Full Press Release Details
Immutep Reports Statistically Significant Survival Benefit for Key
Patient Groups in the Ongoing Phase IIb AIPAC Study in
Metastatic Breast Cancer
SYDNEY, AUSTRALIA 10 December 2020 Immutep
Limited (ASX: IMM; NASDAQ: IMMP) a biotechnology company developing novel immunotherapy treatments for cancer and autoimmune disease, is pleased to report encouraging first Overall Survival (OS) follow up data from its ongoing Phase IIb AIPAC
study evaluating Immutep s lead product candidate eftilagimod alpha in combination with paclitaxel chemotherapy ( efti group ) in comparison to a combination of placebo and paclitaxel chemotherapy ( comparator group ) in
patients with HER2-negative/HR positive metastatic breast cancer (HR+ MBC). These data were selected to be presented in a spotlight presentation at the San Antonio Breast Cancer Symposium 2020, which is being held virtually this week from Texas,
AIPAC Principal Investigator, Hans Wildiers of University Hospital Leuven, Leuven, Belgium, said:
Improving Overall Survival is a key endpoint when evaluating the benefit of new anticancer drugs. Efti is a new drug targeting the immune system in an
innovative way and has the potential to improve outcomes in HER2-negative/hormone receptor positive metastatic breast cancer patients. The AIPAC study investigated efti in combination with first line chemotherapy in this population, a group of about
250,000 patients diagnosed worldwide each year. Although the progression free survival data in the efti group did not show a significant improvement versus the comparator arm in AIPAC earlier this year, the OS data in general looks already very
interesting and will mature further. The OS data in subgroups such as those below age 65 years are highly encouraging and may lead to more effective treatment options for metastatic breast cancer patients.
Immutep CSO and CMO, Dr Frederic Triebel said: We are very excited to see that efti is boosting the immune system by providing a statistically
significant increase in CD8 T cell numbers, which is correlated with prolonged survival for patients. These data provide proof-of-concept and support our long-held
belief that efti can provide a meaningful benefit to patients in a range of cancer settings by pushing the
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gas on the body s immune system, representing an important landmark. Through this mechanism, efti is helping a large proportion of patients in the AIPAC study with Her2-HR+ metastatic breast cancer which is typically a non-immunogenic cancer and is therefore significantly
less responsive to modern immune checkpoint inhibitor (ICI) therapies. As such, chemotherapy continues to be the standard of care in many instances and there continues to be a large unmet medical need. We look forward to reporting final survival
Immutep CEO, Marc Voigt said: AIPAC marks an important milestone for Immutep and builds our confidence that efti is
beneficial for many cancer patients, including those with metastatic breast cancer. Notably, we have seen a more material OS benefit than PFS benefit in this study; however, we note that this is not unusual for some immunotherapies where it can take
time for the body s immune system to be boosted and provide a therapeutic benefit. We are very encouraged by these first OS results which, subject to ongoing data collection, warrant a registrational perspective and regulatory interactions
towards what we hope will be an important new class of medicines.
Key Efficacy Results: data cut-off
In the total patient population, first OS data (based on approx. 60% of events) show that patients in the efti group had an
improving OS trend with a median OS of 20.2 months compared to 17.5 months for patients in the comparator group, indicating a survival benefit of +2.7 months (HR = 0.83; p = 0.14). The OS analysis is based on a
2-sided false positive probability of 0.05. Furthermore, a significant deterioration in quality of life was observed for patients in the comparator group at week 25, which was not observed in the efti group.
This is an encouraging observation as these types of benefits are supportive of efti being eligible for reimbursement upon marketing approval.
predefined patient groups, the study has already demonstrated a statistically significant and clinically relevant OS benefit from treatment with efti in combination with chemotherapy. Patients under the age of 65 years (representing 66.7% of
patients in the efti group) reported a median OS of 21.9 months compared to 14.8 months in the comparator group, indicating a survival benefit of +7.1 months (HR = 0.62; p = 0.012) favoring the efti group.
Figure 1 Kaplan Meyer curve OS for patients < 65 years
The current data suggest that for patients younger than 65 years old, the probability of being alive at three years with
efti plus chemotherapy vs. chemotherapy alone is increased by 100%.
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Furthermore, patients with a low monocyte count at baseline (representing 21.9% of patients in the efti
group) reported a median OS of 22.4 months compared to 12.9 months in the comparator group, indicating a survival benefit of +9.4 months (HR = 0.47; p = 0.02) favoring the efti group.
Trending towards statistical significance, patients with a more aggressive, more immunogenic luminal B type of breast cancer (representing 48.8% of patients
in the efti group) reported a median OS of 16.3 months compared to 12.6 months in the comparator group, indicating a beneficial trend of +3.8 months (HR = 0.69; p = 0.077) favoring the efti group. (See Table 1)
Table 1 Overall Survival in key patient groups
| Group | % of patients in efti group | Efti group / Comparator group | Median OS (months) | Absolute OS benefit from efti | ||||
| Total Population | 100% | Efti + paclitaxel Placebo + paclitaxel | 20.2 17.5 | +2.7 months HR = 0.83 p = 0.14 | ||||
| < 65 years old | 66.7% | Efti + paclitaxel Placebo + paclitaxel | 21.9 14.8 | +7.1 months HR = 0.62 p = 0.012 | ||||
| Low monocytes < 0.25/nl | 21.9% | Efti + paclitaxel Placebo + paclitaxel | 22.4 12.9 | +9.4 months HR = 0.47 p = 0.02 | ||||
| Luminal B | 48.8% | Efti + paclitaxel Placebo + paclitaxel | 16.3 12.6 | +3.8 months HR = 0.69 p = 0.077 |
Note: A lower HR, means a reduced risk of death, e.g. by 53% in the low monocyte group.
Immuno Monitoring Results
Importantly, there was a
statistically significant, sustained long-term increase in peripheral CD8 T cells in patients in the efti group. This is consistent with the mode of action of efti. There was also a statistically significant correlation between those patients having
an increase in the number of CD8 T cells and those having a prolonged OS. This represents a strong proof-of-concept in a randomised, double blinded setting.
The combination of efti and paclitaxel
chemotherapy was overall safe and well tolerated, further building upon efti s strong safety profile to date.
The presentation poster is available
Multivariate analysis of the data is ongoing and final OS data is expected to be reported in mid 2021.
Immutep will present this AIPAC data in
a global webcast for investors, details are as follows:
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A replay of the webcast will also be available at www.immutep.com from the day after the event.
About the AIPAC trial
Active Immunotherapy Paclitaxel
(AIPAC) is a multicentre, placebo-controlled, double-blind, 1:1 randomised Phase IIb clinical trial in HER2-negative/HR positive metastatic breast cancer.
The study is evaluating the combination of Immutep s lead product candidate, eftilagimod alpha (efti, LAG-3Ig or
IMP321), and paclitaxel chemotherapy. 227 HER2-negative/HR positive metastatic breast cancer patients are randomised 1:1 to a chemo-immunotherapy arm (efti plus paclitaxel) or to a comparator arm (placebo plus paclitaxel). Patients receive weekly
paclitaxel at days 1, 8 and 15, with either efti or placebo injected subcutaneously on days 2 and 16 of each 4-week cycle, repeated for 6 cycles. Thereafter, patients pass over to the maintenance phase with
For more information regarding the AIPAC trial, visit clinicaltrials.gov (identifier NCT02614833) and
Immutep is a globally active biotechnology company that is a leader in the development of LAG-3 related
immunotherapeutic products for the treatment of cancer and autoimmune disease. Immutep is dedicated to leveraging its technology and expertise to bring innovative treatment options to market for patients and to maximize value to shareholders.
Immutep is listed on the Australian Securities Exchange (IMM), and on the NASDAQ (IMMP) in the United States.
Immutep s current lead product
candidate is eftilagimod alpha ( efti or IMP321 ), a soluble LAG-3 fusion protein (LAG-3Ig), which is a first-in-class antigen presenting cell (APC) activator being explored in cancer and infectious disease. Immutep is also developing an agonist of LAG-3 (IMP761) for
autoimmune disease. Additional LAG-3 products, including antibodies for immune response modulation, are being developed by Immutep s large pharmaceutical partners.
Further information can be found on the Company s website www.immutep.com or by contacting:
Australian Investors/Media:
+61 (0)406 759 268; cstrong@citadelmagnus.com
Tim McCarthy, LifeSci Advisors
+1 (212) 915.2564; tim@lifesciadvisors.com
announcement was authorised for release by the Board of Immutep Limited.
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