New five-year breast cancer survival data from Greenwich Lifesciences Inc. ignited its stock for a wild ride that climbed nearly 1,000% upward Dec. 9, marking one of the biotech sector’s biggest single-day gains in 2020.

The Stafford, Texas-based company’s stock (NASDAQ:GLSI) closed on Dec. 8 at a mere $5.20 per share and opened the next day at $16.20 each. By the time it was all over Dec. 9, the value increased 998% and shares sat at $57.10 each. Their daily high point was at $129. 93, a 2,398% increase over the previous day’s close.

Barely more than two months ago, it was a completely different story. On Sept. 25, Greenwich’s IPO drew little enthusiasm from investors. The company priced about 1.3 million shares at $5.75 each that day but saw them fall 13% to $5 by the end of trading.

The Dec. 9 hike in share price is due to the final, five-year disease-free survival rates for breast cancer patients treated with Greenwich’s GP2 immunotherapy in a phase IIb study. The data showed 100% survival following surgery and Herceptin (trastuzumab, Roche Holding AG) treatment. The follow-up data come from an efficacy analysis of the company’s study of the 9 amino acid transmembrane peptide of the HER2/neu protein.

The prospective, randomized, placebo-controlled, single-blinded, 16-site trial met all of its clinical endpoints for HER2/neu3-positive patients. The final five-year follow-up disease-free survival curves evaluating reduction of breast cancer recurrences for HER2/neu3-positive and HER2/neu1-2-positive patients, including demographics for stage of cancer, hormone receptor status, node status and prior treatment with chemotherapy, radiation, endocrine therapy or trastuzumab were presented at the 2020 San Antonio Breast Cancer Symposium on Dec. 9.

The first six intradermal injections of GP2+GM-CSF, a monomeric glycoprotein that functions as a cytokine, safely elicited a potent immune response and reduced recurrence rates to 0% in HER2/neu3-positive patients, who received a standard course of Herceptin after surgery, the company said. The recurrence rate reduction was maintained for the five-year follow-up.

The Kaplan-Meier estimator, a tool for measuring patients’ length of life after treatment, found a five-year disease-free survival rate in the 46 HER2/neu3-positive patients treated with GP2+GM-CSF. If a patient completed the patient information sheet, the rate was 100% vs. 89.4% (95% CI:76.2, 95.5%) in the 50 placebo patients treated with GM-CSF (p=0.0338).

Each enrolled and consented patient was randomized and scheduled to receive six GP2+GM-CSF (500 mcg GP2:125 mcg GM-CSF) or placebo (125 mcg GM-CSF alone) intradermal injections every three to four weeks for the first six months and four GP2+GM-CSF booster or placebo intradermal injections every six months afterward. Boosters were introduced during the trial, so some patients did not receive all four.

A phase III study to treat a similar population of moderate to severe (high risk T1, T2-T4) breast cancer patients is being readied.

On Dec. 4, Greenwich entered a contract for the final formulation and filling of GP2 into vials for the study. The contract manufacturer, Polypeptide Laboratories, of San Diego, plans to start activities in 2021. Polypeptide initiated the clinical lot in 2019 at a commercial scale that can produce 50,000 doses and treat up to 4,500 patients.

Baylor College in Houston will be the phase III’s lead clinical site. Mothaffar Rimawi, a professor in Baylor’s hematology and oncology section, will serve as the global principal investigator. Kent Osborne, another Baylor professor, and Rimawi are expected to serve as the first members of Greenwich’s clinical advisory board.

About $2.1 million of the IPO proceeds will support enrollment and treatment of the first 50 to 100 patients in the phase III, while other funds will support manufacturing of the candidate and provide the company with working capital.