In Pre-Clinical Studies Ibrutinib Enhances Anti-tumor Activity When Combined With An Anti-PD-L1 Antibody

SUNNYVALE, CA, USA I February 27, 2015 I Pharmacyclics, Inc. (NASDAQ: PCYC) today highlighted findings from a pre-clinical study published in the Proceedings of the National Academy of Sciences (www.pnas.org/cgi/doi/10.1073/pnas.1500712112) that showed when ibrutinib (IMBRUVICA®) was combined with an anti-PD-L1 antibody (a checkpoint inhibitor), suppression of tumor growth was enhanced suggesting a greater response might be achieved when treating certain hematologic cancers and solid tumors with the combination. IMBRUVICA is jointly developed and commercialized by Pharmacyclics and Janssen Biotech, Inc.

The paper's senior author, Ronald Levy, M.D., a professor of medicine and director of the lymphoma program at the Stanford University School of Medicine, and colleagues found the combination of an anti-PD-L1 antibody and ibrutinib resulted in suppression of tumor growth and extension of survival in a mouse model of lymphoma. The study found while some of the mice responded to anti-PD-L1 treatment alone, the response eventually diminished over time. When ibrutinib was added to anti-PD-L1 treatment, half of the mice were cured and the other half experienced delays of tumor growth and prolonged survival.

The researchers also chose two solid tumor models to investigate the novel combination - triple negative breast cancer and colon cancer, which do not express BTK (Bruton's tyrosine kinase) and have low levels of the PD-L1 protein. When ibrutinib and the PD-L1 antibody were given as single agents neither had any effect on tumor growth. However, the combination reduced the size of the primary tumors, improved survival and resulted in fewer metastases in both breast and colon cancer. Specifically, in the case of the colon cancer tumor model, approximately 30% of the mice were cured.

Most importantly, the researchers tested whether the mice cured from colon cancer had developed long-term immune memory, specific memory T cells, from the novel combination. These mice were re-exposed to colon cancer cells 90 days post cure and after seven days of tumor growth, all the mice cleared the tumor by day 17 without any additional dosing of the ibrutinib and PD-L1 combination.

Programmed death-ligand (PD-L1) is a protein that may suppress the ability of the immune system to fight diseases. In certain cancers, PD-L1 may play a role in inhibiting the ability of T cells (necessary to help the body fight disease) to function properly, which results in the proliferation of tumors in the human body. Anti-PD-L1 antibody therapies have been shown to block the negative effect that PD-L1 can have on T cells, allowing certain cancers to be successfully treated. Recent pre-clinical studies have also demonstrated that ibrutinib, which has been shown to be effective in treating B-cell mediated cancers, can also inhibit interleukin-2-inducible T-cell kinase (ITK), an enzyme important in regulating T-cell effector function. This activity may be relevant to the mechanism by which ibrutinib enhances the efficacy of check point inhibitors. 

"These findings are very encouraging and support our pursuit of a clinical development strategy that combines ibrutinib with anti-PD-L1 antibodies or other checkpoint inhibitors to maximize the effect that both drugs could have in treating cancer," said Darrin Beaupre, M.D., Ph.D., Head of Early Development and Immunotherapy at Pharmacyclics. "Based on what we've seen pre-clinically, we are optimistic that combinations such as these may help to produce new treatment paradigms for patients with cancer."

While no conclusions about the safety of this combination were drawn, the authors noted while ibrutinib and anti-PD-L1 antibodies have each been well tolerated as single agents, additional study of the combination of these two agents is necessary to fully understand the appropriate dosing, timing and sequencing of combination treatment.

IMBRUVICA will be evaluated with AstraZeneca's investigational anti-PD-L1 immune checkpoint inhibitor, MEDI4736 in patients with several hematologic and solid tumor cancers, all of which are investigational uses for both compounds. IMBRUVICA also will be studied with Bristol-Myers Squibb's human programmed death receptor-1 (PD-1) blocking antibody OPDIVO® (nivolumab) in several hematologic cancers. These clinical studies are expected to begin enrollment in the coming months.

About IMBRUVICA
IMBRUVICA (ibrutinib) is a first-in-class, oral, once-daily therapy that inhibits a protein called Bruton's tyrosine kinase (BTK).1 BTK is a key signaling molecule in the B-cell receptor signaling complex that plays an important role in the survival and spread of malignant B cells.1,2 IMBRUVICA blocks signals that tell malignant B cells to multiply and spread uncontrollably.1

IMBRUVICA is approved for the treatment of patients with chronic lymphocytic leukemia (CLL) who have received at least one prior therapy, CLL patients with del 17p, a genetic mutation that occurs when part of chromosome 17 has been lost, and patients with Waldenström's macroglobulinemia.1

IMBRUVICA is also approved for the treatment of patients with mantle cell lymphoma (MCL) who have received at least one prior therapy. Accelerated approval was granted for the MCL indication based on overall response rate (ORR). Continued approval for the MCL indication may be contingent upon verification of clinical benefit in confirmatory trials.1

IMBRUVICA is being studied alone and in combination with other treatments in several blood cancers. Over 5,100 patients have been treated in clinical trials of IMBRUVICA conducted in 35 countries by more than 800 investigators. Currently, 13 Phase III trials have been initiated with IMBRUVICA and 58 trials are registered on www.clinicaltrials.gov.

IMBRUVICA was one the first medicines to receive U.S. FDA approval via the new Breakthrough Therapy Designation pathway, and is the only product to have received three Breakthrough Therapy Designations.

To learn more about the medical terminology used in this news release, please visit http://stedmansonline.com/.

INDICATIONS
IMBRUVICA is indicated to treat people with:

  • Chronic lymphocytic leukemia (CLL) who have received at least one prior therapy
  • Chronic lymphocytic leukemia (CLL) with 17p deletion
  • Waldenström's macroglobulinemia
  • Mantle cell lymphoma (MCL) who have received at least one prior therapy - accelerated approval was granted for this indication based on overall response rate. Continued approval for this indication may be contingent upon verification of clinical benefit in confirmatory trials.

Patients taking IMBRUVICA for CLL or WM should take 420 mg taken orally once daily (or three 140 mg capsules once daily).

Patients taking IMBRUVICA for MCL should take 560 mg taken orally once daily (or four 140 mg capsules once daily).

Capsules should be taken orally with a glass of water. Capsules should be taken whole. Do not open, break, split or chew the capsules.

IMPORTANT SAFETY INFORMATION

WARNINGS AND PRECAUTIONS

Hemorrhage - Fatal bleeding events have occurred in patients treated with IMBRUVICA®. Grade 3 or higher bleeding events (subdural hematoma, gastrointestinal bleeding, hematuria, and post-procedural hemorrhage) have occurred in up to 6% of patients. Bleeding events of any grade, including bruising and petechiae, occurred in approximately half of patients treated with IMBRUVICA®.

The mechanism for the bleeding events is not well understood. IMBRUVICA® may increase the risk of hemorrhage in patients receiving antiplatelet or anticoagulant therapies. Consider the benefit-risk of withholding IMBRUVICA® for at least 3 to 7 days pre and post-surgery depending upon the type of surgery and the risk of bleeding.

Infections - Fatal and non-fatal infections have occurred with IMBRUVICA® therapy. Grade 3 or greater infections occurred in 14% to 26% of patients. Cases of progressive multifocal leukoencephalopathy (PML) have occurred in patients treated with IMBRUVICA®. Monitor patients for fever and infections and evaluate promptly.

Cytopenias - Treatment-emergent Grade 3 or 4 cytopenias including neutropenia (range, 19 to 29%), thrombocytopenia (range, 5 to 17%), and anemia (range, 0 to 9%) occurred in patients treated with IMBRUVICA®. Monitor complete blood counts monthly.

Atrial Fibrillation - Atrial fibrillation and atrial flutter (range, 6 to 9%) have occurred in patients treated with IMBRUVICA®, particularly in patients with cardiac risk factors, acute infections, and a previous history of atrial fibrillation. Periodically monitor patients clinically for atrial fibrillation. Patients who develop arrhythmic symptoms (eg, palpitations, lightheadedness) or new-onset dyspnea should have an ECG performed. If atrial fibrillation persists, consider the risks and benefits of IMBRUVICA® treatment and dose modification.

Second Primary Malignancies - Other malignancies (range, 5 to 14%) including non-skin carcinomas (range, 1 to 3%) have occurred in patients treated with IMBRUVICA®. The most frequent second primary malignancy was non-melanoma skin cancer (range, 4 to 11%).

Tumor Lysis Syndrome - Tumor lysis syndrome has been reported with IMBRUVICA® therapy. Monitor patients closely and take appropriate precautions in patients at risk for tumor lysis syndrome (e.g. high tumor burden).

Embryo-Fetal Toxicity - Based on findings in animals, IMBRUVICA® can cause fetal harm when administered to a pregnant woman. Advise women to avoid becoming pregnant while taking IMBRUVICA®. If this drug is used during pregnancy or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to a fetus.

ADVERSE REACTIONS

The most common adverse reactions ( > 25%) in patients with B-cell malignancies (MCL, CLL, WM) were thrombocytopenia, neutropenia, diarrhea, anemia, fatigue, musculoskeletal pain, bruising, nausea, upper respiratory tract infection, and rash. Seven percent of patients receiving IMBRUVICA® discontinued treatment due to adverse events.

DRUG INTERACTIONS

CYP3A Inhibitors - Avoid co-administration with strong and moderate CYP3A inhibitors. If a moderate CYP3A inhibitor must be used, reduce the IMBRUVICA® dose.

CYP3A Inducers - Avoid co-administration with strong CYP3A inducers.

SPECIFIC POPULATIONS

Hepatic Impairment - Avoid use in patients with moderate or severe baseline hepatic impairment. In patients with mild impairment, reduce IMBRUVICA® dose.

For additional important safety information, please see Full Prescribing Information at http://www.imbruvica.com/downloads/Prescribing_Information.pdf.

About Pharmacyclics

Pharmacyclics, Inc. (NASDAQ: PCYC) is a biopharmaceutical company focused on developing and commercializing innovative small-molecule drugs for the treatment of cancer and immune mediated diseases. The company's mission is to build a viable biopharmaceutical company that designs, develops and commercializes novel therapies intended to improve quality of life, increase duration of life and resolve serious unmet medical needs. It will do so by identifying and controlling promising product candidates based on scientific development and administrative expertise, developing its products in a rapid, cost-efficient manner and, pursuing commercialization and/or development partners when and where appropriate.

Pharmacyclics markets IMBRUVICA and has three product candidates in clinical development and several preclinical molecules in lead optimization. The company is committed to high standards of ethics, scientific rigor and operational efficiency as it moves each of these programs to commercialization. Pharmacyclics is headquartered in Sunnyvale, CA. To learn more, please visit www.pharmacyclics.com.

SOURCE: Pharmacyclics

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