Spectrum Pharmaceuticals Presents Late-Breaking Oral Presentation of Poziotinib Data in First-Line NSCLC Patients with Exon 20 HER2 Insertion Mutations at ESMO 2021

HENDERSON, Nevada – (COMMERCIAL THREAD) – Spectrum Pharmaceuticals, Inc. (NasdaqGS: SPPI), a biopharmaceutical company specializing in innovative and targeted oncology therapies, today announced the presentation of the safety and efficacy results of cohort 4 of the trial ZENITH20 clinic. These data are from 48 first-line non-small cell lung cancer (NSCLC) patients with HER2 exon insertion mutations who received 16 mg of poziotinib orally once daily. These results showed a confirmed objective response rate (ORR) of 44%, as assessed centrally by an independent image review committee using the RECIST 1.1 criteria. The data was presented late at the 2021 congress of the European Society of Medical Oncology (ESMO) to be held in Paris from September 16 to 20, 2021.

“The data presented in Paris for Cohort 4 are very encouraging,” said François Lebel, MD, medical director of Spectrum Pharmaceuticals. “There is currently no specific approved treatment for patients with NSCLC with exon 20 HER2 insertion mutations. These data represent an important step in our development of poziotinib for patients with significant medical need. ”

A copy of the ESMO presentation titled “Efficacy and Safety of Poziotinib in Treatment-Naïve NSCLC Hosting HER2 Exon 20 Mutations: A Multinational Phase 2 Study (ZENITH20-4)” presented by Dr Robin Cornelissen , from the Erasmus MC Cancer Institute in Rotterdam, is available on the Spectrum corporate website at https://investor.sppirx.com/events-and-presentations.

ZENITH20 Trial Design and Early Safety and Efficacy Data for Cohort 4

Cohort 4 of the ZENITH20 clinical trial is recruiting treatment-naïve NSCLC patients with exon 20 HER2 insertion mutations. This cohort is studying the efficacy of poziotinib with a QD and BID dosing strategy (in progress). Poziotinib 16 mg was administered orally once daily to the first 48 patients resulting in dose reductions / interruptions due to toxicity. The primary endpoint was ORR centrally assessed by an independent image review board using RECIST 1.1 criteria. Secondary endpoints included disease control rate (DCR), duration of response (DoR), progression-free survival (PFS), and safety.

The primary endpoint of ORR was 44% (95% CI: 29.5-58.8%) in the 48 patients treated, including complete response. 88% of patients (42/48) experienced tumor reduction with a DCR of 75%. The median DoR was 5.4 months (range 2.8-19.1+). The median PFS was 5.6 months (range 0 to 20.2+). 88% of patients had dose interruptions and 77% had reductions from the initial dose of 16 mg once daily, while 13% had interruptions related to adverse events (AEs). The most common treatment-related Grade ≥ 3 adverse reactions were rash (35%), stomatitis (20%), diarrhea (14%) and paronychia (8%). In addition, only 1 patient had Grade ≥ 3 pneumonitis. Poziotinib demonstrated clinically significant anti-tumor activity in patients with newly diagnosed NSCLC with exon 20 HER2 mutations at a dose of 16 mg a times a day. The safety profile was manageable and similar to that previously observed in previous studies and other second generation tyrosine kinase inhibitors. The 8 mg BID portion of Cohort 4 continues to actively recruit.

About the ZENITH20 clinical trial

The ZENITH20 study includes seven cohorts of patients with NSCLC. Cohorts 1 (EGFR) and 2 (HER2) in NSCLS patients previously treated with exon 20 mutations and Cohort 3 (EGFR) in first-line patients have completed recruitment. Cohort 4 (HER2) in patients with first-line NSCLC with exon 20 mutations is still recruiting patients. Cohorts 1 to 4 are each fed independently for a predefined statistical hypothesis and the primary endpoint is the objective response rate (ORR). Cohort 5 comprises previously treated or treatment naïve NSCLC patients with EGFR or HER2 exon insertion mutations. Cohort 6 includes NSCLC patients with classic EGFR mutations who progressed during treatment with first-line osimertinib and developed an additional EGFR mutation. Cohort 7 includes patients with NSCLC with a variety of less common mutations in EGFR or HER2 exons 18-21 or extracellular or transmembrane domains.

On Spectrum Pharmaceuticals, Inc.

Spectrum Pharmaceuticals is a biopharmaceutical company focused on the acquisition, development and commercialization of new and targeted oncology therapies. Spectrum has a strong track record of successfully executing the biopharmaceutical business model, from licensing and acquisition of differentiated drugs, to clinical development of new assets, to successful regulatory approvals and commercialization. in a competitive healthcare market. Spectrum has an advanced pipeline with new assets that meet unmet needs. This pipeline has the potential to transform the business in the near future. For more information on Spectrum Pharmaceuticals, please visit www.sppirx.com.

Forward-looking statement – This press release may contain forward-looking statements concerning future events and the future performance of Spectrum Pharmaceuticals that involve risks and uncertainties that could cause actual results to differ materially. These statements are based on the beliefs and current expectations of management. These statements include, but are not limited to, statements relating to Spectrum’s business and its future, including certain important business milestones, the timing and results of FDA decisions, and any statements relating to the Spectrum’s intention, belief, plans or expectations or its management, or which are not a statement of historical fact. Risks that could cause actual results to differ include, but are not limited to, the possibility that the different methodologies, assumptions and applications used by the Company to assess particular parameters of safety or efficacy may produce statistical results. different, and although the company believes the data collected from clinical trials of its product candidates, including poziotinib, is positive, that data may not be sufficient to warrant FDA approval; the possibility that the success of the first clinical trials, especially if they are based on a small sample of patients, will not lead to the success of the subsequent clinical trials, and other unforeseen events during the clinical trials which could lead to delays or other undesirable consequences; other uncertainties inherent in the development of new products; the possibility that Spectrum’s new and existing drug candidates, including poziotinib, may not ultimately prove to be safe or effective; the possibility that our existing and new drug candidates, if approved, may not be more effective, safer or more cost effective than competing drugs; the possibility that our efforts to acquire or license and develop other drug candidates will fail; our reliance on third parties for clinical trials, manufacturing, distribution and quality control; and other risks which are more fully described in the Company’s reports filed with the Securities and Exchange Commission (SEC). The company does not intend to update these forward-looking statements and expressly disclaims any obligation to update the information contained in this press release, except as required by law. For more information about the risks and uncertainties that could cause actual results to differ from those expressed in these forward-looking statements, as well as the risks associated with Spectrum’s business in general, see the risk information in the annual report on Spectrum’s Form 10-K for the fiscal year ended December 31, 2020, and in subsequent reports on Forms 10-Q and 8-K and other documents filed with the SEC by Spectrum.

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