End of treatment anti-tumor efficacy in Standard Risk Hepatoblastoma patients shows no adverse outcome related to Sodium Thiosulfate

Research Triangle Park, NC, May 14, 2015 – Fennec Pharmaceuticals, Inc. (TSX: FRX, OTCQB: FENCF), today announced that sodium thiosulfate (STS) will be featured in the abstract titled  “Anti-tumor efficacy in SIOPEL6: A multi-centre open label randomised phase III trial of the efficacy of sodium thiosulphate (STS) in reducing ototoxicity in patients receiving cisplatin (Cis) monotherapy for standard risk hepatoblastoma (SR-HB).” at the American Society of Clinical Oncology (ASCO) being held May 29 through June 2, 2014 in Chicago, IL. The abstract is available as of today on the website http://www.abstract.asco.org/.

The abstract  provides the interim safety results from 94 patients in the study. These results show no adverse outcome related to STS on the anti tumor efficacy in patients receiving cisplatin monotherapy for standard risk hepatoblastoma.

Poster Presentation

Title: Anti-tumor efficacy in SIOPEL 6: A multi-centre open label randomised phase III trial of the efficacy of sodium thiosulphate (STS) in reducing ototoxicity in patients receiving cisplatin (Cis) monotherapy for standard risk hepatoblastoma (SR-HB). (Abstract #10039)
Session: Pediatric Oncology Poster Session
Date: Sunday, May 31, 2015
Presentation Time: 8:00 a.m. – 11:30 AM
Location: McCormick Place, S Hall A, Poster #109
Presenter: Penelope Brock, M.D., PhD, FRCPCH, International Chair of SIOPEL

Preliminary results: From 2007 to end 2014, 45 sites from 12 countries randomized 53 patients to Cis and 60 to Cis+STS, median age at diagnosis was 12.8 months. Treatment was well tolerated and acute toxicity similar between arms. Efficacy results after 4 pre-op chemo cycles for the first 94 patients (47 Cis, 47 Cis+STS) were PR/SD/PD for Cis: 86%/8%/6% and for Cis+STS: 90%/5%/5%. Complete remission after resection and post-op chemo was 92% and 98%. In January 2015, 2 pts had died (Cis arm), and 2 (Cis) and 1 (Cis+STS) had progressed.

Conclusions: End of treatment anti-tumor efficacy in SR-HB treated on the above protocol shows no adverse outcome related to STS. Final evaluation of hearing loss at ≥3.5 yrs of age, the primary endpoint, is expected in 2017.

About Sodium Thiosulfate (STS)

Cisplatin and other platinum compounds are essential chemotherapeutic components for many pediatric malignancies.  Unfortunately platinum-based therapies cause ototoxicity in many patients, and are particularly harmful to the survivors of pediatric cancer.

In the U.S., it is estimated that over 2,000 children are diagnosed with local cancers that may receive platinum based chemotherapy and globally over 5,000.   The incidence of hearing loss in these children depends upon the dose and duration of chemotherapy, and many of these children require lifelong hearing aids. There is currently no established preventive agent for this hearing loss and only expensive, technically difficult and sub-optimal cochlear (inner ear) implants have been shown to provide some benefit. Infants and young children at critical stages of development lack speech language development and literacy, and older children and adolescents lack social-emotional development and educational achievement.

STS has been studied by cooperative groups in two Phase 3 clinical studies of survival and reduction of ototoxicity, The Clinical Oncology Group Protocol ACCL0431 and SIOPEL 6. Both studies are closed to recruitment. The COG ACCL0431 protocol enrolled one of five childhood cancers typically treated with intensive cisplatin therapy for localized and disseminated disease, including newly diagnosed hepatoblastoma, germ cell tumor, osteosarcoma, neuroblastoma, and medulloblastoma.  SIOPEL 6 enrolled only hepatoblastoma patients with localized tumors.

About Fennec Pharmaceuticals

Fennec Pharmaceuticals, Inc., is a specialty pharmaceutical company focused on the development of Sodium Thiosulfate (STS) for  the prevention of platinum-induced ototoxicity in pediatric patients. STS has received Orphan Drug Designation in the US in this setting. For more information, please visit www.fennecpharma.com.

Forward looking statements

Except for historical information described in this press release, all other statements are forward-looking. Forward-looking statements are subject to certain risks and uncertainties inherent in the Company’s business that could cause actual results to vary, including such risks that regulatory and guideline developments may change, scientific data may not be sufficient to meet regulatory standards or receipt of required regulatory clearances or approvals, clinical results may not be replicated in actual patient settings, protection offered by the Company’s patents and patent applications may be challenged, invalidated or circumvented by its competitors, the available market for the Company’s products will not be as large as expected, the Company’s products will not be able to penetrate one or more targeted markets, revenues will not be sufficient to fund further development and clinical studies, the Company may not meet its future capital requirements in different countries and municipalities, and other risks detailed from time to time in the Company’s filings with the Securities and Exchange Commission including its Annual Report on Form 10-K for the year ended December 31, 2014. Fennec Pharmaceuticals, Inc. disclaims any obligation to update these forward-looking statements except as required by law.

For a more detailed discussion of related risk factors, please refer to our public filings available at www.sec.gov and www.sedar.com.

For further information, please contact:

Rosty Raykov

Chief Executive Officer

Fennec Pharmaceuticals Inc.

T: (919) 636-5144