Endpoint of Tumor Regression Could Be Seen Within Months

BETHESDA, Md., March 5, 2013 — Northwest Biotherapeutics (NASDAQ: NWBO) (NW Bio), a biotechnology company developing DCVax® personalized immune therapies for solid tumor cancers, announced today that its Phase I/II DCVax-Direct clinical trial for all inoperable solid tumor cancers is planned to begin within approximately the next sixty days. As a Phase I/II trial, this trial is not blinded and the results will be seen as the trial proceeds. With an efficacy endpoint of tumor regression (i.e., tumor shrinkage or elimination), this innovative trial is expected to yield meaningful ongoing results by the second half of 2013.

This clinical trial is approved by the FDA for all types of solid tumor cancers (i.e., cancers in any tissues of the body), and is configured to provide rapid results. In the Phase I portion, it will test both safety and a variety of dosing regimes, and will do so in multiple different cancers – avoiding the need to conduct separate Phase I studies in each such cancer, as is usually the case. Then, the trial will go directly into the Phase II portion, testing for efficacy, without the need for another FDA review.

The endpoint for measuring efficacy in the Phase II portion of the trial will be tumor regression. This endpoint is a particularly important one clinically: once tumors are established, if they cannot be surgically removed, it is very difficult to stop their growth and their spread. This endpoint is also important from a regulatory standpoint: it is the endpoint used most frequently for FDA-granted accelerated approval. Further, this endpoint is a rapid one: typically, if tumor regression is going to occur, it is anticipated to be seen within a few months after treatment – far sooner than other clinical trial endpoints such as progression free survival (PFS) or overall survival (OS).

In multiple pre-clinical studies of various cancers in animals, direct injection of DCVax-Direct into some of the tumors in each animal resulted in complete clearance of all tumors in 80% to 100% of all of the animals in the various studies – both the tumors that were injected and the tumors that were not injected, indicating a systemic immune response. Further, the tumors were cleared relatively rapidly: within weeks after the DCVax-Direct injections.

Equally as important, sixty days after the tumors were cleared from the animals in these pre-clinical studies, the animals were re-injected with the same tumor cells that readily established tumors at the outset of the studies. This time, tumors failed to establish, indicating immune memory.

The key to this novel approach for potentially fatal inoperable tumors was the NW Bio discovery that partial activation of dendritic cells, in a certain way and to a certain degree, produces dendritic cells that are able to perform both of the two key steps needed to mobilize an overall immune response attacking the cancer. Neither immature dendritic cells nor fully mature dendritic cells are able to do this.

“Inoperable tumors represent a severe and widespread unmet medical need,” commented Linda F. Powers, CEO of NW Bio. “Some types of cancer are inoperable even as to the primary tumors, and many others are inoperable due to the spread of metastases. DCVax-Direct can potentially offer an important new treatment option, which can address many or most of these situations. It is very exciting to contemplate the potential for seeing rapid results in our DCVax-Direct trial later this year, while we continue in parallel to execute our lead program: our international Phase III trial with DCVax-L for brain cancer.”

About Northwest Biotherapeutics

Northwest Biotherapeutics is a biotechnology company focused on developing immunotherapy products to treat cancers more effectively than current treatments, without toxicities of the kind associated with chemotherapies, and on a cost-effective basis, in both the United States and Europe. The Company has a broad platform technology for DCVax dendritic cell-based vaccines. The Company’s lead program is a 312-patient Phase III trial in newly diagnosed Glioblastoma multiforme (GBM). GBM is the most aggressive and lethal brain cancer. The Company also previously received clearance from the FDA for a 612-patient Phase III trial in prostate cancer, and clearance from the FDA for Phase I/II trials in multiple other cancers. The Company has also conducted a Phase I/II trial with DCVax for metastatic ovarian cancer.

Disclaimer

Statements made in this news release that are not historical facts, including statements concerning future treatment of patients with GBM using DCVax and future clinical trials, are forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as “expect,” “believe,” “intend,” “plan,” “continue,” “may,” “will,” “anticipate,” and similar expressions are intended to identify forward-looking statements. Actual results may differ materially from those projected in any forward-looking statement. Specifically, there are a number of important factors that could cause actual results to differ materially from those anticipated, such as the Company’s ability to raise additional capital, risks related to the Company’s ability to enroll patients in its clinical trials and complete the trials on a timely basis, the uncertainty of the clinical trials process, uncertainties about the timely performance of third parties, and whether the Company’s products will demonstrate safety and efficacy. Additional information on these and other factors, including Risk Factors, which could affect the Company’s results, is included in its Securities and Exchange Commission (“SEC”) filings. Finally, there may be other factors not mentioned above or included in the Company’s SEC filings that may cause actual results to differ materially from those projected in any forward-looking statement. You should not place undue reliance on any forward-looking statements. The Company assumes no obligation to update any forward-looking statements as a result of new information, future events or developments, except as required by securities laws.