Study Evaluating Temsirolimus (CCI-779) In Mantle Cell Lymphoma (MCL)

Inclusion Criteria:

* Mantle cell lymphoma (MCL) confirmed with histology, immunophenotype, and cyclin D1 analysis
* Received 2 to 7 prior therapies which may include hematopoietic stem cell transplant (i.e. induction + consolidation + maintenance)
* Prior treatment with an alkylating agent and an anthracycline, rituximab, individually or in combination, and status that is at least one of the following:
* Primary disease refractory to at least 2 regimens;
* Refractory to at least 1 regimen after first relapse;
* Refractory or untreated after second or greater relapse;
* Refractory to first line and relapsed after second line. Chemotherapy combinations may include, but are not limited to: CHOP (Cyclophosphamide, doxorubicin, vincristine, prednisone), R-CHOP (Rituximab, Cyclophosphamide, doxorubicin, vincristine, prednisone), FCM (Fludarabine, cyclophosphamide, mitoxantrone), R-FCM (Rituximab,Fludarabine, cyclophosphamide, mitoxantrone), ICE(Ifosfamide, carboplatin, etoposide), DHAP (Dexamethasone, cisplatin, cytarabine) and hyper-CVAD (Cyclophosphamide, doxorubicin, vincristine, dexamethasone).

Exclusion Criteria:

* Subjects who are less than or equal to six month from allogeneic hematopoietic stem cell transplant and who are on immunosuppressive therapy or have evidence of graft versus host disease
* Prior investigational therapy within 3 weeks of first dose. Investigational therapy is defined as treatment that is not approved for any indication.
* Active central nervous system (CNS) metastases, as indicated by clinical symptoms, cerebral edema, requirement for corticosteroids and/or progressive growth. (Treated CNS metastases must be stable for \> 2 weeks prior to Day 1.)