Company Announcements

IMFINZI® (durvalumab) and tremelimumab with chemotherapy demonstrated sustained survival benefit in metastatic non-small cell lung cancer, nearly doubling the number of patients alive after three years vs. chemotherapy

Exploratory analysis from POSEIDON Phase III trial also showed trends for overall survival benefit with a limited course of tremelimumab added to IMFINZI and chemotherapy in subgroups with high unmet need

WILMINGTON, Del.--(BUSINESS WIRE)--Sep. 11, 2022-- Updated results after approximately four years of follow-up of the POSEIDON Phase III trial showed a limited course of tremelimumab when added to AstraZeneca’s IMFINZI® (durvalumab) plus four cycles of chemotherapy demonstrated a sustained improvement in overall survival (OS) compared to chemotherapy alone in the 1st-line treatment of patients with Stage IV (metastatic) non-small cell lung cancer (NSCLC). Additional post-hoc, exploratory analyses continued to show a trend for OS improvement with this combination in patients with STK11, KEAP1 and KRAS-mutated NSCLC, as well as in patients whose tumors were PD-L1-negative (less than 1% tumor cell expression).

These late-breaking results were presented today at the European Society of Medical Oncology (ESMO) Congress 2022 (Abstract #LBA59).

KRAS mutations are the most common tumor growth driver in NSCLC, occurring in approximately 25% of patients. NSCLC tumors with STK11 and KEAP1 mutations are often associated with poor outcomes and classified as immunologically “cold.” KRAS-mutated NSCLC can be responsive to immunotherapy but also can have poor outcomes, particularly when associated with STK11 or KEAP1 co-mutations.1-6

Melissa Johnson, MD, Director of Lung Cancer Research, Sarah Cannon Research Institute at Tennessee Oncology in Nashville, Tennessee, and a lead investigator in the POSEIDON Phase III trial, said: "Metastatic non-small cell lung cancer is a devastating diagnosis, particularly for patients whose cancers are less responsive to standard treatments such as chemotherapy and immune therapy. These results support the addition of a limited course of tremelimumab to durvalumab plus chemotherapy as a potential new treatment option for patients with these harder-to-treat forms of lung cancer.”

Susan Galbraith, Executive Vice President, Oncology R&D, AstraZeneca, said: "These updated POSEIDON results at nearly four years of follow-up show further evidence that the addition of a limited course of tremelimumab to IMFINZIplus chemotherapy improves outcomes for metastatic non-small cell lung cancer patients, including those with specific tumor mutations where a high unmet need for effective, well tolerated treatments remains. We look forward to bringing this potential new treatment option to patients as quickly as possible."

These latest data show that a limited course of five cycles of tremelimumab added to IMFINZI plus platinum-based chemotherapy improved overall survival by 25% compared to chemotherapy alone (hazard ratio [HR] 0.75; 95% CI 0.63-0.88). Updated median OS was 14 months for the combination versus 11.7 for chemotherapy alone. An estimated 25% of patients treated with the combination were alive at three years versus 13.6% for those treated with chemotherapy alone.

A trend for OS improvement continued to be observed in patients with STK11, KEAP1, and KRAS-mutated mNSCLC when treated with the combination, which reduced the risk of death by 38% (based on a HR of 0.62; 95% CI 0.34-1.12), 57% (based on a HR of 0.43; 95% CI 0.16-1.25), and 45% (based on a HR of 0.55; 95% CI 0.36-0.85), respectively. The combination also extended sustained OS benefit to patients with less than 1% PD-L1 tumor cell expression. These post hoc, exploratory subgroup analyses should be interpreted with caution due to the small sample sizes.

Consistent with previous POSEIDON Phase III trial readouts, OS benefit in these updated results appeared more pronounced with tremelimumab plus IMFINZI and chemotherapy in patients with non-squamous NSCLC histology. A 32% improvement in OS compared to chemotherapy alone (HR 0.68; 95% CI 0.55–0.85) was reported for patients with non-squamous histology, with an updated median OS of 17.2 months for the combination versus 13.1 months for chemotherapy. An estimated 31.4% of patients with non-squamous NSCLC treated with the combination were alive at three years versus 17.3% for those receiving chemotherapy alone.

Summary of efficacy resultsi, ii


Tremelimumab + IMFINZI
+ chemotherapy


Intention-To-Treat (ITT)



Median OS (in months)



Hazard ratio (95% CI)iii

0.75 (0.63, 0.88)

OS rate at 3 years (%)






STK11 mutation



Median OS (in months)



Hazard ratio (95% CI)iv

0.62 (0.34, 1.12)

OS rate at 3 years (%)



KEAP1 mutation



Median OS (in months)



Hazard ratio (95% CI)iv

0.43 (0.16, 1.25)

OS rate at 3 years (%)



KRAS mutation



Median OS (in months)



Hazard ratio (95% CI)iv

0.55 (0.36, 0.85)

OS rate at 3 years (%)




STK11 and KRAS subgroup analyses were presented for patients with non-squamous histology; while the KEAP1 subgroup analysis was presented for all mutation-evaluable patients irrespective of tumor histology, due to a small sample size.


Data cut-off (DCO) date: 11 March 2022. Median follow-up in censored patients at DCO: 46.5 months (range 0.0–56.5)


Stratified analysis by PD-L1 expression (TC ≥50% vs <50%), disease stage (IVA vs IVB) and histology


Unstratified analysis 

Tremelimumab plus IMFINZI and chemotherapy continued to be well-tolerated, with no new safety signals identified based on the collection of serious adverse events (AEs) during the approximately four-years of follow-up. Serious treatment-related AEs of any grade occurred in 27.6% of patients in the IMFINZI, tremelimumab and chemotherapy arm versus 17.7% in the chemotherapy alone arm as assessed by investigators. Treatment-related AEs leading to death occurred in 3.3% of patients in the combination arm versus 2.4% in the chemotherapy arm.

These updated results build on the primary progression-free survival (PFS) and OS results presented at the 2021 World Conference on Lung Cancer (WCLC) in September 2021 as well as post-hoc exploratory results in patients with STK11, KEAP1 or KRAS-mutated metastatic NSCLC recently presented at WCLC 2022 in August.

Tremelimumab is under review by global regulatory authorities in combination with IMFINZI and chemotherapy in 1st-line metastatic NSCLC based on the results of the POSEIDON trial.


There are no contraindications for IMFINZI® (durvalumab).

Immune-Mediated Adverse Reactions

Important immune-mediated adverse reactions listed under Warnings and Precautions may not include all possible severe and fatal immune-mediated reactions. Immune-mediated adverse reactions, which may be severe or fatal, can occur in any organ system or tissue. Immune-mediated adverse reactions can occur at any time after starting treatment or after discontinuation. Monitor patients closely for symptoms and signs that may be clinical manifestations of underlying immune-mediated adverse reactions. Evaluate liver enzymes, creatinine, and thyroid function at baseline and periodically during treatment. In cases of suspected immune-mediated adverse reactions, initiate appropriate workup to exclude alternative etiologies, including infection. Institute medical management promptly, including specialty consultation as appropriate. Withhold or permanently discontinue IMFINZI depending on severity. See Dosing and Administration for specific details. In general, if IMFINZI requires interruption or discontinuation, administer systemic corticosteroid therapy (1 mg to 2 mg/kg/day prednisone or equivalent) until improvement to Grade 1 or less. Upon improvement to Grade 1 or less, initiate corticosteroid taper and continue to taper over at least 1 month. Consider administration of other systemic immunosuppressants in patients whose immune-mediated adverse reactions are not controlled with corticosteroid therapy.

Immune-Mediated Pneumonitis

IMFINZI can cause immune-mediated pneumonitis. The incidence of pneumonitis is higher in patients who have received prior thoracic radiation. In patients who did not receive recent prior radiation, the incidence of immune-mediated pneumonitis was 2.4% (34/1414), including fatal (<0.1%), and Grade 3-4 (0.4%) adverse reactions. In patients who received recent prior radiation, the incidence of pneumonitis (including radiation pneumonitis) in patients with unresectable Stage III NSCLC following definitive chemoradiation within 42 days prior to initiation of IMFINZI in PACIFIC was 18.3% (87/475) in patients receiving IMFINZI and 12.8% (30/234) in patients receiving placebo. Of the patients who received IMFINZI (475), 1.1% were fatal and 2.7% were Grade 3 adverse reactions. The frequency and severity of immune-mediated pneumonitis in patients who did not receive definitive chemoradiation prior to IMFINZI were similar in patients who received IMFINZI as a single agent or with ES-SCLC when in combination with chemotherapy.

Immune-Mediated Colitis

IMFINZI can cause immune-mediated colitis that is frequently associated with diarrhea. Cytomegalovirus (CMV) infection/reactivation has been reported in patients with corticosteroid-refractory immune-mediated colitis. In cases of corticosteroid-refractory colitis, consider repeating infectious workup to exclude alternative etiologies. Immune-mediated colitis occurred in 2% (37/1889) of patients receiving IMFINZI, including Grade 4 (<0.1%) and Grade 3 (0.4%) adverse reactions.

Immune-Mediated Hepatitis

IMFINZI can cause immune-mediated hepatitis. Immune-mediated hepatitis occurred in 2.8% (52/1889) of patients receiving IMFINZI, including fatal (0.2%), Grade 4 (0.3%) and Grade 3 (1.4%) adverse reactions.

Immune-Mediated Endocrinopathies

  • Adrenal Insufficiency : IMFINZI can cause primary or secondary adrenal insufficiency. For Grade 2 or higher adrenal insufficiency, initiate symptomatic treatment, including hormone replacement as clinically indicated. Immune-mediated adrenal insufficiency occurred in 0.5% (9/1889) of patients receiving IMFINZI, including Grade 3 (<0.1%) adverse reactions.
  • Hypophysitis : IMFINZI can cause immune-mediated hypophysitis. Hypophysitis can present with acute symptoms associated with mass effect such as headache, photophobia, or visual field cuts. Hypophysitis can cause hypopituitarism. Initiate symptomatic treatment including hormone replacement as clinically indicated. Grade 3 hypophysitis/hypopituitarism occurred in <0.1% (1/1889) of patients who received IMFINZI.
  • Thyroid Disorders : IMFINZI can cause immune-mediated thyroid disorders. Thyroiditis can present with or without endocrinopathy. Hypothyroidism can follow hyperthyroidism. Initiate hormone replacement therapy for hypothyroidism or institute medical management of hyperthyroidism as clinically indicated.
  • Thyroiditis : Immune-mediated thyroiditis occurred in 0.5% (9/1889) of patients receiving IMFINZI, including Grade 3 (<0.1%) adverse reactions.
  • Hyperthyroidism: Immune-mediated hyperthyroidism occurred in 2.1% (39/1889) of patients receiving IMFINZI.
  • Hypothyroidism : Immune-mediated hypothyroidism occurred in 8.3% (156/1889) of patients receiving IMFINZI, including Grade 3 (<0.1%) adverse reactions.
  • Type 1 Diabetes Mellitus, which can present with diabetic ketoacidosis : Monitor patients for hyperglycemia or other signs and symptoms of diabetes. Initiate treatment with insulin as clinically indicated. Grade 3 immune-mediated type 1 diabetes mellitus occurred in <0.1% (1/1889) of patients receiving IMFINZI.

Immune-Mediated Nephritis with Renal Dysfunction

IMFINZI can cause immune-mediated nephritis. Immune-mediated nephritis occurred in 0.5% (10/1889) of patients receiving IMFINZI, including Grade 3 (<0.1%) adverse reactions.

Immune-Mediated Dermatology Reactions

IMFINZI can cause immune-mediated rash or dermatitis. Exfoliative dermatitis, including Stevens-Johnson Syndrome (SJS), drug rash with eosinophilia and systemic symptoms (DRESS), and toxic epidermal necrolysis (TEN), have occurred with PD-1/L-1 blocking antibodies. Topical emollients and/or topical corticosteroids may be adequate to treat mild to moderate non-exfoliative rashes. Immune-mediated rash or dermatitis occurred in 1.8% (34/1889) of patients receiving IMFINZI, including Grade 3 (0.4%) adverse reactions.

Other Immune-Mediated Adverse Reactions

The following clinically significant, immune-mediated adverse reactions occurred at an incidence of less than 1% each in patients who received IMFINZI or were reported with the use of other PD-1/PD-L1 blocking antibodies.

  • Cardiac/vascular: Myocarditis, pericarditis, vasculitis.
  • Nervous system: Meningitis, encephalitis, myelitis and demyelination, myasthenic syndrome/myasthenia gravis (including exacerbation), Guillain-Barré syndrome, nerve paresis, autoimmune neuropathy.
  • Ocular: Uveitis, iritis, and other ocular inflammatory toxicities can occur. Some cases can be associated with retinal detachment. Various grades of visual impairment to include blindness can occur. If uveitis occurs in combination with other immune-mediated adverse reactions, consider a Vogt-Koyanagi-Harada-like syndrome, as this may require treatment with systemic steroids to reduce the risk of permanent vision loss.
  • Gastrointestinal: Pancreatitis including increases in serum amylase and lipase levels, gastritis, duodenitis.
  • Musculoskeletal and connective tissue disorders: Myositis/polymyositis, rhabdomyolysis and associated sequelae including renal failure, arthritis, polymyalgia rheumatic.
  • Endocrine: Hypoparathyroidism
  • Other (hematologic/immune): Hemolytic anemia, aplastic anemia, hemophagocytic lymphohistiocytosis, systemic inflammatory response syndrome, histiocytic necrotizing lymphadenitis (Kikuchi lymphadenitis), sarcoidosis, immune thrombocytopenia, solid organ transplant rejection.

Infusion-Related Reactions

IMFINZI can cause severe or life-threatening infusion-related reactions. Monitor for signs and symptoms of infusion-related reactions. Interrupt, slow the rate of, or permanently discontinue IMFINZI based on the severity. See Dosing and Administration for specific details. For Grade 1 or 2 infusion-related reactions, consider using pre-medications with subsequent doses. Infusion-related reactions occurred in 2.2% (42/1889) of patients receiving IMFINZI, including Grade 3 (0.3%) adverse reactions.

Complications of Allogeneic HSCT after IMFINZI

Fatal and other serious complications can occur in patients who receive allogeneic hematopoietic stem cell transplantation (HSCT) before or after being treated with a PD-1/L-1 blocking antibody. Transplant-related complications include hyperacute graft-versus-host-disease (GVHD), acute GVHD, chronic GVHD, hepatic veno-occlusive disease (VOD) after reduced intensity conditioning, and steroid-requiring febrile syndrome (without an identified infectious cause). These complications may occur despite intervening therapy between PD-1/L-1 blockade and allogeneic HSCT. Follow patients closely for evidence of transplant-related complications and intervene promptly. Consider the benefit versus risks of treatment with a PD-1/L-1 blocking antibody prior to or after an allogeneic HSCT.

Embryo-Fetal Toxicity

Based on its mechanism of action and data from animal studies, IMFINZI can cause fetal harm when administered to a pregnant woman. Advise pregnant women of the potential risk to a fetus. Advise females of reproductive potential to use effective contraception during treatment with IMFINZI and for at least 3 months after the last dose of IMFINZI.


There is no information regarding the presence of IMFINZI in human milk; however, because of the potential for adverse reactions in breastfed infants from IMFINZI, advise women not to breastfeed during treatment and for at least 3 months after the last dose.

Adverse Reactions

  • In patients with Stage III NSCLC in the PACIFIC study receiving IMFINZI (n=475), the most common adverse reactions (≥20%) were cough (40%), fatigue (34%), pneumonitis or radiation pneumonitis (34%), upper respiratory tract infections (26%), dyspnea (25%), and rash (23%). The most common Grade 3 or 4 adverse reactions (≥3%) were pneumonitis/radiation pneumonitis (3.4%) and pneumonia (7%)
  • In patients with Stage III NSCLC in the PACIFIC study receiving IMFINZI (n=475), discontinuation due to adverse reactions occurred in 15% of patients in the IMFINZI arm. Serious adverse reactions occurred in 29% of patients receiving IMFINZI. The most frequent serious adverse reactions (≥2%) were pneumonitis or radiation pneumonitis (7%) and pneumonia (6%). Fatal pneumonitis or radiation pneumonitis and fatal pneumonia occurred in <2% of patients and were similar across arms
  • In patients with extensive-stage SCLC in the CASPIAN study receiving IMFINZI plus chemotherapy (n=265), the most common adverse reactions (≥20%) were nausea (34%), fatigue/asthenia (32%), and alopecia (31%). The most common Grade 3 or 4 adverse reaction (≥3%) was fatigue/asthenia (3.4%)
  • In patients with extensive-stage SCLC in the CASPIAN study receiving IMFINZI plus chemotherapy (n=265), IMFINZI was discontinued due to adverse reactions in 7% of the patients receiving IMFINZI plus chemotherapy. Serious adverse reactions occurred in 31% of patients receiving IMFINZI plus chemotherapy. The most frequent serious adverse reactions reported in at least 1% of patients were febrile neutropenia (4.5%), pneumonia (2.3%), anemia (1.9%), pancytopenia (1.5%), pneumonitis (1.1%), and COPD (1.1%). Fatal adverse reactions occurred in 4.9% of patients receiving IMFINZI plus chemotherapy

The safety and effectiveness of IMFINZI have not been established in pediatric patients.


IMFINZI is indicated for the treatment of adult patients with unresectable Stage III non-small cell lung cancer (NSCLC) whose disease has not progressed following concurrent platinum-based chemotherapy and radiation therapy.

IMFINZI, in combination with etoposide and either carboplatin or cisplatin, is indicated for the first-line treatment of adult patients with extensive-stage small cell lung cancer (ES-SCLC).

Please see complete Prescribing Information, including Medication Guide.



Lung cancer is broadly split into NSCLC and small cell lung cancer (SCLC), with 80-85% classified as NSCLC. 7-9 Within NSCLC, patients are classified as squamous, representing 25-30% of patients, or non-squamous, the most common type representing approximately 70-75% of NSCLC patients.7 Stage IV is the most advanced form of lung cancer and is often referred to as metastatic disease.10 Approximately 5% of patients with metastatic NSCLC will survive 5 years after diagnosis.11


The POSEIDON trial was a randomized, open-label, multi-center, global, Phase III trial of IMFINZIplus platinum-based chemotherapy or IMFINZI, tremelimumab and chemotherapy versus chemotherapy alone in the 1st-line treatment of 1,013 patients with metastatic NSCLC. The trial population included patients with either non-squamous or squamous disease and the full range of PD-L1 expression levels. POSEIDON excluded patients with certain epidermal growth factor receptor (EGFR) mutations or anaplastic lymphoma kinase (ALK) fusions.

In the experimental arms, patients were treated with a flat dose of 1,500mg of IMFINZI, or IMFINZIand 75mg of tremelimumab with up to four cycles of chemotherapy every three weeks, followed by maintenance treatment with IMFINZIonce every four weeks, or IMFINZI and a fifth dose of 75mg of tremelimumab given at week 16. In comparison, the control arm allowed up to six cycles of chemotherapy. Pemetrexed maintenance treatment was allowed in all arms in patients with non-squamous disease if given during the induction phase. Nearly all patients with non-squamous disease (95.5%) had pemetrexed and platinum, while the majority of patients with squamous disease receiving chemotherapy (88.3%) received gemcitabine and platinum.

Primary endpoints included PFS and OS for the IMFINZI plus chemotherapy arm. Key secondary endpoints included PFS and OS in the IMFINZIplus tremelimumab and chemotherapy arm. As both PFS endpoints were met for IMFINZI plus chemotherapy and IMFINZI, tremelimumab and chemotherapy, the prespecified statistical analysis plan allowed for testing OS in the IMFINZIplus tremelimumab and chemotherapy arm. The trial was conducted in more than 150 centers across 18 countries, including the US, Europe, South America, Asia and South Africa.


IMFINZI(durvalumab) is a human monoclonal antibody that binds to the PD-L1 protein and blocks the interaction of PD-L1 with the PD-1 and CD80 proteins, countering the tumor's immune-evading tactics and releasing the inhibition of immune responses.

IMFINZIis the only approved immunotherapy in the curative-intent setting of unresectable, Stage III non-small cell lung cancer (NSCLC) in patients whose disease has not progressed after chemoradiotherapy, and is the global standard of care in this setting based on the PACIFIC Phase III trial.

IMFINZI is currently approved in a number of countries in multiple tumor types including for the treatment of extensive-stage small cell lung cancer (ES-SCLC); for previously treated patients with advanced bladder cancer and for locally advanced or metastatic BTC in combination with chemotherapy (gemcitabine plus cisplatin).

Since the first approval in May 2017, more than 100,000 patients have been treated with IMFINZI.

IMFINZIcombinations have demonstrated clinical benefit in multiple additional cancer settings with positive Phase III trials in unresectable advanced liver cancer (HIMALAYA), metastatic NSCLC (POSEIDON) and resectable NSCLC (AEGEAN). The data from HIMALAYA and POSEIDON are under review with global health authorities.

As part of a broad development program,IMFINZIis being tested as a single treatment and in combinations with other anti-cancer treatments for patients with SCLC, NSCLC, bladder cancer, several GI cancers, ovarian cancer, endometrial cancer and other solid tumors.


Tremelimumab is a human monoclonal antibody and potential new medicine that targets the activity of cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). Tremelimumab blocks the activity of CTLA-4, contributing to T-cell activation, priming the immune response to cancer and fostering cancer cell death.

Beyond POSEIDON, tremelimumab is being tested in combination with IMFINZI across multiple tumor types including in bladder cancer (VOLGA and NILE), locoregional HCC (EMERALD-3) and SCLC (ADRIATIC).

Tremelimumab is also under review by global regulatory authorities in combination with IMFINZI in unresectable advanced liver cancer based on the results of the HIMALAYA Phase III trial.

AstraZeneca in lung cancer

AstraZeneca is working to bring patients with lung cancer closer to cure through the detection and treatment of early-stage disease, while also pushing the boundaries of science to improve outcomes in the resistant and advanced settings. By defining new therapeutic targets and investigating innovative approaches, the Company aims to match medicines to the patients who can benefit most.

The Company’s comprehensive portfolio includes leading lung cancer medicines and the next wave of innovations including osimertinib; durvalumab and tremelimumab; fam-trastuzumab deruxtecan-nxki and datopotamab deruxtecan in collaboration with Daiichi Sankyo; savolitinib in collaboration with HUTCHMED; as well as a pipeline of potential new medicines and combinations across diverse mechanisms of action.

AstraZeneca is a founding member of the Lung Ambition Alliance, a global coalition working to accelerate innovation and deliver meaningful improvements for people with lung cancer, including and beyond treatment.

AstraZeneca in immuno-oncology (IO)

Immunotherapy is a therapeutic approach designed to stimulate the body’s immune system to attack tumors. The Company’s Immuno-Oncology (IO) portfolio is anchored in immunotherapies that have been designed to overcome evasion of the anti-tumor immune response. AstraZeneca is invested in using IO approaches that deliver long-term survival for new groups of patients across tumor types.

The Company is pursuing a comprehensive clinical-trial program that includes IMFINZI as a single treatment and in combination with tremelimumab and other novel antibodies in multiple tumor types, stages of disease, and lines of treatment, and where relevant using the PD-L1 biomarker as a decision-making tool to define the best potential treatment path for a patient.

In addition, the ability to combine the IO portfolio with radiation, chemotherapy, and targeted small molecules from across AstraZeneca’s oncology pipeline, and from research partners, may provide new treatment options across a broad range of tumors.

AstraZeneca in oncology

AstraZeneca is leading a revolution in oncology with the ambition to provide cures for cancer in every form, following the science to understand cancer and all its complexities to discover, develop and deliver life-changing medicines to patients.

The Company’s focus is on some of the most challenging cancers. It is through persistent innovation that AstraZeneca has built one of the most diverse portfolios and pipelines in the industry, with the potential to catalyze changes in the practice of medicine and transform the patient experience.

AstraZeneca has the vision to redefine cancer care and, one day, eliminate cancer as a cause of death.

About AstraZeneca

AstraZeneca is a global, science-led biopharmaceutical company that focuses on the discovery, development, and commercialization of prescription medicines in Oncology, Rare Diseases, and BioPharmaceuticals, including Cardiovascular, Renal & Metabolism, and Respiratory & Immunology. Based in Cambridge, UK, AstraZeneca operates in over 100 countries and its innovative medicines are used by millions of patients worldwide. For more information, please visit and follow us on Twitter @AstraZenecaUS.

US- 68343 Last Updated 9/22

Media Inquiries
Brendan McEvoy,+1 302 885 2677
Jessica McDuell, +1 302 885 2677

US Media Mailbox:

Source: AstraZeneca