Atossa Genetics’ news that staged a huge Rally of this small firm’s stock

Atossa Genetics (ATOS) announced that the FDA has issued a “Safe to Proceed” letter under their “expanded access” program permitting the use of Atossa’s oral Endoxifen as a post-mastectomy treatment in a pre-menopausal, estrogen-receptor positive (ER+) breast cancer patient. The patient completed a 3-week course of Atossa’s oral Endoxifen prior to her surgery under an FDA-approved expanded access program.

Atossa’s stock rallied from under $2 to over $5 as a result.

Oral Endoxifen Patient Statistics

The tumor activity from the initial biopsy was compared to the tumor activity at surgery. The findings were that the cancer cell biological activity was reduced by two measures: the Ki-67 activity decreased by 50% and the estrogen receptor content decreased by over 20%.

There were no safety or tolerability issues, including vasomotor symptoms such as, hot flashes and night sweats. The latter symptoms are often a tolerability challenge for patients on tamoxifen.

Comments from Atossa

Dr. Steven C. Quay, President and CEO of Atossa, commented, “We are extremely pleased that this patient not only benefitted from Endoxifen prior to her surgery, but that the FDA agrees that continued Endoxifen therapy is appropriate for this pre-menopausal patient. This positive progress supports our expansion of oral Endoxifen clinical trials.  After surgery is completed, the current standard of care in the USA to prevent a recurrence and/or a new cancer is for patients to undergo ovarian ablation (chemical treatment to induce menopause) and take aromatase inhibitors (AI) for 5 to 10 years.  Alternatively, tamoxifen therapy can be used for 5-10 years for those patients who do not want to take AIs, or for whom these medications are contraindicated. This patient, like many others, was not a good candidate for tamoxifen therapy due to low liver enzyme (CYP2D6) activity which means her liver would not adequately metabolize tamoxifen. Unlike tamoxifen, oral Endoxifen does not require liver metabolism so it may be a better treatment approach.”

Under the FDA expanded access IND program the use of Atossa’s proprietary oral Endoxifen is restricted solely to this patient. Approval from the Institutional Review Board (IRB) must be obtained prior to providing oral Endoxifen to this patient. 

About Endoxifen

Endoxifen is an active metabolite of tamoxifen; an FDA-approved drug to prevent new, as well as recurrent, disease in breast cancer patients. Tamoxifen itself must be broken down by the liver into active compounds (metabolites) of which Endoxifen is the most active.

Studies by other researchers have shown that breast cancer patients with endoxifen levels of 30 nM and above have a lower risk for developing future breast cancer. Up to half of the patients taking tamoxifen do not produce therapeutic levels of endoxifen frequently because of limited liver metabolism capability.

Other studies demonstrate that endoxifen’s molecular mechanisms of action are concentration dependent and different than that of other anti-estrogens, including fulvestrant. Pathway analysis of differentially regulated genes revealed substantial differences related to endoxifen concentrations. This includes significant induction of cell cycle arrest and markers of apoptosis following treatment with high, but not low, concentrations of endoxifen.

Many patients taking tamoxifen eventually stop responding. Endoxifen provided an acceptable safety profile and promising anti-tumor activity. Another class of drugs called aromatase inhibitors are also frequently used to treat breast cancer; however, those drugs are not FDA-approved for use in pre-menopausal women. They can only be given to pre-menopausal women in conjunction with drugs for ovarian suppression/oblation, which can cause cardiovascular and other toxicities.

Atossa’s press release noted also that 20-30% of those taking aromatase inhibitors may experience factures, bone pain or osteoporosis. Because of these potential advantages, Atossa is developing oral and topical forms of Endoxifen.

Atossa Genetics Inc

A clinical-stage biopharmaceutical company developing novel therapeutics and delivery methods to treat breast cancer and other breast conditions. For more information, please visit

Prohost Observations 

This news is important and accordingly, the stock has staged a big rally, trading now at $5.28, UP $3.80. The news cannot be ignored and following up on this firm is a must for investors in the biotech sector.  

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