The main purpose of this study is to evaluate the safety and efficacy of the study drug known as galunisertib administered in combination with the anti-programmed cell death-ligand 1 (PD-L1) antibody durvalumab in participants with refractory metastatic pancreatic cancer.

Inclusion Criteria:

• Must have histologic or cytologic confirmation of recurrent metastatic pancreatic adenocarcinoma based on standard diagnostic criteria. Recurrence must be documented by diagnostic biopsy.
• Have measurable disease as defined by Response Evaluation Criteria in Solid Tumours (RECIST) version 1.1.
• Have had disease progression, been refractory or intolerant to no more than 2 prior systemic regimens for locally advanced or metastatic pancreatic cancer. Participants who have received prior neoadjuvant therapy and who now have metastatic disease must have received 1 of the following for their metastatic disease: FOLFIRINOX, nanoparticle albumin-bound paclitaxel/gemcitabine, TS-1 (tegafur gimeracil oteracil potassium), irinotecan liposome injection/5-fluorouracil (5FU)/Leucovorin or single-agent gemcitabine prior to enrolment in this study.
• Dose Escalation: Able and willing to give valid written consent to undergo a new tumour biopsy (prior to study treatment) or to provide an available archival tumour sample if taken <3 years prior to enrolment if a new tumour biopsy is not feasible with an acceptable clinical risk.
• Cohort Expansion: Able and willing to give valid written consent to undergo a new tumour biopsy (prior to study treatment). Able and willing to undergo a second tumour biopsy on treatment. Where possible, tumour lesions used for new biopsies should not be the same lesions used as RECIST target lesions, unless there are no other lesions suitable for biopsy. Archival samples may be required if there is inadequate tissue in the biopsy specimen.
• Have adequate organ function.
• Have a performance status of 0 or 1 on the Eastern Cooperative Oncology Group (ECOG) scale.
• Use approved contraceptive methods.

Exclusion Criteria:

• Have moderate or severe cardiovascular disease:

  • Have the presence of cardiac disease, including a myocardial infarction within 6 months prior to study entry, unstable angina pectoris, New York Heart Association Class III/IV congestive heart failure, or uncontrolled hypertension.
  • Have documented major electrocardiogram (ECG) abnormalities (not responding to medical treatments; for example, atrial fibrillation, bundle branch blocks, or as approved by the sponsors).
  • Have major abnormalities documented by ECHO with Doppler (for example, moderate or severe heart valve function defect including moderate or severe valve stenosis or regurgitation, left ventricular ejection fraction <50%, evaluation based on the institutional lower limit of normal, septal aneurysm or other heart aneurysm, any aneurysm of the major vessels or any condition that results in increased risk of aneurysm (eg, Marfan syndrome, patent foramen ovale [PFO]).
  • Have predisposing conditions that are consistent with development of aneurysms of the ascending aorta or aortic stress (for example, family history of aneurysms, Marfan syndrome, PFO, bicuspid aortic valve, evidence of damage to the large vessels of the heart documented by computerized tomography [CT] scan with contrast or magnetic resonance imaging [MRI]).

• Have evidence of interstitial lung disease that is symptomatic or may interfere with the detection or management of suspected drug-related pulmonary toxicity or active, noninfectious pneumonitis.