A Study of MORAb-202 Versus Investigator's Choice Chemotherapy in Female Participants With Platinum-resistant High-grade Serous (HGS) Ovarian, Primary Peritoneal, or Fallopian Tube Cancer

Inclusion Criteria: Female participants with histologically-confirmed diagnosis of HGS ovarian, primary peritoneal, or fallopian tube cancer. Platinum-resistant disease, defined as: For participants who had only 1 line of platinum-based therapy: progression between > 1 month and ≤ 6 months after the last dose of platinum-based therapy of at least 4 cycles. For participants who had 2 or 3 lines of platinum-based therapy: progression ≤ 6 months after the last dose of platinum-based therapy. Participants have received at least 1 but no more than 3 prior lines of systemic therapy and for whom single-agent therapy is appropriate as the next line of therapy. Participants may have been treated with up to 1 line of therapy subsequent to determination of platinum-resistance. Disease progression per RECIST v1.1 (by investigator assessment) of at least 1 measurable lesion on or after the most recent therapy. Either formalin-fixed, paraffin-embedded (FFPE) tissue (up to 5 years old) or newly-obtained biopsies must be available for FRα assessment prior to randomization. Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0 or 1. Exclusion Criteria: Medical Conditions Clear cell, mucinous, endometrioid or sarcomatous histology, or mixed tumors containing components of any of these histologies, or low grade or borderline ovarian cancer. Primary platinum-refractory ovarian cancer defined as disease progression within 1 month of the last dose of the first line platinum-containing regimen. Pulmonary function test (PFT) abnormalities: FEV1 < 70% or FVC < 60%, and DLCO < 80%. Investigator-assessed current ILD/pneumonitis, or ILD/pneumonitis suspected at screening or history of ILD/pneumonitis of any severity including ILD/pneumonitis from prior anti-cancer therapy. Significant third-space fluid retention (eg, ascites or pleural effusion) that requires repeated drainage. Physical and Laboratory Test Findings Evidence of organ dysfunction or any clinically-significant deviation from normal in physical examination, vital signs, ECG, or clinical laboratory determinations beyond what is consistent with the target population. Allergies and Adverse Drug Reactions Has any prior severe hypersensitivity (≥ Grade 3) to monoclonal antibodies or eribulin or contraindication to the receipt of corticosteroids or any of the excipients (investigators should refer to the prescribing information for the selected corticosteroid). History of allergy or contraindication to IC chemotherapy agent selected if randomized to Arm C. Other protocol-defined inclusion/exclusion criteria apply.