Intranasal drug delivery for brain metastatic breast cancer

Institution: University of Southern California
Investigator(s): Axel Schonthal, Ph.D. -
Award Cycle: 2013 (Cycle 19) Grant #: 19IB-0141 Award: $242,382
Award Type: IDEA
Research Priorities
Detection, Prognosis and Treatment>Innovative Treatment Modalities: search for a cure

Initial Award Abstract (2013)

Non-technical overview of the research topic and relevance to breast cancer:
There is no effective therapy for breast cancer that has spread to the brain. A major roadblock is the fact that the usual breast cancer drugs are not able to penetrate the blood-brain-barrier (BBB) and therefore do not reach metastases in the brain. We are seeking to develop a novel chemotherapeutic agent that enables dosing via nasal inhalation, which will circumvent the BBB and increase brain-targeted activity, while keeping full-body exposure low.

We will take advantage of, but substantially improve upon, certain criteria that have worked well for the treatment of aggressive brain tumors, such as glioblastoma multiforme (GBM). The current gold standard chemotherapy for GBM is temozolomide (TMZ), which is given orally and crosses the BBB reasonably well (although sub-optimally). However, its full-body distribution can cause harmful bone marrow suppression.

Many years ago, the natural product perillyl alcohol (POH), which is found in many plants including fruits, had been tested for anticancer activity. Although it was fairly potent, there were severe intestinal side effects after oral dosing; therefore POH did not enter clinical practice. However, recent studies in Brazil demonstrated that simple inhalation of POH through the nose (with a vaporizer 4 times daily) is effective against brain tumors that have stopped responding to other treatments. Additionally, there were little to no side effects resulting from POH “sniffing”, which favorably impacted quality of life. This gave us the idea that POH might be useful as a vehicle to facilitate delivery of other chemotherapeutic agents into the brain via simple nasal inhalation.

Consequently, the applicant’s long-term collaborator, Dr. Thomas Chen and NeOnc Technologies generated a novel chemical entity where TMZ was fused with POH. Computer modeling predicts that this unique molecule, called T-P, has excellent brain entry, much better than TMZ. We hypothesize that T-P can be given to patients via inhalation and will be effective against breast cancer metastases in the brain, without major side effects.

While our primary intent was to generate a therapeutic molecule that can very effectively enter the brain, we made the surprising discovery that T-P is several-fold more effective at killing cancer cells in a culture dish than either parental compound, TMZ or POH, alone. Moreover, simply mixing TMZ with POH cannot replicate the potency of T-P, showing that stable fusion of the two molecules into a new entity is essential for the greatly improved potency. Administration of T-P to a few mice did not reveal major side effects, and the animals continued to thrive, indicating that the drug is well tolerated. In our proposed study, we intend to investigate whether intranasal T-P exerts therapeutic effects in animals with breast cancer-derived brain metastases.

The question(s) or central hypotheses of the research:
Our hypothesis is the following: (i) T-P is able to circumvent the BBB and enter the brain more effectively than other anticancer drugs. Therefore, in combination with its increased tumor-killing potency, therapeutically effective concentrations can be delivered to intracranial breast metastases. (ii) Intranasal delivery will (a) help concentrate the drug in the brain, and thus reduce systemic (full-body) exposure to the drug, and (b) minimize metabolism/turnover of the drug in the liver. This will enable us to give overall lower drug dosages and thus reduce the chances of unwanted toxic side effects.

The general methodology:
On one hand, we will perform studies in vitro to investigate the molecular mechanisms by which T-P attacks and kills breast cancer cells. With the use of breast cancer cell lines in culture, we will study the known targets of TMZ and POH to find out whether T-P attacks the same molecular targets, and which target(s) is (are) the critical ones to effect tumor cell death. On the other hand, we will use mouse breast tumor models with metastatic spread to the brain. We will apply two methods of drug administration, oral and intranasal, in order to determine which is more effective and has the least side effects.

Innovative elements of the project:
The innovative elements are: (i) The fusion of POH to a chemotherapeutic drug will enable intranasal delivery of the drug and, if therapeutic proof of principle with TMZ indeed can be verified, should be applicable to other drugs as well; (ii) the fusion of POH with TMZ has generated a novel compound that is substantially more potent than its individual parts; (iii) compared to conventional oral or intravenous drug administration, which distributes the drug throughout the entire body, intranasal drug delivery will increase brain targeting but decrease full-body exposure, and thus will minimize the risks of unwanted side effects, such as bone marrow suppression, which is a serious effect of many oral or i.v. chemotherapeutics.

Progress Report 1 (2014)

There is no effective therapy for breast cancer that has spread to the brain. A major roadblock is the blood-brain¬barrier (BBB), which prevents the usual breast cancer drugs from effectively reaching intracranial metastases. The alkylating agent temozolomide (TMZ) is able to penetrate the BBB and has become the gold standard for chemotherapeutic treatment of glioblastoma. However, when it was tested in clinical trials for activity against brain metastases of breast cancer, the results were mixed and ranged from “encouraging activity” to “no objective responses.” In an effort to generate an agent with greater activity against intracranial breast metastases, we synthesized a TMZ analog where the natural product perillyl alcohol (POH) was covalently linked to TMZ, in order allow more effective access to tumor growth located inside the brain. We hypothesized that this novel molecule may overcome the BBB more effectively, and may also allow drug delivery via intranasal administration.

Supported by funding from the CBCRP, we have established that the resulting novel compound, called TMZ¬POH, displayed greatly increased anticancer activity in a variety of breast cancer cell lines, inclusive of TMZ-resistant ones. It caused DNA damage and cell death much more efficiently than its parental compound TMZ, because linkage with POH increased its biological half-life and thus provided greater opportunity for placement of cytotoxic DNA lesions. In an intracranial mouse tumor model with triple-negative breast cancer, TMZ-POH revealed considerably greater therapeutic efficacy than TMZ, where a single cycle of treatment extended median survival benefit from 6 days (in the case of TMZ) to 28 days. This finding indicated that TMZ-POH was quite effective at crossing the BBB, with greater efficacy than TMZ. At the same time, TMZ-POH appeared to be well tolerated by the animals and there were no detectable side effects.

Our work so far has established the veracity of our initial hypothesis, namely that TMZ-POH may have potential as a novel therapy for brain-targeted breast cancer metastases. The important next steps of this project will include testing of TMZ-POH in HER2/neu-positive breast cancer, as this subtype, similar to triple-negative breast cancer, exhibits a propensity to spread to the brain. As well, we will now pursue drug delivery via intranasal administration, in an effort to increase therapeutic outcome even further. Intranasal delivery may support direct brain entry of the drug, which may lead to further concentrated anticancer activity against those difficult-to-treat breast brain metastases.

Progress Report 2 (2015)

There is no effective therapy for breast cancer that has spread to the brain. During the first year, our CBCRP-funded project had established that a novel compound, temozolomide covalently conjugated to perillyl alcohol (called TMZ-POH, T-P), displayed greatly increased anticancer activity against breast cancer cell lines in vitro and in vivo, thus establishing the veracity of our initial hypothesis that TMZ-POH may have potential as a novel therapy for brain-targeted breast cancer metastases.

During the second year period, we have included primary HER2/neu-positive breast cancer cells derived from the brain of a breast cancer patient (HER2/neu-positive cells are known to have a propensity to metastasize to the brain of breast cancer patients). We could establish that TMZ-POH exerts significant activity against these cells as well. We used a metastasis model where cancer cells are injected into the heart of mice. For this approach, we injected HER2/neu-positive primary breast cancer cells that we established from a brain-metastatic lesion of a breast cancer patient. These cells were labeled with luciferase, so that tumor growth could be monitored by non-invasive whole-body imaging of animals and followed over several weeks to months. During the first run of this model with only small numbers of mice, there was impressive therapeutic activity of TMZ-POH, in that drug treatment greatly reduced metastatic spread of cancer cells that were injected into the heart. Not only was there much less metastasis in the brain, but other organs as well showed greatly reduced metastasis. In contrast, in control animals without drug treatment, the cancer cells effectively spread throughout the entire body, including into the brain. We are currently repeating this same experiment with larger number of animals in order to validate these impressive outcomes. As well, we are performing experiments where drug treatment starts at later time points, after metastatic spread has taken place, in order to determine whether TMZ-POH not only minimizes seeding, but whether it can also reduce the growth of already established lesions in brain (and other organs) that were not experimentally placed (by direct injection), but that arrived and seeded more naturally (via dissemination through the bloodstream).

We will use this same HER2/neu-positive mouse model in order to further investigate whether different modes of drug delivery will result in substantial therapeutic differences. While we find very effective activity in cases where TMZ-POH is administered by oral gavage or by subcutaneous injection, we still need to compare these modes of delivery to intranasal drug administration. Initial experiments have been successful; we will need to use larger number of animals for validation of the results. Altogether, we envision that the above studies will be completed within the next several months.

Conference Abstract (2016)

Intranasal Drug Delivery of a Novel Agent for the Treatment of Breast Cancer that has Spread to the Brain

Axel H. Schönthal1, Diana T. Chingos2, Florence M. Hofman1, Thomas C. Chen1
1 University of Southern California Keck School of Medicine, Los Angeles, CA. 2 Patient Advocate, Los Angeles, CA.

Overall Goal of Project: There is no effective therapy for breast cancer that has spread to the brain, and such patients are faced with dismal prognosis. We are developing a novel chemotherapeutic agent with high brain-targeted activity that is well tolerated and can be administered via nasal inhalation. Delivery through the nose is expected to support brain-targeted drug activity, while at the same time minimizing side effects throughout the rest of the body. Our goal is to assemble convincing preclinical data, so that this new type of therapeutic approach will receive authorization from the FDA for testing in clinical trials with breast cancer patients suffering from brain lesions.

Description of Work: The efficient delivery of many drugs into the brain is greatly hampered by the blood-brain barrier (BBB), which functions to protect the brain from bacteria and foreign substances, including many therapeutic drugs. We are seeking to overcome this obstacle by modifying existing pharmaceutical agents with the natural compound perillyl alcohol (POH). Our computer modeling has predicted that permanently linking POH to certain drugs can result in a fusion compound that is then able to much better penetrate the BBB. Independently, clinical studies (performed by others in Brazil) have demonstrated that POH can be delivered via inhalation through the nose, resulting in significant therapeutic effects in patients with primary brain cancer. We have combined these two observations to devise a novel therapeutic approach that involves the drug temozolomide (TMZ).

TMZ has been used for over a decade for patients with brain cancer. However, its therapeutic impact is far from optimal, because it enters the brain only sub-optimally. We have fused POH to TMZ, resulting in a novel chemical entity called TMZ-POH or NEO212. We predicted that NEO212 would be effective against tumors in the brain, based on two major features: (i) it would cross the BBB more effectively than TMZ, and (ii) it could also be delivered via nasal inhalation, which would further increase its access to the brain tumor, altogether delivering a therapeutic one-two punch to the tumor.

With support from the CBCRP, we have investigated our predictions in different mouse tumor models. For instance, with the use of mice carrying breast cancer cells in their brains, we found that NEO212 exerted pronounced therapeutic activity. These NEO212-treated animals lived much longer than others that received no treatment or received TMZ as the treatment. Importantly, NEO212 was also effective against breast cancer cells that were drug-resistant. At the same time, treated animals did not show signs of side effects, indicating that NEO212 treatment was very well tolerated.

Potential Impact: We are working on obtaining FDA approval to test NEO212 in patients with breast cancer where malignancy has entered the brain. If successful, these clinical trials will establish NEO212 as a novel therapy that proves superior to the (low-efficiency) treatments currently used in this patient group. Combined with increased quality of life (due to fewer side effects), therapy with NEO212 is expected to reduce morbidity and mortality of breast cancer patients with advanced disease.

A novel temozolomide-perillyl alcohol conjugate exhibits superior activity against breast cancer cells in vitro and intracranial triple-negative tumor growth in vivo.
Periodical:Molecular Cancer Therapeutics
Index Medicus: Mol Cancer Ther
Authors: T.C. Chen, H.-Y. Cho, W. Wang, M. Barath, N. Sharma, F.M. Hofman, A.H. Schonthal
Yr: 2014 Vol: 13 Nbr: 5 Abs: Pg:1181-93

Preclinical development and clinical use of perillyl alcohol for chemoprevention and cancer therapy
Periodical:American Journal of Cancer Research
Index Medicus: Am J Cancer Res
Authors: Thomas C Chen, Clovis O Da Fonseca, Axel Schonthal
Yr: 2015 Vol: 5 Nbr: 5 Abs: Pg:1580-1593