A 45 year old male, diagnosed with Acute Myeloid Leukemia (AML), a form of blood cancer, underwent chemotherapy to treat the cancerous cells. Treatments with chemotherapy remove cancerous cells as well as normal cells in the bone marrow, leaving the patient needing bone marrow transplantation. The patient received an unrelated (allogeneic) bone marrow transplant. However, he suffered from severe and long standing pancytopenia with associated complications after receiving hematopoietic stem cell transplantations.
Due to the patient’s major life threatening condition, 144 days post bone marrow transplantation, PLX cells were injected intramuscularly (IM) at a dose of 600x106 cells, divided into two administrations, one week apart, under compassionate use treatment. No local or systemic side effects were observed. In addition, the patient’s general clinical condition and well being significantly improved, resulting in his release from Hadassah Medical Center.
We are not told in the Pluristem announcement what 'general clinical condition and well being significantly improved' means except for the following statement:
This is the third patient, out of three treated, to display impressive clinical improvement following the administration of PLX cells. The first two patients responded, four and nine days respectively, after the second PLX cell administration, with improvement of tri-linage hematopoiesis.
On the basis of this report as well as certain announced initiatives, Pluristem's market capitalization has increased by close to $100M since mid July of this year, roughly twenty days ago. As some Sector Companies are currently in Phase II trials and others are in the process of study design and financial arrangements to pursue them, the apparent success and limited explanatory detail raise several questions.
Would Osiris's Prochymal or Athersys Multistem have worked as well in this application? Better? Are Pluristem's PLX cells the only cells that could have provided such improvement? Would Advanced Cell Technology's embryonic cells have been as good, better? Early success by publicly traded companies is currently implicitly defined as obtaining regulatory approval for any indication, all the better if it has a large market. Osiris has moved past this threshold with approval for Prochymal as a GVHD therapy in Canada, a step that has significantly increased the company's market capitalization. In the end, however, it will not be efficacy alone that will count, assuming more than one stem cell therapeutic application is effective. The scalability and resultant cost of the therapy will determine success given equal efficacy.
The series of Pluristem compassionate use treatments were led by Professor Reuven Or, Director of the Bone Marrow Transplantation and Cancer Immunology at Hadassah Medical Center in Jerusalem. Professor Or received a special permission by the Ministry of Health of the State of Israel, to try treating critically ill patients with bone marrow transplant failure that have no available alternative treatments, with PLX cells.
According to Professor Or, “Following three successful treatments, which were conducted for the first time in the world, in Hadassah Medical Center, we can say that PLX cells from the placenta saved the life of patients suffering from bone marrow failure. We are very encouraged by the results and hope that future clinical trials will show the effectiveness of the PLX cells.
Adapted from the Pluristem announcement.
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