Antigen Express's AE37 Vaccine at ASCO 2013

Abstracts for the American Society of Clinical Oncology (ASCO) Annual Meeting were released today at 6 pm, ahead of the meeting which will be held May 31 - June 4, 2013 in Chicago, Illinois. Two abstracts featuring AE37 were accepted for poster publication, whith another published in conjunction with the 2013 Annual Meeting, but not presented at the Meeting. While none of the abstracts contain pivotal data, they do illustrate positive trends from studies of AE37 in breast and prostate cancer patients.

Here are the abstracts:

Booster inoculations of the AE37 peptide vaccine enhance immunological responses in a phase II study. Abstract No: 3095

Author(s): Eleftheria A Anastasopoulou, Efi Pappou, Panagiotis Tzonis, Alexandros Ardavanis, Sathibalan Ponniah, Constantin N. Baxevanis, James L. Murray, Michael Papamichail, Sonia A. Perez, George Earl Peoples, Elizabeth Ann Mittendorf; Cancer Immunology and Immunotherapy Center Saint Savas Cancer Hospital, Athens, Greece; Cancer Immunology and Immunotherapy Center, Saint Savas Cancer Hospital, Athens, Greece; Cancer Vaccine Development Program, United States Military Cancer Institute, USUHS, Bethesda, MD; The University of Texas MD Anderson Cancer Center, Houston, TX; Cancer Immunology and Immunotherapy Center, Athens, Greece; San Antonio Military Medical Center, San Antonio, TX

Background: We are conducting a multicenter randomized phase II trial of AE37, the Ii-Key hybrid peptide of HER2 776-790 (AE36). The purpose of the study is to determine if the AE37 vaccine can prevent recurrence in disease-free conventionally treated node-positive (NP) and high-risk node-negative (NN) breast cancer patients at significant risk for recurrence. Since clinical efficacy is anticipated to occur as the result of long lasting memory immune responses induced by vaccination, repeated booster inoculations were scheduled as part of the trial. Here we present data on immune responses in patients who received boosters up to 24 months after completion of the primary vaccination series (PVS).

Methods: The trial is enrolling NP or high-risk NN patients with any degree of HER2 expression (IHC 1-3+ or FISH > 1.2) rendered disease-free following standard of care therapy. The vaccine group (VG) received AE37+GM-CSF and control group (CG) GM-CSF alone in 6 monthly i.d. inoculations followed by boosters administered every 6 months x 4. Immunologic responses were assessed in vivo by dermal reactions at the inoculation site, and in vitro, against the AE36 peptide, with proliferation and IFN-γ ELISPOT assays.

Results: 25 patients in the VG and 23 in the CG have completed their boosters. After the last booster (BRC24), 100%, 54% and 54% in the VG (vs. 9%, 18% and 27% in the CG) responded by dermal reaction, proliferation and IFN-γ ELISPOT, respectively. Mean dermal reactions (orthogonal mean in mm) in vaccinated patients was 25.9±3.13 at completion of the PVS (R6) and increased to 35.47±4.35 at BRC24 (p=0.01). VG patients increased their proliferation response (stimulation index, SI) to AE36 from 0.97±0.046 at baseline (R0) before vaccination to 2.27±0.57 at R6 (p=0.0003) which was maintained until BRC24 (SI 2.21±0,33, p<0.0001). The number of IFN-γ specific spots/106 PBMC increased from 26.88±12.36 at R0 to 40.35±17.02 (p=0.07) at R6, up to 62±16.82 (p=0.0076) at BRC24. Conclusions: Our data demonstrate that AE37 vaccine boosters enhance the immune responses against HER elicited during the PVS, thus sustaining long lasting immunity, a prerequisite for possible clinical efficacy which is currently being evaluated.

Risk factors for development of delayed urticarial reactions in the phase II trial of HER2 peptide vaccines plus GM-CSF versus GM-CSF alone in high-risk breast cancer patients to prevent recurrence Abstract No: 3097

Author(s): Alfred F Trappey, John S. Berry, Timothy J Vreeland, Diane F. Hale, Alan K. Sears, Sathibalan Ponniah, Sonia A. Perez, Guy T. Clifton, Michael Papamichail, Nathan M. Shumway, Elizabeth Ann Mittendorf, George Earl Peoples; Brooke Army Medical Center, San Antonio, TX; Cancer Vaccine Development Program, United States Military Cancer Institute, USUHS, Bethesda, MD; Cancer Immunology and Immunotherapy Center, Saint Savas Cancer Hospital, Athens, Greece; Cancer Immunology and Immunotherapy Center, Athens, Greece; San Antonio Military Medical Center, Fort Sam Houston, TX; The University of Texas MD Anderson Cancer Center, Houston, TX; Department of Surgery, Brooke Army Medical Center, Fort Sam Houston, TX

Background: We are monitoring the incidence of delayed urticarial reactions (DURs) in our phase II trial evaluating adjuvant HER2-specific vaccines (AE37 and GP2) for the prevention of breast cancer recurrence. Here, we characterize DURs and analyze risk factors for their development.

Methods: After completion of standard of care therapy, disease-free node-positive or high-risk node-negative patients (pts) were randomized to receive either a peptide+GM-CSF (VG) or GM-CSF (CG). Pts receive 6 monthly intradermal inoculations during the primary vaccine series (PVS) then four boosters (B) every 6 mos. Immune response is measured by delayed type hypersensitivity (DTH) pre- (R0) and post-PVS (R6) and local reaction (LR) at R1 – R6.

Results: Twenty-four (6.1%) of 393 initiated patients report a DUR; 13 VG (vDUR), and 11 CG (cDUR); vDUR - 9 AE37, 4 GP2. Time to onset of symptoms is 9±5 days (d) and is similar in vDUR/cDUR (p = 0.27). DURs manifest as hives/pruritis in all patients. Average duration of symptoms is 32.6 d ± 8.8 d (no difference in vDUR/cDUR [p = 0.23]). Episodes have resolved with antihistamines or IV/oral steroids. Ten (4 cDUR, 6 vDUR) patients have had recurrent episodes that have resolved similarly. 75% of first episodes occur between R6-B3. For DUR patients v. those who have not had a DUR (noDUR), there are no differences in demographics. DTH response is similar in vDUR pts v. noDUR VG pts (R0- p = 0.34; R6- p=0.40). cDUR pts had a greater DTH response v. CG noDUR pts at R6 (13.2 v 4.7 mm, p=0.01). LRs are greater in DUR pts compared to noDUR pts after the second vaccination (R2 – 66.2 v 48.2 mm, p=0.02). LR for DUR pts decrease and are less than noDUR at R6 (45.4 v 57.4 mm, p=0.09). Relative risk for developing DUR for LR > 100 mm at R2 is 3.49 (1.58-7.68, 95% CI [p=0.004]). At 29.9 months median follow-up, there have been no recurrences in VG and CG DUR v. 75.9% DFS for noDUR (p=0.05).

Conclusions: DURs occur infrequently and without long-term sequelae. Pts at risk for developing DUR are identified early in the vaccine series using LR. Robust immune response in DUR may explain the survival benefit demonstrated here.

The following is the publish only abstract:

Effect of immunization with Ii-key modified HER2 (776-790) peptide vaccine (AE37) on immunologic responses in prostate cancer patients.

Author(s): Sonia A. Perez, Eleftheria Anastasopoulou, Efi Pappou, Panagiotis Tzonis, Stratos Bisias, Anastasios Thanos, Eric von Hofe, Michael Papamichail, Constantin N. Baxevanis; Cancer Immunology and Immunotherapy Center, Saint Savas Cancer Hospital, Athens, Greece; Antigen Express, Worcester, MA

Background: We have shown that the AE37 vaccine (Ii-Key modified HER2(776-790) peptide) is safe and induces HER2/neu–specific cellular immune responses in patients with prostate cancer (Perez SA et al Clin. Cancer Res. 2010, 16:3495). We now present data from 4-year immunological assessments of prostate cancer patients who received AE37.

Methods: Seventeen patients in a phase I study were given 6 doses of AE37 at monthly intervals and one additional dose a year after initiating treatment. Immunological testing to assess active versus suppressive immunity was conducted one month (intermediate-term immunomonitoring [ITI]) and 3 years (long-term immunomonitoring [LTI]) after the final dose of AE37. ELISPOT and proliferation assays were conducted to assess cytokine secretion and mitogenic response to antigen. DTH reactions were measured to assess in vivo immune response to antigen. All assays were conducted using native HER2(776-790) peptide (AE36). The percent Treg cells and ng/ml TGFβ were determined as markers for immune suppression.

Results: Neither ELISPOT nor proliferation assays were statistically different at LTI compared to ITI. While clearly above pre-vaccine responses, the drop in DTH was statistically significant (p < 0.05). Similarly, the increase in Treg cells and circulating TGFβ was also statistically significant. An increase of >200 % in PSA-doubling time at any point during the study was observed in 6/17 patients, with 3 retaining this effect to 5 years.

Conclusions: AE37 generates immunological memory associated with possible clinical efficacy in spite of Tregs and TGF-β levels returning at 4 years after being decreased for up to 6 months after initial AE37 vaccination. These results support further randomized testing of the AE37 vaccine.

The publish only abstract is interesting. We know from an earlier publication (see here) that nine of the subjects who completed the vaccine series were stage IV metastatic (later stage) patients with bone metastases. In that earlier publication, the researchers noted,

The maximum increase of specific IFN-γ–producing T cells in response to vaccination with AE37, detected by ELISPOT and expressed as mean fold increase from baseline levels, was higher in stage II-III and castrate-sensitive patients compared with stage IV and castrate-resistant patients, respectively, although this difference was not statistically significant. Similarly, DTH responses to the vaccine, determined as the difference of post vac minus baseline DTH, were statistically significantly lower in stage IV patients.

In that report, the researchers conclude that,

In conclusion, the use of the AE37 immunotherapeutic vaccine is a novel strategy for managing patients with prostate cancer. This clinical trial shows that the vaccine is safe and immunologically active. However, proof of clinical benefit will require a phase II trial in a homogeneous group of patients with less extensive disease, including disease-free patients at high risk of recurrence.

Therefore, it appears reasonable to assume that results for the Phase I study would be even more positive if the appropriate traget population had been identified, with booster innoculations to prolong the effectiveness of the vaccine. The incease of >200 % in PSA-doubling time at any point during the study for 6/17 patients is remarkable, and since this earlier Phaser I study was initiated Antigen Express has learned much about the vaccine. Booster series have been added to the breast cancer Phase II, with a targeting of lower HER2 expressing early stage subjects.

As we can see with the first ASCO abtract, titled "Booster inoculations of the AE37 peptide vaccine enhance immunological responses in a phase II study", Antigen Express is on the right tract in developing AE37. The prostate cancer Phase I illustrates that AE37 stimulates long lasting memory, and the new booster program can help add to the desired effect. The second ASCO abstract,titled "Risk factors for development of delayed urticarial reactions in the phase II trial of HER2 peptide vaccines plus GM-CSF versus GM-CSF alone in high-risk breast cancer patients to prevent recurrence", highlights the strong safety profile of AE37/GM-CSF + booster, so all appears on track, even if these abstracts don't yet outline final results of the ongoing Phase II study in early stage HER2 breast cancer patients, which may be needed to lift GNBT's dreadful stock. Those final results may come later this year.

Click on the abstract titles to view the content at ASCO's 3013 Annual Meeting website.

Two Abstracts Pertaining to the AE37 HER2/neu Vaccine Accepted as Poster Presentations at ASCO 2013

Two abstracts pertaining to Antigen Express' AE37 Her2/neu vaccine have been accepted for poster presentations at the 2013 American Society of Clinical Oncology ("ASCO") Annual Meeting. The annual ASCO meeting is being held in Chicago, Illinois from May 31 through June 4, 2013.

The abstract titles, with the name of the lead author, were revealed today with the launch of the meeting's iplanner. Here is the available information:

Abstract #3095

Booster inoculations of the AE37 peptide vaccine enhance immunological responses in a phase II study.

Eleftheria A. Anastasopoulou

Abstract #3097

Risk factors for development of delayed urticarial reactions in the phase II trial of HER2 peptide vaccines plus GM-CSF versus GM-CSF alone in high-risk breast cancer patients to prevent recurrence.

Alfred F. Trappey, MD

The iplanner is available for review here.

Emerging Vaccines Take Aim at Preventing Recurrent Breast Cancer

The following article was written by Joe Munch, and published in MD Anderson's OncoLog.

OncoLog, January 2013, Vol. 58, No. 1

Myriad advances have been made in the treatment of breast cancer, and cures are achieved in many patients. However, there are still patients whose cancer recurs, and most of these patients will die of their disease. This indicates a need for other therapies that can be used to prevent recurrent disease. One potential option is breast cancer vaccines.

“Breast tumors are made up of so many different types of cells that we have to use many different drugs and therapies to treat them,” said Jennifer Litton, M.D., an assistant professor in the Department of Breast Medical Oncology at The University of Texas MD Anderson Cancer Center. “Vaccines come at the cancer in a totally different way than our current systemic therapies do.” Vaccines thus may augment the effects of adjuvant treatments currently used to forestall recurrence.

Potential clinical role

Several types of adjuvant therapy are used to prevent breast cancer from returning; the therapy or combination of therapies used depends on the individual patients and their disease. For example, radiation therapy is used for patients who have undergone breast-conserving surgery, and chemotherapy may benefit patients at high risk of recurrence. Hormonal therapy with tamoxifen or an aromatase inhibitor is used in patients with estrogen receptor–positive disease, and immunotherapy with trastuzumab is used in those with tumors that highly express human epidermal growth factor receptor 2 (HER2).

Today, several clinical trials are evaluating the use of breast cancer vaccines—not as an alternative to currently available preventive therapies for recurrent disease but as an additional adjuvant therapy.

“This is a novel approach specifically for people who want another form of therapy to decrease the chance of the cancer coming back,” Dr. Litton said. “People are looking for something extra that may improve their outcome but doesn’t expose them to a lot of extra toxicity.”

Peptide vaccines

Cancer vaccines stimulate patients’ immune systems to recognize and kill tumor cells. The vaccines consist of a tumor-associated antigen that, once introduced into a patient’s body, elicits an immune response. Several systems have been devised to deliver tumor-associated antigens into the body, including whole-cell vaccines, viral vector vaccines, and dendritic cell vaccines, which are custom made from the patient’s own white blood cells. The only therapeutic cancer vaccine currently approved by the U.S. Food and Drug Administration is sipuleucel-T (Provenge), a dendritic cell vaccine used in men with metastatic hormone-refractory prostate cancer.

The breast cancer vaccines being investigated at MD Anderson are of a fourth type, peptide vaccines. Peptide vaccines are made by taking a small amino acid sequence (peptide) from a tumor-associated antigen. The tumor-associated antigen most frequently used in breast cancer vaccines is the HER2 oncoprotein, which promotes tumor growth.

Once taken from the antigen, the peptide is mixed with an immunoadjuvant to help stimulate an immune response. The immunoadjuvant used in the trials being conducted at MD Anderson is granulocyte-macrophage colony-stimulating factor (GM-CSF), which has been used primarily to treat neutropenia in transplant recipients.

When the peptide–GM-CSF combination is injected, GM-CSF stimulates the dendritic cells in the area of injection to take up and process the peptide so that it can be better presented to the immune system. The length of the peptide dictates the type of immune cell it stimulates.

Current clinical studies

Several HER2-derived peptide vaccines are being studied in clinical trials at MD Anderson. Although the vaccines are based on a HER2 peptide, they have the most benefit in the 60% of breast cancer patients with low HER2 expression (1+ or 2+ by immunohistochemistry).

Phase III trial of E75

The E75 vaccine (NeuVax) is the most studied of the HER2-derived peptide vaccines. The 9-amino-acid peptide E75 binds with major histocompatibility complex (MHC) class I molecules to stimulate CD8-positive T cells; when these T cells recognize a target as foreign, they attack it and release cytotoxic enzymes to kill it. Because E75 is an MHC class I peptide, the vaccine works only in patients whose cells are positive for human leukocyte antigen (HLA)-A2 or HLA-A3; only cells with those HLA types will present the peptide on the cell surface to activate T cells.

In May 2012, Elizabeth Mittendorf, M.D., Ph.D., an assistant professor in the Department of Surgical Oncology, and her colleagues published the 24-month landmark analysis of their phase I and II trials of E75. The group’s findings opened the door to the phase III PRESENT (Prevention of Recurrence in Early-Stage, Node-Positive Breast Cancer with Low to Intermediate HER2 Expression with NeuVax Treatment) study, currently the only phase III trial of a breast cancer vaccine. Dr. Mittendorf is the overall principal investigator of the multinational study.

This randomized, double-blind, placebo-controlled trial will enroll approximately 700 breast cancer patients who were rendered disease free following standard treatment. Patients must be positive for HLA-A2 or HLA-A3 and have had cancers that were scored as HER2 1+ or 2+ by immunohistochemistry. The vaccine will be given once a month for 6 months and then given as a booster inoculation every 6 months thereafter through 3 years. Because GM-CSF causes inflammation at the injection site, it will be given to patients in each study group, serving as the immunoadjuvant for the vaccine group and as an active placebo for the control group. The primary endpoint of the study is 3-year disease-free survival.

Positive results from this trial, researchers hope, would eventually lead to indications for the E75 vaccine in the routine care of breast cancer patients. “We are all cautiously optimistic—and excited—as we wait for the results. If they do show that E75 has significant benefit, it could be an amazing opportunity for our cancer patients,” Dr. Litton said.

Phase II trial of GP2 and AE37

The GP2 vaccine works in much the same way as the E75 vaccine. Like E75, the GP2 peptide is 9 amino acids long and binds to MHC class I molecules to stimulate CD8-positive T cells; thus, the vaccine works only in patients who are positive for HLA-A2 or HLA-A3. In contrast, the AE37 peptide, which is longer than the E75 and GP2 peptides, binds to MHC class II molecules and stimulates CD4-positive T cells, thereby eliciting a more robust immune response. Although MHC class II peptides can be HLA-restricted, AE37 is a promiscuous peptide, meaning that blood cells of almost any HLA type can present it. In addition, the AE37 peptide is paired with the Ii-Key protein, which enhances the presentation of the peptide to the immune system.

Both the GP2 and AE37 vaccines are being investigated in an ongoing phase II trial to determine whether the individual vaccines can prevent the recurrence of node-positive or high-risk node-negative breast cancer. Patients are sorted into groups depending on their HLA status and then randomly assigned to receive the appropriate vaccine plus GM-CSF or GM-CSF alone (as the control).

The AE37 trial’s planned interim analysis revealed that at a median of 22 months, the recurrence rate in the vaccinated patients was 10.3%, whereas the recurrence rate in the control group receiving only GM-CSF was 18.0%. The difference represents a 43% reduction in recurrence rate.

“These data are encouraging,” Dr. Mittendorf said. “Obviously, we need longer follow-up, and we need to finish accrual in the trial, but the data suggest that it is reasonable to look forward to investigating the AE37 vaccine in a phase III setting.”

The interim results for the GP2 vaccine are not yet available.

Potential benefits

One of the benefits of peptide vaccines such as those being investigated at MD Anderson is that they can be given “off the shelf.” This makes them more convenient and less expensive than the custom-made dendritic cell vaccines.

Dr. Litton, who has referred a number of patients to the breast cancer vaccine trials, said that patients’ enthusiasm about participating in a vaccine trial has been overwhelmingly positive. “Some patients tell me that they feel empowered by using their own bodies, their own immune systems, to fight the cancer,” she said.

But the main reason the trials are so popular with patients is that the vaccines offer a potential anticancer benefit with very little risk of toxicity. Most patients have a grade 1 or 2 local toxic response, which means redness at the injection site; and some patients experience grade 1 or 2 systemic symptoms, mostly in the form of minor flu-like symptoms for 4–6 hours after receiving the vaccine.

“These are people who have gone through chemotherapy, lost their hair, and had terrible gastrointestinal side effects, toxicity in their nails, and all those other things,” Dr. Mittendorf said. “So a treatment that is basically not toxic is very attractive.”

Dr. Litton echoed Dr. Mittendorf’s sentiments. “It has not been a hard trial for people to become interested in. In fact, I’ve had several people come from different parts of the country just to be part of the trial,” Dr. Litton said. “And we really appreciate all the patients who have stepped forward to participate. It’s always important to encourage people to participate in clinical trials; otherwise we could never move forward with therapies such as this.”

These vaccines are not for everyone, however. Earlier clinical trials revealed that the peptide vaccines had limited efficacy in patients with late-stage, metastatic breast cancer.

“There’s a long list of reasons why these vaccines are not set up to be administered to patients who have diffusely metastatic disease,” Dr. Mittendorf said. “It would be difficult, with a peptide vaccine, to mount enough of an immune response to eradicate bulky disease. The microenvironment and immune environment around tumors change as tumors progress, so bulky metastatic tumors also have a less favorable environment for the immune system to function in. And a lot of patients with diffusely metastatic disease have received multiple lines of chemotherapy, which we suspect has a detrimental effect on the immune system.”

Future directions

The future of breast cancer vaccines holds many possibilities. Antigens such as cyclin E and folate-binding protein may be targeted for vaccination. Novel immunoadjuvants are being developed that may elicit an immune response more potent than that elicited by GM-CSF. And new approaches using vaccines and harnessing other aspects of the body’s immune system against recurrent breast cancer may be forthcoming.

“I would like to see some of these vaccines combined with other exciting immunotherapies that are coming on board,” Dr. Mittendorf said. For instance, a vaccine could be paired with a drug that inhibits CTLA-4, a protein that downregulates T cells. “Ipilimumab, an antibody that targets CTLA-4, could be used to take the brakes off the immune system. A vaccine would stimulate the T cells, and the anti–CTLA-4 treatment would allow them to proliferate,” she said.

Eventually, such vaccines could be used to treat patients much earlier in the course of their disease. “I think it would be an exciting route to look forward to in the frontline setting as well,” Dr. Litton said. “We could potentially cure more people up front at the time of diagnosis.”

Please click HERE to view this article at OncoLog.

Army Surgeons Present New Research on Cancer Vaccine

The following press release was issued by the U.S. Army Medical Department on October 3rd, 2012:

CHICAGO, Oct. 3, 2012 – Yesterday U.S. Army surgeons exhibited new research findings at the American College of Surgeons Clinical Congress.

The poster presentation titled, "Assessment of Disease Features and Immune Response in Breast Cancer Patients with Recurrence after Receiving AE37, a HER2 Peptide Vaccine," outlined outcomes of injecting AE37, a HER-2 derived vaccine, in breast cancer survivors following completion of standard therapy. Those who received injections of AE37 were more likely to survive disease-free than the control group.

Meanwhile, the poster presentation titled, "A NSQIP Evaluation of Practice Patterns and Outcomes Following Surgery for Anorectal Abscess and Fistula in Patients with and without Crohn's Disease," showed patients with Crohn's Disease (CD) – a form of inflammatory bowel disease – had more aggressive anorectal abscess and fistula disease and suffered more complications following emergency surgery than patients who did not have CD.

AE37 breast cancer vaccine creates robust immunologic response in cancer survivors

The poster "Assessment of Disease Features and Immune Response in Breast Cancer Patients with Recurrence after Receiving AE37, a HER2 Peptide Vaccine," showed after completing standard treatment, breast cancer survivors who received injections of AE37 with granulocyte-macrophage colony-stimulating factor (GM-CSF) – an immune stimulant – were more likely to survive five years disease-free than a control group that received GM-CSF alone. AE37 works by stimulating the immune system to recognize and target for destruction a protein called HER2 that is expressed at some level by most breast cancer cells.

While AE37 did not prevent recurrence in all patients, it provoked an immunologic response in patients across the board, including survivors at high risk of recurrence, those with the hard-to-treat "triple negative" form of breast cancer and those with lower levels of HER2 expression. "Patients with a lower level of expressed HER2 protein, who wouldn't be eligible for the HER2-binding antibody, trastuzumab (Herceptin), had a survival rate of more than 88 percent, compared to 70 percent in the control group," said U.S. Army Capt. John Berry, MD, a research associate. "The vaccine may have benefited patients with less aggressive cancers."

Study director Col. George E. Peoples, M.D., explained how the Cancer Vaccine Development Program differs from other groups investigating cancer vaccines. "Our program was one of the first to enroll cancer survivors with healthy immune systems rather than focus on people with end-stage, metastatic cancer. Our goal is to increase health and survivorship in this group, including specifically those with a high risk of cancer recurrence."

This study is part of an ongoing prospective, multi-center, randomized, single-blinded phase IIb adjuvant therapy trial. AE37 was co-developed by the Cancer Vaccine Development Program, housed at Brooke Army Medical Center in San Antonio, Texas.

Capt. Diane F. Hale, M.D., Sonia Perez, Ph.D., Capt. Timothy Vreeland, M.D., Capt. Dabney Raetasha, M.D., Michael Papamichail, M.D., Ph.D., Maj. Guy T. Clifton, M.D., Capt. Alan Sears, M.D., Sathibalan Ponniah Ph.D., and Elizabeth A. Mittendorf, M.D., FACS, also participated in the study.

Generex's AE37 Vaccine Press Release Appears Off Target

I'm someone so clumsy that I'd be better off throwing an apple at an arrow, as opposed to an attempt at shooting an arrow at an apple. There's a better chance that I'd shoot the arrow at my foot, or straight up in the air, so I'd only split my head. The wiser move is to simply eat the apple, and forget the arrow. Generex, and their wholly owned subsidiary Antigen Express, appear equally clumsy when it comes to writing press releases detailing the latest data that researchers are presenting for their novel AE37 HER2/neu peptide vaccine. I'm joking a bit, so I hope the good folks at Generex have a sense of humor. Yet, their follies in this area are true.

The latest example of the reporting of interim efficacy results for AE37 in a company press release that are actually lower than the lead researcher's findings came a few hours ago. Here's a quick look. The following sentence is from Generex's press release dated today, where they provide details of a study abstract that will be presented at the ASCO Breast Cancer Symposium this Friday:

While the study showed an overall reduction of 42% in the risk of relapse in all patients of the study who received the vaccine, the reduction in the risk of relapse was 66% in patients with low expression of the HER2 oncoprotein who were classified as having triple negative breast cancer.

That's impressive data, although the actual results are even better. The lead author of the study is Dr Elizabeth Mittendorf from MD Anderson. The following two sentences are from the study abstract:

"After a median follow-up of 22.3 months, the disease-free survival (DFS) rate in the VG is 90.3% vs 81.1% in the CG (p=.46), a 49% risk reduction."

"The DFS rate in the VG of TNBC patients is 83.3% vs 47.6% in the CG (p=.23), a 68% risk reduction."

Generex reports that there was a 42% risk reduction for relapse in all patients who received the vaccine (VG) in the latest interim look at the ongoing study, but the true risk reduction as stated in the abstract is 49%. Generex also reports that there was a 66% risk reduction for relapse in subjects classified as having triple negative breast cancer (TNBC), but the true risk reduction as stated in the abstract is 68%. Here's a link to the press release, and a link to the abstract.

In June, during the ASCO Annual Meeting, Generex's AE37 vaccine was the topic of discussion in a podium presentation titled "From bench to bedside: The use of the li-Key technology to improve helper peptides for clinical use in cancer vaccines". The report highlights earlier interim results for the same ongoing study as discussed today. At the time, Generex issued a press release informing of the presentation, and the following sentence described key data:

With a median follow-up of 22 months in breast cancer patients, Kaplan Meier projections estimate recurrence rates of 10% in vaccinated patients versus 17% in the control group, a risk reduction of 41%.

Once again, that's impressive data. However, Generex also misreported the true findings. The lead author of this report is Dr Tim Vreeland from the San Antonio Military Medical Center. The following sentence reveals the actual data from his presentation:

With a median f/u of 22 months, Kaplan Meier projections estimate recurrence rates of 10.3% in the VG compared to 18% in the CG; a 43% risk reduction

Generex reported that there was a 41% risk reduction for relapse in all patients who received the vaccine up to that time period, with recurrence rates of 10% in the AE37 group vs. 17% in the control group. Dr Vreeland actually reported a 43% risk reduction, with a relapse rate of 10.3% in the AE37 group vs. 18% in the control group. Here's a link to Generex's press release from June, and a link to the actual abstract.

If we go back a little further in time, say to 2009, we may recall this press release from Generex that came one day after an errant corporate update for this same Phase II study. This press release came on the heels of the first look at early efficacy findings, as were presented at the San Antonio Breast Cancer Symposium in December 2009:

Generex Clarifies Previous Announcement of Breast Cancer Study Interim Results

WORCESTER, Mass., Dec 15, 2009 (GlobeNewswire via COMTEX News Network) -- On December 14, 2009, Generex Biotechnology Corporation (Nasdaq:GNBT) (www.generex.com) issued a press release announcing the presentation of interim results from a Phase II efficacy study of a novel immunotherapeutic vaccine being developed by its wholly-owned subsidiary, Antigen Express, Inc. (www.antigenexpress.com), at the 32nd Annual San Antonio Breast Cancer Symposium (www.sabcs.org).

That press release stated that "only half the number of patients in the treatment arm of the study relapsed compared to those not receiving the vaccine," and that "the results presented at the conference were those observed in patients 13.5 months after treatment." Those statements were incorrect. In fact, as COL George Peoples, MD reported to the symposium, at a median follow-up of 13 months, there were NO relapses in patients receiving the AE37 immunotherapeutic vaccine for breast cancer (0 of 49 patients) while relapses were observed in the control group (5 of 71 patients).

The ultimate goal of the study is to demonstrate that, after a follow-up period of 24 months, the relapse rate in the AE37 group of the study is less than half the relapse rate in the control group. The interim results of this study reported by COL Peoples clearly show that the study is on track to achieve that positive endpoint.

Putting 2009 aside, if we just went with the recent information provided by Generex's press releases, we would assess that the study is going well, with a risk reduction of relapse for all subjects staying relatively even, improving from 41% to 42%, as additional subjects are enrolled into the study. From the abstracts, we can see that the risk reduction was factored at a higher 43% in June, and has since improved to 49%.

What's the difference between a 42% risk reduction in relapse vs. 49%? The difference is an extra few early stage breast cancer patients who are participants in this remarkable study that will continue to lead healthy lives, all because Generex and Antigen Express have done an extraordinary job in creating a revolutionary cancer vaccine, even if they struggle with media relations. Generex and Antigen Express may trip on a pebble, such as writing a press release, yet they appear ready to move what was thought to be the toughest of all mountains, CURING CANCER!

Reasearchers from MD Anderson Present Interim Phase II Date for AE37 at ASCO's 2012 Breast Cancer Symposium

Early Efficacy Analysis of the AE37 Vaccine in Patients with HER2 Low-Expressing and Triple-Negative Breast Cancer.

Abstract No:
109

Author(s):
Elizabeth Ann Mittendorf, Sonia A. Perez, Diane F. Hale, Timothy J. Vreeland, Alan K. Sears, Guy T. Clifton, Alexandros Ardavanis, Nathan M. Shumway, James L. Murray, Sathibalan Ponniah, Michael Papamichail, George Earl Peoples

Abstract:

Background: Peptide vaccines comprised of HLA class II epitopes, which elicit CD4+ T cell responses, play a critical role in potentiating immune responses. We are conducting a randomized phase II trial of AE37, a hybrid peptide created by the addition of the Ii-Key moiety (LRMK) to the HER2 helper epitope, AE36 (HER2 aa776-790). Here, we present efficacy data focusing on outcomes in patients with low HER2 (IHC 1+ or 2+) expression and triple negative breast cancer (TNBC).

Methods: The trial is enrolling node positive or high risk node negative breast cancer patients with any degree of HER2 expression (IHC 1+, 2+ or 3+ or FISH > 1.2) rendered disease-free following standard of care therapy. Patients are randomized to receive either AE37+GM-CSF or GM-CSF alone in 6 monthly intradermal inoculations followed by booster inoculations administered every 6 months.

Results: The trial has enrolled 254 patients; 105 in the vaccine group (VG) and 149 in the control group (CG). After a median follow-up of 22.3 months, the disease-free survival (DFS) rate in the VG is 90.3% vs 81.1% in the CG (p=.46), a 49% risk reduction. Evaluating patients with low HER2 expression (IHC 1+ or 2+), there are 53 VG patients and 77 CG patients. The groups are well-matched with respect to the percentage of patients with high grade tumors, tumors > 2cm, the rate of node positivity and ER/PR status (all p>.5).

The DFS rate in the VG of low HER2 expressers is 89.8% vs 68.2% in the CG (p=.12), a 68% risk reduction.

When limiting analyses to patients with TNBC (ER/PR negative, HER2 1+ or 2+), there are 13 VG patients and 23 CG patients. The groups are again well-matched with the exception of control patients having a larger percentage of tumors > 2 cm (70% vs 31%; p=.02).

The DFS rate in the VG of TNBC patients is 83.3% vs 47.6% in the CG (p=.23), a 68% risk reduction.

Conclusions: Early analyses suggest clinical benefit to vaccination with AE37, particularly in patients with low HER2-expressing tumors. Importantly, the benefit appears to persist in TNBC patients. Patients will continue to be followed per protocol for 5 years; however, these data suggest that a subsequent phase III trial should evaluate the vaccine in patients with low HER2-expressing disease to include TNBC.

Here is a link to the abstract.

Let's get wonky! Generex Pipeline Review's unexpert discussion:

The most differential aspect between the results Dr Mittendorf et all present at this week's ASCO Breast Cancer Symposium vs. the ASCO Annual Meeting from June is the inclusion of disease free survival rates for triple negative cancer subjects. Triple negative patients test negative for estrogen receptors (ER-), progesterone receptors (PR-), and HER2 (HER2-). According to breastcancer.org,

These negative results mean that the growth of the cancer is not supported by the hormones estrogen and progesterone, nor by the presence of too many HER2 receptors. Therefore, triple-negative breast cancer does not respond to hormonal therapy (such as tamoxifen or aromatase inhibitors) or therapies that target HER2 receptors, such as Herceptin (chemical name: trastuzumab). However, other medicines can be used to treat triple-negative breast cancer.

About 10-20% of breast cancers — more than one out of every 10 — are found to be triple-negative. For doctors and researchers, there is intense interest in finding new medications that can treat this kind of breast cancer. Early studies are trying to find out whether certain medications can interfere with the processes that cause triple-negative breast cancer to grow.

In the new AE37 study, a much higher percentage (70%) of triple negative subjects within the control group have a tumor size greater that 2 cm, while 69% of triple negative subjects in the vaccine group have a tumor size less than 2 cm. Share cancersupport.org informs that-

triple negative breast cancer tumors are also classified into four stages on the basis of size and lymph-node involvement. Stage I means that the tumor is less than 2 cm in size and there is no lymph node involvement. Stages II and III indicate larger size and degrees of lymph node involvement. Stage IV means that metastasis has already occurred.

With this in mind, it appears that the majority of triple negative subjects in the control group have Stage II tumors, while the majority of triple negative subjects in the vaccine group have Stage I tumors. The difference is noted by the authors of the abstract as being statistically significant, p=.02. For an optimum comparison, the groupings in a planned Phase III study will need to more evenly matched.

However, all of that aside, the results for triple negative subjects within the AE37 arm of the study are quite promising. These subjects have a disease free survival rate of 83.3% at 23.3 months, and the first 24 months appear to be the most critical.

The Oncologist's 2012 article titled Triple-Negative Breast Cancer: An Unmet Medical Need states that "fundamentally, in the early-stage setting, triple-negative breast cancer is associated with earlier versus later events, as well as a shorter period from the time of recurrence until death." They inform in their conclusion remarks that-

triple-negative breast cancer is clearly a distinct subtype, from the perspective of both ER and HER-2, and there may yet be further distinct subclassifications. This disease presentation clearly represents an important clinical challenge. Triple-negative breast cancer is also a surrogate of basal-like breast cancer. Therefore, trials designed to accrue patients with basal-like breast cancer using ER/PR and HER-2 negativity provide an approximation of the triple-negative population, but, as described in the introduction, there is some discordance, including some HER-2 positives and some ER positives among the basals. At present, there is not a clear, proven effective single agent that targets a driving vulnerability in triple-negative breast cancer. However, there are a number of potential therapies currently under investigation that may eventually improve outcomes in these patients.

WebMD estimates that between 10 - 17% of cancers are triple negative. Previous reports estimated that approximately 80% of breast cancer patients could be treated with AE37 if the vaccine gains approval by the FDA. In this estimate, they appeared to be noting subjects that are low and high expressors of HER2/neu. We now see the researchers adding triple negative subjects to their Phase III plannings, and this certainly is a positive development for Generex and Antigen Express.

Currently, Generex's shareholders are waiting to hear an update on the long planned spin out of Antigen Express. Such an update is long overdue, and until then any plans for a Phase III appear to be in a state of limbo. Hopefully, the continued positive results for AE37 bring Generex much needed momentum in their spinout plans for Antigen Express.

One other quick note- during the ASCO Annual Meeting held in June, the researchers noted that they "have enrolled 201 patients to our phase II trial (Vaccine (VG)=103, Control (CG)=98)." This new abstract notes that they have "enrolled 254 patients; 105 in the vaccine group (VG) and 149 in the control group (CG)." The new abstract shows results at 23.3 months, and the June abstract shows results at 22 months. In this update, only 4 subjects have been added to the AE37 arm, while 51 have been added to the control group. Overall, this is the largest controlled study for a peptide based vaccine to treat breast cancer in the adjuvant setting.

As Generex's stock continues to decline, their AE37 breast cancer vaccine continues to shine. At some point, AE37 should have a long lasting positive effect on shares of GNBT, while the more important goal is to cure early stage breast cancer.

Breast Cancer Vaccine Reduces Recurrence

The following is an article published by the American Association for Cancer Research for the May edition of Cancer Discovery

Women with a history of HER2-positive breast cancer show lower rates of relapse after inoculation.

A novel hybrid vaccine reduced recurrence rates in patients with HER2-positive breast cancer by 43% after 22 months in early results of a phase IIb randomized clinical trial. Of 201 patients rendered disease free by standard treatment, those who received the vaccination had a recurrence rate of about 10.3% compared to 18% in the control group.

“We need to continue to follow these patients, but there is enough of a trend that a phase III trial is warranted,” says Elizabeth Mittendorf, MD, a surgical oncologist at MD Anderson Cancer Center in Houston and the trial's national principal investigator. The results will be presented June 4 at the 2012 Annual Meeting of the American Society of Clinical Oncology.

Antigen Express of Worcester, MA, the company producing the vaccine and a partial funder of the trial, plans to follow up with a phase III study.

The vaccine teaches CD4+ T-helper cells, immune cells that are critical in mounting a response against foreign invaders, to recognize the HER2 protein, which is expressed at some level in 75% to 80% of breast cancer tumors. The vaccine's hybrid design combines a fragment of HER2 with a novel peptide based on the immune-regulatory li protein that, in laboratory tests, was found to enhance the potency of the vaccine 250-fold.

Because the vaccine is effective in tumors with any level of HER2 expression, it may aid patients who are not eligible for targeted therapy with Herceptin (trastuzumab; Genentech) because their tumor HER2 levels are too low.

If it is eventually approved, the vaccine could be delivered in any physician's office. The ongoing trial included monthly injections for 6 months followed by boosters every 6 months for 3 years. To heighten immune response, the vaccine was paired with an immune stimulant known as granulocyte macrophage colony-stimulating factor, which was also given to patients in the control arm of the trial.

The trial targets women who are disease free after standard-of-care treatment rather than those with metastatic disease, because the vaccine was not likely to overcome aggressive and invasive tumors. “It's a paradigm shift in trial design for cancer vaccines,” says Mittendorf, who is now developing a trial giving the vaccine with chemotherapy prior to surgery to test whether inoculation during immune system reconstitution improves outcomes.

©2012 American Association for Cancer Research.

Source HERE.

ABC News Features a Report on the AE37 HER2 Cancer Vaccine

Click the word VIDEO to see the ABC news segment.

Two Late Breaking Abstracts Featuring Antigen Express' AE37 Peptide Vaccine for HER2/Neu Breast Cancer Patients to be Presented at AACR 2012

The AACR Annual Meeting will highlight the best and latest findings in all major areas of cancer research. Cancer researchers continue to make incredible strides and breakthroughs, with an impact on global health. The theme of the AACR Annual Meeting 2012, “Accelerating Science: Concept to Clinic,” reflects this amazing progress and emphasizes the synergy between basic, clinical and translational research that will continue to lead to effective cancer therapies and prevention strategies. The meeting takes place March 31-April 4 in Chicago.

Two late breaking abstracts featuring Antigen Express' AE37 Peptide Vaccine for HER2/Neu breast cancer patients will be presented at the AACR Annual Meeting. The titles of the abstracts, and names of the authors, have been made available at the meetings website:

Late-Breaking Poster Session
LBPO.IM01. Late-Breaking Research: Immunology
Mon, Apr 2, 1:00 - 5:00 PM
Abstract Number:
LB-130

Presentation Title:
Immune reconstitution after chemotherapy correlates with increased in vitro immune response in breast cancer patients undergoing peptide vaccine therapy

Location:
McCormick Place West (Hall F), Poster Section 40

Author Block:
Timothy J. Vreeland, Raetasha S. Dabney, Diane F. Hale, Alan K. Sears, Guy T. Clifton, Athina Zacharia, Yusuf Jama, Anna Chiplis, Mohamed Mursal, Nathan M. Shumway, Ritesh Patil, Jarrod P. Holmes, Elizabeth A. Mittendorf, George E. Peoples, Sathibalan Ponniah. San Antonio Military Medical Center, San Antonio, TX, Cancer Vaccine Development Lab, USUHS, Bathesda, MD, Roswell Park Cancer Institute, Buffalo, NY, Redwood Regional Medical Group, Santa Rosa, CA, UTMD Anderson, Houston, TX

Late-Breaking Poster Session
LBPO.CL01. Late-Breaking Research: Clinical Trials
Tue, Apr 3, 8:00 AM - 12:00 PM
Abstract Number:
LB-218

Presentation Title:
Immune response assessment in a phase II trial of AE37 HER2 peptide vaccine

Location:
McCormick Place West (Hall F), Poster Section 40

Author Block:
Diane F. Hale, Timothy J. Vreeland, Raetasha S. Dabney, G Travis Clifton, Alan K. Sears, Efi Pappou, Eleftheria Anastasopoulou, Alexandros Ardavanis, Sathibalan Ponniah, Michael Papamichail, Sonia Perez, Nathan Shumway, George E. Peoples, Elizabeth Mittendorf. Brooke Army Medical Center, Ft. Sam Houston, TX, St. Savas Cancer Hospital, Athens, Greece, Athens, Greece, Cancer Vaccine Development Lab, U.S. Military Cancer Institute, Uniformed Services University of the Health Sciences, Bethesda, MD, University of Texas MD Anderson Cancer Center, Houston, TX


The AACR 2012 website can be found by clicking here.

Antigen Express' AE37 HER2 Peptide Vaccine Named to Shortlist for 5th Annual ViE Awards

Antigen Express' lead vaccine, the AE37 HER2/neu synthetic peptide vaccine, has has been named as a nominee for the BEST THERAPEUTIC VACCINE (approved or in development) according to the shortlist published today for the 5th Annual Vaccine Industry Excellence (ViE) Awards. The ViE awards, sponsored by Novartis Vaccines and Diagnostics, were created to recognize the accomplishments and contributions of companies and individuals in the vaccine industry over the previous 12 months.

The full list of nominees in the Best Therapeutic Vaccine category are:

•Advaxis: ADXS-HPV - HPV

•Antigen Express: AE37 - Breast cancer

•BioSante Pharmaceuticals: GVAX

•Galena Biopharma: NeuVax - Breast cancer

•ImmusanT: Nexvax2 - Celiac disease

•Inovio Pharmaceuticals: VGX-3100 - Cervical cancer

The ViE Award nominees are voted on by those in the global vaccine industry and also judged by a panel of representatives from pharma, biotech, academia, government, non-governmental organizations (NGOs), and public health. Winners are announced at the annual ViE Awards dinner and ceremony, taking place this year on April 11 during the World Vaccine Congress in Washington, D.C. Click on AE37 Vaccine to go to the ViE Awards link on the World Vaccine Congress' website.

Bring it home, Antigen Express!

The Journal of Immunology to Publish Study Detailing Generex Biotechnology's Research Collaboration with the Mayo Clinic in July Edition

The July edition of the Journal of Immunology, a peer-reviewed research publication of the American Association of Immunologists, features an article that will detail the research collaboration between Generex's (GNBT) wholly owned subsidiary, Antigen Express, and the Mayo Clinic. The research is a continuation of scientific study between Antigen Express, lead by President Dr. Eric von Hofe, and the Mayo Clinic's Dr. Keith Knutson, a leader in the field of peptide vaccines in breast cancer. The title of the future article is "MHC Class II Epitope Nesting Modulates Dendritic Cell Function and Improves Generation of Antigen-Specific CD4 Helper T Cells". The abstract and article are not yet available for view, but the title is included in the Journal's future table of contents.

Antigen Express has been developing a series of CD4+ T Cell helper epitopes, based upon their proprietary Ii-Key hybrid technology. Ii-Key is a portion of the MHC class II associated invariant chain, which is known as Ii. Antigen Express explains that Ii-Key facilitates the direct loading of epitopes to the MHC class II molecule groove. Utilizing their technology, Antigen Express' Ii-Key/MHC class II epitope hybrids have shown clinical evidence of greatly enhancing the vaccine potency of the tethered epitope. Antigen Express' most advanced vaccine is AE37, a HER-2/neu hybrid peptide which is currently in a multi-center Phase II study.

The Mayo Clinic's Dr. Knutson has long studied adoptive T Cell therapy strategies to create cancer vaccines designed for immunotherapy of HER-2/neu breast cancer. Adoptive T Cell therapy strategies have largely focused generation of CD8+ T Cells, due to observations that most tumours express MHC class I, but not MHC class II. This gets tricky, so here is some info on CD4+ T Cells vs CD8+ T Cells. CD4+ T Cells recognize antigen-derived peptides in the context of self-MHC class II molecules, while CD8+ T Cells recognize antigen derived peptides in the context of self MHC class I molecules.

The problem Dr. Knutson had previously encountered is that CD8+ T-cells have a short lifespan. Earlier, Dr. Knutson reported that a problem with the use of adoptive T Cell therapy included the lack of CD4+ T cell help. In further work, Dr. Knutson has found that patients immunised with with CD4+ HER-2/neu helper epitopes, such as being developed by Antigen Express, are able to develop long lasting HER-2/neu specific CD8+ T Cell immunity. Specifically, Dr. Knutson found that greater than 60% of patients immunised with CD4+ HER-2/neu helper epitopes, each containing an encompassed HLA-A2 epitope, were able to develop HER-2/neu specific CD8+ T-cell immunity. The CD8+ T Cell response was maintained, in some patients, for at least one year following vaccination.

In contrast, 40% patients immunised with a single CD8+ T Cell HER-2/neu HLA-A2 9-merpeptide, RXI Pharmaceuticals' (RXII) NeuVax, or E75, developed HER-2/neu CD8 T Cell immunity that declined to undetectable levels within 5 months of the last vaccination. AE37 is the HER-2/neu CD4+ T Cell helper containing an encompassed HLA-A2 epitope that outshines E75 given alone in his study. If a main problem for Dr. Knuston's adoptive transfer research had been the lack of CD4+ T cell help, Dr. von Hofe and Antigen Express presented the solution.

Since we know the title of the upcoming research article authored by Dr. Knutson and Dr. von Hofe, with other Mayo Clinic researchers, is "MHC Class II Epitope Nesting Modulates Dendritic Cell Function and Improves Generation of Antigen-Specific CD4 Helper T Cells", we have a clue on where they are going with this research. A 2010 patent by Dr. Knutson, titled "METHODS AND MATERIALS FOR GENERATING T CELLS", explains what is invloved in generating antigen-specific CD4+ T cells. The patent outlines methods and materials for using nested MHC class II epitopes to generate CD4+ T cells. The patent states that the nested MHC class II epitopes provided can include an invariant chain, or Ii, and a MHC class II epitope. The patent is describing his work with Antigen Express, and the upcoming article will provide peer review documentation.

Antigen Express is also involved in a separate collaboration with the Mayo Clinic's Dr. Svetomir Markovic, a distinguished translational researcher with expertise in melanoma trials. That agreement focuses on advancing an immunotherapeutic vaccine for melanoma into the clinic. Generex is planning a spin out of Antigen Express, following approval of a reverse stock split of Generex's shares. Top industry scientists, like those found at the prestigious Mayo Clinic, are already excited about the potential found within Antigen Express' pipeline. I am certainly no scientist, so read my opinions and rough analysis with that in mind, but the potential for Antigen Express is obviously high.

Should Generex's planned reverse stock split proposal be approved, followed by a spin out of Antigen Express, adequate funding may finally be within Antigen Express' grasp, which will serve as the fuel to propel all of this successful research deeper into human studies. The winners in that scenario will be Generex's current and Antigen Express' future shareholders, and most importantly the cancer patients in need of better therapy. We are looking at the future when active immunotherapy will be a commercialized reality, designed by Antigen Express.

Generex's Antigen Express and France's Stallergenes Co-Author Allergen Research

Scientists from Antigen Express, a wholly owned subsidiary of Generex Biotechnology (GNBT), and France's Stallergenes (GENP.PA) have co-authored a peer review article titled "Researchers Distinct Characteristics of Seasonal Bet v 1 vs. Perennial Der p 1/Der p 2 Allergen-Specific CD4+ T Cell Responses". The article will appear in a future edition of "Clinical & Experimental Allergy" and is available online ahead of print as of November 24th. Stallergenes is a biopharmaceutical company dedicated to immunotherapy treatments for the prevention and treatment of allergy-related respiratory diseases, such as allergic rhinoconjunctivitis, rhinitis and asthma.

Stallergenes has been researching the potential of using Ii-Key peptide tetramers as an assay to monitor T cell responses to allergens as part of a collaboration with Antigen Express that was signed in 2005. Since Antigen Express' proprietary Ii-Key peptide hybrids are potent at stimulating CD4+ T cells, in theory they would be useful in detecting the presence of allergen-specific autoimmune T cells in the blood. The CD4+ T cell responses to the Ii-Key assay will evidently help Stallergenes identify which patients would benefit from the specific immunotherapies which they are developing.

The new research article compares the CD4+ T cell responses against seasonal (Bet v 1) and perennial (Der p 1, Der p 2) allergens. Bet v 1 refers to birch pollen allergen while Der p 1, Der p 2 are considered to be the major allergens derived from house dust mites. The researchers inform that "major histocompatibility complex class II peptide tetramers were engineered to monitor allergen-specific T cell responses". A little cheating from Wikipedia tells us that "histocompatibility is the property of having the same, or mostly the same, alleles of a set of genes called the major histocompatibility complex. These genes are expressed in most tissues as antigens, to which the immune system makes antibodies".

The new report from Antigen Express and Stallergenes states that "tetramer+ cells were detected in 19 patients allergic to house dust mites (HDM), seven allergic to birch pollen, 13 allergic to both and nine non-allergics". The report concludes that "different memory CD4+ T cell responses are elicited in the context of chronic vs. seasonal stimulation with the allergen(s). The heterogeneity in the patterns of CD4+ T cell responses observed in patients allergic to HDMs should be taken into account for specific immunotherapy".

A previous peer review published in 2008 by Antigen Express and Stallergenes, titled "Single Cell Assessment of Allergen-Specific T Cell Responses with MHC Class II Peptide Tetramers", revealed that the complex class II peptide tetramers, such as those mentioned in in the new report, were peptides that are "chemically conjugated with the Ii-Key peptide from the MHC invariant chain to facilitate peptide exchange and binding to MHC class II molecules". In the report, the researchers described that the CD4+ T helper cells that are activated to respond to specific allergens can be identified with high sensitivity ex vivo using Ii-Key hybrids. The researchers of the article remarked that Ii-Key peptide tetramers "will also be extremely useful to monitor the efficacy of various immunotherapeutic strategies in humans, using an immunological readout, possibly helping to identify surrogate biological markers of clinical efficacy" and that "Ii-Key conjugate peptides is the most efficient procedure to expand Bet v 1(141-155)-specific CD4+ T cells, allowing to detect such cells in both allergic and healthy individuals".

In April, Stallergenes announced the positive results of a phase III clinical trial conducted in the US for its sublingual grass pollen immunotherapy tablet, Oralair. The Phase III study is the first conducted in the US, after successfully completing four Phase III clinical trials conducted in Europe. Oralair has already been approved by German regulators, and Stallergenes has retained Torreya Partners in hopes of helping them secure a partner for the US market by mid-2011. Stallergenes is currently planning their NDA filing to be submitted to the FDA.

Stallergenes is aware that they also need help in evaluating which patients would most benefit from their allergen immunotherapy tablets, and in their scientific research reports we find evidence that this help may come from an Antigen Express designed assay. Antigen Express' ability to turn their Ii-Key peptide tetramer assay research into a revenue generating asset may not be such a far fetched dream. While that dream remains to be seen, this positive research report concerning Antigen Express' proprietary Ii-Key technology is certainly a step in the right direction.