FibroGen Announces Topline Results from Two Late-Stage Pamrevlumab Pancreatic Cancer Studies and Provides Corporate Update

On July 30, 2024 FibroGen, Inc. (NASDAQ: FGEN) reported topline results from two late-stage trials evaluating the efficacy and safety of pamrevlumab in patients with pancreatic cancer and a corporate update (Press release, FibroGen, JUL 30, 2024, View Source [SID1234645155]).

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The pamrevlumab experimental arm in PanCAN’s Precision Promise Phase 2/3 adaptive platform trial compared treatment with pamrevlumab combined with gemcitabine + nab-paclitaxel to gemcitabine + nab-paclitaxel alone for treatment in first line (1L) and second line (2L) patients with metastatic pancreatic ductal adenocarcinoma (mPDAC). The pamrevlumab arm of the study did not meet the primary endpoint of overall survival as determined by the protocol pre-specified Bayesian statistical analysis.

The Phase 3 LAPIS trial compared treatment with pamrevlumab combined with gemcitabine + nab-paclitaxel or FOLFIRINOX to placebo combined with gemcitabine + nab-paclitaxel or FOLFIRINOX for the treatment of locally advanced, unresectable pancreatic cancer (LAPC). The study did not meet the primary endpoint of overall survival.

"We are deeply disappointed that the pamrevlumab arm in the Precision Promise trial and the LAPIS trial did not meet the primary endpoint of overall survival," said Thane Wettig, Chief Executive Officer, FibroGen. "We were hopeful that pamrevlumab could bring meaningful innovation to pancreatic cancer patients in desperate need of new therapies. FibroGen would like to thank the patients, their families and the clinical trial investigators and teams for their dedication to participating in these studies. I would also like to express my deepest gratitude to our FibroGen colleagues who have dedicated so much of their time and energy for the prospect of bringing much needed therapies to some of the most challenging and deadly diseases affecting humanity."

Based upon the results of the late-stage pamrevlumab trials in pancreatic cancer, the Company plans to implement an immediate and significant cost reduction plan in the U.S. The pamrevlumab development program will be terminated and the Company plans to expeditiously wind down any remaining pamrevlumab obligations. As a result of the cost reduction plan, headcount in the U.S. will be reduced by approximately 75%.

FibroGen’s collaboration agreement with AstraZeneca for roxadustat in China, where roxadustat is the market leader by brand value share in the chronic kidney disease (CKD) anemia category, as well as FibroGen’s collaboration agreement with Astellas for roxadustat in the E.U., Japan, and other territories, remain in place.

PanCAN’s Precision Promise Pamrevlumab Arm Efficacy Results

Given both 1L and 2L pamrevlumab treatment groups graduated into Stage 2 of PanCAN’s Precision Promise study, the hazard ratio for the primary overall survival (OS) analysis assumed a common hazard ratio to estimate a single treatment effect for both 1L and 2L pamrevlumab patients combined compared to patients treated with gemcitabine + nab-paclitaxel. In addition, the pre-specified Bayesian model utilized a hierarchical model that included the borrowing of data from the mFOLFIRINOX control arm to the gemcitabine + nab-paclitaxel control arm for the primary efficacy analysis. The pre-specified primary efficacy analysis was performed in a modified intention-to-treat (mITT) population that included only subjects who initiated treatment. The mITT population in the pamrevlumab arm was comprised of a total of 102 patients in the 1L treatment group and 111 patients in the 2L treatment group and the gemcitabine + nab-paclitaxel control arm was comprised of a total of 34 patients in the 1L treatment group and 36 patients in the 2L treatment group.

Primary OS Analysis as Determined by Pre-Specified Bayesian Statistical Analysis (mITT Population)

Bayesian Model Common Hazard Ratio (HR) Posterior Probability
Median Mean (SD) 95% CI Pr(HR < 1)
Primary Efficacy Analysis 1.170 1.184 (0.175) (0.882, 1.563) 0.13977
LAPIS Efficacy Results

The study did not meet the primary endpoint of overall survival (stratified log-rank p-value=0.55). Median overall survival of 17.3 months was observed in the pamrevlumab combined with gemcitabine + nab-paclitaxel or FOLFIRINOX arm compared to median overall survival of 17.9 months in the control arm of placebo combined with gemcitabine + nab-paclitaxel or FOLFIRINOX (HR: 1.08; 95% CI – 0.83 to 1.41).

Pamrevlumab Safety Results (Precision Promise and LAPIS)

The preliminary safety analyses across both studies indicate that the safety profile of pamrevlumab combined with gemcitabine + nab-paclitaxel or FOLFIRINOX was generally well tolerated with an acceptable safety profile in pancreatic cancer patients. No clinically meaningful differences in treatment emergent adverse events were seen between the treatment arms.

About PanCAN’s Precision Promise
PanCAN’s Precision Promise adaptive platform trial (NCT04229004) is a U.S.-based, seamless Phase 2/3 study sponsored by PanCAN that enrolled patients in 24 sites nationwide. The multi-arm study consists of experimental treatment arms and two comparator arms: gemcitabine + nab-paclitaxel and mFOLFIRINOX. The pamrevlumab experimental arm enrolled 102 patients with mPDAC in first line (1L) and 111 patients with mPDAC in second line (2L). Both 1L and 2L patients received pamrevlumab in combination with gemcitabine and nab-paclitaxel. The final analysis was based upon the data collected up to 12 months after the last patient initiated treatment.

About LAPIS
The LAPIS study is a global Phase 3, randomized, double-blind trial to evaluate the efficacy and safety of neoadjuvant treatment with pamrevlumab or placebo in combination with either gemcitabine + nab-paclitaxel or FOLFIRINOX in the treatment of participants with locally advanced, unresectable pancreatic cancer (LAPC). The study enrolled 284 patients, who were randomized at a 1:1 ratio to receive either pamrevlumab or placebo, in combination with either gemcitabine + nab-paclitaxel or FOLFIRINOX. All patients were dosed up to six cycles of treatment and patients who completed study treatment were evaluated for surgical exploration for possible R0 or R1 resection. Participants who were ineligible for surgical exploration continued to receive treatment as per standard of care (SOC) for each institution.

About Pamrevlumab
Pamrevlumab is a potential first-in-class anti-CTGF fully human monoclonal antibody being developed by FibroGen to inhibit the activity of connective tissue growth factor (CTGF). Pamrevlumab is in clinical development for the treatment of metastatic pancreatic cancer and locally advanced unresectable pancreatic cancer (LAPC). The U.S. Food and Drug Administration has granted Orphan Drug Designation for the treatment of patients with pancreatic ductal adenocarcinoma (PDAC), and Fast Track designation to pamrevlumab for the treatment of patients with LAPC. Pamrevlumab is an investigational drug and not approved for marketing by any regulatory authority. For information about our pamrevlumab studies please visit www.clinicaltrials.gov.