(Solved by Humans)-A recent advance in cancer immunotherapy has been in activating

Question

A recent advance in cancer immunotherapy has been in activating the cellular immune response against cancer cells. Specific antibodies are injected into cancer patients in order to activate dormant or dying lymphocytes that are in or around tumors such that the lymphocytes then can kill the tumor cells.

a) (35 pts) Describe in detail the glycoproteins on the surface of the lymphocytes and the tumor cells that are responsible for shutting the lymphocytes down (what kind of proteins they are, their structures, etc.) and the mechanism of this inactivation (including signaling pathways). How do the therapeutic antibodies function to allow activation of the lymphocytes? Read and cite primary scientific literature, not just reviews or web pages from companies. Don't simply rely on Wikipedia! Diagrams may aid your descriptions.

b) (15 pts) Describe any recent clinical data (2014 to present) from experiments that are evaluating, or have evaluated, the efficacy of these types of antibodies in treating a human cancer (choose the Highest quality published study you can find).

Review Article

Clinical evaluation of compounds
targeting PD-1/PD-L1 pathway for cancer
immunotherapy

J Oncol Pharm Practice
2015, Vol. 21(6) 451?467
! The Author(s) 2014
Reprints and permissions:
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DOI: 10.1177/1078155214538087
opp.sagepub.com

Jing Lu1, Linda Lee-Gabel1, Michelle C Nadeau1,
Thomas M Ferencz1 and Scott A Soefje2

Abstract
Significant enthusiasm currently exists for new immunotherapeutic strategies: blocking the interaction between programmed death-1 receptor on T-cells and programmed death-ligand 1 on tumor cells to boost immune system stimulation to fight cancer. Immunomodulation with the antiprogrammed death-1/programmed death-ligand 1 monoclonal
antibodies has shown to mediate tumor shrinkage and extend overall survival from several pivotal phase I/II studies in
melanoma, renal cell carcinoma, and non-small cell lung cancer. This has prompted multiple large ongoing phase III trials
with the expectation for fast-track FDA approvals to satisfy unmet medical needs. Compounds targeting the programmed death-1 pathway that are in clinical trials fall into two major categories, namely antiprogrammed death-1
antibodies: Nivolumab, MK-3475, and pidilizumab; and antiprogrammed death-ligand 1 antibodies: MPDL3280A, BMS936559, MEDI4736, and MSB0010718C. We reviewed the clinical efficacy and safety of each compound based upon
major registered clinical trials and published clinical data. Overall, response rate of more than 20% is consistently seen
across all these trials, with maximal response of approximately 50% achieved by certain single antiprogrammed death-1
agents or when used in combination with cytotoxic T-lymphocyte antigen-4 blockade. The responses seen are early,
durable, and have continued after treatment discontinuation. Immune-related adverse events are the most common side
effects seen in these clinical trials. Overall, the skin and gastrointestinal tract are the most common organ systems
affected by these compounds while hepatic, endocrine, and neurologic events are less frequent. These side effects are
low grade, manageable, and typically resolve within a relatively short time frame with a predictable resolution pattern
given proper management. We therefore propose detailed guidelines for management of major immune-related adverse
events that are anticipated with antiprogrammed death-1/programmed death-ligand 1 therapies based on general experience with other monoclonal antibodies and the established management algorithms for immune-related adverse events
for cytotoxic T-lymphocyte antigen-4 blockade with ipilimumab. We anticipate that the antiprogrammed death-1 strategy
will become a viable and crucial clinical strategy for cancer therapy.

Keywords
Antiprogrammed death-1/programmed death-ligand 1, nivolumab, MK-3475, pidilizumab, MPDL3280A, BMS-936559,
MEDI4736, MSB0010718C, CTLA-4 blockade, ipilimumab, immune-related adverse event, management of adverse
events

Introduction
Immuno-oncology is an innovative approach to
research and drug development that focuses on harnessing the intelligence of the body?s own immune
system to ?ght cancer.1 Immunomodulation through
cytokines such as interferon (IFN) and interleukin
(IL) is established due to their particular relevance to

1

Department of Pharmacy, Smilow Cancer Hospital at Yale-New Haven,
New Haven, USA
2
Department of Pharmacy, University Medical Center Brackenridge,
Seton Healthcare Family, Austin, USA
Corresponding author:
Jing Lu, Department of Pharmacy, Smilow Cancer Hospital at Yale-New
Haven, 35 Park Street, Room 8-110, New Haven, CT 06510, USA.
Email: jing.lu@ynhh.org

452
cancer immunology. IFN-a has been shown to increase
the immunogenicity of tumors and also have direct antiproliferative/apoptotic e?ects. High-dose IL-2 therapy
is approved by the Food and Drug Administration
(FDA) for melanoma for enhancing cytotoxic T- and
NK-cell activity leading to antitumor activity.2 More
recently, immunotherapy approaches have centered on
cancer vaccination and immune checkpoint blockade
due to many recent studies which have shed considerable
light on the clinical e?ects of immune therapy on
survival.3
Cancer vaccination introduces cancer antigens by
therapeutic vaccination to speci?cally initiate or amplify
a
host
response
against
evolving
tumors.
Immunostimulatory molecules in the vaccine preparations (adjuvants/conjugates) activate dendritic cells,
which in turn interact, upregulate, and activate T-cells.
When an activated T-cell senses a cell bearing its target
tumor antigen, it can then lyse that cell and potentially
mediate an antitumor response.3 Over the last couple
decades, various animal and human studies have been
conducted in the ?eld of cancer vaccination. Although
several phase I and II studies have shown promising
results, the phase III data have been disappointing. To
date, Provenge? by Dendreon is the only FDA approved
therapeutic vaccine to treat cancer and speci?cally indicated for the treatment of advanced prostate cancer.4
Currently, most cancer vaccines fail to induce objective
tumor shrinkage or demonstrate clinical bene?t in
patients likely because current vaccines are unable to
e?ectively elude the multiple immunosuppressive mechanisms in the tumor microenvironment.3
By contrast, tumor shrinkage, disease regression,
and durable complete responses (CRs) have been
observed with immune checkpoint blockade in several
cancer types. Immune checkpoint blockade involves
cell surface expression of one or more of a series of
molecules that e?ectively limit T-cell proliferation and
killing capacity.5 Collectively, such molecules are
referred to as immune checkpoints,6,7 perhaps, the
two best known examples are cytotoxic T-lymphocyte
antigen-4 (CTLA-4)8 and programmed death-1
(PD-1).5,7
In an ideal state, activated T-cells are capable of
eradicating tumor cells from the body through tumor
immune surveillance via two steps. First, antigen-presenting cells capture and process the antigens released
by tumors. Second, activated T-cells proliferate,
migrate to, and attack the tumor. However, most
tumors have developed immune evasion techniques,
exempli?ed by exploiting the immune checkpoint pathway through expressing ligands bound to immune
checkpoints on T-cells to inhibit T-cell activation.
Therefore, blocking the interaction between the
immune checkpoint and its ligand, for example,

Journal of Oncology Pharmacy Practice 21(6)
CTLA-4 expressed on CD8+ and CD4+ T-cells, and
its ligand expressed on tumor cells, is expected to counteract immunosupression.3 Indeed, antibodies directed
against CTLA-4 (ipilimumab,9?11 tremelimumab12)
upregulate the T-cell activation which resulted in signi?cant survival bene?ts seen in two large, randomized
phase III trials.13,14 In 2011, ipilimumab was approved
by the FDA for all patients with unresectable or metastatic melanoma.
Another major checkpoint is mediated by the interaction between PD-1 on T-cells and its ligand on either
antigen-presenting cells or tumor cells.3?7,15 As previously described, some tumors exploit the PD-1 immune
checkpoint pathway to evade the body?s protective
immune response to cancer. In response to a normal
immune attack, tumor cells express PD-1 ligands, i.e.
PD ligand-1 (PD-L1) and PD ligand-2 (PD-L2). Both
PD-L1 and PD-L2 bind to PD-1 receptor on T cells,
inhibiting the activation of T-cells and suppressing Tcell attack (see Figure 1). Thus, cancer cells e?ectively
form a shield against T-cell attack, evade the immune
response, and continue to proliferate.16 Nearly all
human cancer types can express PD-L1, and aberrant
PD-L1 expression is associated with aggressive disease,
poor prognosis, and poor survival.17 E?cacy of PD-1
blockade has gathered substantial interest as the blockade of PD-1 with a single agent was associated with
objective responses in melanoma, kidney cancer, and
perhaps somewhat amazingly, lung cancer.18?23
Suggesting that compared to CTLA-4, the negative
immune e?ect of PD-1 may have a broader impact,
and antitumor immunotherapy via PD-1 blockade is
not limited in principle to any single tumor type, but
rather may have activity in augmenting a therapeutic
immune response to a number of histologically distinct
tumors. Furthermore, the rate of grade 3 and 4
immune-related adverse events (irAEs) with PD-1
blockade appears lower when compared to CTLA-4
blockade,21,22 possibly because the PD-1 pathway acts
more peripherally than the lymph node focus of the
CTLA-4 pathway.3
Blocking the PD-1 pathway has emerged as a promising avenue to pursue as an antitumor therapy with
great enthusiasm for results from ongoing phase III and
combination trials with PD-1 and CTLA-4 blockade.
In this review, we will be conducting a comprehensive
evaluation of compounds targeting the PD-1 pathway.
Research and development of PD-1 blockade compounds has fallen into two major categories, antibodies
blocking PD-1 receptor on T-cells or antibodies blocking PD-L1 on tumor cells.24 Collectively, compounds
that are in clinical trials under either one of the two
categories include anti-PD-1 antibodies: Nivolumab,
MK-3475, and pidilizumab; anti-PD-L1 antibodies:
MPDL3280A, BMS-936559, MEDI4736,25 and

Lu et al.

453

Figure 1. Mechanism of PD-1/PD-L inhibitors in the immune checkpoint pathways: (a) T cells recognize tumor specific antigens
through their T-cell receptor (TCR) following presentation by the major histocompatibility complex (MHC) on cancer cells.
Programmed death 1 (PD-1) receptor expression is induced on T-cells in response to an inflammatory state. In response to a normal
immune attack, tumor cells also express PD ligands, i.e., PD-L1 and PD-L2. Both PD-L1 and PD-L2 bind to PD-1 receptor on T-cells,
inhibit activation of T cells, and suppress T-cell attack. Thus, cancer cells evade the immune response and continue to proliferate.
(b) Antibody specific inhibition of the PD-1 receptor on T-cells and the PD-ligands promotes antigen-specific T-cell responses against
the cancer cell and results in cancer cell death. PD-L1?Programmed death receptor 1; PD-L1?Programmed death ligand 1; PD-L2?
Programmed death ligand 2; TLR?Toll-like-receptor; MHC?Major histocompatibility complex.

454
MSB0010718C.26 Through our review and discussion
of published clinical trial results for each of the compounds in major tumor types, particularly focusing on
mechanisms of action, clinical e?cacy, and safety, we
hope to provide a summary of insights from a pharmacy perspective and propose management of adverse
events for anti-PD-1/PD-L1 agents.

Anti-PD-1 antibodies
Nivolumab (also referred to as BMS-936558 or
MDX-1106, developed by Bristol-Myers Squibb)
Mechanism of action. Nivolumab is a fully human monoclonal immunoglobulin G4 (IgG4-S228P) antibody
(HuMAb) that inhibits the PD-1 receptor expressed
on activated T- and B-lymphocytes, thereby promoting
antigen-speci?c T-cell responses.27
Pharmacokinetics and pharmacodynamics. Pharmacokinetic
analyses suggest dose-dependent pharmacokinetics
with the half-life (t?) ranging between 12 and 20 h
with higher dosing (10 mg/kg) correlating with a
longer t?. The median time to peak concentration
(Cmax) and area under the curve (AUC) are also dose
dependent increasing linearly with escalating doses of
drug in the range of 0.3?10 mg/kg.21
Clinical efficacy and safety
Nivolumab monotherapy plus nivolumab in combination with conventional chemotherapy. Nivolumab
entered clinical trials in late 2007. Two phase I studies
(CA209001 and CA209003) have contributed to most of
the clinical experience with nivolumab as monotherapy.
CA20900128 was a phase I single dose escalation study in
39 subjects with previously treated advanced or metastatic cancer. Subjects received a single dose of nivolumab at 0.3, 1, 3, or 10 mg/kg. Brahmer et al. reported
that all treated subjects (n ? 39) were evaluable for
tumor response. There were no dose-limiting toxicities
after one dose of nivolumab, thus the maximum tolerated dose (MTD) was not de?ned. The most common
treatment-related adverse events included lymphopenia
(25.6%), fatigue (15.4%), and musculoskeletal pain
(15.4%). Immune-related adverse events (irAEs) including in?ammatory colitis and hypothyroidism occurred
in 5.2% of patients. One patient developed grade 3
in?ammatory colitis after receiving a total of ?ve doses
of nivolumab at 1 mg/kg, which was successfully managed with corticosteroids and in?iximab.18
Overall, one patient with metastatic colorectal
cancer achieved a CR and one patient with metastatic
renal-cell carcinoma (RCC) achieved a partial response
(PR) that was maintained without further therapy. A

Journal of Oncology Pharmacy Practice 21(6)
second patient with metastatic melanoma also achieved
a PR that was maintained for 3 months. Two additional patients with non-small cell lung cancer
NSCLC and melanoma had tumor regression following
treatment with nivolumab. Of note, no objective
responses were seen in patients with castrate-resistant
prostate cancer.18
CA20900329 is an ongoing phase I open-label, multiple dose escalation study in patients with previously
treated advanced solid tumors. Subjects received nivolumab at doses of 0.1, 0.3, 1, 3, or 10 mg/kg intravenously every 2 weeks. Topalian et al.21 reported the
preliminary results of the CA209003 study that evaluated 296 patients. The MTD was not de?ned and the
most common treatment-related adverse events
included fatigue (24%), rash (12%), pruritus (10%),
diarrhea (11%), decreased appetite (8%), and nausea
(8%). irAEs including diarrhea, vitiligo, hepatitis, and
pneumonitis occurred in 18% of patients. Six patients
with grade 1 or 2 pneumonitis were successfully managed with treatment interruption and administration of
corticosteroids. The incidence and severity of treatment-related adverse events including irAEs was similar
across all dosing schedules and tumor types.21
Overall, out of 122 patients with NSCLC, 14 objective responses were observed across all dosing schedules
with an objective response rate (ORR) of 18% for all
histologic types. For squamous NSCLC, the ORR
was 33% and for nonsquamous NSCLC, the ORR
was 12%.
For patients with melanoma (104 patients), 26
objective responses were observed with an ORR of
28% across all dosing schedules. Stable disease lasting
24 weeks or more was observed in six patients (6%).
The ORR for patients with RCC (34 patients) was 27%
across all dosing schedules. Stable disease lasting 24
weeks or more was observed in nine patients (27%).
No objective responses were achieved in patients with
colorectal (19 patients) or prostate cancer (17 patients).
Of note, patients with tumor expression of PD-L1
achieved higher ORR compared to patients lacking
tumor expression of the ligand.21
Nivolumab is also being evaluated in the
CheckMate 012 trial.30 This study is a 14-arm, phase
I, open-label, randomized study designed to assess the
safety and e?cacy of nivolumab in patients with stage
IIIB/IV NSCLC as ?rst line monotherapy, as switch
maintenance therapy, and as combination therapy
with three platinum-based doublet chemotherapy regimens. Results from an interim analysis of this phase I
study suggest durable responses across the histologic
subtypes of NSCLC.31 Thus far, 43 patients have been
enrolled and randomized to one of three treatment
cohorts of the nivolumab/platinum-based doublet
combination: (a) nivolumab/gemcitabine/cisplatin; (b)

Lu et al.
nivolumab/pemetrexed/cisplatin, or (c) nivolumab/carboplatin/paclitaxel. Preliminary e?cacy analysis suggests favorable response rates to the nivolumab/
platinum-doublet combination with ORR of 33, 33,
and 31% for treatment arms A, B, and C
respectively.31
These initial experiences provide an impetus for several phase III clinical studies with the expectation to
expedite the approval of nivolumab by FDA. Such
trials include one study comparing nivolumab to standard docetaxel-based chemotherapy in stage IIIB/IV
squamous cell NSCLC patients32 and in metastatic nonsquamous NSCLC patients.33 Additionally, there is an
ongoing randomized open-label phase III trial of nivolumab versus investigator?s choice in advanced melanoma patients progressing from anti-CTLA-4 therapy.34
Nivolumab and immunotherapy combinations. Based
upon preclinical evidence that CTLA-4 and PD-1
could play complementary roles in regulating adaptive
immunity,24 and preliminary evidence from the phase I
study CA20900435 suggesting synergistic e?ect between
nivolumab and ipilimumab for a higher frequency of
patients with increased tumor burden reduction,
Wolchok et al. conducted the ?rst clinical trial to
evaluate the safety and e?cacy of combining two
immune-checkpoint inhibitors.36 This study was a
phase Ib, open-label, multicenter, multidose, dose-escalation study of nivolumab in combination with ipilimumab in subjects with unresectable stage III/IV
melanoma with the intent to investigate the safety
and e?cacy of combined CTLA-4 and PD-1 blockade.
A total of 53 patients received therapy with nivolumab
and ipilimumab administered concurrently every 3
weeks for four doses, followed by nivolumab alone
every 3 weeks for four doses. The combined treatment
was subsequently continued every 12 weeks for up to
eight doses. Whereas a total of 33 patients received
sequenced treatment who were required to have
received at least three previous doses of ipilimumab,
with the last dose administered 4?12 weeks before the
administration of nivolumab to be given every 2 weeks
for up to 48 doses. The ORR for all patients in the
concurrent-regimen group was 40%. At the maximum
doses that were associated with an acceptable level of
adverse events (nivolumab at 1 mg/kg and ipilimumab
at 3 mg/kg), 53% of patients had an objective response,
all with tumor reduction greater than 80%. Grade 3 or
4 adverse events related to therapy occurred in 53% of
patients in the concurrent regimen and were generally
reversible. Among patients in the sequenced-regimen
group, 18% had grade 3 or 4 adverse events related
to therapy and the ORR was 20%.36
A phase III, randomized, double-blind study of
nivolumab monotherapy or nivolumab combined with

455
ipilimumab versus ipilimumab monotherapy in subjects
with previously untreated, unresectable, or metastatic
melanoma is being conducted.37 This study will allow
for direct comparison of the clinical bene?t, as measured by overall survival (OS), provided by nivolumab
monotherapy or nivolumab plus ipilimumab versus ipilimumab monotherapy. If the safety pro?le is acceptable and OS is improved either by nivolumab
monotherapy or nivolumab combined with ipilimumab, this study would be supportive for FDA approval
of either one for treatment of advanced melanoma.

MK-3475 (also referred to as Lambrolizumab,
developed by Merck)
Mechanism of action. MK-3475 is a highly selective,
humanized IgG4 anti-PD-1 antibody that contains a
mutation at C228P designed to prevent Fc-mediated
antibody-dependent cellular cytotoxicity (ADCC).38
In essence, the drug works by disabling the brake that
prevents the immune system from attacking cancer
cells. This allows the immune system to recognize and
target cancer cells by selectively achieving dual ligand
blockage.19,21,39
Pharmacokinetics. Serum concentrations of MK-3475
were lower by approximately ?ve-fold in patients
receiving 2 mg/kg every 3 weeks than in those receiving
10 mg/kg every 3 weeks; steady-state trough concentrations were 20% greater in the patients receiving 10 mg/
kg every 2 weeks than in those receiving the same dose
every 3 weeks. The increase in trough serum concentrations over time is consistent with the half-life of  2?3
weeks.38
Clinical efficacy and safety. Currently, studies of MK-3475
are being conducted in the following disease states:
NSCLC, solid tumors, melanoma, colorectal, and
hematological malignancies. The ?rst phase I of these
studies (i.e. MK-3475-00140) began in 2011 involving
participants with progressive locally advanced metastatic carcinoma, melanoma, or NSCLC. This study
was designed in six parts in which MK-3475 is infused
over 30 min on day 1 of every 2?3 week cycle.40
Hamid et al.38 recently published preliminary data
discussing the safety and tumor responses of MK-3475
in patients with melanoma from study MK-3475-001. A
total of 135 patients with advanced melanoma were
treated, and patients were randomized to either
10 mg/kg every 2 or 3 weeks or 2 mg/kg every 3
weeks. Of all patients who received at least one dose
of MK-3475, 79% reported drug-related adverse events
of any grade, and 13% reported grade 3 or 4 drugrelated adverse events. Generalized symptoms, including fatigue, asthenia, fever/chills, myalgias, and

456
headaches were most frequently reported but were of
low grade in more than 95% of all cases. The highest
incidence of treatment-related AEs was noted in the
cohort of patients who received 10 mg/kg of drug every
2 weeks. Treatment-related rashes and pruritus, low
grade pneumonitis, and diarrhea were reported in 21,
4, and 20% of patients, respectively. Hypothyroidism
was reported in 8% of the cases which was managed
with thyroid replacement therapy.38
The ORR across all dosing schedules was 38%. The
?rst imaging was performed at 12 weeks and 77% of
the patients had a reduction in the tumor burden during
the study, in which eight of those patients had stable
disease for longer than 24 weeks. The median duration
of response was not reached at the time of their analysis
with a median follow-up time of 11 months. Eighty one
percent of the patients who had a response were still
receiving study treatment at the time of analysis in
March 2013. Of the 52 patients with a response, ?ve
discontinued treatment due to progression of disease
and ?ve discontinued treatment due to adverse events.
The median progression-free survival (PFS) among the
135 patients was estimated at 7 months (estimated OS
had not been reached). The majority of responses were
ongoing at the time of analysis. The cohort with the
maximum administered dose of 10 mg/kg showed the
highest response rate of 52%. This cohort also
showed the highest rate of drug-related adverse
events.38 In this study, patients with disease progression
from immunotherapy or chemotherapy have responded
to MK-3475, and prior exposure to other immunotherapy drugs such as ipilimumab or IL-2 did not have a
signi?cant in?uence on e?cacy of MK-3475 nor did it
contribute to any additional AEs. These preliminary
results have prompted larger studies.38
Other ongoing studies are currently recruiting
patients for MK-3475. There are three open studies
that involve patients with NSCLC. One study involves
MK-3475 alone dosed at 10 mg/kg every 3 weeks (Part
C of study MK-3475-001).40 A second phase I study
compares MK-3475 monotherapy versus MK-3475 in
combination with cisplatin/pemetrexed or carboplatin/
paclitaxel per institutional standards for NSCLC.41 The
third study is a phase II/III study examining two doses
of MK-3475 versus docetaxel in previously treated
NSCLC patients.42 Based upon interim results from
the NSCLC cohort of a phase I dose expansion trial
of MK-3475 demonstrating a 24% response rate in 38
NSCLC patients,43 a phase 1 study will examine MK3475 10 mg/kg every 3 weeks for up to 2 years in PD-L1
positive NSCLC patients.44
For melanoma, one phase III study is comparing
two di?erent dosing schedules of MK-3475, 10 mg/kg
once every 2 weeks or 10 mg/kg once every 3 weeks
versus ipilimumab 3 mg/kg every 3 weeks for a total

Journal of Oncology Pharmacy Practice 21(6)
of four doses.45 Another phase II study with melanoma
compares a low dose and a high dose of MK-3475
versus an investigator?s choice of one of four chemotherapy regimens (carboplatin and paclitaxel, paclitaxel
alone, dacarbazine, or temozolomide).46
A phase I multicohort study is currently underway
to investigate the safety, tolerability, and antitumor
activity of MK-3475 10 mg/kg every 2 weeks in participants with solid tumors, speci?cally, advanced triple
negative breast cancer, advanced head and neck
cancer, advanced urothelial cancer, or advanced gastric
cancer.47 There is also a phase II study in colorectal
cancers randomized based upon microsatellite
instability status.48 In hematological malignancies
(myelodysplatic syndrome, Hodgkin?s lymphoma, and
non-Hodgkin?s lymphoma), MK-3475 is also being
used in a phase I study involving patients dosed at
10 mg/kg every 2 weeks.49 Lastly, there is a phase I/II
study that is not yet open for participant recruitment
which will compare MK-3475 monotherapy with pazopanib in patients with advanced RCC.50

Pidilizumab (also referred to as CT-011, developed
by CureTech)
Mechanism of Action. Pidilizumab is a humanized IgG-1
kappa recombinant MAb directed against PD-1.
Pidilizumab speci?cally blocks the PD-1/PD-1-ligand
interaction on CD4 + CD45RO + e?ector/memory Tlymphocytes and prevents apoptosis of T-lymphocytes.
Pidilizumab is also...