December 10, 2022
AbbVie Presents Data at the 64th American Society of Hematology (ASH) Annual Meeting for Investigational Navitoclax in Combination With Ruxolitinib for JAK Inhibitor-Naïve Myelofibrosis Patients
  • Exploratory analysis from Cohort 3 of the Phase 2 REFINE study presented in an oral session at ASH

NORTH CHICAGO, Ill., Dec. 10, 2022 /PRNewswire/ -- AbbVie (NYSE: ABBV) today announced new data from Cohort 3 of its Phase 2 REFINE study of investigational navitoclax in combination with ruxolitinib in JAK inhibitor-naïve patients with myelofibrosis (MF). The exploratory analysis suggests the combination of navitoclax and ruxolitinib led to reductions in bone marrow fibrosis (BMF) and variant allele frequency (VAF) for common genetic mutations found in individuals with myelofibrosis that may indicate potential disease modification.1 The findings were shared in an oral presentation (abstract #237) at the 64th American Society of Hematology Annual Meeting & Exposition (ASH).

"While the current standard of care for patients with myelofibrosis can improve disease symptoms, impact on underlying disease biology is limited. It is our hope that patients have an option that goes beyond symptom control," said Mohamed Zaki, M.D., Ph.D., vice president and global head of oncology clinical development, AbbVie. "Consistent with previous evidence, these results suggest navitoclax combination may have disease modifying potential, both as an anti-fibrosis agent and by reducing variant allele frequency of driver mutations."

REFINE (NCT03222609) is a Phase 2 non-randomized open-label multi-cohort study evaluating the safety and efficacy of navitoclax alone or in combination with ruxolitinib in MF.2

These data build on AbbVie's history of transforming standards of care in blood cancers, including recent presentations of investigational navitoclax data from the REFINE study earlier this year at the American Association for Cancer Research (AACR) Annual Meeting and the European Hematology Association (EHA) Annual Congress.  

The findings presented at ASH were based on an exploratory analysis of 32 JAK inhibitor-naïve patients with MF from Cohort 3 of the Phase 2 REFINE study. The primary endpoint was spleen volume reduction of ≥35 percent (SVR35) from baseline at week 24.1 Key secondary and exploratory endpoints evaluated in this analysis were a reduction in BMF and a reduction in VAF for the driver gene mutations (JAK2V617, CALR, MPL or Triple-negative), respectively.1

In this exploratory analysis, SVR35 at week 24 was observed in higher-risk groups, improving over time. The four poor prognosis subgroups were: Type (primary or secondary) of MF (primary MF, 59 percent [n = 10/17]; age (≥75 years, 50 percent [n = 4/8]); prognostic risk score, as measured by Dynamic International Prognostic Scoring System or DIPSS (intermediate-2, 63 percent [n = 12/19]; high, 33 percent [n = 1/3]); and presence of high molecular risk (HMR) mutations (47 percent [n = 9/19].1

In Cohort 3, BMF grade improvement was evaluable in 81 percent (26/32) of patients.1 Of these study participants, 35 percent (9/26) achieved ≥ 1 grade improvement at any time during treatment with a median time-to-improvement of 12.3 weeks.1 Complete resolution of BMF was observed in 22 percent (2/9) of patients.1

Reduction in driver gene mutation VAF > 20% from baseline at week 12 or 24 was observed in 50 percent (14/28) of patients, while 18 percent (5/28) of patients achieved > 50% VAF reduction from baseline. There were no differences in > 20% VAF reductions from baseline to week 12 or 24 between those with or without HMR mutations (47 percent [7/15] versus 54 percent [7/13], respectively).

Preliminary safety analysis identified no new safety signals. Twenty-five (78 percent) patients reported one or more adverse events (AE). The most common grade ≥3 AEs were thrombocytopenia (47 percent), anemia (34 percent), and neutropenia (25 percent). 9.4 percent of patients discontinued therapy due to an AE.3

"These results are promising for patients who need a treatment option that goes beyond just symptom control," said Francesco Passamonti, full professor of hematology, University of Insubria and chief, hematology, Varese Hospital, Italy. "The suggestion of disease modification in this analysis from combination therapy with navitoclax is encouraging, particularly when combined with clinical efficacy in terms of SVR35 rates in the higher risk groups that improved over time." 

About Navitoclax
Navitoclax is an investigational, oral BCL-XL/BCL-2 inhibitor. Navitoclax is not approved by any health authority worldwide at this time. Its safety and efficacy are under evaluation as part of ongoing Phase 2 and registrational Phase 3 studies.

AbbVie has an extensive late-stage clinical trial program for investigational navitoclax that is currently enrolling. Please visit us here for more information about enrolling in a clinical trial.   

About the REFINE Study
REFINE is a multi-cohort, Phase 2, randomized, open-label, multicenter study evaluating the tolerability and efficacy of navitoclax alone or when added to ruxolitinib in patients with myelofibrosis (MF).2 The primary outcome measure is the percentage of patients who achieve spleen volume reduction of greater than or equal to 35 percent (SVR35) from baseline to week 24.2 Secondary outcomes measures include percentage of participants achieving 50 percent reduction in total symptom score from baseline to week 24; anemia response every 12 weeks up to approximately 96 weeks, measured according to current International Working Group-Myeloproliferative Neoplasms Research and European LeukemiaNet (IWG-MRT/ELN) criteria; and change in grade of bone marrow fibrosis assessed according to the European Consensus Grading System.2

Data presented at ASH 2022 include safety and efficacy results from Cohort 3 of REFINE (n=32). Patients in Cohort 3 had primary or secondary MF with splenomegaly (DIPSS ≥ intermediate-1) and had not received JAK-2 therapy or bromodomain and extra terminal motif (BET) inhibitors prior to enrollment. The primary endpoint of SVR35 was assessed by MRI conducted by central review. Key secondary and exploratory endpoints evaluated in this analysis were a reduction in BMF obtained from BM biopsies by local evaluation and a reduction in VAF for the driver gene mutations (JAK2V617, CALR, or MPL), respectively. Studied HMR mutations included ASXL1, EZH2, SRSF2, IDH1/2, and U2AF1 p.Q157. Driver gene VAF and HMR mutations were determined in whole blood with a 50-gene focus myeloid next-generation sequencing panel. The findings presented at ASH 2022 are representative of data from Cohort 3 of the REFINE study as of February 7, 2022.

More information about the REFINE study can be found at (NCT03222609).

About Myelofibrosis
Myelofibrosis (MF) is a rare, difficult-to-treat blood cancer that results in excessive scar tissue formation (fibrosis) in the bone marrow. Patients living with MF experience symptoms such as an enlarged spleen, fatigue, weakness, and severe anemia which are often debilitating and greatly impact quality of life. MF also carries a risk of transformation to more aggressive disease such as acute myeloid leukemia.4

About AbbVie in Oncology
At AbbVie, we are committed to transforming standards of care for multiple blood cancers while advancing a dynamic pipeline of investigational therapies across a range of cancer types. Our dedicated and experienced team joins forces with innovative partners to accelerate the delivery of potentially breakthrough medicines. We are evaluating more than 20 investigational medicines in over 300 clinical trials across some of the world's most widespread and debilitating cancers. As we work to have a remarkable impact on people's lives, we are committed to exploring solutions to help patients obtain access to our cancer medicines. For more information, please visit and our Blood Cancer Press Kit page.

About AbbVie
AbbVie's mission is to discover and deliver innovative medicines that solve serious health issues today and address the medical challenges of tomorrow. We strive to have a remarkable impact on people's lives across several key therapeutic areas: immunology, oncology, neuroscience, eye care, virology, women's health and gastroenterology, in addition to products and services across our Allergan Aesthetics portfolio. For more information about AbbVie, please visit us at Follow @abbvie on Twitter, Facebook, Instagram, YouTube and LinkedIn.

Forward-Looking Statements
Some statements in this news release are, or may be considered, forward-looking statements for purposes of the Private Securities Litigation Reform Act of 1995. The words "believe," "expect," "anticipate," "project" and similar expressions, among others, generally identify forward-looking statements. AbbVie cautions that these forward-looking statements are subject to risks and uncertainties that may cause actual results to differ materially from those indicated in the forward-looking statements. Such risks and uncertainties include, but are not limited to, failure to realize the expected benefits from AbbVie's acquisition of Allergan plc ("Allergan"), failure to promptly and effectively integrate Allergan's businesses, competition from other products, challenges to intellectual property, difficulties inherent in the research and development process, adverse litigation or government action, changes to laws and regulations applicable to our industry and the impact of public health outbreaks, epidemics or pandemics, such as COVID-19. Additional information about the economic, competitive, governmental, technological and other factors that may affect AbbVie's operations is set forth in Item 1A, "Risk Factors," of AbbVie's 2021 Annual Report on Form 10-K, which has been filed with the Securities and Exchange Commission, as updated by its subsequent Quarterly Reports on Form 10-Q. AbbVie undertakes no obligation to release publicly any revisions to forward-looking statements as a result of subsequent events or developments, except as required by law.


  1. Passamonti F, Foran J, Tandra A, et al. The Combination of Navitoclax and Ruxolitinib in JAK Inhibitor-Naïve Patients With Myelofibrosis Mediates Responses Suggestive of Disease Modification. [Oral Presentation #237]. Presented at 2022 American Society of Hematology (ASH) Annual Meeting and Exhibition, December 10-13, 2022.
  2. A Study Evaluating Tolerability and Efficacy of Navitoclax Alone or in Combination With Ruxolitinib in Participants With Myelofibrosis (REFINE). NCT03222609. Available at Last accessed October 2022.
  3. Navitoclax plus ruxolitinib in JAK inhibitor-naïve patients with myelofibrosis: Preliminary safety and efficacy in a multicenter, open-label Phase 2 study. [Oral Presentation S197]. Presented at European Hematology Association 2022 Congress (EHA 2022), June 9-12, 2022.
  4. Tsujimoto Y. (1998). Role of Bcl-2 family proteins in apoptosis: apoptosomes or mitochondria?. Genes to cells: devoted to molecular & cellular mechanisms, 3(11), 697–707.


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