Spectrum Pharmaceuticals Presents Results in HER2 Exon 20 Insertion Mutations from Cohort 2 of the Poziotinib ZENITH20 Clinical Trial

Spectrum Pharmaceuticals (NasdaqGS: SPPI), a biopharmaceutical company focused on novel and targeted oncology therapies, today presented additional results from its pivotal Phase 2 clinical trial, ZENITH20, evaluating poziotinib in previously treated non-small cell lung cancer (NSCLC) patients with HER2 exon 20 insertion mutations (Cohort 2). The on-demand mini oral session is part of the European Society for Medical Oncology (ESMO) Virtual Congress 2020 Science Weekend being held September 19 – 21, 2020.

“This is the first presentation to the medical and scientific community of the positive results from our registrational Cohort 2 from the ZENITH20 clinical trial,” said Francois Lebel, M.D., Chief Medical Officer of Spectrum Pharmaceuticals. “There is no approved treatment for NSCLC patients with HER2 exon 20 insertion mutations, and we look forward to sharing this data with the FDA and discussing the path forward for poziotinib registration.”

The presentation titled “ZENITH20, a multinational, multi-cohort Phase 2 study of poziotinib in NSCLC patients with EGFR or HER2 Exon 20 mutations” is available to members of ESMO and can be accessed on the meeting website here: https://cslide.ctimeetingtech.com/esmo2020/attendee/confcal_1/session/ .... A copy of the slides can also be found at: https://investor.sppirx.com/index.php/events-and-presentations.

ZENITH20 Trial Design and Results for Cohort 2

Cohort 2 of the ZENITH20 trial enrolled 90 patients who received an oral once daily dose of 16 mg of poziotinib. The intent-to-treat analysis demonstrated a confirmed objective response rate (ORR) of 27.8% (95% CI, 18.9%-38.2%). The observed lower bound of 18.9% exceeded the pre-specified lower bound of 17%. The disease control rate (DCR) was 70% while tumor reduction occurred in 67 patients (74%), with median tumor reduction of 22%. The evaluable patient analysis (n=74) demonstrated a confirmed ORR of 35.1% (95% CI, 24.4% – 47.1%) with a disease control rate of 82.4%.

The median duration of response was 5.1 months (range 1 to >12.3), with a median follow up of 8.3 months and the median progression free survival was 5.5 months (range 0 to >13.1). 13 patients (14%) had treatment-related serious adverse events and 11 patients (12%) permanently discontinued due to adverse events. Grade 3 treatment related rash was observed in 27 patients (30%) with diarrhea in 23 patients (26%). Stomatitis/mucosal inflammation Grades 3 and 4 occurred in 21 patients (23%). Dose interruptions were reported in 78 patients (87%), and dose reductions in 70 patients (78%), which was similar to the rates in Cohort 1.