,
Bandyopadhyay
A
,
Phelps
DA
,
Erickson
SW
,
Lai
Z
, et al
Evaluation of eribulin combined with irinotecan for treatment of pediatric cancer xenografts
.
Clin Cancer Res
2020
;
26
:
3012
23
.
40.
Murphy
B
,
Yin
H
,
Maris
JM
,
Kolb
EA
,
Gorlick
R
,
Reynolds
CP
, et al
Evaluation of alternative in vivo drug screening methodology: a single mouse analysis
.
Cancer Res
2016
;
76
:
5798
809
.
41.
Collins
M
,
Ling
V
,
Carreno
BM
. 
The B7 family of immune-regulatory ligands
.
Genome Biol
2005
;
6
:
223
.
42.
Chapoval
AI
,
Ni
J
,
Lau
JS
,
Wilcox
RA
,
Flies
DB
,
Liu
D
, et al
B7-H3: a costimulatory molecule for T cell activation and IFN-γ production
.
Nat Immunol
2001
;
2
:
269
74
.
43.
Luo
L
,
Chapoval
AI
,
Flies
DB
,
Zhu
G
,
Hirano
F
,
Wang
S
, et al
B7-H3 enhances tumor immunity in vivo by costimulating rapid clonal expansion of antigen-specific CD8 + cytolytic T cells
.
J Immunol
2004
;
173
:
5445
50
.
44.
Veenstra
RG
,
Flynn
R
,
Kreymborg
K
,
McDonald-Hyman
C
,
Saha
A
,
Taylor
PA
, et al
B7-H3 expression in donor T cells and host cells negatively regulates acute graft-versus-host disease lethality
.
Blood
2015
;
125
:
3335
46
.
45.
Steinberger
P
,
Majdic
O
,
Derdak
SV
,
Pfistershammer
K
,
Kirchberger
S
,
Klauser
C
, et al
Molecular characterization of human 4Ig-B7-H3, a member of the B7 family with four Ig-like domains
.
J Immunol
2004
;
172
:
2352
9
.
46.
Hartley
JA
. 
The development of pyrrolobenzodiazepines as antitumour agents
.
Expert Opin Investig Drugs
2011
;
20
:
733
44
.
47.
Earley
E
,
Gorlick
R
,
Houghton
PJ
,
Maris
JM
,
Li
X-N
,
Lock
RB
, et al
Re-evaluating sample sizes in preclinical testing of patient-derived xenografts [abstract]
.
In
:
Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29–Apr 3
;
Atlanta, GA. Philadelphia (PA)
:
AACR
;
Cancer Res
2019
;
79
(
13 Suppl
):
Abstract nr LB-321
.
48.
Saber
H
,
Simpson
N
,
Ricks
TK
,
Leighton
JK
. 
An FDA oncology analysis of toxicities associated with PBD-containing antibody-drug conjugates
.
Regul Toxicol Pharmacol
2019
;
107
:
104429
.