IMFINZI® (durvalumab)-based regimen demonstrated statistically significant and clinically meaningful improvement in event-free survival in resectable early-stage gastric and gastroesophageal junction cancers

Rhea-AI Summary

AstraZeneca announced positive results from the MATTERHORN Phase III trial evaluating IMFINZI® (durvalumab) in combination with FLOT chemotherapy for resectable early-stage gastric and gastroesophageal junction (GEJ) cancers.

The trial demonstrated a statistically significant improvement in event-free survival (EFS) when using IMFINZI plus chemotherapy before and after surgery, followed by IMFINZI monotherapy. The study also showed a strong trend favoring IMFINZI in overall survival at interim analysis.

Notably, the IMFINZI combination more than doubled the pathologic complete response rate (19% versus 7%) compared to neoadjuvant chemotherapy alone. The safety profile remained consistent with known profiles of each medicine, with no new safety findings.

This marks the first Phase III trial demonstrating superior EFS with immunotherapy combination in this setting. The disease affects nearly one million people globally annually, with approximately 62,000 new diagnoses expected in the US, EU, and Japan by 2030 in early-stage and locally advanced cases.

Positive

• Statistically significant improvement in event-free survival
• Pathologic complete response rate doubled to 19% vs 7%
• Strong trend in overall survival improvement
• First successful Phase III immunotherapy trial in this setting

Negative

• None.

Insights

Oncology Clinical Trial Expert

AstraZeneca's MATTERHORN trial results represent a significant breakthrough in gastric cancer treatment. The trial demonstrated that adding IMFINZI to standard FLOT chemotherapy in the perioperative setting significantly improved event-free survival - a critical endpoint measuring time without cancer recurrence or progression following surgery. This positions AstraZeneca to potentially establish a new standard of care in an indication with substantial unmet need.

The magnitude of benefit is compelling, particularly the previously reported pathologic complete response rate of 19% versus 7% with chemotherapy alone. This 2.7-fold improvement in pCR suggests robust anti-tumor activity that translated into the significant EFS improvement. While overall survival data remains immature, the "strong trend" noted suggests the treatment effect will likely extend to this gold-standard endpoint.

With ~43,000 drug-treated patients in advanced markets and projections of 62,000 newly diagnosed patients by 2030, this indication represents a substantial commercial opportunity. Gastric cancer's challenging prognosis (fifth leading cause of cancer death globally) creates an urgent need for more effective therapies.

The clean safety profile (consistent with known profiles of each medication) further strengthens the clinical utility. This perioperative approach aligns with the growing oncology treatment paradigm of moving effective therapies earlier in disease management where curative potential is highest.

Pharmaceutical Market Analyst

These MATTERHORN results meaningfully expand IMFINZI's potential market reach into a significant new indication. Gastric cancer represents AstraZeneca's latest success in their strategy of extending immunotherapy into earlier disease settings where treatment can prevent recurrence rather than just treating advanced disease.

The perioperative treatment approach (pre-surgery, post-surgery, then maintenance) maximizes revenue opportunity with extended treatment duration across multiple phases of care. With gastric cancer being the fifth leading global cancer killer with nearly one million diagnoses annually, this indication offers substantial volume potential.

The market opportunity is clearly quantified: 43,000 current drug-treated patients in US/EU/Japan for early-stage and locally advanced gastric/GEJ cancer, growing to 62,000 newly diagnosed patients by 2030. This represents a valuable addition to IMFINZI's current indications.

AstraZeneca has positioned this development perfectly in its announcement, highlighting it as the "first Phase III trial" showing significant EFS improvement with immunotherapy in this setting. The first-mover advantage gives AstraZeneca significant competitive leverage. The doubling of pathologic complete response rate provides compelling data for both clinicians and payers.

With plans to present at an upcoming medical meeting and engage global regulators, we should expect regulatory submissions within months, setting up potential approvals by late 2025 or early 2026, depending on review timelines.

MATTERHORN is first global, randomized Phase III trial to demonstrate superior event-free survival with an immunotherapy combination over standard of care in this setting

IMFINZI plus chemotherapy more than doubled pathologic complete response rate in previously reported analysis of this trial in 2023

WILMINGTON, Del.--(BUSINESS WIRE)-- Positive high-level results from the MATTERHORN Phase III trial showed perioperative treatment with AstraZeneca’s IMFINZI^® (durvalumab) in combination with standard-of-care FLOT (fluorouracil, leucovorin, oxaliplatin, and docetaxel) chemotherapy demonstrated a statistically significant and clinically meaningful improvement in the primary endpoint of event-free survival (EFS). Patients were treated with neoadjuvant IMFINZI in combination with chemotherapy before surgery, followed by adjuvant IMFINZI in combination with chemotherapy, then IMFINZI monotherapy. The trial evaluated this regimen versus perioperative chemotherapy alone for patients with resectable, early-stage and locally advanced (Stages II, III, IVA) gastric and gastroesophageal junction (GEJ) cancers.

For the secondary endpoint of overall survival (OS), a strong trend was observed in favor of the IMFINZI-based regimen at this interim analysis. The trial will continue to follow OS, which will be formally assessed at the final analysis.

Gastric cancer is the fifth leading cause of cancer death globally, with nearly one million people diagnosed each year.¹ In 2024, there were roughly 43,000 drug-treated patients in the US, European Union (EU) and Japan in early-stage and locally advanced gastric or GEJ cancer.² Approximately 62,000 patients in these regions are expected to be newly diagnosed in this setting by 2030.³

Yelena Y Janjigian, MD, Chief Attending Physician of the Gastrointestinal Medical Oncology Service, Memorial Sloan Kettering Cancer Center, New York and principal investigator in the trial, said: “Despite receiving curative-intent chemotherapy and surgery, patients with gastric cancer commonly face disease recurrence and have a poor prognosis. These exciting data from MATTERHORN show that a durvalumab-based perioperative regimen resulted in a clinically meaningful improvement in patient outcomes, including decreasing the risk of the cancer coming back.”

Cristian Massacesi, Chief Medical Officer and Oncology Chief Development Officer, AstraZeneca, said: “MATTERHORN is the first Phase III trial of an immunotherapy to show a statistically significant improvement in event-free survival in patients with resectable gastric and gastroesophageal junction cancers. This perioperative approach with IMFINZI underscores our commitment to moving into earlier stages of cancer where novel therapies can have the biggest impact on patients’ lives.”

The safety profile for IMFINZI and FLOT chemotherapy was consistent with the known profiles of each medicine, and there were no new safety findings.

In a previously reported interim analysis for the key secondary endpoint of pathologic complete response (pCR), the IMFINZI combination more than doubled the pCR rate compared to neoadjuvant chemotherapy alone (19% versus 7%, odds ratio 3.08; p<0.00001).⁴

Data will be presented at a forthcoming medical meeting and shared with global regulatory authorities.

IMPORTANT SAFETY INFORMATION

There are no contraindications for IMFINZI^® (durvalumab) or IMJUDO^® (tremelimumab-actl).

Severe and Fatal 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 clinical chemistries including liver enzymes, creatinine, adrenocorticotropic hormone (ACTH) level, and thyroid function at baseline and before each dose. 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 and IMJUDO depending on severity. See USPI Dosing and Administration for specific details. In general, if IMFINZI and IMJUDO 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 and IMJUDO can cause immune-mediated pneumonitis, which may be fatal. The incidence of pneumonitis is higher in patients who have received prior thoracic radiation.

• IMFINZI as a Single Agent
  • 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 incidence of pneumonitis (including radiation pneumonitis) in patients with LS-SCLC following chemoradiation within 42 days prior to initiation of IMFINZI in ADRIATIC was 14% (37/262) in patients receiving IMFINZI and 6% (16/265) in patients receiving placebo. Of the patients who received IMFINZI (262), 0.4% had a fatal adverse reaction and 2.7% had 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 or BTC when given in combination with chemotherapy.
• IMFINZI with IMJUDO
  • Immune-mediated pneumonitis occurred in 1.3% (5/388) of patients receiving IMFINZI and IMJUDO, including fatal (0.3%) and Grade 3 (0.2%) adverse reactions.
• IMFINZI with IMJUDO and Platinum-Based Chemotherapy
  • Immune-mediated pneumonitis occurred in 3.5% (21/596) of patients receiving IMFINZI in combination with IMJUDO and platinum-based chemotherapy, including fatal (0.5%), and Grade 3 (1%) adverse reactions.

Immune-Mediated Colitis

IMFINZI with IMJUDO and platinum-based chemotherapy can cause immune-mediated colitis, which may be fatal.

IMFINZI and IMJUDO 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.

• IMFINZI as a Single Agent
  • Immune-mediated colitis occurred in 2% (37/1889) of patients receiving IMFINZI, including Grade 4 (<0.1%) and Grade 3 (0.4%) adverse reactions.
• IMFINZI with IMJUDO
  • Immune-mediated colitis or diarrhea occurred in 6% (23/388) of patients receiving IMFINZI and IMJUDO, including Grade 3 (3.6%) adverse reactions. Intestinal perforation has been observed in other studies of IMFINZI and IMJUDO.
• IMFINZI with IMJUDO and Platinum-Based Chemotherapy
  • Immune-mediated colitis occurred in 6.5% (39/596) of patients receiving IMFINZI in combination with IMJUDO and platinum-based chemotherapy including fatal (0.2%) and Grade 3 (2.5%) adverse reactions. Intestinal perforation and large intestine perforation were reported in 0.1% of patients.

Immune-Mediated Hepatitis

IMFINZI and IMJUDO can cause immune-mediated hepatitis, which may be fatal.

• IMFINZI as a Single Agent
  • 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.
• IMFINZI with IMJUDO
  • Immune-mediated hepatitis occurred in 7.5% (29/388) of patients receiving IMFINZI and IMJUDO, including fatal (0.8%), Grade 4 (0.3%) and Grade 3 (4.1%) adverse reactions.
• IMFINZI with IMJUDO and Platinum-Based Chemotherapy
  • Immune-mediated hepatitis occurred in 3.9% (23/596) of patients receiving IMFINZI in combination with IMJUDO and platinum-based chemotherapy, including fatal (0.3%), Grade 4 (0.5%), and Grade 3 (2%) adverse reactions.

Immune-Mediated Endocrinopathies

• Adrenal Insufficiency: IMFINZI and IMJUDO can cause primary or secondary adrenal insufficiency. For Grade 2 or higher adrenal insufficiency, initiate symptomatic treatment, including hormone replacement as clinically indicated.
  • IMFINZI as a Single Agent
    • Immune-mediated adrenal insufficiency occurred in 0.5% (9/1889) of patients receiving IMFINZI, including Grade 3 (<0.1%) adverse reactions.
  • IMFINZI with IMJUDO
    • Immune-mediated adrenal insufficiency occurred in 1.5% (6/388) of patients receiving IMFINZI and IMJUDO, including Grade 3 (0.3%) adverse reactions.
  • IMFINZI with IMJUDO and Platinum-Based Chemotherapy
    • Immune-mediated adrenal insufficiency occurred in 2.2% (13/596) of patients receiving IMFINZI in combination with IMJUDO and platinum-based chemotherapy, including Grade 3 (0.8%) adverse reactions.
• Hypophysitis: IMFINZI and IMJUDO 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.
  • IMFINZI as a Single Agent
    • Grade 3 hypophysitis/hypopituitarism occurred in <0.1% (1/1889) of patients who received IMFINZI.
  • IMFINZI with IMJUDO
    • Immune-mediated hypophysitis/hypopituitarism occurred in 1% (4/388) of patients receiving IMFINZI and IMJUDO.
  • IMFINZI with IMJUDO and Platinum-Based Chemotherapy
    • Immune-mediated hypophysitis occurred in 1.3% (8/596) of patients receiving IMFINZI in combination with IMJUDO and platinum-based chemotherapy, including Grade 3 (0.5%) adverse reactions.
• Thyroid Disorders (Thyroiditis, Hyperthyroidism, and Hypothyroidism): IMFINZI and IMJUDO 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.
  • IMFINZI as a Single Agent
    • Immune-mediated thyroiditis occurred in 0.5% (9/1889) of patients receiving IMFINZI, including Grade 3 (<0.1%) adverse reactions.
    • Immune-mediated hyperthyroidism occurred in 2.1% (39/1889) of patients receiving IMFINZI.
    • Immune-mediated hypothyroidism occurred in 8.3% (156/1889) of patients receiving IMFINZI, including Grade 3 (<0.1%) adverse reactions.
  • IMFINZI with IMJUDO
    • Immune-mediated thyroiditis occurred in 1.5% (6/388) of patients receiving IMFINZI and IMJUDO.
    • Immune-mediated hyperthyroidism occurred in 4.6% (18/388) of patients receiving IMFINZI and IMJUDO, including Grade 3 (0.3%) adverse reactions.
    • Immune-mediated hypothyroidism occurred in 11% (42/388) of patients receiving IMFINZI and IMJUDO.
  • IMFINZI with IMJUDO and Platinum-Based Chemotherapy
    • Immune-mediated thyroiditis occurred in 1.2% (7/596) of patients receiving IMFINZI in combination with IMJUDO and platinum-based chemotherapy.
    • Immune-mediated hyperthyroidism occurred in 5% (30/596) of patients receiving IMFINZI in combination with IMJUDO and platinum-based chemotherapy, including Grade 3 (0.2%) adverse reactions.
    • Immune-mediated hypothyroidism occurred in 8.6% (51/596) of patients receiving IMFINZI in combination with IMJUDO and platinum-based chemotherapy, including Grade 3 (0.5%) adverse reactions.
  • IMFINZI with Carboplatin and Paclitaxel
    • Immune-mediated hypothyroidism occurred in 14% (34/235) of patients receiving IMFINZI in combination with carboplatin and paclitaxel.
• 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.
  • IMFINZI as a Single Agent
    • Grade 3 immune-mediated Type 1 diabetes mellitus occurred in <0.1% (1/1889) of patients receiving IMFINZI.
  • IMFINZI with IMJUDO
    • Two patients (0.5%, 2/388) had events of hyperglycemia requiring insulin therapy that had not resolved at last follow-up.
  • IMFINZI with IMJUDO and Platinum-Based Chemotherapy
    • Immune-mediated Type 1 diabetes mellitus occurred in 0.5% (3/596) of patients receiving IMFINZI in combination with IMJUDO and platinum-based chemotherapy including Grade 3 (0.3%) adverse reactions.

Immune-Mediated Nephritis with Renal Dysfunction

IMFINZI and IMJUDO can cause immune-mediated nephritis.

• IMFINZI as a Single Agent
  • Immune-mediated nephritis occurred in 0.5% (10/1889) of patients receiving IMFINZI, including Grade 3 (<0.1%) adverse reactions.
• IMFINZI with IMJUDO
  • Immune-mediated nephritis occurred in 1% (4/388) of patients receiving IMFINZI and IMJUDO, including Grade 3 (0.5%) adverse reactions.
• IMFINZI with IMJUDO and Platinum-Based Chemotherapy
  • Immune-mediated nephritis occurred in 0.7% (4/596) of patients receiving IMFINZI in combination with IMJUDO and platinum-based chemotherapy, including Grade 3 (0.2%) adverse reactions.

Immune-Mediated Dermatology Reactions

IMFINZI and IMJUDO 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), has occurred with PD-1/L-1 and CTLA-4 blocking antibodies. Topical emollients and/or topical corticosteroids may be adequate to treat mild to moderate non-exfoliative rashes.

• IMFINZI as a Single Agent
  • Immune-mediated rash or dermatitis occurred in 1.8% (34/1889) of patients receiving IMFINZI, including Grade 3 (0.4%) adverse reactions.
• IMFINZI with IMJUDO
  • Immune-mediated rash or dermatitis occurred in 4.9% (19/388) of patients receiving IMFINZI and IMJUDO, including Grade 4 (0.3%) and Grade 3 (1.5%) adverse reactions.
• IMFINZI with IMJUDO and Platinum-Based Chemotherapy
  • Immune-mediated rash or dermatitis occurred in 7.2% (43/596) of patients receiving IMFINZI in combination with IMJUDO and platinum-based chemotherapy, including Grade 3 (0.3%) adverse reactions.

Immune-Mediated Pancreatitis

IMFINZI in combination with IMJUDO can cause immune-mediated pancreatitis. Immune-mediated pancreatitis occurred in 2.3% (9/388) of patients receiving IMFINZI and IMJUDO, including Grade 4 (0.3%) and Grade 3 (1.5%) 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 and IMJUDO or were reported with the use of other immune-checkpoint inhibitors.

• 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, other transplant (including corneal graft) rejection.

Infusion-Related Reactions

IMFINZI and IMJUDO 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 and IMJUDO based on the severity. See USPI Dosing and Administration for specific details. For Grade 1 or 2 infusion-related reactions, consider using pre-medications with subsequent doses.

• IMFINZI as a Single Agent
  • Infusion-related reactions occurred in 2.2% (42/1889) of patients receiving IMFINZI, including Grade 3 (0.3%) adverse reactions.
• IMFINZI with IMJUDO
  • Infusion-related reactions occurred in 2.6% (10/388) of patients receiving IMFINZI and IMJUDO.
• IMFINZI with IMJUDO and Platinum-Based Chemotherapy
  • Infusion-related reactions occurred in 2.9% (17/596) of patients receiving IMFINZI in combination with IMJUDO and platinum-based chemotherapy, 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 their mechanism of action and data from animal studies, IMFINZI and IMJUDO can cause fetal harm when administered to a pregnant woman. Advise pregnant women of the potential risk to a fetus. In females of reproductive potential, verify pregnancy status prior to initiating IMFINZI and IMJUDO and advise them to use effective contraception during treatment with IMFINZI and IMJUDO and for 3 months after the last dose of IMFINZI and IMJUDO.

Lactation

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

Adverse Reactions

Unresectable Stage III NSCLC

• 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 pneumonia (7%) and pneumonitis/radiation pneumonitis (3.4%).
• 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.

Resectable NSCLC

• In patients with resectable NSCLC in the AEGEAN study, the most common adverse reactions (occurring in ≥20% of patients) were anemia, nausea, constipation, fatigue, musculoskeletal pain, and rash.
• In patients with resectable NSCLC in the neoadjuvant phase of the AEGEAN study receiving IMFINZI in combination with platinum-containing chemotherapy (n=401), permanent discontinuation of IMFINZI due to an adverse reaction occurred in 6.7% of patients. Serious adverse reactions occurred in 21% of patients. The most frequent (≥1%) serious adverse reactions were pneumonia (2.7%), anemia (1.5%), myelosuppression (1.5%), vomiting (1.2%), neutropenia (1%), and acute kidney injury (1%). Fatal adverse reactions occurred in 2% of patients, including death due to COVID-19 pneumonia (0.5%), sepsis (0.5%), myocarditis (0.2%), decreased appetite (0.2%), hemoptysis (0.2%), and death not otherwise specified (0.2%). Of the 401 IMFINZI treated patients who received neoadjuvant treatment and 398 placebo-treated patients who received neoadjuvant treatment, 1.7% (n=7) and 1% (n=4), respectively, did not receive surgery due to adverse reactions.
• In patients with resectable NSCLC in the adjuvant phase of the AEGEAN study receiving IMFINZI as a single agent (n=265), permanent discontinuation of IMFINZI due to an adverse reaction occurred in 8% of patients. Serious adverse reactions occurred in 13% of patients. The most frequent serious adverse reactions reported in >1% of patients were pneumonia (1.9%), pneumonitis (1.1%), and COVID-19 (1.1%). Four fatal adverse reactions occurred during the adjuvant phase of the study, including COVID-19 pneumonia, pneumonia aspiration, interstitial lung disease and aortic aneurysm.

Metastatic NSCLC

• In patients with mNSCLC in the POSEIDON study receiving IMFINZI and IMJUDO plus platinum-based chemotherapy (n=330), the most common adverse reactions (occurring in ≥20% of patients) were nausea (42%), fatigue (36%), musculoskeletal pain (29%), decreased appetite (28%), rash (27%), and diarrhea (22%).
• In patients with mNSCLC in the POSEIDON study receiving IMFINZI in combination with IMJUDO and platinum-based chemotherapy (n=330), permanent discontinuation of IMFINZI or IMJUDO due to an adverse reaction occurred in 17% of patients. Serious adverse reactions occurred in 44% of patients, with the most frequent serious adverse reactions reported in at least 2% of patients being pneumonia (11%), anemia (5%), diarrhea (2.4%), thrombocytopenia (2.4%), pyrexia (2.4%), and febrile neutropenia (2.1%). Fatal adverse reactions occurred in a total of 4.2% of patients.

Limited-stage Small Cell Lung Cancer

• In patients with limited-stage SCLC in the ADRIATIC study receiving IMFINZI (n=262), the most common adverse reactions occurring in ≥20% of patients receiving IMFINZI were pneumonitis or radiation pneumonitis (38%), and fatigue (21%). The most common Grade 3 or 4 adverse reactions (≥3%) were pneumonitis or radiation pneumonitis and pneumonia.
• In patients with limited-stage SCLC in the ADRIATIC study receiving IMFINZI (n=262), IMFINZI was permanently discontinued due to adverse reactions in 16% of the patients receiving IMFINZI. Serious adverse reactions occurred in 30% of patients receiving IMFINZI. The most frequent serious adverse reactions reported in ≥1% of patients receiving IMFINZI were pneumonitis or radiation pneumonitis (12%), and pneumonia (5%). Fatal adverse reactions occurred in 2.7% of patients who received IMFINZI including pneumonia (1.5%), cardiac failure, encephalopathy and pneumonitis (0.4% each).

Extensive-stage Small Cell Lung Cancer

• 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.

Locally Advanced or Metastatic Biliary Tract Cancers

• In patients with locally advanced or metastatic BTC in the TOPAZ-1 study receiving IMFINZI (n=338), the most common adverse reactions (occurring in ≥20% of patients) were fatigue (42%), nausea (40%), constipation (32%), decreased appetite (26%), abdominal pain (24%), rash (23%), and pyrexia (20%).
• In patients with locally advanced or metastatic BTC in the TOPAZ-1 study receiving IMFINZI (n=338), discontinuation due to adverse reactions occurred in 6% of the patients receiving IMFINZI plus chemotherapy. Serious adverse reactions occurred in 47% of patients receiving IMFINZI plus chemotherapy. The most frequent serious adverse reactions reported in at least 2% of patients were cholangitis (7%), pyrexia (3.8%), anemia (3.6%), sepsis (3.3%) and acute kidney injury (2.4%). Fatal adverse reactions occurred in 3.6% of patients receiving IMFINZI plus chemotherapy. These include ischemic or hemorrhagic stroke (4 patients), sepsis (2 patients), and upper gastrointestinal hemorrhage (2 patients).

Unresectable Hepatocellular Carcinoma

• In patients with unresectable HCC in the HIMALAYA study receiving IMFINZI and IMJUDO (n=388), the most common adverse reactions (occurring in ≥20% of patients) were rash (32%), diarrhea (27%), fatigue (26%), pruritus (23%), musculoskeletal pain (22%), and abdominal pain (20%).
• In patients with unresectable HCC in the HIMALAYA study receiving IMFINZI and IMJUDO (n=388), serious adverse reactions occurred in 41% of patients. Serious adverse reactions in >1% of patients included hemorrhage (6%), diarrhea (4%), sepsis (2.1%), pneumonia (2.1%), rash (1.5%), vomiting (1.3%), acute kidney injury (1.3%), and anemia (1.3%). Fatal adverse reactions occurred in 8% of patients who received IMFINZI and IMJUDO, including death (1%), hemorrhage intracranial (0.5%), cardiac arrest (0.5%), pneumonitis (0.5%), hepatic failure (0.5%), and immune-mediated hepatitis (0.5%). Permanent discontinuation of treatment regimen due to an adverse reaction occurred in 14% of patients.

Primary advanced or Recurrent dMMR Endometrial Cancer

• In patients with advanced or recurrent dMMR endometrial cancer in the DUO-E study receiving IMFINZI in combination with carboplatin and paclitaxel followed by IMFINZI as a single-agent (n=44), the most common adverse reactions, including laboratory abnormalities (occurring in >20% of patients) were peripheral neuropathy (61%), musculoskeletal pain (59%), nausea (59%), alopecia (52%), fatigue (41%), abdominal pain (39%), constipation (39%), rash (39%), decreased magnesium (36%), increased ALT (32%), increased AST (30%), diarrhea (27%), vomiting (27%), cough (27%), decreased potassium (25%), dyspnea (25%), headache (23%), increased alkaline phosphatase (20%), and decreased appetite (18%). The most common Grade 3 or 4 adverse reactions (≥3%) were constipation (4.5%) and fatigue (4.5%).
• In patients with advanced or recurrent dMMR endometrial cancer in the DUO-E study receiving IMFINZI in combination with carboplatin and paclitaxel followed by IMFINZI as a single-agent (n=44), permanent discontinuation of IMFINZI due to adverse reactions occurred in 11% of patients. Serious adverse reactions occurred in 30% of patients who received IMFINZI with carboplatin and paclitaxel; the most common serious adverse reactions (≥4%) were constipation (4.5%) and rash (4.5%).

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

Indications:

IMFINZI, as a single agent, 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 (cCRT).

IMFINZI in combination with platinum-containing chemotherapy as neoadjuvant treatment, followed by IMFINZI continued as a single agent as adjuvant treatment after surgery, is indicated for the treatment of adult patients with resectable (tumors ≥4 cm and/or node positive) NSCLC and no known epidermal growth factor receptor (EGFR) mutations or anaplastic lymphoma kinase (ALK) rearrangements.

IMFINZI, in combination with IMJUDO and platinum-based chemotherapy, is indicated for the treatment of adult patients with metastatic NSCLC with no sensitizing EGFR mutations or ALK genomic tumor aberrations.

IMFINZI, as a single agent, is indicated for the treatment of adult patients with limited-stage small cell lung cancer (LS-SCLC) whose disease has not progressed following concurrent platinum-based chemotherapy and radiation therapy (cCRT).

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).

IMFINZI, in combination with gemcitabine and cisplatin, is indicated for the treatment of adult patients with locally advanced or metastatic biliary tract cancer (BTC).

IMFINZI in combination with IMJUDO is indicated for the treatment of adult patients with unresectable hepatocellular carcinoma (uHCC).

IMFINZI in combination with carboplatin and paclitaxel followed by IMFINZI as a single agent is indicated for the treatment of adult patients with primary advanced or recurrent endometrial cancer that is mismatch repair deficient (dMMR).

Please see additional Important Safety Information throughout and Full Prescribing Information including Medication Guide for IMFINZI and IMJUDO.

You may report side effects related to AstraZeneca products.

Notes

Gastric and gastroesophageal junction cancers

Gastric (stomach) cancer is the fifth most common cancer worldwide and the fifth-highest leading cause of cancer mortality.¹ In many regions, its incidence has been increasing in patients younger than 50 years old, along with other gastrointestinal (GI) malignancies.⁵ Nearly one million new patients were diagnosed with gastric cancer in 2022, with approximately 660,000 deaths reported globally.¹

GEJ cancer is a type of gastric cancer that arises from and spans the area where the esophagus connects to the stomach.⁶

Disease recurrence is common in patients with resectable gastric cancer despite undergoing surgery with curative intent and treatment with neoadjuvant/adjuvant chemotherapy. Approximately one in four patients with gastric cancer who undergo surgery develop recurrent disease within one year, and one in four patients do not survive beyond two years, reflecting high unmet medical need.^7-8 Additionally, the five-year survival rate remains poor, with less than half of patients alive at five years.⁹

MATTERHORN

MATTERHORN is a randomized, double-blind, placebo-controlled, multi-center, global Phase III trial evaluating IMFINZI as perioperative treatment for patients with resectable Stage II-IVA gastric and GEJ cancers. Perioperative therapy includes treatment before and after surgery, also known as neoadjuvant/adjuvant therapy. In the trial, 948 patients were randomized to receive a 1500mg fixed dose of IMFINZI plus FLOT chemotherapy or placebo plus FLOT chemotherapy every four weeks for two cycles prior to surgery. This was followed by IMFINZI or placebo every four weeks for up to 12 cycles after surgery (including two cycles of IMFINZI or placebo plus FLOT chemotherapy and 10 additional cycles of IMFINZI or placebo monotherapy).

In the MATTERHORN trial, the primary endpoint is EFS, defined as the time from randomization until progression that precludes surgery or requires non-protocol therapy, local or distant recurrence or progression of disease, or death due to any cause as assessed by blinded independent central review (BICR) according to RECIST 1.1 and/or local pathology testing. Key secondary endpoints include pCR rate, defined as the proportion of patients who have no detectable cancer cells in resected tumor tissue following neoadjuvant therapy, and OS. The trial enrolled participants in 176 centers in 20 countries, including in the US, Canada, Europe, South America and Asia.

IMFINZI

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.

IMFINZI is approved in combination with chemotherapy (gemcitabine plus cisplatin) in locally advanced or metastatic biliary tract cancer (BTC) and in combination with IMJUDO^® (tremelimumab-actl) in unresectable hepatocellular carcinoma (HCC). IMFINZI is also approved as a monotherapy in unresectable HCC in Japan and the EU.

In addition to its indications in GI cancers, IMFINZI is the global standard of care based on OS in the curative-intent setting of unresectable, Stage III non-small cell lung cancer (NSCLC) in patients whose disease has not progressed after chemoradiotherapy (CRT). Additionally, IMFINZI is approved as a perioperative treatment in combination with neoadjuvant chemotherapy in resectable non-small cell lung cancer (NSCLC), and in combination with a short course of IMJUDO and chemotherapy for the treatment of metastatic NSCLC. IMFINZI is also approved for limited-stage small cell lung cancer (SCLC) in patients whose disease has not progressed following concurrent platinum-based CRT; and in combination with chemotherapy (etoposide and either carboplatin or cisplatin) for the treatment of extensive-stage SCLC.

IMFINZI in combination with chemotherapy followed by IMFINZI monotherapy is approved as a 1^st-line treatment for primary advanced or recurrent endometrial cancer (mismatch repair deficient disease only in US and EU). IMFINZI in combination with chemotherapy followed by olaparib and IMFINZI is approved for patients with mismatch repair proficient advanced or recurrent endometrial cancer in EU and Japan.

Since the first approval in May 2017, more than 374,000 patients have been treated with IMFINZI. As part of a broad development program, IMFINZI is being tested as a single treatment and in combinations with other anti-cancer treatments for patients with SCLC, NSCLC, bladder cancer, breast cancer, several GI and gynecologic cancers, and other solid tumors.

AstraZeneca in GI cancers

AstraZeneca has a broad development program for the treatment of GI cancers across several medicines and a variety of tumor types and stages of disease. In 2022, GI cancers collectively represented approximately 5 million new cancer cases leading to approximately 3.3 million deaths.¹⁰

Within this program, the Company is committed to improving outcomes in gastric, liver, biliary tract, esophageal, pancreatic, and colorectal cancers.

In addition to its indications in BTC and HCC, IMFINZI is being assessed in combinations, including with IMJUDO, in liver, esophageal and gastric cancers in an extensive development program spanning early to late-stage disease across settings.

The Company is also assessing rilvegostomig (AZD2936), a PD-1/TIGIT bispecific antibody, in combination with chemotherapy as an adjuvant therapy in BTC and as a 1st-line treatment in patients with HER2-negative, locally advanced unresectable or metastatic gastric and GEJ cancers.

Fam-trastuzumab deruxtecan-nxki, a HER2-directed antibody drug conjugate, is approved in the US and several other countries for HER2-positive advanced gastric cancer. Fam-trastuzumab deruxtecan-nxki is jointly developed and commercialized by AstraZeneca and Daiichi Sankyo.

Olaparib, a first-in-class PARP inhibitor, is approved the US and several other countries for the treatment of BRCA-mutated metastatic pancreatic cancer. Olaparib is developed and commercialized in collaboration with Merck & Co., Inc. (MSD outside the US and Canada).

AstraZeneca is advancing multiple modalities that provide complementary mechanisms for targeting Claudin 18.2, a promising therapeutic target in gastric cancer. These include AZD0901, a potential first-in-class antibody drug conjugate licensed from KYM Biosciences Inc., currently in Phase III development; AZD5863, a novel Claudin 18.2/CD3 T-cell engager bispecific antibody licensed from Harbour Biomed in Phase I development; and AZD6422, an armored autologous chimeric antigen receptor T-cell (CAR T) therapy, currently being evaluated in an Investigator Initiated Trial (IIT) in collaboration with AbelZeta in China.

In early development, AstraZeneca is developing two Glypican 3 (GPC3) armored CAR Ts in HCC. AZD5851, currently in Phase I development, is being developed globally, and C-CAR031 / AZD7003 is being co-developed with AbelZeta in China where it is under evaluation in an IIT.

AstraZeneca in immuno-oncology (IO)

AstraZeneca is a pioneer in introducing the concept of immunotherapy into dedicated clinical areas of high unmet medical need. The Company has a comprehensive and diverse IO portfolio and pipeline anchored in immunotherapies designed to overcome evasion of the anti-tumor immune response and stimulate the body’s immune system to attack tumors.

AstraZeneca strives to redefine cancer care and help transform outcomes for patients with IMFINZI as a monotherapy and in combination with IMJUDO as well as other novel immunotherapies and modalities. The Company is also investigating next-generation immunotherapies like bispecific antibodies and therapeutics that harness different aspects of immunity to target cancer, including cell therapy and T-cell engagers.

AstraZeneca is pursuing an innovative clinical strategy to bring IO-based therapies that deliver long-term survival to new settings across a wide range of cancer types. The Company is focused on exploring novel combination approaches to help prevent treatment resistance and drive longer immune responses. With an extensive clinical program, the Company also champions the use of IO treatment in earlier disease stages, where there is the greatest potential for cure.

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.

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 125 countries, and its innovative medicines are used by millions of patients worldwide. For more information, please visit www.astrazeneca-us.com and follow us on social media @AstraZeneca.

References

1. World Health Organization. International Agency for Research on Cancer. Stomach Fact Sheet. Available at: https://gco.iarc.who.int/media/globocan/factsheets/cancers/7-stomach-fact-sheet.pdf. Accessed March 2025.
2. AstraZeneca PLC. Investor Relations Epidemiology Spreadsheet. Available at: https://www.astrazeneca.com/investor-relations.html. Accessed March 2025.
3. Kantar Health, validated with SEER stage at diagnosis and Cabasag et al. and Kuzuu et al. 2021.
4. Janjigian YY, et al. LBA73 Pathological complete response (pCR) to durvalumab plus 5-fluorouracil, leucovorin, oxaliplatin and docetaxel (FLOT) in resectable gastric and gastroesophageal junction cancer (GC/GEJC): Interim results of the global, phase III MATTERHORN study. Ann Oncol. 2023;34(S2):S1315 - S1316.
5. Li Y, et al. Global burden of young-onset gastric cancer: a systematic trend analysis of the global burden of disease study 2019. Gastric Cancer. 2024;27(4):684-700.
6. National Cancer Institute. Gastroesophageal junction. Available at: https://www.cancer.gov/publications/dictionaries/cancer-terms/def/gastroesophageal-junction. Accessed March 2025.
7. Li Y, et al. Postoperative recurrence of gastric cancer depends on whether the chemotherapy cycle was more than 9 cycles. Medicine. 2022;101(5):e28620.
8. Ilic M, Ilic I. Epidemiology of stomach cancer. World J Gastroenterol. 2022;28(12):1187-1203.
9. Al-Batran SE, et al. Perioperative chemotherapy with fluorouracil plus leucovorin, oxaliplatin, and docetaxel versus fluorouracil or capecitabine plus cisplatin and epirubicin for locally advanced, resectable gastric or gastro-oesophageal junction adenocarcinoma (FLOT4): a randomised, phase 2/3 trial. Lancet. 2019;393(10184):1948-1957.
10. World Health Organization. World Cancer Fact Sheet. Available at https://gco.iarc.who.int/media/globocan/factsheets/populations/900-world-fact-sheet.pdf. Accessed March 2025.

Dr. Janjigian provides consulting and advisory services to AstraZeneca.

US-99020 Last Updated 3/25

View source version on businesswire.com: https://www.businesswire.com/news/home/20250307294024/en/

Media Inquiries

Fiona Cookson +1 212 814 3923

Chelsea Tressler +1 302 885 2677

US Media Mailbox: usmediateam@astrazeneca.com

Source: AstraZeneca

FAQ

What were the key results of the MATTERHORN Phase III trial for IMFINZI (AZN)?

The trial showed statistically significant improvement in event-free survival with IMFINZI plus FLOT chemotherapy, and doubled the pathologic complete response rate to 19% vs 7% compared to chemotherapy alone.

How does the IMFINZI treatment regimen work in the MATTERHORN trial for gastric cancer?

Patients received IMFINZI with chemotherapy before surgery (neoadjuvant), followed by IMFINZI with chemotherapy after surgery (adjuvant), and then IMFINZI alone (monotherapy).

What is the market size for gastric cancer treatment that IMFINZI (AZN) targets?

In 2024, about 43,000 patients in US, EU, and Japan were treated for early-stage and locally advanced gastric cancer, with 62,000 new diagnoses expected by 2030.

What makes the MATTERHORN trial results significant for AZN's IMFINZI?

It's the first Phase III trial showing superior event-free survival with immunotherapy combination in resectable gastric and gastroesophageal junction cancers.