Roche’s bid for Perjeta to become the first breast-cancer medicine approved for treatment before surgery just got a boost. Perjeta’s pre-op regimen for use in early stage breast cancer, or neoadjuvant therapy, was given “Priority Review” by the FDA, the drug maker said today.

There are currently no FDA-approved neoadjuvant treatments for cancer, treatment options given after diagnosis but before surgery in early stages of the disease. Neoadjuvant therapies aim to shrink tumors so they can more easily be removed during surgery or allow surgeons to operate to conserve the breast. Roche expects a decision on its sBLA by October, according to a statement.

The combination of Perjeta, Herceptin and chemotherapy had already been approved in the US for use in HER2-positive metastatic cancer, as well as in the EU. If FDA deems earlier therapy with Perjeta safe and effective, the drug could now find a use on both sides of breast cancer treatment.

Highlighting the upside potential in a monthly investor note, Bernstein analyst Tim Anderson wrote that Perjeta’s ability to show benefit in the earlier setting is “more important” than the drug’s first setting of metastatic breast cancer.

Roche said its sBLA is based primarily on results from NEOSPHERE and TRYPHAENA, two Phase II studies of Perjeta in HER2-positive early-stage breast cancer, as well as on longer-term safety data from the Phase III CLEOPATRA study of Perjeta in HER2-positive metastatic breast cancer.

Anderson added that Perjeta, along with Roche’s already approved cancer med Kadcyla, could also “help blunt the impact of biosimilar Herceptin.” Both Celltrion and Pfizer presented data on their Herception biosimilars at ASCO (American Society of Clinical Oncology) this past June. Those drug makers join Amgen and Novartis, which are also in the running to produce a Herceptin follow-on biologic.

Herceptin’s US patents don’t expire until 2018/2019 at the earliest, according to a recent Goldman Sachs report.