Company Reports Phase III Trial Progress, Positive Regulatory and ASCO Decisions;

Feuerstein Falsely Claims Opposite of Positive Trial Information Announced by NW Bio

BETHESDA, Md., March 28, 2014 – Northwest Biotherapeutics (NASDAQ: NWBO) (NW Bio), a biotechnology company developing DCVax® personalized immune therapies for solid tumor cancers, today refuted false and misleading claims by Adam Feuerstein in an article posted Thursday, March 27, after NW Bio’s public presentation of significant positive news about all of the Company’s programs.

Feuerstein’s headline falsely claims that NW Bio’s CEO, Linda Powers, “disclosed problems” with the Company’s Phase III clinical trial. On the contrary, Ms. Powers announced entirely positive news about the Company’s Phase III trial as well as its other programs, and Ms. Powers emphasized in her presentation that prior claims by a commentator (i.e., Feuerstein) that there were problems with the Company’s Phase III trial were unfounded and wrong. Ms. Powers reiterated that the Phase III trial is progressing well, and further centers of excellence are joining the trial.

The Company urges investors, analysts and other interested parties to view Ms. Powers’ presentation (which is available via webex on the Company’s website) to hear the correct, positive information and form their own opinions.

Feuerstein makes a series of false and misleading claims in his article. First, Feuerstein describes the Company’s Phase III trial as “requiring a p value of 0.02 to reach statistical significance” and claims that this makes it more difficult for this trial to succeed. Feuerstein is factually wrong on both points: the Company’s trial does not “require” a p value of 0.02 to reach statistical significance, and the Company’s trial design increases, not decreases, the trial’s ability to succeed.

The Company’s Phase III trial, like all other trials, will be considered to reach statistical significance if it reaches a p value of 0.05. “P value” is a measure of the probability that trial results were due to chance, and not the result of the experimental treatment being tested. So, the lower the p value, the better it is. The p value generally required by regulators for statistical significance is 0.05.

The Company has created a significant cushion or buffer for achieving this p value of 0.05 by designing its trial to a level of 0.02 rather than designing to the exact 0.05 level. Having this cushion makes the Company’s trial design more likely for the trial to succeed, not less likely as Feuerstein claims. If the trial were designed to aim just for a p value of 0.05 (as Feuerstein tries to argue would be better), there would be no cushion at all, the risk would be correspondingly higher, and it would be more difficult for the trial to achieve success.

A second false claim by Feuerstein in his article is a “guess” that the Company’s Phase III trial has been “poorly run” and that the trial data “have been looked at some [sic] many times already that the ‘alpha spend’ has been gobbled up” — meaning that unblinded reviews of the data have used up some of the statistical cushion. Feuerstein’s “guess” is utterly baseless and is factually wrong again. There has been no such “alpha spend” to date. Further, the interim analyses in the Company’s Phase III trial are structured so that there will never be large amounts of “alpha spend” in this trial.

Feuerstein further tries to claim that the Company’s trial could originally have been considered statistically significant with a p value of 0.05 but somehow must now meet a totally different standard and reach a p value of 0.02 in order to be considered statistically significant. Once again, Feuerstein’s claim is baseless and wrong. There has been no such change: the Company’s trial design and target p value are the same now as they have been throughout the trial. The Company has consistently reported throughout the trial that it is designed to the 0.02 level. That is a major strength and an intentional trial design, as already explained – not a weakness or the result of problems, as Feuerstein falsely asserts.

A third false claim by Feuerstein in his article is that if the Company makes a choice to increase the number of patients in the Phase III trial, the Company “will do so out of concern that the original enrollment figure (312 patients) is too small to produce a positive result,” and that for the Company to exercise this choice (or even to have the possibility for this choice built into the Company’s trial design) is something negative. Once again, Feuerstein is factually wrong. If the Company exercises its choice, the Company will be doing so on an entirely blinded basis. The Company will have no access to any accumulated trial data, and will not be acting out of such alleged “concern.”

As Ms. Powers conveyed in her March 27 presentation (and prior presentations), the key to successful trials and regulatory approvals is strongly powered trial results. The Company has shaped it Phase III trial design in order to provide strong powering, reduce risks, and provide cushions. An increase in patient numbers is simply another way to enhance the cushion relating to the p value – and thereby further reduce risks and make it easier for the trial to succeed.

“We can only conclude that Feuerstein and those with whom he is allied are disturbed by NW Bio’s continued and increasing strong progress in all of its programs,” commented Linda Powers, CEO of NW Bio. “We note that his attacks seem to regularly coincide with positive NW Bio news and with substantial short seller activity. Perhaps they are all just coincidences.”

“Feuerstein’s long history of false and unfounded attacks on NW Bio is directly contrary to the major validations we have received and continue to receive from leading medical institutions, and the most demanding regulatory agencies and health care authorities. We encourage investors, analysts and other interested parties to take a close look at these validations, compare them to Feuerstein’s ongoing attacks, and form their own opinions about whom to believe.”

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 form of brain cancer, and is an “orphan disease.” The Company is under way with a 60-patient Phase I/II trial with DCVax-Direct for all inoperable solid tumors cancers, with a primary efficacy endpoint of tumor regression. The Company previously received clearance from the FDA for a 612-patient Phase III trial in prostate cancer. The Company conducted a Phase I/II trial with DCVax for metastatic ovarian cancer together with the University of Pennsylvania.

Disclaimer

Statements made in this news release that are not historical facts, including statements concerning future treatment of patients 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,” “design,” “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 risks related to 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, uncertainties about the clinical trials process, uncertainties about the timely performance of third parties, risks related to whether the Company’s products will demonstrate safety and efficacy, risks related to the Company’s and Cognate’s abilities to carry out the intended manufacturing expansions contemplated in the Cognate Agreements, risks related to the Company’s ability to carry out the Hospital Exemption program and risks related to possible reimbursement and pricing. 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.