– ISA101b and cemiplimab studied in patients with platinum refractory HPV16-positive oropharyngeal cancer (OPC)

Leiden, The Netherlands, January 21, 2019 – ISA Pharmaceuticals B.V., a clinical-stage company dedicated to the development of rationally designed immunotherapeutics, today announced randomization of the first patient in a Phase 2 combination trial of its lead compound ISA101b and Regeneron´s (NASDAQ: REGN) anti-PD-1 antibody cemiplimab (REGN2810).

This double blind, placebo-controlled, randomized, phase 2 study (NCT03669718) will enroll approximately 164 patients with HPV16-positive oropharyngeal cancer (OPC), who have failed first-line chemotherapy. Patients will be randomly allocated on a 1:1 basis to the combination of cemiplimab/ISA101b or cemiplimab/placebo. In both study arms, patients will receive treatment in cycles of 3 weeks for up to 24 months. The primary efficacy objective of this trial is to assess whether the addition of ISA101b to cemiplimab will elicit a higher Overall Response Rate (ORR, as per RECIST 1.1 criteria) compared to cemiplimab plus placebo. Secondary endpoints include Progression Free Survival (PFS), Overall Survival (OS), as well as safety and tolerability of cemiplimab plus ISA101b (as compared to cemiplimab plus placebo). The study will be conducted at approximately 50 investigative sites in the USA and Europe.

ISA Pharmaceuticals´ lead compound ISA101 is a clinical-stage SLP^® immunotherapy targeting HPV16-induced diseases such as cervical cancer and head–and-neck cancer. It induces specific immune responses to the oncogenic E6 and E7 antigens of HPV16. Cemiplimab, also known as REGN2810, is currently under review by EMA and was approved by the U.S. Food and Drug Administration in September 2018 under the brand name Libtayo^® as monotherapy for patients with advanced cutaneous squamous cell carcinoma. Regeneron, in collaboration with Sanofi, is developing cemiplimab both alone and in combination with other therapies for the treatment of various cancers.

“We are excited about this new clinical trial with ISA101b and cemiplimab,” said Dr. Leon Hooftman, CMO of ISA Pharmaceuticals. “ISA101b has already demonstrated very promising results when combined with nivolumab in a previous study in advanced HPV16-positive cancers. Particularly in patients with relapsed head-and-neck cancer the percentage of patients with a meaningful tumor response appeared to be twice as high as achieved with nivolumab alone. The objective of the current randomized trial is to confirm such clinical benefit of ISA101b in a controlled setting.”

“In our collaboration with Regeneron that was announced in December 2017, this is the first of two indications in which we jointly aim to develop novel combination immunotherapies for cervical cancer and head-and-neck cancer,” said Gerben Moolhuizen, CEO of ISA Pharmaceuticals. “I am very proud of the efforts of the joint team that allowed us to advance quickly to this stage. We look forward to the first read-out from the trial, which is expected in the second half of 2020.”

Oropharyngeal cancer, a subtype of head-and-neck cancer, affects tissues of the throat (oropharynx), e.g. the base of the tongue, the tonsils, the soft palate, and the walls of the pharynx. Oropharyngeal cancers can be divided into two types: HPV-positive, which are related to human papillomavirus infection, and HPV-negative cancers, which are usually linked to alcohol or tobacco use.

¹Massarelli et al. 2018 JAMA Oncology doi:10.1001/jamaoncol.2018.4051

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About ISA Pharmaceuticals

ISA Pharmaceuticals B.V. is an immunotherapy company developing rationally designed, fully synthetic immunotherapeutics against cancer and persistent viral infections. The Company has built a proprietary immunotherapy platform based on the Synthetic Long Peptide (SLP^®) concept and AMPLIVANT^® technology and its next-generation manufacturing technology. SLP^® immunotherapies are designed to fully harness and direct the body’s own defenses towards fighting the disease. In December 2017, ISA Pharmaceuticals closed a clinical immuno-oncology collaboration with Regeneron to advance its SLP^® lead compound ISA101, an immunotherapy targeting human papillomavirus type 16 (HPV16)-induced cancer, in combination with cemiplimab / Libtayo^® (REGN2810), a PD-1 (programmed cell death protein 1) antibody. In addition, ISA develops SLP^® immunotherapies to advance novel treatment options for orphan indications.

For more information, please visit www.isa-pharma.com.

SLP^® and AMPLIVANT^® are registered trademarks in Europe.

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