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cardiovascular and respiratory diseases > Lung cancer immunotherapy > Flashcards

Lung cancer immunotherapy Flashcards

1
Q

give an overview on lung cancer

A

• Lung cancer is the leading cause of cancer death and the second most common cancer in the world.
• Lung cancer has an estimated incidence of 1.6 million new cases every year, 12.9% of the global cancer incidence
• For years the standard treatment strategies of lung cancer have been surgery, chemotherapy, radiation therapy and targeted therapy.
–>Targeted therapy isn’t as affective for those that are at a more advanced stage
• To date, surgery is the first-choice treatment, but most clinically diagnosed cases are inoperable.
• Chemotherapy and/or radiotherapy are the next options considered for such cases however these treatment modalities have adverse effects and are sometimes lethal to patients.
• Thus, new effective strategies with minimal side effects are urgently needed.
• Recently, tumour immunotherapy has attracted attention as a first line treatment for lung cancer.

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2
Q

what are the 2 types of lung cancer?

A

• Non-small cell lung cancer (NSCLC)–> focusing on this one
– 80% of cases; can be either squamous cell carcinoma, or non-squamous adenocarcinoma or large-cell carcinoma
• Small cell lung cancer
– less common type that usually spreads faster than non-small-cell lung cancer

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3
Q

what are the causes of lung cancer?

A 
•	Causes of lung cancer:
Smoking - over 85% of cases
•	Other causes of lung cancer:
- Exposure to cancer-causing chemicals 
- Family history of lung cancer (genetic associations)
- High levels of air pollution
- High levels of arsenic in drinking water
- Radiation therapy to the lungs
- Asbestos
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4
Q

what is the incidence and prognosis of NSCLC?

A

• Lung cancer mainly affects older people. It’s rare in people younger than 40, and the rates of lung cancer rise sharply with age. Lung cancer is most commonly diagnosed in people aged 70-74.

5 year survival is very poor in stage 3 and 4–> new treatments are requires!

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5
Q

how is lung cancer currently treated?

A

• Early-stage disease is potentially curable, although curative-intent surgery is only feasible in 25–30% of patients (in the USA).
• Squamous cell lung cancer (sqCLC) is an aggressive form of cancer. Patients tend to be older, present at a later stage, and have a high incidence of comorbidities.
• 57% of patients have already distant metastatic disease at diagnosis with a 5-year survival rate of less than 5%.
• 10-35% of NSCLC patients have activating mutations in Epidermal growth factor receptor (EGFR). Targeted therapies against EGFR and other mutated genes have significantly improved outcomes for a molecularly defined subgroup of patients.
• For the majority of patients platinum-based chemotherapy (e.g. Cisplatin, Carboplatin, Pemetrexed) is still the first-line therapy and provides an OS of 10 months.
–>Not that great

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6
Q

what are the advantages and disadvantages of surgery?

A

Pro: potential cure for early stage lung cancer

Con: Tumour cells may remain

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7
Q

what are the advantages and disadvantages of radiotherapy?

A

Pro: could be used as a intent to cure treatment for early NSCLC

Con: Toxicity and poor outcomes for advanced disease

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8
Q

what are the advantages and disadvantages of platinum based chemotherapy?

A

Pro: available as first line therapy, numerous combinations.

Con: toxic and prone to tumour resistance

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9
Q

what are the advantages and disadvantages of targeted therapy?

A

Pro: relatively effective against tumours with defined mutations

Con: Not available for most lung cancer patients, tumours develop resistance

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10
Q

What are the advantages and disadvantages of immunotherapy?

A

Advantages: specific tumour killing with potentially less toxicity. Lots of potential strategies.

Disadvantages: Development of autoimmune reactions, expensive

Immunotherapy has become the 4th modality of cancer–>if its potential is realised= will be best for tumours that can’t be removed by surgery.

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11
Q

what do we mean when say the immune response to cancer?

A

a number of ideas and evidence have emerged to show that the immune response is targeting the tumours at an early stage and clearing them without anyone noticing–>happens on a regular basis. Only when it’s failed= tumour progresses to a clinical stage.

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12
Q

• Paul Ehrlich 1854-1915: Pioneered both chemotherapy and the concept of a ‘magic bullet’
• Burnet and Thomas
– Formulated the immunosurveillance theory in 1957.
Immunosurveillance theory: the immune system constantly monitors the body for transformed cells which maybe malignant. Just as it also scans the body for particular infections it has seen before. Therefore IL-2 has been shown to be efficacious in cancer treatment

A

immunotherapy

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13
Q

in terms of immunotherapy, what has been used since the 1980s?

A

• Interluekin-2: IL-2 is an essential cytokine in the proliferation of T-cells. It’s been used as a cancer therapy since the 1980’s

• Immune-deficiency and cancer
o Evidence that IL-2 plays a role: SCID mice demonstrate increased susceptibility to cancer (particularly Lymphoma’s). HIV-1 patients are more susceptible to certain cancers

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14
Q

what 2 immune responses are involved in cancer immunology?

A

innate and adaptive immune responses.

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15
Q

name and describe the cells of the innate immune system

A

macrophages–> phagocytose tumour cells in a process called immunogenic cell death.

NK cells–> take part in various cytotoxic immune responses.

Dendritic cells–> infiltrate the tumour microenvironment and present antigen to T cells.

Cytokines–> active immune networks and cytotoxic immune responses against tumours.

Chemokines–> recruit leukocytes to different regions.

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16
Q

name and describe the cells of the adaptive immune system

A

T cells–> Involved in tumour elimination and co-ordination of the immune response. these cells are the most important immune cells in cancer therapy immune response…
CD8 cytotoxic T cells, CD4 helper T cells

B cells–> induce antibodies but are also found at a high number within the tumour (Don’t know what they are doing there!)

Gamma-delta T cells–> can target tumour cells via phosphoantigen and NKG2D. These cells have a non-specific mechanism of killing; identify stress ligands like NK cells. They can also target tumours which induce more stress ligands.

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17
Q

what is the immune response to cancer?

A
  • Elimination: The Immune response targets and kills tumour cells
  • Equilibrium: Tumour cells survive but growth and metastasis are held in check by the immune system
  • Escape: Resistant tumour cells lead to clinically apparent cancers
18
Q

what cells are in the tumour mass?

A

• Myeloid-derived suppressor cells–>
o DCs and macrophages
o In the tumour mass, can become myeloid-derived suppressor cells: have an inhibitory function on neighbouring T cells and immune response in general

• Cancer associated fibroblasts–>
o Sometimes the actual tumour cells are a small part of the tumour mass and the tumour microenvironment
o cancer associated fibroblasts and various immunosuppressive cells in the mass can protect the tumour from chemotherapy and immune responses through expressing GFs for tumours

• T-regulatory cells—>
o Can switch off the immune response through the expression of IL-10
o Or checkpoints on the T-reg

• Tumour associated macrophages–>
o Defined as M1 or M2
o M1: anti-tumour (inflammatory phenotype interferon gamma expression)
o M2: pro-tumour (inhibit immune responses)

• TGF-β–>
o Switches off the immune response and helps the tumour cell metastasise
• VEGF
o Can induces angiogenesis and metastasis

The tumour microenvironment is also hypoxic and has various environmental ques and triggers- hostile environment for an immune response

19
Q

what is cancer immunotherapy?

A

• Cancer immunotherapy:
“harnesses the immune system as a therapeutic agent for cancer treatment”

Immunotherapy can involve:
•	Cytokines
•	Cells
•	Antibody
•	Vaccines
•	Oncolytic viruses
•	Immune modulatory compounds (drugs, adjuvants)
20
Q

The virus specifically targets the tumour cell due to the receptor expressed only on tumour cell or overexpressed on tumour cell–> viruses can lyse the tumours and induce a subsequent immune response
If a tumour dies in an immunogenic way= releases DAMPs (damage associated molecular patterns) which activate immune response.
It will also release cytokines like IFN-alpha.
When the tumour dies in that way–> those signals activate the immune response (DCs)–> DCs take the dying cells’ antigen= activate CD8 T cells= epitope spreading
THEREFORE: although the virus hasn’t got an antigen and doesn’t activate CD8 T cells, by targeting the tumour cell in a particular way= you can have epitope spread–> induce diverse CD8 T cell response.

A

lung cancer immunotherapy

21
Q

The first immunotherapies developed for NSCLC were recombinant cytokines. Describe their potential in lung cancer management

A

• These included IL-2 and interferon α which were found to be toxic and ineffective.
• Initial phase II trials for IL-2 were not indicative of clinical benefit either.
• A phase III trial of IL-2 with chemotherapy and hormone therapy reporting a 20% partial response and 50% stable disease among 20 advanced NSCLC patients.
• A subsequent phase II trial showed that the addition of IL-2 to chemotherapy (gemcitabine plus docetaxel) in patients with advanced NSCLC improved responses rates with good tolerability (PMID: 19242101).
• But these findings were not replicated in a phase III randomized trial of IL-2 in combination with chemotherapy with a cisplatin doublet (PMID: 21720704).
• Cytokine therapy is very toxic. Cytokines used ex vivo are more promising.
• Low dose IL-2 is being used slightly more
• Engineered cytokines like engineered IL-15, have similar effects to iL-2 but with lower toxicity–> very promising
• Cytokines like IL-15 and IL-7 have still got potential- as well as low dose IL-2
- Not being used very often
- If they are used in the future, will be in combination with other therapies

22
Q

what is adoptive cell therapy?

A

Cells that direct target the tumour:

  • CAR T-cells
  • CIK cells
  • gamma-delta T cells

one of the ways that tumour cells escapes the immune response= downregulates HLA (used to bind peptide–> HLA-peptide combination interacts with TCR on CD8 T cell). Therefore, if a tumour downregulates HLA, CD8 T cell has no target.
Lots of tumours have low HLA expression–> BUT Lowering HLA= signal for NK cells to kill tumour
= not always easy for the tumour to downregulate or completely remove HLA

23
Q

describe Chimeric antigen receptor (CAR) T cells–

A

Express a fusion protein with an antibody-derived targeting component and T cell activating component.
i.e. involves an antibody that can target a receptor on the tumour (not HLA-peptide).
T cell component activates T cell immune responses (to kill tumour cell)…

  • Promising data targeting CD19 for hematologic malignancies (Approved in –
  • CD19 is on b cells
  • Found that the CAR T cells kill the malignant B cells expressing CD19 and healthy B cells BUT patients seemed to be fine…
  • HOWEVER–> don’t know the cell’s off target effects e.g. if you target CAR T cells to other tumours like lung cancer and healthy lung cells are killed–>maybe a problem
  • Antigen receptors to the tumour antigen mesothelin to target solid tumours including NSCLC.
  • EGFR-targeted CAR T-cells have been tested in a phase I trial of EGFR-positive NSCLC.
  • Next generation CAR T cells: each T cell can have 2-3 CARs for different receptors….
    o i.e. there can be a CAR T cell which will bind to any of 3 receptors on the lung cancer cell if they are present and killed
    o if the cell downregulates 2 of them= CAR T cell can still kill
    o if those 3 receptors are all specific for lung cancer tumour cell, less likely that all 3 will be unhealthy cells–> potentially less toxicity and off-target effects
24
Q

CAR-T-cells
• CAR T-cells have yet to prove efficacious in solid tumours. They will likely select for tumour escape mutants.
• Numerous antigens are being targeted for solid malignancies.
• In bold are the ones that involve antigen found in NSCLC

A

Target antigen- CEF.
Tumour- breast, colerectal, lung, pancreatic.
Phase: 1

Target antigen- EGFR.
Tumour: EGFR positive colerectal, NSCLC, ovarian, pancreatic, renal.
Phase: 1 /2

Target antigen- Mesothelin.
Tumour: Cervical, lung, mesothelioma, ovarian, pancreative

25
Q

How Cytokine-induced killer cells (CIK) cells be used for NSCLC treatment?

A

• Take the blood from the patient–>ex vivo, generate MHC-unrestricted cytotoxic lymphocytes/ expand with anti-CD3 antibodies and cytokines like IFN-gamma, IL-2 and anti-CD3.

  • CIK cells are cytotoxic effector T cells expressing CD3, CD56 and NKG2D
  • CIK cell therapy has showed significant survival benefits in a few NSCLC clinical trials
  • A Meta study found that CIK cell therapy significantly improved the objective response rate and overall survival
  • The CIK cell combined therapy did not present any evidence of major adverse events in patients with NSCLC.

Cheaper, quicker and easier than CAR t cells- but not licensed yet!

26
Q

what do lung cancer vaccines do?

A

• Induce lasting immune responses in the patient.
• Based upon antigen/adjuvant combinations–>
Antigen is so that the T cells which are activated target the tumour

• Many types of vaccine:
DNA/RNA
Peptide (binds to the HLA)
Whole protein
Viral vector
Whole tumour cell
Dendritic cell
27
Q
  • During the last 20 years numerous efforts have been made to use vaccination to enhance anti-lung tumour responses against specific antigen.
  • Most studies have not been successful.
  • Whilst immunological responses are often observed they have rarely corresponded to clinical efficacy.
  • Combination of vaccines and other immunotherapy may result in improving vaccine efficacy.
A

EXAMPLE—>

Vaccine:
MAGE-A3 + proprietary immunological adjuvant.

Phase: 2

Stages: IB/11, MAGE-A3-expressing early stage NSCLC

Results: humoral and cellular immune responses to MAGE-A3 and stastically nonsignificant improvements in disease-free intervals were observed.

vaccines:In phase 2 they show promising immune responses and indicators of efficacy. When they go into larger phase 3 study: the responses are modest and not enough to be licensed.

28
Q

Why haven’t vaccines worked for lung cancer?

A 
•	Vaccines have the potential to induce lasting immune responses with little cytotoxicity.
•	Why haven’t they worked for NSCLC? 
•	They demonstrate a lack of clinically significant outcomes, despite their ability to prime and expand tumour antigen-specific T cells.
• Inhibition by the tumour:
- Reduced antigenicity
- Checkpoints
- Immune suppressive cells
- Loss of antigen

• More recent vaccines regimens are beginning to consider these factors.

29
Q

what has been a breakthrough for immunotherapy?

A

CHECKPOINT INHIBITORS!

• Now licensed by the FDA for use against various tumours:

  • Metastatic melanoma (2015)
  • NSCLC (2015)
  • Renal cell carcinoma (2015)
  • bladder cancer (2016)

cancer cells that have more mutations are more amenable to immunotherapy= the mutations produce antigen (“neoantigen”) which is unique to the tumour= t cells can target

30
Q

“Lung cancer—for so long, the poster child of failed trials—has seen tremendous advances in the last decade. Immunotherapy, previously only considered a promising concept, is now front and centre news as a therapeutic reality in the treatment of advanced NSCLC”.

A

Example:

Nivolumab stops cancerous cells hiding from the body’s own defences, leaving the cancer vulnerable to attack.

The results from 582 people, presented at the American society of clinical oncology, were described as giving real hope to patients”

Lung cancer is the most deadly type of cancer.

31
Q

Checkpoint inhibitors have significantly improved outcomes in patients with metastatic NSCLC and are currently an established second-line therapeutic option.

what are the 2 programmed death-1 (PD-1) inhibitors that have been approved by the Food and Drug Administration (FDA)?

A

• Two programmed death-1 (PD-1) inhibitors named nivolumab and pembrolizumab have been approved by the Food and Drug Administration (FDA) to treat metastatic disease in second line.
Pembro approved as first line therapy for tumours with 50% PDL-1.

• Several clinical trials are ongoing to expand the use of checkpoint inhibitors including in the refractory or front-line setting:

  • As first line therapy
  • In combination with anti-CTLA4 antibodies.
  • In combination with chemotherapy, radiotherapy and vaccines
32
Q

describe PD-1 (a checkpoint inhibitor)

A
  • PD-1 is expressed on T-cells
  • Limits the onset of autoimmunity during inflammation
  • PD-L1 and PDL-2 are expressed on antigen presenting cells and switch off T cell activation
  • Tumour cells express PD-L1 to inhibit anti-tumour immune responses
33
Q

describe the clinical trials around nivolumab (a checkpoint inhibitor)

A

• Randomized, open-label, international phase 3 study of non-squamous NSCLC patients who had progressed during or after platinum-based doublet chemotherapy:

  • Nivolumab OS 12.2 months
  • Docetaxel OS 9.4 months
34
Q

describe the clinical trials around pembrolizumab (a checkpoint inhibitor)

A

• Randomised, open-label, phase 2/3 study at 202 academic medical centres in 24 countries. Patients with previously treated non-small-cell lung cancer with PD-L1 expression on at least 1% of tumour cells:
o 8.5 months with docetaxel.
o 10.4 months with pembrolizumab 2 mg/kg
o 12.7 months with pembrolizumab 10 mg/kg

• Phase III trial for Pembrolizumab as first line therapy for PDL-1 expressing tumours:
o 10.4 months PFS with Pembrolizumab 200mg/kg
o 6 months PFS with platinum-based doublet chemotherapy

35
Q

describe CTLA-4, a checkpoint inhibitor

A
  • T cells require two activating signals
  • Peptide-HLA
  • Co-stimulation of CD28-B7/B8
  • Activated T-cells express CTLA-4 which binds B7/B8 with far greater affinity than CD28
  • This inhibits T-cell activation
  • TGF-β expression by tumour cells upregulates CTLA-4 on T cells.
36
Q

what are problems with checkpoint inhibitors?

A

• It’s very expensive
• They do not work in the majority of people
• Toxicity:
- Autoimmune phenomena, especially combination checkpoint inhibitor therapy.
- Treatment-related adverse events reported in phase II/III trials of checkpoint inhibitors in non-small cell lung cancer.

37
Q

what does the gut microbiome have anything to do with this?

A

• The types of bacteria in the intestine correlate with checkpoint receptor efficacy
• Certain types of bacteria are associated with response
- Bifidobacterium
- Lactobacillus
- Others
- Mechanism of action is unknown however may involve dendritic cells and Th1 immune responses. Colitis is a marker of checkpoint inhibitor efficacy.

• Currently FMT is being studied to determine whether it can improve CPI efficacy.

38
Q

describe combination therapy

A

• The combination of drugs/immunotherapy acting through different mechanisms to inhibit/enhance the same process is the basis for immunotherapeutic combinations with synergistic effect.
• Chemotherapy - Immunotherapy
• Immunotherapy – Immunotherapy
• E.G Phase I study in patients with NSCLC (NCT01454102) comparing nivolumab (checkpoint inhibitor) as monotherapy or combined with:
1. Chemotherapy (Gemcitabine/cisplatin/Carboplatin),
2. Targeted therapy (Erlotinib - EGFR inhibitor or Bevacizumab – VEGF inhibitor)
3. Checkpoint inhibitor (Ipilimumab – anti-CTLA4).

•	Vaccine – chemotherapy/Radiotherapy
•	Vaccine – checkpoint inhibitor:
- Reduced antigenicity
- Checkpoints
- Immune suppressive cells
- Loss of antigen
  • Some combinations can be antagonistic rather than synergistic
  • Combinations may also synergise to increase adverse effects and toxicities
39
Q

what are the potential advances of lung cancer therapy?

A
  • Biomarker discovery to select patients that may respond to a particular therapy.
  • Combination therapy rendering checkpoint inhibitors less toxic, more efficacious and cheaper.
  • The development of CAR T-cells against NSCLC.
  • Combination therapy with vaccination, chemotherapy and immune modulation.
  • Personalised vaccination and neo-antigen.
  • Tackling the Tumour microenvironment (TME).
  • Harnessing intestinal immunity to target cancer.
40
Q

what are the future challenges of lung cancer therapy?

A
  • Costs of therapy
  • Toxicity
  • Increasing incidence of lung cancer; Lung cancer epidemic in China
41
Q

what are some ongoing trials?

A

Trial: Phase III START2 tecemotide vaccine

Details: Effect of tecemotide or placebo in patients with unresectable stage III NSCLC with either stable disease or objective response following primary concurrent chemoradiotherapy.

Trial: Phase III study of MPDL3280A

details: Combination with carboplastin + paclitaxel with or without Bevacizumab in patients with stage IV Non-squamous Non-small cell ljung cancer

Another 360 trials…

cardiovascular and respiratory diseases (13 decks)

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