A novel oral formulation of BIO 300 confers prophylactic radioprotection from acute radiation syndrome in mice

Figures & data

Figure 1. The Kaplan–Meier curves and net radioprotection of 30-day survival of mice administered BIO 300 OP twice daily using various dose schedules. CD2F1 mice (n = 16/group) were administered (A) BIO 300 OP (200 mg/kg) or vehicle po, BID for 6 d prior to TBI or (B) BIO 300 IS (200 mg/kg) or its vehicle administered as a single im injection 24 h prior to TBI. (C) Net radioprotection of BIO 300 OP administered twice daily using various dose schedules or BIO 300 IS administered 24 h prior to TBI. Percent net radioprotection at 30 days was determined by subtracting BIO 300 treatment survival from the respective vehicle group’s survival for each dose schedule and BIO 300 formulation tested. All mice were irradiated with 9.2 Gy cobalt-60 (0.6 Gy/min, approximately LD_70/30 dose). Survival was monitored for 30 d post-irradiation. Statistical significance for 30-day survival was determined by log-rank test (*p<.05).

Table 1. Summary of BIO 300 oral powder 30-day dose scheduling study.

Treatment group	Route of administration	Dosing schedule (30-day survival)
		6 d pre	5 d pre	4 d pre	3 d pre	2 d pre	1 d pre	1 d post
BIO 300 IS	im						93.8%
IS Vehicle	im						31.3%
BIO 300 OP	po, BID	68.8%	62.5%	100%	56.3%	87.5%	93.8%	25%
OP Vehicle	po, BID	6.25%	31.3%	50%	12.5%	31.3%	37.5%	12.5%

BIO 300 OP (oral powder, 200 mg/kg, twice a day for different days as mentioned prior to irradiation) and BIO 300 IS (injectable suspension, 200 mg/kg, 24 h prior to irradiation) were evaluated in CD2F1 mice using 9.2 Gy total-body cobalt-60 gamma-radiation exposure.

Figure 2. The Kaplan–Meier curves of 30-day survival of CD2F1 mice administered BIO 300 IS, OP, OS, or Neulasta. (A) Mice (n = 16/group) were administered BIO 300 IS (200 mg/kg) or its vehicle by im 24 h prior to TBI. BIO 300 OP (200 mg/kg) and BIO 300 OS (200 mg/kg) or their respective vehicle controls were administered BID, po to mice for 6 d prior to TBI. (B) Mice (n = 16/group) were administered Neulasta (300 µg/kg) sc or its vehicle 24 h post-TBI. All animals were irradiated with 9.2 Gy cobalt-60 (0.6 Gy/min, approximately LD_70/30). Survival was monitored for 30 d post-TBI. *Statistical significance at day 30 between the drug treated group and respective vehicle control as determined by log-rank test (*p<.05, **p<.01, ***p<.001).

Figure 3. The Kaplan–Meier curves of 180-day survival of CD2F1 mice administered BIO 300 IS, OP, OS, or Neulasta. Mice that survived 30 d post-TBI in the above study were monitored for an additional 150 d until 180 d post-TBI. (A) Mice (n = 16/group) were administered the indicated BIO 300 formulation or vehicle as described above. (B) Mice (n = 16/group) were administered Neulasta or vehicle as described above. Survival was analyzed at 180 d post-TBI. *Statistical significance at day 180 between the drug treated group and respective vehicle control as determined by log-rank test (*p<.05, **p<.01, ***p<.001).

Table 2. Histopathological effects of total-body irradiation on lungs of CD2F1 male mice at day 180 after total-body irradiation.

Lung (microscopic findings)	Treatment group (number of animals)
	BIO300 OS (n = 10)													Vehicle OS (n = 1)
Mononuclear cell infiltrate	1	1	1	1	1	1	1	1	1	1				2
Fibrosis, interstitial, alveolar wall	1	0	1	1	1	0	1	1	1	1				2
	BIO300 OP (n = 13)													Vehicle OP (n = 2)
Mononuclear cell infiltrate	1	1	1	1	1	1	1	1	1	1	1	1	1	2	2
Fibrosis, interstitial, alveolar wall	0	0	1	1	1	1	0	0	1	0	0	1	1	2	2
	BIO300 IS (n = 13)													Vehicle IS (n = 0)
Mononuclear cell infiltrate	1	2	1	2	1	1	1	1	1	1	1	1	1
Fibrosis, interstitial, alveolar wall	0	0	1	1	0	1	1	0	0	0	1	0	0
Lymphoid hyperplasia	5	0	0	0	0	0	0	0	0	0	0	0	0
Type II pneumocyte hyperplasia	0	1	0	0	0	0	0	0	0	0	0	0	0
Alveolar mixed cell infiltrate	0	1	0	0	0	0	0	0	0	0	0	0	0
Thymic lymphosarcoma													P*
	PEG-G-CSF (n = 9)													Vehicle PEG-G-CSF (n = 2)
Mononuclear cell infiltrate	1	1	1	1	1	1	1	1	1					2	1
Fibrosis, interstitial, alveolar wall	0	0	0	0	1	0	0	0	0					1	1
Lymphoid hyperplasia	0	0	0	0	0	0	0	0	5
Type II pneumocyte hyperplasia	0	0	0	0	1	1	0	0	0

Values in the table are histopathological scores from an individual lung harvested from CD2F1 male mice exposed to 9.2 Gy that underwent scheduled euthanasia on completion of the study (SD180 post-irradiation). Surviving mice at 180 days post lethal radiation totaled 50; these mice were terminated with lungs collected, fixed in preservative, trimmed, and sectioned for histopathology. Two slides were cut from each block; one slide was stained with hematoxylin and eosin (HE) and the other slide was stained with Masson’s trichrome stain that imparted a blue color to collagen structures. Lesions coded were semi-quantitatively scored as 1 (minimal), 2 (mild), 3 (moderate), 4 (marked), or 5 (severe) with the exception of the thymic lymphosarcoma noted in animal #13 of BIO300 IS group, which was coded as P* (present). Sections were evaluated by a board-certified veterinary pathologist. All mice had minimal or mild mononuclear inflammatory cell infiltrates either in the interstitial wall of alveoli or presenting as increased macrophages within alveolar spaces. Rarely, a few neutrophils were also present. Rather than code these morphologies separately, the single term ‘mononuclear cell infiltrate’ was used. This finding is expected in mice exposed to lethal radiation. A few mice also had evidence of type II pneumocyte hyperplasia, indicative of an ongoing repair of alveolar cell damage. One mouse had excessive numbers of neutrophils within alveolar spaces, and this was coded ‘alveolar mixed cell infiltrate’. The trichrome stained slides were examined for evidence of mature collage formation within alveolar walls; this was found in many mice but not all at this 180-day period. Finally, two mice had marked lymphoid hyperplasia in addition to the mouse with thymic lymphosarcoma. While such findings may be seen in older mice, it is possible that the radiation insult was related to these findings.

Data availability statement

All data generated or analyzed during this study are included in this article.