Hingorani, Sunil R.

Background: Stromal hyaluronic acid (HA) poses a physical barrier and protects tumor cells from immune surveillance. Stroma targeting with pegylated human recombinant PH20 hyaluronidase (PEGPH20) demonstrated improved infiltration of cytotoxic T-lymphocytes and delivery of chemotherapy and PD1/PD-L1 antibodies in tumor models. This multicenter phase II study of PEGPH20 plus pembrolizumab evaluated the efficacy, safety and immune and stromal biomarkers in patients with HA-high refractory metastatic pancreatic ductal adenocarcinoma (mPDA). Patients and Methods: Patients were treated with PEGPH20 3 µg/kg IV weekly and pembrolizumab 200 mg IV in 3-week cycles. Tumor and blood samples were collected at baseline and on-study for biomarker analyses. Results: Between May and November 2019, 38 patients were screened and 8 treated, with median age 68 years (range 60–73) and median two (range 1–4) prior therapies. The study was closed to accrual early by pharmaceutical sponsor. Treatment was well tolerated, with expected grade 1/2 musculoskeletal toxicities. Best response was stable disease in 2 of 7 evaluable patients (29%). Median overall and progression-free survival were 7.2 months (95% CI 1.2–11.8) and 1.5 months (95% CI 0.9–4.4), respectively. Prolonged survival (range 10.2–27.6 months) occurred in patients treated with subsequent chemotherapy. Higher baseline tumor T cell receptor (TCR) clonality correlated with longer survival. Conclusions: Pembrolizumab with PEGPH20 was safe but did not have significant efficacy in refractory HA-high metastatic PDA.

PURPOSE Pegylated recombinant human hyaluronidase (PEGPH20) degrades hyaluronan (HA) and, in combination with chemotherapy, prolongs survival in preclinical models. The activity of PEGPH20 with modified fluorouracil, leucovorin, irinotecan, and oxaliplatin (mFOLFIRINOX) was evaluated in patients with metastatic pancreatic cancer (mPC). MATERIALS AND METHODS Patients had untreated mPC, a performance status of 0 to 1, and adequate organ function. Tumor HA status was not required for eligibility. After a phase Ib dose-finding study of mFOLFIRINOX plus PEGPH20, the phase II open-label study randomly assigned patients (1:1) to the combination arm or to mFOLFIRINOX alone (n = 138). The primary end point was overall survival (OS). RESULTS PEGPH20 dosages of 3 µg/kg every 2 weeks were more tolerable than twice-weekly dosages used in the phase I study, so 3 µg/kg every 2 weeks was the phase II dosage. An amendment instituted enoxaparin prophylaxis in the PEGPH20 combination arm as a result of increased thromboembolic (TE) events. The planned interim futility analysis when 35 deaths (of 103 analyzable patients) occurred resulted in an OS hazard ratio (HR) of 2.07 that favored the control arm, and the study was closed to accrual. The treatment-related grade 3 to 4 toxicity was significantly increased in the PEGPH20 combination arm relative to control (odds ratio, 2.7; 95% CI, 1.1 to 7.1). The median OS in the mFOLFIRINOX arm was 14.4 months (95% CI, 10.1 to 15.7 months) versus 7.7 months (95% CI, 4.6 to 9.3 months) in the PEGPH20 combination arm. CONCLUSION Addition of PEGPH20 to mFOLFIRINOX seems to be detrimental in patients unselected for tumor HA status. This combination caused increased toxicity (mostly GI and TE events) and resulted in decreased treatment duration compared with mFOLFIRINOX alone. The median OS in the mFOLFIRINOX control arm (14.4 months) is, to our knowledge, the longest yet reported and can be considered for patients with good PS.

208 Background: PEGPH20 degrades hyaluronan (HA), a major component of the stroma, increases delivery of gemcitabine and prolongs survival in preclinical models. We evaluated the activity of PEGPH20 in combination with mFFOX in mPC , unselected for tumor HA. Methods: Pertinent eligibility: untreated mPC, PS of 0-1 and adequate organ function. Standard FFOX was modified to add prophylactic growth factor support and omit bolus 5FU. Due to increased thromboembolic (TE) events with PEGPH20, an amendment instituted LMWH prophylaxis in the PEGPH20 arm only. Following a dose finding cohort of mFFOX + PEGPH20, the Phase II study randomized patients (1:1) to the combination arm or mFFOX alone (n = 138). The primary endpoint was overall survival (OS), with a null median OS of 10 mo and an alternative of 15 mo (1-sided type 1 error 0.1, 80% power). Results: PEGPH20 at 3 mcg/kg, q2 weeks was more tolerable than twice weekly dosing. The randomized phase II study began May 2015. The planned interim futility analysis when 35 deaths occurred gave a HR of 0.44 favoring the standard arm, thus the study was closed to accrual (March 2017). As of August 22, 2017 (n = 111), the estimated median OS in the mFFOX arm was 15.1 mo (95% CI 10.1-15.7) vs 7.6 mo (95% CI 4.6-9.2) in the PEGPH20 arm. Conclusions: OS in the mFFOX control arm (15.1 mo) is longest yet reported. Addition of PEGPH20 to mFFOX is not recommended for further study and appears to be detrimental (HR = 0.48). The impact of PEGPH20 on OS was unexpected and in contrast to favorable results reported for the combination of gemcitabine/nab-paclitaxel + PEGPH20 especially in the HA high cohort (Hingorani S et al. A 4008, ASCO 2017). PEGPH20 with mFFOX caused increased toxicity (mostly GI and TE events) and decreased treatment duration compared to mFFOX alone. Tumor HA content will be analyzed. Funding: NIH/NCI grants CA180888, CA180819; and in part by Halozyme Inc. Clinical trial information: 01959139. [Table: see text]

Abstract Background. nab-Paclitaxel in combination with gemcitabine has emerged as a new treatment option for patients with metastatic pancreatic cancer (MPC), based on superiority over gemcitabine demonstrated in the phase III MPACT trial. Previously, Karnofsky performance status (KPS) score and the presence of liver metastases were shown to be predictive of survival with nab-paclitaxel plus gemcitabine treatment. This analysis sought to further explore the relationship between clinical characteristics and survival in the MPACT trial and to identify potential predictors of overall survival and progression-free survival in patients with MPC. Materials and Methods. Cox regression models adjusted for stratification factors and a stepwise multivariate analysis of prespecified baseline prognostic factors were performed. Results. Treatment effect was significantly associated with survival, with a similar magnitude of reduction in risk of death compared with the previously reported primary analysis. Treatment effect consistently favored nab-paclitaxel plus gemcitabine across the majority of the prespecified factors. In addition to KPS score and presence of liver metastases, age and number of metastatic sites were independent prognostic factors of overall and progression-free survival. Baseline carbohydrate antigen 19-9 was not found to be an independent prognostic factor of survival in this analysis. Conclusion. The results of this analysis confirm broad utility of nab-paclitaxel plus gemcitabine for the treatment of MPC. In addition, these findings suggest that KPS score, presence of liver metastases, age, and number of metastatic sites are important predictors of survival that may be useful when making treatment decisions and designing future clinical trials.