(CPXX) Enrollment is Complete in CPX-351 Phase 2 Study

– Encouraging response rate achieved; including patients with high-risk (secondary) AML (the Phase 3 study population), de novo AML, relapsed AML, and relapsed ALL –

EWING, N.J., June 3, 2015  — Celator Pharmaceuticals, Inc. (Nasdaq: CPXX), a biopharmaceutical company that is transforming the science of combination therapy and developing products to improve patient outcomes in cancer, today announced that enrollment is complete in a Phase 2 pharmacokinetic and pharmacodynamics (PK/PD) study evaluating the effects of CPX-351 (cytarabine:daunorubicin) Liposome Injection on cardiac repolarization in adult patients with acute hematologic malignancies, including acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), and myelodysplastic syndrome (MDS).

The open-label, single-arm, Phase 2 study is a thorough PK/PD assessment designed to: (1) measure the effects of CPX-351 on cardiac repolarization following the first induction cycle of CPX-351, and (2) correlate changes in cardiac repolarization with plasma pharmacokinetic data for cytarabine and daunorubicin and their metabolites. The study began enrolling patients in August 2014.  Each patient received a first induction of CPX-351 on days 1, 3 and 5 and, if necessary, a second induction for patients with reduced leukemia/MDS burden not yet achieving a disease-free state. Responding patients were eligible for up to four consolidation courses. Analysis of treatment impact on cardiac electrophysiology, as measured by the QTc interval, and PK assessments were performed following the first induction course.

The study enrolled patients with newly diagnosed de novo and high-risk (secondary) AML, relapsed/refractory AML and relapsed ALL.  Fifteen of the 26 patients enrolled are evaluable for response at this time. Six of the 15 patients responded to CPX-351 (defined as CR-complete response or CRi-complete response with incomplete hematologic recovery) including 2 of 3 patients (67%) with high-risk (secondary) AML, the study population of the ongoing Phase 3 trial. Responses were also seen in patients with de novo AML, relapsed AML, and relapsed ALL.

“We are happy to report that this study confirms the broad activity of CPX-351 in multiple populations of acute leukemia patients,” said Tara Lin, M.D., Assistant Professor of Medicine at The University of Kansas Cancer Center, the lead investigator of this study, “and will report cardiac repolarization and pharmacokinetic data necessary for the registration of CPX-351 later this year.”

The Phase 2 study was conducted to support the U.S. Food and Drug Administration (FDA) requirements of a New Drug Application (NDA) for CPX-351.  Our Phase 3 study comparing CPX-351 to the current standard of care, known as 7+3, is being conducted in patients with high-risk (secondary) AML.  The Phase 3 study completed enrollment in November 2014.  Initial data from a secondary endpoint, induction response rate, is expected by the end of June 2015.  The primary endpoint data, of overall survival, is expected in the first quarter of 2016.

“We continue to work expeditiously to bring CPX-351 before the FDA as a potential new treatment option for patients with acute hematologic malignancies,” said Scott Jackson, Chief Executive Officer of Celator Pharmaceuticals. “Clinical pharmacology studies are required by the FDA for new drugs in development, so we are pleased to have completed enrollment in this Phase 2 study to support a NDA submission for CPX-351. We expect to report top-line results from this study by the end of the year.”

About Celator Pharmaceuticals, Inc.

Celator Pharmaceuticals, Inc., with locations in Ewing, N.J., and Vancouver, B.C., is a clinical stage biopharmaceutical company that is transforming the science of combination therapy, and developing products to improve patient outcomes in cancer. Celator’s proprietary technology platform, CombiPlex®, enables the rational design and rapid evaluation of optimized combinations incorporating traditional chemotherapies as well as molecularly targeted agents to deliver enhanced anti-cancer activity.  CombiPlex addresses several fundamental shortcomings of conventional combination regimens, as well as the challenges inherent in combination drug development, by identifying the most effective synergistic molar ratio of the drugs being combined in vitro, and fixing this ratio in a nano-scale drug delivery complex to maintain the optimized combination after administration and ensure its exposure to the tumor.  Celator’s pipeline includes lead product, CPX-351 (a liposomal formulation of cytarabine:daunorubicin) for the treatment of acute myeloid leukemia; CPX-1 (a liposomal formulation of irinotecan:floxuridine) for the treatment of colorectal cancer; and a preclinical stage product candidate, CPX-8 (a hydrophobic docetaxel prodrug nanoparticle formulation), being studied by the National Cancer Institute’s Nanotechnology Characterization Laboratory.  The company is advancing the CombiPlex platform and broadening its application to include molecularly targeted therapies and epigenetic modulators.

For more information, please visit Celator’s website at www.celatorpharma.com. Information on ongoing trials is available at www.clinicaltrials.gov.

Forward-Looking Statements:

To the extent that statements contained in this press release are not descriptions of historical facts regarding Celator, they are forward-looking statements reflecting the current beliefs and expectations of management made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Words such as “may,” “will,” “expect,” “anticipate,” “estimate,” “intend,” and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) are intended to identify forward-looking statements. Examples of forward-looking statements contained in this press release include, among others, statements regarding the safety,  efficacy and therapeutic potential of CPX-351, the availability of data from clinical studies, our expectations regarding regulatory approvals and our expectations regarding our research and development programs, expanding our pipeline and advancing our CombiPlex platform. Forward-looking statements in this release involve substantial risks and uncertainties that could cause our clinical development programs, future results, performance or achievements to differ significantly from those expressed or implied by the forward-looking statements. Such risks and uncertainties include, among others, the uncertainties inherent in the conduct of clinical studies, whether the final results of our clinical studies will be supportive of regulatory approval to market CPX-351 and other matters that could affect the commercial potential of our drug candidates. Celator undertakes no obligation to update or revise any forward-looking statements. For a further description of the risks and uncertainties that could cause actual results to differ from those expressed in these forward-looking statements, as well as risks relating to the business of Celator in general, see Celator’s Form 10-K for the year ended December 31, 2014 and other filings by Celator with the U.S. Securities and Exchange Commission.