Northwest Biotherapeutics Further Expands Ongoing Brain Cancer Trial

BETHESDA, Maryland, May 26, 2011 -

- Addition of Clinical Sites Ahead of Projections

Northwest Biotherapeutics (OTC.BB: NWBO) today announced that it has
accelerated the addition of clinical trial sites, exceeding its projections
for the doubling of such sites across the U.S. this calendar quarter, for
enrollment of new patients into the Company's ongoing 240-patient randomized,
double blind, placebo controlled clinical trial of DCVax(R) immune therapy
for Glioblastoma multiforme (GBM), the most lethal form of brain cancer.

(Logo: photos.prnewswire.com/prnh/20110329/SF73084LOGO)

The Company previously announced 4 clinical sites for new enrollment into
the ongoing trial, located in Rochester, Cleveland, Detroit and Minneapolis.
The Company has now added New York City (NYU) and Los Angeles (UCLA). In
addition, the Company is nearing completion on 4 further sites, in New
Jersey, Michigan, Texas and Washington. As a result, the Company expects to
have a total of 10 clinical trial sites for new enrollment into its GBM brain
cancer trial within this calendar quarter. This will substantially exceed the
Company's projections in regard to the expansion of the clinical trial this
quarter. At least 5 further clinical sites are anticipated to be added in the
third quarter of this year, resulting in a total of 15 sites.

"We are gratified to have received such strong interest and cooperation
from clinical centers throughout the U.S., and pleased to be ahead of
schedule in completing the lengthy and complex institutional processes to
make these centers operational for enrollment of additional new patients into
our ongoing GBM brain cancer clinical trial," said Dr. Alton Boynton, CEO of
NWBT.

In prior clinical trials of DCVax(R) immune therapy for GBM brain cancer,
the results were striking: the patients who received DCVax(R) showed a median
survival of 3 years, compared with median survival of only 14.6 months with
standard of care today (surgery, radiation and chemotherapy). In addition,
the patients treated with DCVax(R) did not have recurrence of their tumor for
approximately 2 years, on average, as compared with tumor recurrence in just
7 months with standard of care today. Moreover, the patients treated with
DCVax(R) did not experience any toxic side effects, in stark contrast to
chemotherapies.

About Northwest Biotherapeutics

Northwest Biotherapeutics is a biotechnology company focused on
developing immunotherapy products that treat cancers more effectively than
current treatments, without toxicities of the kind associated with
chemotherapies, and on a cost-effective basis. The Company has a broad
platform technology for dendritic cell-based vaccines. The Company's lead
clinical trial is a 240-patient Phase II trial in newly diagnosed
Glioblastoma multiforme ("GBM"), the most aggressive and lethal of 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 trials in five other cancers. The Company has also conducted a
Phase I/II trial with DCVax(R) for recurrent metastatic ovarian cancer.

For further information about clinical sites and about the Company,
please visit the Company's web site at www.nwbio.com.

Disclaimer

Statements made in this news release that are not historical facts,
including statements concerning future treatment of patients with GBM using
DCVax(R)-Brain and future clinical trials, are forward-looking statements
within the meaning of the Private Securities Litigation Reform Act of 1995.
Words such as "expects," "believes," "intends," 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.

Dr. Alton Boynton, +1-425-503-6351