Study Evaluating NEOadjuvant Immunotherapy in Resectable PANCreatic Ductal Adenocarcinoma

Brief summary public domain (ClinicalTrials.gov)

The purpose of this study is to determine if study treatment with atezolizumab and PEGPH20 given before and after surgery, followed by chemotherapy is safe and if it can further increase the immune response against the tumor rather than increase the chance of cure.

Detailed description public domain (ClinicalTrials.gov)

Presently, surgical resection offers the only therapeutic means of cure. However only 15%-20% of patients are found to have resectable disease at time of initial diagnosis. Of the patients who undergo curative surgery, most will relapse and eventually succumb to the disease. 5-year survival rates for node-negative and -positive disease at time of pancreatic duodenectomy are 25%-30% and 10%, respectively. Although early phase trials have not offered great success in the metastatic setting for patients with pancreas adenocarcinoma (PDA), interim analysis of a multicenter, phase 1 trial with durvalumab presented at European Society for Medical Oncology (ESMO) indicated a disease control rate of 21%. As mentioned previously, PD-L1 expression correlates with poor prognosis and decreased CD4+ and CD8+ T cell infiltration within the tumor. Targeting PD-L1 in the micrometastatic setting (resectable disease), when robust mature immunosuppressive pathways may not have yet formed, may be the optimum time to investigate anti-PD-L1 therapy. This arm of the study aims to test if atezolizumab is able to modulate CD8+ T-cell infiltration compared to historical matched controls. As a secondary endpoint we will also evaluate how clinical outcomes compare to matched historical controls. Neoplastic, immune, and stromal cells within PDA reside in a highly dense desmoplastic environment composed of an extracellular matrix of which hyaluronidase (HA) is an abundant component. HA is a linear glycosaminoglycan and an integral component of not only PDA tumors, but has also been shown to accumulate in many solid tumors and is associated with a poor prognosis and increased immunosuppression. In a preclinical autochthonous mouse model of PDA, Sunil Hingorani's group demonstrated that the interstitial fluid pressures were unusually high within tumors that exhibited a high HA content. Furthermore, high HA tumors contained low vascularity, which compromised delivery of chemotherapeutic agents, such as gemcitabine. Mice treated with hyaluronidase resulted in decreased HA content and microvasculature re-expansion within tumors which led to a survival benefit. These preclinical studies led to early phase clinical studies in metastatic PDA where addition of PEGPH20 to gemcitabine and nab-paclitaxel (GA) in a randomized phase 2 study demonstrated a survival benefit in patients with HA-high tumors. The objective response rate for patients who were treated with a combination of PEGPH20 and GA compared to GA alone was 45% versus 31%, respectively, and the median overall survival was 11.5 versus 8.5 months, respectively (hazard ratio (HR), 0.96; 95% Confidence Interval (CI), 0.57 to 1.61). A large phase 3 randomized clinical trial in the high HA stage IV PDA population in the first line setting is ongoing.

Detailed description public domain (ClinicalTrials.gov)

PDA likely invokes multiple immune evading mechanisms which result in its aggressive behavior; it is expected that multiple agents will likely be needed to develop effective therapies. One such rationale is the combination of PEGPH20 and immune checkpoint blockade to allow increased cytotoxic T-cell infiltration by increasing vascular permeability and decreasing interstitial pressure. In a breast cancer preclinical model, PEGPH20 resulted in an increase accumulation of CD8+ tumor-infiltrating lymphocytes (TIL) by 176% (p=0.0025) and improved tumor growth inhibition by 38% relative to anti-PD-L1 alone (86% vs 62.4%, p=0.0024). Other preclinical studies are also demonstrating increased CD8+ T-cell infiltration with addition of PEGPH20 and improved tumor control in combination with immune checkpoint blockade. These and other preclinical studies suggest that this combination is worth pursuing in patients with resectable PDA. The combination is hoped to increase CD8+ T-cell infiltration within the primary tumor for improved immune mediated cytotoxicity and decreased interstitial pressure to allow improved surgical resections. Hypothetically, the combination should also be effective in foci of micrometastasis, where the tumor microenvironment (TME) may not be as mature. Identified risks for PEGPH20 include musculoskeletal events (MSEs), infusion-related reactions (IRRs), and thromboembolic (TE) events.

Posted results (ClinicalTrials.gov registry) · primary outcome public domain (ClinicalTrials.gov)

Change in the Number of CD8+ T Cells Within the Tumor [At time of surgery (approximately 3 weeks)].

Posted results (ClinicalTrials.gov registry) · secondary outcome public domain (ClinicalTrials.gov)

18-Month Survival Rate [18 Months].

Posted results (ClinicalTrials.gov registry) · secondary outcome public domain (ClinicalTrials.gov)

Overall Survival [Up to 5 years].

Posted results (ClinicalTrials.gov registry) · secondary outcome public domain (ClinicalTrials.gov)

R0 Resection Rate [At time of surgery (approximately 3 weeks)].

Posted results (ClinicalTrials.gov registry) · secondary outcome public domain (ClinicalTrials.gov)

Incidence of Treatment-Emergent Adverse Events [Cycle 1 through 28 days after adjuvant chemotherapy period].