Safety and Tolerability of GTX-104 Compared with Oral Nimodipine in Patients with ASAH

Inclusion Criteria: 1. Male or female ≥18 years of age. 2. Diagnosis of aneurysmal subarachnoid hemorrhage (aSAH) based on CT scan and angiography (computed tomography angiography \[CTA\], magnetic resonance angiography \[MRA\], or digital subtraction angiography \[DSA\]). 3. Hunt and Hess score from I to V just prior to randomization. 4. Subject or the subject's legal representative has signed informed consent (either in person or by fax, scan, or email) before any study-specific procedures are performed. 5. Able to start IP within 96 hours from the onset of aSAH. Note 1: The onset of aSAH is defined as the time when the subject experienced the first symptom of aSAH (e.g., severe headache or loss of consciousness reported either by the subject or by a witness). Note 2: If found unconscious or the time of first symptoms is unknown, the onset of aSAH will be defined as the last time the subject was seen at baseline neurological state. 6. If a woman of childbearing potential (WOCBP), must have a negative pregnancy test during the pre-randomization phase (screening). A woman is not of childbearing potential if she has undergone surgical sterilization (total hysterectomy, or bilateral tubal ligation, or bilateral oophorectomy at least 6 weeks before taking IP) or if she is abstinent (see below) or postmenopausal and has had no menstrual bleeding of any kind including menstrual period, irregular bleeding, spotting, etc., for at least 12 months, with an appropriate clinical profile, and there is no other cause of amenorrhea (e.g., hormonal therapy, prior chemotherapy). WOCBP and males whose sexual partners are WOCBP must agree to use barrier contraception and a second form of contraception while receiving IP and for 30 days following their last dose of IP. Alternatively, total abstinence is also considered a highly effective contraception method when this is in line with the preferred and usual lifestyle of the subject. Periodic abstinence (e.g., calendar, ovulation, symptothermal, post-ovulation methods) and withdrawal are not acceptable methods of contraception. 7. Sexually active males must use a condom during intercourse while taking IP and for 30 days after the last dose of IP and should not father a child during this period. A condom is required to be used also by vasectomized men as well as during intercourse with a male partner to prevent delivery of the IP via seminal fluid. Exclusion Criteria: 1. Is at imminent risk of death and/or has Do Not Resuscitate (DNR) orders. 2. Required cardiopulmonary resuscitation within 4 days prior to randomization. 3. Has second- or third-degree atrio-ventricular block or bradycardia (heart rate ≤50 bpm) prior to randomization. 4. Has history of cirrhosis (Child-Pugh class B and C) prior to randomization. 5. Has alanine aminotransferase (ALT) and/or aspartate aminotransferase (AST) more than 2.5 times the upper limit of normal (ULN). 6. Has history of malabsorption syndrome, recent ileus (in the last 3 months), or other gastrointestinal (GI) conditions that would interfere with absorption of nimodipine, in the opinion of the Investigator. 7. Has a severe or unstable concomitant condition or disease other than what may be attributed to the SAH that, in the opinion of the Investigator, may increase the risk associated with study participation or nimodipine administration, or may interfere with the interpretation of study results. 8. Has a history of recurrent syncope or hypotension that may interfere with the safety assessments of nimodipine. 9. Has a known hypersensitivity to nimodipine or capsule constituents or to GTX-104. 10. Is pregnant/has a positive serum or urine pregnancy test. 11. Has received more than 12 doses (or 720 mg) of oral nimodipine (as a solution \[e.g., Nymalize\] or capsules) as part of the standard of care (SOC) for the ruptured aneurysm prior to randomization. 12. Is receiving strong inhibitors of CYP3A4 such as some macrolide antibiotics (e.g., clarithromycin, telithromycin), some anti-HIV protease inhibitors (e.g., delavirdine, indinavir, nelfinavir, ritonavir, saquinavir), some azole antimycotics (e.g., ketoconazole, itraconazole, voriconazole), and some antidepressants (e.g., nefazadone). See Appendix 5. 13. Is receiving or has received any other investigational agent(s)/device(s) in the last 30 days.