Summit Therapeutics plans Phase III Datroway breast cancer trial
AstraZeneca or Daiichi Sankyo will sponsor the planned breast cancer study, with all three companies sharing trial costs and retaining drug rights.
Adrian Kessler
A planned Phase III breast cancer study would test ivonescimab alongside Datroway as Summit Therapeutics Inc. NASDAQSMMT joined a three-company clinical collaboration on Friday. The agreement follows AstraZeneca's Sept. 28 announcement of a US$2 billion equity investment in Summit that it said would partly support combination studies.
AstraZeneca PLC LONAZN NYSEAZN and Daiichi Sankyo TYO4568 jointly develop and commercialize Datroway. Their Oct. 2 statement says AstraZeneca or Daiichi will sponsor the planned trials, all three partners will contribute to costs, and each will retain rights to its own medicine.
Summit is a U.S.-listed cancer drug developer with rights to ivonescimab in major markets outside China.
Summit shares NASDAQSMMT closed Oct. 1 at US$16.69 on Nasdaq at 4 p.m. EDT. That share close preceded Friday's announcement. AstraZeneca said Sept. 28 it expected the investment to close within one week. The partners' Oct. 2 releases give no enrolment target, primary endpoint or first-patient date for the planned Phase III breast cancer study.
The Planned Study Opens a Breast Cancer Combination Program
Ivonescimab is designed to block PD-1, a protein involved in suppressing an immune response, and VEGF, which helps tumours grow blood vessels. Datroway delivers a chemotherapy payload through an antibody directed at TROP2. The companies intend to begin with first-line triple-negative breast cancer and also plan to evaluate the pair in lung cancer.
According to AstraZeneca's Oct. 2 release, a U.S. FDA application for ivonescimab in EGFR-mutated non-small cell lung cancer is under review. That filing concerns a different cancer and regimen, so its outcome cannot establish whether the planned breast cancer combination works.
Daiichi's Oct. 2 release says Datroway is already approved in more than 30 countries or regions for adult patients with unresectable or metastatic triple-negative breast cancer who are not candidates for PD-1 or PD-L1 inhibitors. The new study will test Datroway with ivonescimab. Neither Oct. 2 release spells out eligibility criteria or a comparison arm for that study.
"Beginning with a phase 3 study in first-line triple negative breast cancer, this collaboration represents an important expansion of Summit’s global development program into breast cancer and a path for additional solid tumor settings," Summit president and co-chief executive Maky Zanganeh said in the joint release.
The Datroway trial follows AstraZeneca's separate Sept. 28 clinical collaboration with Summit to test sonesitatug vedotin and ivonescimab in gastrointestinal cancers. AstraZeneca said then that its planned equity investment would help advance combinations with its cancer medicines; the Oct. 2 announcement identifies Datroway as one of those combinations.
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Listed Partners Retain Their Drug Rights
For listed oncology holders, the partner set spans Summit's ivonescimab program and the Datroway portfolios of AstraZeneca and Daiichi Sankyo. Daiichi's statement says it manufactures and supplies Datroway under its existing collaboration with AstraZeneca, while each of the three companies keeps development and commercial rights to its own medicine under the new trial agreement.
AstraZeneca's U.S. shares NYSEAZN closed Oct. 1 at US$157.70 at 4 p.m. EDT. For sector context, the iShares Biotechnology ETF NASDAQIBB closed Sept. 30 at US$210.53 at 4 p.m. EDT.
AstraZeneca said Sept. 28 that it had agreed to invest US$2 billion in Summit preferred shares and expected the transaction to close within one week, by Oct. 5.
