Results of a Randomized, Double-Blind, Placebo-Controlled, Phase 1b/2 Trial of Nabpaclitaxel + Gemcitabine ± Olaratumab in Treatment-Naïve Participants with Metastatic Pancreatic Cancer

The efficacy and safety of olaratumab plus nabpaclitaxel and gemcitabine in treatment-naïve participants with metastatic pancreatic ductal adenocarcinoma was evaluated. An initial phase 1b dose-escalation trial was conducted to determine the olaratumab dose for the phase 2 trial, a randomized, double-blind, placebo-controlled trial to compare overall survival (OS) in the olaratumab arm vs. placebo arms. In phase 1b, 22 participants received olaratumab at doses of 15 and 20 mg/kg with a fixed dose of nabpaclitaxel and gemcitabine. In phase 2, 159 participants were randomized to receive olaratumab 20 mg/kg in cycle 1 followed by 15 mg/kg in the subsequent cycles (n = 81) or the placebo (n = 78) on days 1, 8, and 15 of a 28-day cycle, plus nabpaclitaxel and gemcitabine. The primary objective of the trial was not met, with a median OS of 9.1 vs. 10.8 months (hazard ratio [HR] = 1.05; 95% confidence interval [CI]: 0.728, 1.527; p = 0.79) and the median progression-free survival (PFS) was 5.5 vs. 6.4 months (HR = 1.19; 95% CI: 0.806, 1.764; p = 0.38), in the olaratumab vs. placebo arms, respectively. The most common treatment-emergent adverse event of any grade across both arms was fatigue. Olaratumab plus chemotherapy failed to improve the OS or PFS in participants with metastatic PDAC. There were no new safety signals.

A phase Ib study evaluating olaratumab in combination with nab-paclitaxel and gemcitabine in first-line treatment of metastatic pancreatic cancer

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Background: Increased platelet-derived growth factor receptor alpha (PDGFRα) expression is linked to epithelial-mesenchymal transition in pancreatic cancer. Olaratumab (O) is a fully human monoclonal antibody against PDGFRα previously approved for the treatment of advanced soft tissue sarcoma. Here, we report the initial safety and antitumor activity data of O in combination with nab-paclitaxel + gemcitabine (nPG) in first-line metastatic pancreatic cancer patients (pts). Methods: In this 3+3 dose escalation study, pts with stage IV pancreatic cancer received intravenous 15 mg/kg (cohort 1) or 20 mg/kg (cohort 2) O + nPG (125 mg/m2/1000 mg/m2) on D1, 8, and 15 of a 28-day cycle. Following dose escalation, additional pts were enrolled in an expansion phase to confirm safety. Primary objective was to determine a dose of O that can be safely combined with nPG. Results: As of September 2018, 10 pts were treated in dose escalation (cohort 1: 3 pts; cohort 2: 7 pts) with no dose-limiting toxicities (DLTs) observed. Safety of 20 mg/kg O + nPG was confirmed in the expansion cohort; 1 of 12 pts (8.3%) experienced a DLT of grade 4 neutropenia. Most frequent adverse events (AEs) (≥ 25%) reported across all cohorts included fatigue (50%); neutropenia (50%); nausea (46%); thrombocytopenia (41%); and constipation (32%). Related grade ≥ 3 AEs reported in > 2 pts were neutropenia (N = 7; 32%), infusion-related reaction, and neuropathy (both N = 3; 14%). There were no deaths related to study drugs. Among pts evaluable for response, 2 of 15 pts had a partial response and 11 pts had stable disease as best response for an objective response rate of 13%. Notably, 2 of 3 pts in cohort 1 continue on treatment for more than 12 months as of the data cut-off. Updated data will be presented at the meeting. Conclusions: Both dose levels were tolerated. Safety profile was similar to nPG chemotherapy with most toxicity manageable through dose adjustments of nPG. Clinical trial information: NCT03086369.

A phase 1b (open-label)/phase 2 (randomized, double-blinded) study evaluating nab-paclitaxel and gemcitabine with or without olaratumab in first-line treatment of metastatic pancreatic cancer

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Background: Olaratumab is a human IgG1 monoclonal antibody that specifically binds human platelet-derived growth factor receptor (PDGFR)-α and blocks PDGF-mediated signaling pathways. Increased PDGFRα expression is observed in pancreatic cancer tissue, and has been suggested to play a role in the mesenchymal transition of pancreatic cancer. An ongoing trial designed to evaluate the safety and efficacy of olaratumab in combination with nab-paclitaxel/gemcitabine (nPG) in patients with unresectable metastatic pancreatic cancer not previously treated for metastatic disease is currently being conducted. Methods: JGDP (NCT03086369) is a global Phase 1b/Phase 2 study being conducted to evaluate the safety and efficacy of olaratumab in combination with nPG as first-line therapy in patients with Stage IV pancreatic cancer (ECOG PS ≤1). In the Phase 1b portion of the study, patients will receive intravenous (iv) olaratumab following a 3+3 dose escalation scheme at two different schedules: on Days 1, 8 and 15 at doses of 15 mg/kg and 20 mg/kg, or on Days 1 and 15 at 20 mg/kg and 25 mg/kg. Olaratumab will be given in combination with nPG (125 mg/m2 iv/1000 mg/m2 iv) on Days 1, 8, and 15 of a 28-day cycle. After the maximum tolerated dose has been identified, additional patients will be enrolled in a cohort expansion to confirm the safety of the combination prior to proceeding to the Phase 2 portion of the study. In the Phase 2 study, approximately 162 patients will be randomized at a 1:1 ratio to receive olaratumab at the recommended Phase 2 dose regimen or placebo, both in combination with nPG (125 mg/m2 iv/1000 mg/m2 iv). Treatment will continue until disease progression or other discontinuation criteria are met. The primary end point of the Phase 2 study is overall survival; a 2-sided α level of 0.20 will be applied. Assuming OS HR = 0.67, there is ≥80% power to show a significant difference in OS between study arms. Secondary end points include progression free survival, duration of response, objective response rate, patient-reported outcomes, and safety. As of September 2017, enrollment for the Phase 1b study is currently ongoing. Clinical trial information: NCT03086369.

A Randomized, Double-Blinded, Phase II Trial of Gemcitabine and Nab-Paclitaxel Plus Apatorsen or Placebo in Patients with Metastatic Pancreatic Cancer: The RAINIER Trial

LESSONS LEARNED

The addition of the heat shock protein 27 (Hsp27)-targeting antisense oligonucleotide, apatorsen, to a standard first-line chemotherapy regimen did not result in improved survival in unselected patients with metastatic pancreatic cancer.Findings from this trial hint at the possible prognostic and predictive value of serum Hsp27 that may warrant further investigation.

BACKGROUND

This randomized, double-blinded, phase II trial evaluated the efficacy of gemcitabine/nab-paclitaxel plus either apatorsen, an antisense oligonucleotide targeting heat shock protein 27 (Hsp27) mRNA, or placebo in patients with metastatic pancreatic cancer.

METHODS

Patients were randomized 1:1 to Arm A (gemcitabine/nab-paclitaxel plus apatorsen) or Arm B (gemcitabine/nab-paclitaxel plus placebo). Treatment was administered in 28-day cycles, with restaging every 2 cycles, until progression or intolerable toxicity. Serum Hsp27 levels were analyzed at baseline and on treatment. The primary endpoint was overall survival (OS).

RESULTS

One hundred thirty-two patients were enrolled, 66 per arm. Cytopenias and fatigue were the most frequent grade 3/4 treatment-related adverse events for both arms. Median progression-free survival (PFS) and OS were 2.7 and 5.3 months, respectively, for arm A, and 3.8 and 6.9 months, respectively, for arm B. Objective response rate was 18% for both arms. Patients with high serum level of Hsp27 represented a poor-prognosis subgroup who may have derived modest benefit from addition of apatorsen.

CONCLUSION

Addition of apatorsen to chemotherapy does not improve outcomes in unselected patients with metastatic pancreatic cancer in the first-line setting, although a trend toward prolonged PFS and OS in patients with high baseline serum Hsp27 suggests this therapy may warrant further evaluation in this subgroup.

RAINIER: A randomized, double-blinded, placebo-controlled phase II trial of gemcitabine (gem) plus nab-paclitaxel (nab-P) combined with apatorsen (A) or placebo (Pl) in patients (pts) with metastatic pancreatic cancer (mPC)

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Background: Heat shock protein 27 (Hsp27) is over-expressed in PC, enabling tumor growth and metastasis. A is an antisense oligonucleotide that binds to Hsp27 mRNA and inhibits production of Hsp27 protein. This randomized phase II trial evaluates the efficacy of gem/nab-P plus A or Pl in pts with mPC. Methods: Pts with untreated mPC were randomized 1:1 to Arm A (gem, nab-P, A) or Arm B (gem, nab-P, Pl). 3 loading doses of 600mg A IV or Pl IV were given, then 600 mg A or Pl weekly with chemotherapy in 28 day cycles. Both arms received gem 1000mg/m2 IV, nab-P 125mg/m2 IV days 1, 8, and 15. Restaging was every 2 cycles. Serum Hsp27 levels were collected at baseline and on treatment. Primary endpoint compared overall survival (OS); secondary endpoints were progression free survival (PFS), response rate (RR), CA 19-9 response, and toxicity. Results: 132 pts were randomized: median age 66 yrs, 57% male, 47% ECOG 0. Demographics were similar for both arms. 36% of pts on Arm A and 48% of pts Arm B discontinued due to progressive disease, and 24% and 14% due to adverse events (AEs). There was a higher incidence of ≥Grade (G) 4 and serious adverse events (SAEs) in Arm A. The most frequently reported G 3/4 treatment-related AEs were anemia (20%), neutropenia (17%), and fatigue (16%) on Arm A and anemia (27%), neutropenia (19%), and thrombocytopenia (13%) on Arm B. Overall RR was 18% on each arm. With a median f/u of 9.1 mos, median PFS and OS are 2.7 and 5.2 mos on Arm A and 3.8 and 6.9 mos on Arm B (p=NS). Correlative analyses between Hsp27 expression and clinical outcomes will be presented. In a statistical model using only Arm B data, 3 base attributes, ECOG >0, liver mets, and neutrophil levels had a strong prognostic relationship to OS. Conclusions: This study showed no improvement in clinical outcomes adding A to gem plus nab-p. G 4 AEs and SAEs were increased with A. We await analysis for Hsp 27 and CA 19-9 levels and further analysis to identify any pt subgroup who might have benefited from the experimental treatment. Clinical trial information: NCT01844817.