Stock Update (NASDAQ:MACK): Merrimack Pharmaceuticals Inc Stops the Phase 2 HERMIONE Trial of MM-302 in HER2-Positive Metastatic Breast Cancer Patients

Merrimack Pharmaceuticals Inc(NASDAQ: MACK) announced that, following a recent independent Data and Safety Monitoring Board (DSMB) recommendation and subsequent futility analysis, it has decided to stop the Phase 2 HERMIONE study of MM-302 (HER2 antibody-targeted liposomal doxorubicin) in HER2-positive metastatic breast cancer patients who had previously been treated with trastuzumab (Herceptin), pertuzumab (Perjeta) and ado-trastuzumab emtansine (T-DM1, Kadcyla).

The decision to stop the trial was made following the DSMB’s opinion that continuing would be unlikely to demonstrate benefit over the comparator treatments. Subsequent to this recommendation, a futility assessment was performed that confirmed the DSMB’s opinion. Both the treatment and control arms were found to have shorter than expected median progression free survival.

Importantly, there were no new or unexpected safety concerns. Patients currently enrolled in the trial may choose to continue on their assigned treatment based upon discussion with their study physician.

“Late line HER2-positive breast cancer is very difficult to treat, especially in this new and previously unstudied group of patients who appear to experience rapid cancer progression following treatment with trastuzumab, pertuzumab and ado-trastuzumab emtansine,” said Istvan Molnar, MD, Vice President of Clinical Development at Merrimack Pharmaceuticals. “While we are disappointed with this outcome, we would like to thank the study Steering Committee, the investigators and, most importantly, the patients who participated in the HERMIONE trial. We will report our learnings from this study at a later date.”

In light of this development, Merrimack now expects to provide further details about MM-302, as well as the results of its full pipeline review, in January. (Original Source)

Shares of Merrimack Pharmaceuticals Inc. are currently falling 1.21% to $5.30, or down $0.06. MACK has a 1-year high of $9.02 and a 1-year low of $4.39. The stock’s 50-day moving average is $5.71 and its 200-day moving average is $5.52.

On the ratings front, Merrimack Pharmaceuticals Inc. has been the subject of a number of recent research reports. In a report issued on November 10, BTIG analyst Ling Wang maintained a Hold rating on MACK. Separately, on November 9, J.P. Morgan’s Anupam Rama reiterated a Hold rating on the stock and has a price target of $7.

According to, which ranks over 7,500 financial analysts and bloggers to gauge the performance of their past recommendations, Ling Wang and Anupam Rama have a yearly average loss of -30.2% and -8.7% respectively. Wang has a success rate of 18% and is ranked #4214 out of 4291 analysts, while Rama has a success rate of 32% and is ranked #3981.

Merrimack Pharmaceuticals, Inc. engages in discovering, developing and preparing to commercialize innovative medicines consisting of novel therapeutics paired with diagnostics for the treatment of cancer. Its offers its first commercial product, Onivyde, which is a novel encapsulation of the marketed chemotherapy drug irinotecan in liposomal formulation. 

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